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THE LIFE
SIR ISAAC NEWTON.








THE LIFE
OR
SIR ISAAC NEWTON,'
CONTMAINING AN
ACCOUNT OF HIS NUMEROUS
INVENTIONS AND DISCOVERIES;
AND A. BRUIll
-S.KETCH OF THE HISTORY OF ASTRONOMY
PP.EVIOUS3 TO HIS TIME*
COMPILED FROM AUTHENTIC DOCUMENTS.
BY GEORGE GRANT.
ATJTOR OP "SIR WILLIAM WALACe " "ROBET BRUCcE," "Sm
WALTER SCOWP," ETC.
D U BL IN:
PUBLISHED      BY   JAMES M'GLASHAN,
21, D'OLIE1L STREET.
XDvaqKLix.




. 14
I




,.
PREFACE.
I compiling this Life of Sir Isaac Newton, there has been
considerable difficulty experienced from the scantiness of maIVterials collected by preceding biographers, both as regards the
IA particulars of the early life and the historical details of the
discoveries of one of the greatest men whom England has had
the honour of having produced-a person alike distinguished.for the great originality and depth of his philosophic view,
and the simplicity and amiableness of his character-one whom
we are perhaps called on to admire more than to imitate, yet
one whose virtues and piety may well serve as an example to
individuals in every sphere of life.
How frequently are the lives of men of ordinary talent recorded for our instruction. It certainly must be much more
interesting to follow the most exalted genius through the inci.
dents of common life;-to remark the steps by which he at.
taned his lofty pre-eminence;-to observe how he performs the
functions of the social and the domestic compact;-how he
e xrises his lofty powers of invention and discovery;-how
lhie omports himself in the arena of intellectual strife;-and
lb what sentiments, and with what aspirations he quits the
wold which he has adorned. In almost all these bearing, the
life and writings of Sir Isaac Newton abound with the richest




PREFACE.


counsel; and in them the philosopher, the moralist, and the
divine, will find instruction.
Aware that several eminent and talented authors have pre.
ceded him, the editor acknowledges himself under many obligations for much valuable information; their works are more
extended, and although he unhesitatingly admits, they possess
much greater merit than the present unpretending volume,
yet they are also more expensive, and consequently beyond the
reach of the working-classes, who are now thirsting after
scientific knowledge.
The object of the present publication is to present to the
world a cheap edition of the Life of Sir Isaac Newton, and it
is confidently hoped that it will meet with the approbation of
a liberal and enlightened public.
London, November, 1849.
I!




CONTENTS.
CHAPTER I.
PAGQ,
His birth and Parentage. His Early Education. Is sent to Gran.
tham School. His Attachment to Mechanical Pursuits in his
youth.   His Windmill; his Water-Clock; his self.moving
Carriage.  His Sun-Dials. Preparations for the University.
Enters Trinity College, Cambridge. His propensity for Mathe.
matics. His Geometrical Studies. Purchases a Prism. Employed to revise Dr. Barrow's Optical Lectures.  Takes his
Degrees. Is appointed a Fellow of Trinity College. Succeeds
Dr. Barrow in the Lucasian Chair of Mathematics               15
CHAPTER II.
Newton engaged in forming lenses. His first experiments with the
prism. Discovers the composition of White Light, and the
different refrangibility of the rays which compose it. Abamts
dons his attempts to improve Refractiag Telescopes, and re.
solves upon the construction of Reflecting ones. Quits Cambridge on account of the Plague.      Constructs the Reflecting
Telescope, the first ever executed. One of them examined by
the Royal Society and shown to the king. Construets a TAeles
cope with Glass Specula. Delivers a course of Optical Lectures.
Elected a Fellow of the Royal Society.   Communicates to
them his discoveries. Popular account of them. They involve
him in various controversies.    i      5.: M




Zli                       CONTENTS.
CHAPTER IIl.
PAGB,
Hall invents the Achromatic Telescope.  Principles of it explained. Re-invented by Dolland, and Improved by future
Artists. Blair's Achromatic Telescope. Mistakes in Newton's
Analysis of the Spectrum. Structure of the Spectrum. Colours
of thin Plates. Newton determines the law of their production. His Theory of fits of easy reflexion and transmission.
Colours of thick Plates.  Newton's Theory of the Colours
of Natural Bodies explained...           6
CHAPTER IV.
ltew Classification of Colours.  Outline of a New  Theory.
'Newton's Discoveries respecting the Inflexion or Diffraction of. Light. Previous Discoveries.  Labours of succeeding Philosophers. New Theory of Infiexion.  Miscellaneous Optical Researches of Newton.  Experiments on Refraction.   Conjecture respecting the Inflammability of the Diamond. Law of
Double Refraction, Observations on the Polarization of Light.
Newton's Theory of Light.   His "Optics."   Astronomical.Discoveries.  Sketch of the History of Astronomy previous to
the time of Newton..                   7
CHAPTER V.
Newton's first speculations on Gravity. He discovers the true
law of Gravity and the cause of the Planetary Motions.' lHis
prineiples of Natural Philosophy.  His "PrinCipia" appears
in 1687. Account of it and the Discoveries it contains. They
meet with great opposition. The reception of the Newtonian
Philosophy. Doctrine of Infinite Quantities. Discovers the
Binomial Theorem. Doctrine of Fluxions. His Mathematical
Tracts. His Universal Arithmetic. Account of the celebrated
Controversy respecting the Invention of Fluxions,        1 S0:   ~''',  ';




CONTENTS.


*Xi


CHAPTER VI.
PAGE.
The privileges of the University attacked by James II. Newton
chosen one of the delegates to resist this encroachment.
Elected a member of the Convention Parliament. Burning of
his manuscript. Supposed derangement of mind. Refutation
of the statement. Friendship between Newton and Charles
Montague. Newton appointed Master of the Mint. Newton
elected Associate of the Academy of Sciences. Member for
Cambridge. President of the Royal Society. Queen Anne
confers upon him the honour of Knighthood.,  181
CHAPTER VII.
Respect in which Newton is held at the court of George I.
The Princess of Wales delighted with his conversation. She
obtains a manuscript copy of his system of Chronology. She
allows the Abbe Conti to take a copy of it on the promise of
secrecy. He publishes it surreptitiously in French. Sir Isaac's
defence of his system.  Theological studies of Sir Isaac.
Origin of Newton's Theological studies.  Analogy between
the Book of Nature and that of Revelation. Minor Discoveries of Newton.   His Reflecting Sextant.  Reflecting
Microscope.  Prismatic Reflector.  His method of varying
the MagnifyiSg power of Newtonian Telescopes.   His Ex.
periments on Impressions on the Retina,..   212
CHAPTER VIII.
Newton's acquaintance with Dr. Pemberton, who edits the
third edition of the " Principia."  Sir Isaac's first attack of
ill health.  His recovery.  Is again taken ill.  His death.
His Funeral. A medal struck in honour of him. Division
of his property. Permanence of Newton's reputation. Character of his Genius.  His social character.  Simplicity of
his character.  Religious and moral character.  Hospitality
and mode of life. His absence. Personal appearance.  Memorials....          254




I




LIFE OF


SIR ISAAC NEWTON.
CHAPTER I.
His Birth and Parentage.  His Early Education. Is sent to Grantham
School. His Attachment to Mechanical Pursuits in his youth.  His
Windmill; his Water Clock; his self-moving Carriage.  His SunDials. Preparations for the University.  Enters Trinity College,
Cambridge.  His propensity for Mathematics.  His Geometrical
Studies. Purchases a Prism. Employed to revise Dr. Barrow's Op.
tica Lectures.  Takes his Degrees. Is appointed a Fellow of Trinity
College. Succeeds Dr. Barrow in the Lucasian Chair of Mathematics.
THE    name, of   this celebrated    philosopher has by
general consent been placed at the head of those great
men who have been acknowledged as the ornaments
of their species.   The character of Newton cannot be.
delineated and discussed like that of ordinary men;
its unity is so beautiful, that the biographer must
dwell upon it with delight, and the inquiry by what
means he attained an undisputed superiority over his
fellow-creatures, must be both interesting and useful.
It has been asserted that all men are born equal in
ialets, and that the difference which exists amongst
Aer is the effect of education; but this is disproed




16                 THE LIFE OF
by the observation of every parent and teacher, a decided inequality in capacity, for receiving instruction
being distinctly exhibited by children even in infancy.
Newton was endowed with talents of the highest
order, but those who are less eminently gifted may
study his life with advantage, and derive instruction
from every part of his career.  With a power of intellect almost divine he demonstrated the motion of
the planets, the orbits of the comets, and the causes
of the tides of the ocean: he investigated with complete success the proportions of light and colours,
which no man before had even suspected; he was the
diligent, sagacious, faithful interpreter of Nature, antiquity, and Scripture; his philosophy tended to
exalt the glory of the Creator, and he exhibited in
his manners the purity and simplicity of the doctrines
of the Gospel. He was a firm believer in Christianity, not as men in general believe, by coldly assenting to the truth of doctrines, merely because they
have been early inculcated by parents and preceptors.
He was deeply learned in history and chronology, and
he applied the unrivalled powers of his mighty intellect to the complete examination of a subject compared with which all others sink into insignificance;
the result was a clear conviction of the truth of re
vealed religion, which is demonstrated in all his
works, and which was still more effectually shown
in his life and conduct.  Those who consider the
character of an individual so highly renowned will
duly appreciate the value of his testimony. His bicgraphy, therefore, cannot fail to excite a general in;
terest.
Sir Isaac Newton was born at Woolsthorpe, a
hamlet in the parish of Colsterworth, in Lincolnshire,
about six miles south of Grantham, on the 25th day
of December (old style) 1642, and was baptized at
Colsterworth on the 1st day of January 1642-3. His
father, Mr. Isaac Newton, died at the early age o
o.,                                   1




SIR ISAAC NEWTON.


17


thirty-six, only a few months after his marriage to
Harriet Ayscough, daughter of James Ayscough of
Market Overton in Rutlandshire.  The consequence
was, that the mother of the interesting subject of
these pages was left in a state of pregnancy, and appears, from the grief occasioned by the death of her
husband, to have given birth to her first and posthumous child.  The helpless infant thus ushered into
the world was of such an extremely diminutive, and
seemed of so delicate a frame, that two women who
were hurried off to Lady Pakenham's at North Witham, to procure some medicine for the purpose of
strengthening the puling infant, declared that they
did not expect to find him in life on their return. Sir
Isaac in after life has repeatedly asserted that he had
often heard his mother say, that " when he was born
he was so little that they might have put him into a
quart mug, and did not expect that he could live."
But an all-wise Providence had otherwise decreed,
and that feeble body which appeared scarcely qualified
to contain its immortal mind, was destined to shoot
forth and enjoy a vigorous maturity, and to survive
the threescore years and ten allotted as the term of
human existence. The property of Woolsthorpe, in
the manor-house of which this remarkable birth took
place, has been in the possession of the family of
Newton for more than a hundred years.  This family
came originally from Newton in Lancashire, but,
before purchasing the estate of Woolsthorpe, had
settled at Westby in Lincolnshire. The manor-house
is situated in a beautiful little valley, celebrated for
its copious wells of excellent spring water, on the
west side of the river Witham, which takes its rise
in the vicinity, and commands a remarkably pleasing
prospect to the east towards Colsterworth. The paternal property of Woolsthorpe was worth no more
than ~30 a-year; but Mrs. Newton was proprietor
B3




18                THE LIFE OF
of another small estate at Sewstern, in Leicestershir%
and only three miles distant from Woolsthorpe which
raised the yearly value of their property to nearly
~80; and being a woman of an active disposition, it
is probable that the cultivation of the small farm on
which she resided somewhat increased the limited
income upon which she had to support herself and her:
favourite child, as well as to provide for his education.
Mrs. Newton continned to nurture and watch over
her tender charge for three years, with the most exemplary parental solicitude; but at the end of that
period, in consequence of her marriage to the Reverend Barnabas Smith, rector of North Witham, she
removed to the parsonage, and Isaac was left under
the care of his maternal grandmother.  At an early
age he was sent to two day schools at Skillington and
Stoke, where he acquired the little learning usually
afforded at these seminaries; but upon reaching
his twelfth year he went to the public school
at Grantham, conducted by Mr. Stokes, and was
at the house of Mr. Clark, an apothecary in that
town. At this time he was a thoughtless boy, very
inattentive to his lessons, and much attached to boyish
amusements, and consequently very low in the school,
and presented little hopes of his future success. The
boy, however, who happened to be above him in the
class, having one day given him a severe kick upon
his stomach, from which he suffered great pain, Isaac '
mode of revenge was peculiar; from  his little size,
and delicate constitution, he was unable to punish his
antagonist in the usual method, by giving him a good
beating; but he laboured incessantly at his studies,
and gave up his amusements, till he got above him in
the school; and from that period he rose by degrees,
till he was the head boy. From the industrious
habits of application which this trifling incident had
led him to form, the peculiar character of mind of
the future philosopher was speedily displayed.



SIR ISAAC NEWTON.


19


During the hours of play, when his companions were
occupied with these amusements, his attention was
taken up with mechanical contrivances, either in imitation of something which he had previously observed,
or in the execution of some original conception of his
own. To enable him to do so, he embraced every
opportunity of providing himself with little saws,
hatchets, hammers, and all sorts of tools, which, by
constant practice, he soon acquired the art of using
with a workmanlike dexterity. The principal pieces
of mechanism which he thus constructed at this early
age were a windmill, a water-clock, and a carriage
put in motion by the person who sat in it. When a
windmill was in the course of erection in the neigh.
bourhood of Grantham, on the road to Gunnerly,
young Newton frequently attended and anxiously
watched the operations of the workmen, and attained
such a complete knowledge of the machinery, that in
a short time he completed a working model of it, to
the great surprise and admiration of every person who
beheld it, The young mechanist frequently placed
this model on the top of Mr. Clarke's house, in which
he lodged, where it was put in motion by the action
of the wind upon its sails; but not content with this
exact representation of the original machine, he conceived the idea of driving it by animal power; and
for this purpose he entrapped a mouse, which he
called the miller; and this little animal, by acting on
a sort of tread-wheel, gave motion to the machine.According to some accounts, the mouse was made to
advance by having a string tied to its tail; while
others allege that the power of the diminutive agent
was instigated by its fruitless attempts to reach a
small piece of toasted cheese placed above the wheel.
His water-clock was formed out of a box, which,
with great earnestness, he had solicited from the brother of his landlady, without giving any notice of his
intentions. It was about four feet high, and of proi,             '   ':




20                THE LIFE OF
portionate breadth, not unlike a common house-clock.
The index of the dial-plate was turned by a piece of
wood, which either rose or fell by the action of dropping water. As it stood in Isaac's own bed-room, he
supplied it every morning with the requisite quantity
of water; and this same machine was used as a
time-keeper by Mr. Clarke's family, and remained in
the house many years after its inventor had left Grantham. Dr. Stukely, in a letter to Dr. Mead says,
c' I remember once, when I was deputy to Dr. Halley,
Secretary to the Royal Society, Sir Isaac talked of
these kind of instruments. That he observed the
chief inconvenience in them  was, that the hole
through which the water was transmitted was necessarily very small, and subject to be furred up by the
impurities in the water, as those made with sand will
wear bigger, which at length causes an inequality in
time."  This satisfactorily proves that Newton's mind
was occupied by the consideration of his youthful
inventions, when more important avocations attracted
his attention in after years.
His mechanical carriage was a vehicle with four
-wheels, which was put in motion with a handle
wrought by the person who sat in it, but it seems
-only to have been calculated for a smooth surface, and.not fitted to overcome the inequalities of a road. It
was, however, a most useful invention for invalids,
which enabled them to move from one place to another in a room, when unable to walk.
Isaac Newton    was at this period 'C a sober,
silent, thinking lad" who seldom ever joined in the
ordinary games and more boisterous amusements of
his companions, yet he took great delight in providing
them  with pastimes of a scientific character. He
introduced among his schoolfellows the flying of
paper kites; and he is said to have been at great
pains in determining their best forms and proportions,
and in ascertaining the position and number of the




SIR ISAAC NEWTON.


21


points by which the string ought to be attached. He
also made paper lantherns, by the light of which he
went to school in the winter mornings; and in dark
nights he frequently attached these lantherns to the
tails of his kites, which inspired the country people
with the belief that they were comets.
' In the house of Mr. Clark at Grantham, where he
lodged, there were also some female boarders in whose
company he appears to have taken much pleasure.
One of these young ladies, a Miss Storey, sister to
Dr. Storey, a physician at Buckminster, near Colsterworth, was Newton's junior by two or three years,
and to great personal attractions she seems to have
added more than the customary share of female
talent.  The society of Miss Storey and her companions was always preferred to that of his own
schoolfellows, and it was one of his most agreeable
occupations to exercise his mechanical abilities in
constructing for them little tables, chairs, cupboards,
and other utensils for holding their dolls and their
trinkets.  He had lived nearly six years in the same
house with Miss Storey, and there is every reason to
believe, that during this time their youthful friendship gradually rose to a stronger passion; and his
attachment is said to lave continued even after he
was sent to college, but as he could not marry without forfeiting his chance of a fellowship, and as he
had no means of supporting a wife and family, he
subdued his predilection in silence, and found consolation in the severest labour of study. This young
lady was afterwards twice married, and under the
name of Mrs. Vincent, Dr. Stukely visited her at
Grantham in the year 1727, when she had attained
the mature age of eighty-two, and from her he
obtained many interesting particulars respecting the
early history of Sir Isaac. Newton's esteem for this
his first love, continued unabated during his life. He
never visited Lincolnshire without calling upon her;




22


THE LIFE OF


and, when she sunk into poverty, liberally supplied
her wants, by relieving her from little pecuniary
difficulties which appear to have frequently perplexed
her.
But Newton's genius was not engrossed by mechanical pursuits.   Among his early     passions we
have to recount his love of drawing, and even of
writing verses. His own room was furnished with
pictures, drawn, coloured, and neatly framed by himself, sometimes from  copies, but often from  life.  Mr.
Clark informed Dr. Stukely that the walls of the
room in which Sir Isaac lodged were covered with
charcoal drawings of birds, beasts, men, ships, and
mathematical figures, all of which were very well
designed.
Among the portraits in Newton's room were those
of Dr. Donne, Mr. Stokes, the master of Grantham
school, and King Charles I., under whose picture
were the following lines:A secret art my soul requires to try,
If prayers can give me what the wars deny.
Three crowns distinguished here, in order do
Present their objects to my knowing view.
Earth's crown, thus at my feet I can disdain,
Which heavy is, and at the best but vain.
But now a crown of thorns I gladly greet,
Sharp is this crown, but not so sharp as sweet;
The crown of glory that I yonder see
Is full of bliss and of eternity.
These verses were repeated to Dr. Stukely by Mrs.
Vincent, who believed them to be the composition of
Newton, a circumstance which seems to be the more
probable, as he himself many years after assured Mr.
Conduit, with some expression of pleasure, that he
"at one time excelled in making verses," though he
had been frequently heard to express his great contempt for poetical composition; but like all young men
who are anxious in gaining a respectable livelihood, he
gave up the idle trade for a more serious calling.




SIR ISAAC NEWTON.


23


But during these early years, while the mind of
Newton was occupied principally with the pursuits
which we have already detailed, it was by no means
inattentive to the motions of the celestial bodies, on
which he was afterwards enabled to throw such a flood
of brilliant light. His thoughts had probably been
directed to the more accurate measure of time which
the motion of the sun afforded, by the imperfections of
his water-clock. In the back-yard of Mr. Clark's
house where he lived, he marked the varying movements of that luminary upon the walls and roofs of
the outbuildings, and by means of fixed pins he noted
the hourly and half-hourly subdivisions. One of these
dials, which went by the name of " Isaac's dial," and
was long after frequently referred to by the country
people for the hour of the day, appears to have been
drawn solely from the observations of several years;
but we have now no means of obtaining information
whether the numerous dials which he drew on the
walls of his house at Woolsthorpe, and which existed
many years after his death, were of the same description, or were projected from his knowledge of the
doctrine of the sphere.
In the year 1656, upon the death of the Reverend
Mr. Smith, his widow, the mother of Newton, left
the rectory of North Witham, and took up her residence at Woolsthorpe along with her three children,
Mary, Benjamin, and Hannah Smith. Isaac had now
attained the fifteenth year of his age, and had made
great progress in his studies under Mr. Stokes; and
as his mother considered that he was capable of being
useful in the management of the farm and country
business at Woolsthorpe, she, chiefly from a motive of
economy, recalled him from the school at Grantham,
and brought him home. In order to accustom the
young farmer to two of the most important branches
of agricultural labour-the art of selling and buying
-he was generally sent on the Saturdays to Grantham




T4 THE LIFE OF
-market, to dispose of grain and other farm produce,
and to purchase such articles as was requisite for the
use of the family. But as Isaac was yet void of experience in such matters, an old trust-worthy servant
generally accompanied him for the purpose of initiating
him into the mysteries of the business of marketmaking. The inn where they put up was the Saracen's
Head at West Gate; but no sooner had they put up
their horses than our youthful philosopher deserted his
commercial concerns, and betook himself to his former
lodgings in Mr. Clark's garret, where a number of the
apothecary's old books afforded him abundance of entertainment till his aged guardian had finished the
more intricate business of inarket-making, and called
for him with the announcement that it was time for them
to return home. At other times he did not trouble
himself by going so far, but deserted his duties on the
road, and ensconced himself under a hedge, where he
remained with some favourite volume till the servant
returned from market at Grantham.    (c One of his
uncles," says Mr. Biot, " having one day found him
under a hedge with a book in his hand and entirely
absorbed in meditation, took it from him, and found
that he was occupied in the solution of a mathematical
problem. Struck with finding so serious and so active
a disposition at so early an age, he urged his mother
no longer to thwart him, and to send him back to
Grantham  to continue his studies."  This advice his
mother shortly after found it necessary to comply
with, as the more immediate affairs of the farm were
not more prosperous under his management, than
would have been his marketings at Grantham if they
had been left to his own discretion. The perusal of
a book, the execution of a model, or the superintendence of a water-wheel of his own construction,
whirling the glittering spray from some neighbouring
stream, absorbed all Isaac's thoughts, while the sheep




SIR ISAAC NEWTON.             25
were left to wander at will, and the cattle making sad
havock in the cornfields.
Mrs. Smith was soon convinced from experience
that her son's genius took a higher flight than the
cultivation of the soil, and as his passion for study,
and his dislike for rural occupations increased with
his years, she wisely resolved to give him all the
advantage which education could confer. He was
accordingly sent back to Grantham school, and his
lodgings in Mr. Clark's house, where he continued
for some months busily engaged in preparation for his
academical studies. His uncle, the Reverend William
Ayscough, who was rector of Burton Coggles, about
three miles east of Woolsthorpe, and who had himself studied at Trinity College, recommended it to his
nephew to enter tiat society, and it was acccordingly
determined that he should proceed to Cambridge at
the commencement of the approaching term.  v
It has been justly remarked by a celebrated scientific author that, "to a young mind thirsting for
knowledge, and ambitious of the distinction which it
brings, the transition from a village school to an university like that of Cambridge —from the absolute
solitude of thought to the society of men imbued
with all the literature and science of the age, must be
one of eventful interest. To Newton, it was a source
of peculiar excitement. The history of science affords
many examples where the young aspirant had been
early initiated into the mysteries, and had even exercised his powers of invention and discovery before he
was admitted within the walls of a college; but he
who was to give philosophy her laws did not exhibit
srch early talent;-no friendly counsel regulated his
youthful studies, and no work of scientific eminence
seems to have guided him in his course. In yielding
to the impulse of his mechanical genius, his mind
obeyed the laws of its own natural expansion, and, following the line of least resistance, it was thus drawn




THE LIFE OF


aside from the strongholds with which it was destined
to grapple.   When Newton, therefore, arrived at
Trinity College, he brought with him a more slender
portion of science than falls to the lot of ordinary
scholars; but this state of his acquirements was, perhaps, not unfavourable to the development of his
powers.   Unexhausted by premature growth, and
invigorated by healthful repose, his mind was the
better fitted to make those vigorous and rapid shoots
which soon covered with foliage and with fruit, the
genial soil to which it had been transferred.  Cambridge was consequently the real birth-place of his
(Newton's) genius. Her teachers fostered his earliest
studies-her institutions sustained his mightiest efforts
-and within her precincts were all his discoveries
made and perfected. When he was called to higher
official functions his disciples kept up the pre-eminence
of tieir master's philosophy, and their successors have
maintained this seat of learning in the fullness of its
glory, and rendered it the most distinguished among
the universities of Europe."
Isaac Newton was admitted into Trinity College,
Cambridge, on the 5th day of June, 1660, in the 18th
year of his age. Dr. Barrow was elected professor
of Greek in that university during the same year.
Newton's attention was first directed to the study of
mathematics by an ardent desire to inquire into the
truth of judicial astrology; and he is said to have
discovered the folly of that study by erecting a figure
with the aid of one or two of the problems of Euclid.
The propositions contained in this ancient system of
geometry he regarded as self-evident truths; and, by
his genius and patient application, without any preliminary study, he made himself master of Descartes's
Geometry.   He afterwards discovers, as a mistake in
his mathematical studies, this neglect of the elementary truths of geometry; and he expressed to Dr.
Pemberton his regret that "( he had applied himself




SIR ISAAC NEWTON.


27


to the works of Descartes and other algebraic writers
before he had considered the elements of Euclid with
that attention which so excellent a writer deserved."
Dr. Wallis's Arithmetic of Infinities, Saunderson's
Logic, and the Optics of Kepler, were among the
works which he appears to have studied with much
care. On these books he wrote numerous comments
during their perusal; and so great was his progress
in his scientific studies, that he is reported to have
found himself more deeply versed in several branches
of knowledge than the tutor who was employed to
direct his studies.
During the first three years that he spent at Trinity
College, neither history nor tradition has handed down
to us any particular account of his progress. It appears from an account (which he regularly kept) of
his expenses, that in the year 1664 he purchased a
prism, for the purpose, as has been reported, of examining Descartes's Theory of Colours; and it is
stated by Mr. Conduit, that he not only soon established his own views on the subject, but detected the
errors in those of the French philosopher. This, however, does not appear to have been the case. Had he
really made such an important discovery as the composition of light so early as the year 1664 or 1665, it
is not at all probable that he would have withheld it
not only from the Royal Society, but from his personal
friends at Cambridge, till 1671. Dr. Barrow, his
friend and tutor, was made Lucasian Professor of
Mathematics in 1663, and he delivered a course of
optical lectures, which he afterwards published in
1669. In the preface of this work he acknowledges
his obligations to his esteemed colleague, Mr. Isaac
Newton, for having revised the MSS., and corrected
several oversights, and made some important suggestions. In the twelfth lecture there are some observations on the origin and nature of colours, which
Newton, had he been then in possession of their trun




28


THE LIFE OF


theory, could not have permitted his friend to publish.
According to Dr. Barrow, WHITE is that which discharges a copious light, equally clear in every direction. BLACK is that which does not emit light at all,
or which does it very sparingly. RED is that which
emits a light more clear than usual, but interrupted
by shady interstices. BLUE is that which discharges
a rarified light, as in bodies which consist of white
and black particles arranged alternately.  GREEN is
nearly allied to blue. YELLOW is a mixture of much
white and a little red; and PURPLE consists of a great
deal of blue, mixed with a small portion of red. The
blue colour of the sea arises from the whiteness of the
salt which it contains, mixed with the blackness of the
pure water in which the salt is dissolved; and the
blueness of the shadows of bodies, seen at the same
time by candle and daylight, arises from the whiteness
of the paper mixed with the faint light or blackness
of the twilight.  These opinions savour so little of
genuine philosophy that they must have attracted the
observation of Newton; and had he discovered at
that time, when he revised these MSS., that white
was a mixture of all the colours, and black a privation
of them all, he could not have permitted the absurd
speculations of his master to pass uncorrected.
That Newton had not distinguished himself by any
positive discovery, so early as 1664 or 1665, we think
may be satisfactorily proved; but it may also be inferred from  the circumstances which attended the
competition for the law-fellowship of Trinity College.
The only candidates for this appointment were Newton
and Mr. Robert Uvedale; and, on examination, Dr.
Barrow, then Master of Trinity, having found them
perfectly equal in their attainments, conferred the
fellowship on Uvedale as the senior candidate. Had
Isaac Newton made the important discovery alluded
to, at this time, there can be little doubt that he
would have received the appointment from his friend.




SIR ISAAC NEWTON.              29
In the books of the University, we find Isaac Newton recorded as having been admitted sub-sizor in
1661. He became a scholar in 1664. In 1665, he
took his degree of Bachelor of Arts; and in 1666, in
consequence of the breaking out of the plague, he
returned home to Woolsthorpe. In 1667, he was
made Junior Fellow. In 1668, he took his degree of
Master of Arts; and in the same year he was appointed to a Senior Fellowship. In 1669, when Dr.
Barrow had resolved to devote his attention to theology, he resigned the Lucasian Professorship of Mathematics in favour of Newton, who may now be considered as having entered upon that brilliant career of
discovery, which has, by general consent, placed his
name at the head of those great men who have been
the ornaments of their species. However imposing
be the attributes with which time has invested the
sages and the heroes of antiquity, the brightness of
their fame has been eclipsed by the splendour of Sir
Isaac Newton's reputation; and neither the partiality
of rival nations, nor the vanity of a presumptuous age,
has ventured to dispute the ascendancy of his genius.
"The life and writings of this great philosopher
abound with the richest counsel. Here the philosopher will learn the art by which alone he can acquire
an immortal fame. The moralist will trace the lineaments of a character adjusted to all the symmetry of
which an imperfect nature is susceptible; and the
Christian will contemplate with delight the high priest
of science quitting the study of the material universe
-the scene of his intellectual triumphs-to investigate, with humility and patience, the mysteries of his
faith."
The history of the scientific discoveries of this eminent philosopher will form the subject of some of the
following chapters.




THE LIFE OF


CHAPTER II.
Newton engaged in forming lenses. His first experiments with the prism.
Discovers the composition of White Light, and the different refrangi.
bility of the rays which compose it. Abandons his attempts to improve Refracting Telescopes, and resolves upon the construction of
Reflecting ones.  Quits Cambridge on account of the Plague. Constructs the Reflecting Telescope, the first ever executed. One of them
examined by the Royal Society and shown to the king. Constructs a
Telescope with Glass Specula. Delivers a course of Optical Lectures.
Elected a Fellow of the Royal Society. Communicates to them his
discoveries. Popular account of them. They involve him in various
controversies.
THE appointment of Isaac Newton to the Lucasian
Chair, at Trinity College, Cambridge, appears to have
been contemporary with some of his most important
discoveries. The first of these, of which the date is
properly authenticated, is that of the different refrangibility of the rays of light, which he satisfactorily
established in 1666. The germ of the doctrine of
universal gravitation seems to have presented itself to
him in the same year, or at latest in the year following; and in the year 1666 or before, as he expresses
himselfip a letter to the Abbe Conti, he was in possession of his method of fluxions, and he had brought
it to such a state in the beginning of the year 1669,
that he permitted his friend, Dr. Barrow, to communicate it to Mr. Collins on the 20th of June in that
year.
Although we have already mentioned, on the authority of accounts kept by Newton himself, that he
had purchased a prism, in 1664, at Cambridge, yet he
does not appear to have made any use of it, as he informs us that it was in 1666 that he " purchased a triangular glass prism to try therewith the celebrated




SIR ISAAC NEWTON.              31
phenomena of colours." During the same year he had
applied himself to the grinding of "optic glasses,"of
other figures than spherical," and having, no doubt,
experienced the impractibility of executing such lenses,
the idea of examining the phenomena of colour was
one of those sagacious and fortunate impulses which
more than once led him to discovery. Descartes in
his Dioptrice, published in 1629, and more recently
James Gregory in his Optica Promota published in
1663, had shown that parallel and diverging rays
could be reflected, with mathematical accuracy, to a
point or focus, by giving the surface a parabolic, an
elliptical, or a hyperbolic form, or some other form not
spherical. Descartes had even invented and described
machines by which lenses of these shapes could be
ground and polished, and the perfection of the refracting telescope was supposed to depend on the degree
of accuracy with which they could be executed.
In endeavouring to grind glasses that were not spherical, Newton seems to conjecture that the defects
of lenses, and consequently of refracting telescopes,
might arise from some other cause than the imperfect
conveyancy of rays to a simple point, and this conjecture was happily realised in those fine discoveries of
which we shall endeavour to give some account.
When Newton commenced making this inquiry,
philosophers of the highest genius were directing all
the energies of their mind to the subject of light, and
to the improvement of the refracting telescope. Mr.
Gregory, of Aberdeen, had invented his reflecting telescope. Descartes had explained his theory, and exerted himself in perfecting the construction of the common refracting telescope, and Huygens had not only
executed the magnificent instruments, by which he
discovered the ring and the satellites of Saturn, but had
begun those splendid researches respecting the natutte
of ight, and the phenomena of double refraction Which
have led his successors to such brilliant discoveries.




Ad                THE LIFE OF
Newton, therefore, came forward when the science of
light was prepared for some great accession, and at the
very time when he was required to propagate the impulse which it received from his illustrious predecessors.
The ignorance which at that time prevailed respecting the nature and origin of colours, is sufficiently
apparent from the account we have previously given
of Dr. Barrow's speculations on this subject, as published in his lectures, which were revised by Newton.
It was then the general supposition that light of every
colour was equally refracted or bent out of its direction, when it passed 'through any lens or prism,
or other refracting medium; and though the exhibition
of colours by the prism had frequently been made
before the time of Newton, yet no philosopher appears
to have attempted to analyse the phenomena.
Newton was well aware that when a ray of light
proceeds through the same medium-say the air, it
moves in a straight line, and if admitted through a
small hole into a dark room, appears white; but if it
passes obliquely from a rarer into a denser medium,
as from air into water, it is then urged 'out of the
straight line, and appears as if it had been suddenly
bent. For this reason a straight rod or stick, when
immersed in water, appears to be broken at the surface of the water; and the portion immersed seems to
be bent upwards. The light thus proceeding out of
its straight course is said to be reflected, and our
observations on objects placed in water, are liable
from  this circumstance, to considerable deception.
For example, a deep-bodied fish seen near the surface
of the water, appears a flat-fish; a round body there
seems oval, and objects seen at the bottom do not
appear to be so deep as they really are. Now we are to
bear in mind that light in passing into our atmosphere,
has moved from a rarer into a denser medium-that
ie from the thin ether above the highest stratum  of




SIR ISAAC NEWTON.


33


air into the denser mass of air which more immediately
surrounds the earth. This air is generally loaded
with watery vapour, so that the medium through
which light has to pass in our atmosphere, undergoes
many remarkable changes.     Hence the distance,
height, and relative position of the mountains, hills,
valleys, towns, often appear altered. A certain range
of mountains in one condition of the atmosphere, will
appear nearer; in another, more remote from the
spectator than usual. But in being thus bent out of
its course, a ray of light exhibits a variety of beautiful
colours, the cause of which it fell to the lot of our
illustrious professor to discover.
We have already observed that if a ray of light
be admitted through a small hole into a dark room, it
appears of uniform whiteness; but Newton discovered
that this white ray of light is a combination of seven
differently coloured rays, which may be separated
easily from each other. He proceeded in his experiment thus;-he made a hole in one of his window
shutters, and having darkened his chamber, let in a
convenient quantity of the sun's light. He then
intercepted this light with his triangular glass prism,
and found that in passing through the glass, the light
was so refracted, as to exhibit on the wall an image
of seven different colours, viz:-violet, indigo, blue,
green, yellow, orange, and red; the image was about
five times as long as it was broad. It was at first,
says our author, "a very pleasing divertizement to
view the vivid and intense colours presented thereby;"
but this pleasure was immediately succeeded by surprise at various circumstances which he had not expected. According to the received laws of refraction,
he expected the image from the prism to be circular,
like the white image which the sunbeam had formed
on the wall, previous to the interposition of the prism;
but when he found it to be no less than five times
c




84                THE LIFE OF
longer than it was broad, it " excited in him more
than ordinary curiosity to examine from whence it
might proceed. He could scarcely think that the
various thickness of the glass, or the termination with
shadow or darkness, could have any influence on light
to produce such an effect; yet he thought it not amiss
first to examine those circumstances, and so find what
would happen by transmitting through parts of the
glass of divers thicknesses, or through holes in the
window shutter of divers bignesses, or by setting the
prism without, (the window), so that the light might
pass through it, and be refracted before it was terminated by the hole; but he found none of these
circumstances natural. The fashion of the colours
was, in all these cases the same."
Newton next suspected that some unevenness in
the glass or other accidental irregularity, might cause
the extension of the colours. In order to try this, he
took another prism, and placed it in such a manner
that the light passing through them both might be refracted contrary ways, and thus returned by the
second prism into that course from which the first
had diverted it, for by this means he thought the
regular effects of the first prism would be destroyed
by the second, and the irregular effects more augmented by the multiplicity of refractions. The result
was, that the light which was diffused by the first
prism into an oblong form, was reduced by the second
prism into a circular one, with as much regularity as
when it did not pass through them at all; so that
whatever was the cause of the length of the image, it
did not arise from any irregularity in the prism.
Our philosopher next proceeded to examine more
critically what might be effected by the difference of
the incidence of the rays proceeding from different
parts of the sun's disc; but by taking accurate
measures of the lines and angles, he found that the
angle of the emergent rays should be 31 min. equal




SIR ISAAC NEWTON.


35


to the sun's diameter, whereas the real angle subtended at the hole in the shutter was 2 deg. 49 min.
But as this computation was founded on the hypothesis, that the sine of the angle of incidence was proportional to the sine of the angle of refraction, which,
from his own experience, he could not imagine to be so
erroneous as to make that angle but 31 min., which,was in reality 2 deg. 49 min.; yet "his curiosity
caused him again to take up his prism," and having
turned it round in both directions, so as to make the.rays fall both with greater and with less obliquity
upon the face, he found that the colours on the wall
did not sensibly change their place; and hence he obtained a decided proof that they could not be occasioned by a difference in the incidence of the light
radiating from different parts of the sun's disc.
Sir Isaac then began to suspect that the rays after
passing through the prism might move in curved lines,
and, in proportion to the different degrees of curvature,
might tend to different parts of the wall; and this
suspicion was strengthened by the recollection that he
had often seen a tennis-ball struck with an oblique
racket describe such a curved line. In this case a
circular and a progressive motion is communicated to
the ball by the stroke, and in consequence of this, the
direction of its motion was curvilineal, so that if the
rays of light were globular bodies, they might acquire
a circular motion by their oblique passage out of one
medium into another, and thus move like the tennisball in a curve line. Notwithstanding " this plausible
ground of suspicion," as he terms it, he could dis-.cover no such curvature in their direction, and, what
was enough for his, purpose, he observed that the,difference between the length of the image and the
diameter of the hole was proportional to their distance, which could not have happened had the rays
moved in curvilineal paths.
These different hypotheses, or suspicions, being thus




WJ            THE LIFE OF
gradually removed, he was at length led to an experiment which determined beyond a doubt the true
cause of the elongation of the coloured figure. Having
taken a board with a small hole in it, he placed it
behind the face of the prism, and close to it, so that
he could transmit through the hole any one of the
colours in the figure, and keep back all the rest..
When the hole, for example, was near the corner of
the prism, no other light but the red fell upon the
wall. He then placed behind this another board with
a hole in it, and behind this board he placed another
prism, so as to receive the red light which passed
through this hole in the second board.   He then
turned round the first prism, so as to make all the
colours in succession pass through these two holes, and
he marked their places on the wall. From the variation of these places, he saw that the red rays were
less refracted by the second prism than the orange
rays, the orange less than the yellow, and so on, the
violet being more refracted than all the rest.
Hence he drew the general conclusion, "that light.
was not homogeneous, but consisted of rays, some of
which were more refrangible than others."
This discovery revealed at once the explanation of
many of the most interesting appearances in nature..
Nothing can be more beautiful than the colours with
which the tops of mountains, the surface of the
ocean, and the different-shaped clouds are tinged at
sunrise and at sunset, the cause of which now became
obvious. The white rays of the sun, entering into;
an atmosphere of varying density, pass through it like
the sunbeams through Sir Isaac's glass prism, and are
in a similar way decomposed. The rays that are the
least refracted, or diverted, out of their course, reach.
the earth in all the purity and beauty of their own
individual colours, and enter into a thousand varied,
combinations. When the sun is shining in all its noon.
of splendour high above the horizon, its rays, falling




SIR ISAAC NEWTON.              37
on the wide expanse of the ocean, are reflected back
unchanged in all their original silvery lustre; but
when the sun is setting, and its rays fall obliquely on
the waters, the red being the least refrangible of the
primary rays, floods with a fiery glow the heaving
billows and the line of the visible horizon. Around
the heavenly bodies-the sun and the moon-circles
of light of the most varying colours often appear,
which may be explained on the same principle, these
halos being nothing more than the rays of light reflected and refracted by the globules of vapour through
which they pass before they reach the sphere of our
vision. But the most familiar instance of the decomposition of light into its prismatic colours is exhibited
to us by the rainbow, which is occasioned by the light
of the sun shining on the spherical drops of water
falling in an opposite shower. In this instance the
rays of white light are refracted or resolved into their
primary rays, which are reflected in the form of an
arch across the heavens.
As soon as Sir Isaac had established this important
truth, he saw that a lens which refracts light exactly
like a prism, must also refract the different-coloured
rays with different degrees of force, bringing the violet
rays to a focus nearer the glass than the red rays, and
so on. As soon as he perceived this result of his discovery, he abandoned all attempts to improve the
refracting telescope, and took into his consideration
the principle of reflexion; and, as he found that rays
of colours were reflected regularly, so that the angle of
reflexion was equal to the angle of incidence, he concluded that, upon this principle, "optical instruments
might be brought to any degree of perfection imaginable," provided that a reflecting substance could be
found which could polish as finely as glass, and reflect
as much light as glass transmits, and provided a method of communicating to it a parabolic figure could be
obtained. These difficulties appeared to him very




38                THE LIFE OF
great, and he even thought them insuperable, when he
considered that, as any irregularity in a reflecting surface makes the rays deviate five or six times more
from their true path than similar irregularities in a
refracting surface, a much greater degree of nicetywould be required in figuring reflecting specula than
refracting lenses.
Such was the progress of Newton's optical discoveries, when the students of the University of Cambridge were suddenly dispersed by the breaking out
of the plague, in 1666, which then desolated England.
Newton retired for safety to his paternal estate; and
though he lost for a time the advantages of public
libraries and literary conversation, he rendered the two
years of his retreat a memorable era in his own existence and in the history of science, by another of his
great discoveries, that of the theory of gravitation, or
the tendency of bodies towards the centre of the globe.
His time was never idle; experiments, conclusions,
and reflections, occupied it continually. He saw an'
apple fall from a tree, and immediately began to consider thegeneral laws which must regulate all falling
bodies. At that time a degree had never been actually
measured upon the face of the earth; his first attempts
to account for the wonders of the whole solar system,
by the principle of gravitation alone, were, therefore,
imperfect, from the want of sufficient data; but these
subjects he afterwards resumed.
On his return to Cambridge, in 1668, he resumed
the subject of a reflecting telescope, and having thought
of a delicate method of polishing proper for metals, by
which, as he conceived, " the figure would be corrected to the last," he began to put this method to the
test of experiment. At this time he was acquaint
with the proposal of Mr. James Gregory, contained in
his " Optima Promata," to construct a reflecting telescope with two concave specula, the largest of which
had a hole in the middle of the larger speculum to




SIR ISAAC NEWTON.


39


transmit the light to an eye-glass; but he conceived
it would be an improvement on this instrument to
place the eye-glass at the side of the tube, and to reflect the rays to it by an oval plane speculum. M.
Biot, in his Life of Newton, has erroneously stated
that Newton was preceded in the invention of the
reflective telescope by Gregory, but probably witlout
knowing it. It is quite certain, that Newton was perfectly well acquainted with Mr. Gregory's invention,
as appears from the following avowal of it, in a letter
to Oldenburg. "When I first applied myself to try
the effects of reflection, Mr. Gregory's ' Optima Promata,' (printed in the year 1663,) having fallen into
my hands, where there is an instrument described with
a hole in the midst of the object-glass to transmit the
light to an eye-glass placed behind it, I had thence an
occasion of considering that sort of construction, and
found their disadvantages so great, that I saw it neces
sary, before I attempted anything in the practice, to
alter the design of them, and place the eye-glass at
the side of the tube, rather than at the middle."
One of these instruments he actually constructed
with his own hands; and he gave an account of it in
a letter to a friend, dated February 23rd, 1668-9, a
letter which is also remarkable for containing the first
allusion to his discoveries respecting colours. Previous to this, he was in correspondence with Mr. Ent,
(afterwards Sir George Ent,) one of the original council of the Royal Society, an eminent medical writer of
his day, and President of the College of Physicians.
In a letter to Mr. Ent, he had promised an account of
his telescope to their mutual friend, and the letter to
which we now allude contained the fulfilment of that
promise. The telescope was six inches long. It bore
an aperture in the large speculum something more
than an inch, and as the eye-glass was a plano-convex
lens, whose focal length was one-sixth or one-seventh
of an inch, it magnified about forty times, which, as




40                THE LIFE OF
Newton remarks, was more than any six foot tube
(meaning refracting telescopes) could do with distinctness. On account of the badness of the materials,
however, and the want of a good polish, it represented
objects less distinct than a six feet tube, though he
still thought it would be equal to a three or four feet
tube directed to common objects. He had seen through
it Jupiter distinctly, with his four satellites, and also
the horns or moon-like phases of Venus, though, he
confessed, this last phenomenon required particular
niceness in adjusting the instrument.
Although Newton considered this little instrument
as in itself contemptible, yet he regarded it as an
"epitome of what might be done" and he expressed
his thorough conviction that a six feet telescope might
be made after this method, which would perform as
well as a sixty or a hundred feet telescope made in the
common way; and that if a common refracting telescope
could be made of the "purest glass exquisitely
polished, with the best figure that any geometrician
(Descartes, &c.) hath or can design, it would
scarcely perform better than a common telescope.
This," he adds, " may seem a paradoxical assertion, yet"
lie continues, " it is the necessary consequence of some
experiments which I have made concerning the nature
of light."
This telescope, which we have been describing possesses a very peculiar interest, as being the first reflecting telescope which was ever executed and directed
to the heavens. Mr. James Gregory had, indeed, attempted to construct his instrument some years previous. Messrs. Rivers and Cox, who were celebrated
glass-grinders of that time, were employed by him,
to execute a concave speculum of six feet radius, and
likewise a small one; but as they had failed in polishing the large one, and as Mr. Gregory was on the eve
of going abroad, he gave himself no further trouble
about the experiment, and the tube of the telescope




SIR ISAAC NEWTON..


41


was never made. Some time afterwards, it is true, he
(" made some trials both with a little concave and convex speculum, but possessed with the fancy of the defective figure, he would not be at the pains to fix every
thing in its due distance."
Such were the earliest attempts to construct the
reflecting telescope, that valuable instrument which has
since been the means of effecting such splendid discoveries in astronomy. WVhen we look back from the
present advanced state of practical science, how great
is the contrast between the loose specula of Gregory,
and the fine Gregorian telescopes of Hadley, Short,
and Yeitch-between the diminutive six inch tube of
Sir Isaac Newton and the forty-feet instrument of
Herschel, and the huge telescope of Ramage.
The success of his first experiment inspired Newton
with fresh zeal, and though his mind was now occupied with his optical discoveries, with the elements of
his methods of fluxions, and with the expanding germ
of his theory of universal gravitation, yet with all the
ardour of youth he applied himself to the laborious
operation of constructing another reflecting telescope
with his own hands. This instrument which was considerably better than the first, though it lay by him
several years, excited great interest at Cambridge;
and Sir Isaac himself informs us, that one of the fellows of Trinity College, had completed a telescope of
the same kind, which he considered as somewhat
superior to his own. The existence of these telescopes
having become known to the Royal Society, as well
as the history of their invention, Newton received a
letter from the secretary of the institution, earnestly
requesting him to send his instrument for examination
to that learned body. In accordance with this request
he transmitted it to Mr. Oldenburg in December 1671,
and from this epoch the name of Newton began to
acquire that celebrity by which it has continued ever
since to be so peculiarly distinguished.




A-)
A4O


THE LIFE OFP


On the 11th of January, 1671-2, it was announced
to the Royal Society, that Newton's reflecting telescope had been shown to the king, and had been
examined by the president Sir Robert Moray, Sir
Paul Neale, Sir Christopher Wren, and Mr. Hook.
These scientific gentlemen entertained so high an
opinion of the telescope, that, in order to secure the
honour of the invention to its author, they advised
him to forward a drawing and particular description
of it to Mr. Huygens at Paris. Mr. Oldenburgh
according drew up a description of the instrument in
Latin, which, after being revised and corrected by
Mr. Newton, was transmitted to that celebrated
philosopher.  This telescope is still carefully preserved in the library of the Royal Society of London,
with the following inscription:"INVENTED BY SIR ISAAC NEWTON, AND MADE WITH
HIS OWN HANDS, 1671."
We have no evidence that Newton executed any
other reflecting telescopes than the two we have
mentioned. He informs us, however, that he repolished and greatly improved a fourteen feet objectglass, executed by a London artist of celebrity, and
having, in 1678, proposed to substitute glass reflectors
in place of metallic specula, he tried to make a
reflecting telescope on this principle four feet long,
and with a magnifying power of 150. The glass was
wrought by a London artist, and though it appeared
to be well finished, yet, when it was quicksilvered
on its convex side, it exhibited all over the glass
innumerable inequalities, which gave an indistinctness
to every object. He expresses his firm conviction,
however, that nothing but good workmanship is
wanting to perfect these telescopes, and he recommends their careful consideration " to the curious in
figuring glasses."




SIR ISAAC NEWTON.


43


Strange as it may appear, a period of fifty years
was allowed to elapse before this recommendation
excited any notice. About that time, however, Mr.
James Short, of Edinburgh, an artist of consummate
skill, constructed, in the year 1730, no fewer than
six reflecting telescopes with glass specula; three of
these were fifteen inches, and three were nine inches
in focal length. He found it extremely troublesome
to give them a true figure with parallel surfaces; and
several of them when finished turned out useless, in
consequence of the veins which appeared in the glass.
Although these instruments performed perfectly well,
yet the light was fainter than he expected, and from
this cause, combined with the difficulty of finishing
them, he afterwards devoted his labours solely to
those with metallic specula.
At a later period, in 1822, Mr. G. B. Airy of
Trinity College, Cambridge, and one of the distinguished successors in the Lucasian chair of Mathematics in that university, resumed the consideration
of glass specula, and clearly denonstrated that the
observation both of figure and colour might be corrected in these instruments.  Upon this ingenious
principle, Professor Airy executed more than one
telescope, but though the result of the experiment
was such as to excite hopes of ultimate success, yet
the construction of such instruments is still a desideratum in practical science.
Such were the attempts which Sir Isaac Newton
made to construct reflecting telescopes; but notwithstanding the success of his labours, neither the philosopher nor the practical optician seems to have been
possessed of that patient and accurate investigation
necessary to pursue them. A London artist, of considerable skill, undertook to imitate these instruments;
but Sir Isaac informs us that " he fell much short of
what he had attained, as he afterwards ascertained by
discoursing with the under-workmen he had em



44


Tt1E LIFE OF


ployed."  After a long period of fifty years, John
Hadley, Esq., of Essex, a Fellow of the Royal Society, began, in 1719 or 1720, to execute a reflecting
telescope. The scientific knowledge of this gentleman, and his manual dexterity, fitted him admirably
for the task; and-probably after many failures-he
constructed two large telescopes, about five feet three
inches long-one of which, with a speculum six
inches in diameter, was presented to the Royal Society, in 1723. The celebrated Dr. Bradley and the
Rev. Mr. Pound compared this telescope with the great
Huygenian refractor, 123 feet long. Itbore as high
a magnifying power as the Huygenian telescope: it
showed objects equally distinct, though not altogether
so clear and bright: and it exhibited every celestial
object that had been discovered by Huygens-viz., the
five satellites of Saturn; the shadow of Jupiter's
satellites on his disc, the black list in Saturn's ring,
and the edge of his shadow cast on the ring. Encouraged and instructed by Mr. Hadley, Dr. Bradley
began the construction of reflecting telescopes, and
succeeded so well, that he would have completed one
of them, had he not been under the necessity of
changing his residence. Some time afterwards, he
and the Honourable Samuel] Molyneux undertook the
task together, at Kew, and attempted to execute specula about twenty-six inches in focal length; but notwithstanding the Doctor's former experience, and Mr.
Hadley's frequent instructions, it was a long time before they succeeded in their undertaking. The first
good instrument which they completed was in May,
1724. It was twenty-six inches in focal length; but
they afterwards constructed a very large one of eight
feet, the largest that had ever been made. The first
of these instruments was afterwards elegantly fitted
up, and presented by Mr. Molyneux, to his Majesty,
John V., King of Portugal, a zealous patron of all
the sciences.




SIR ISAAC NEWTON.


45:


The great object of these two able astronomers appears to have been to reduce the method of making
specula to such a degree of certainty, that they could
be manufactured for public sale. Mr. Hauksbee had
indeed made a good one, about three and a half feet
long, and proceeded to the execution of two othersone of six feet, and another of twelve feet in focal
length; but Mr. Scarlet and Mr. Hearne, having received all the information which Mr. Molyneux had
acquired, constructed them for public sale; and the
reflecting telescope has ever since continued to be an
article of trade with every regular optician.
"As Sir Isaac Newton," observes his modern biographer, "was at this time President of the Royal
Society, he had the high satisfaction of seeing his own
invention become an instrument of public use, and of
great advantage to science; and he no doubt felt the
full influence of this trial of his skill. Still, however,
the reflecting telescope had not achieved any new discovery in the heavens. The latest accession to astronomy had been made by the ordinary refractors of
Huygens, labouring under all the imperfections of
coloured light; and this long pause in astronomical
discovery seemed to indicate that man had carried to
its furthest limits his power of penetrating into the
depths of the universe. This, however, was only one
of those stationary positions from which human genius takes a new and loftier elevation. While the
English opticians were thus practising the recent art
of grinding specula, Mr. James Short, of Edinburgh,
was devoting to the subject all the energies of his
youthful mind. In 1732, and in the 22nd year of his
age, he began his labours; and he carried to such high
perfection the art of grinding and polishing specula,
and of giving them  the true parabolic figure, that,
with a telescope fifteen inches in focal length, he read
in the Philosophical Transactions, at the distance of 500
feet, and frequently saw the five satellites of Satunr




46 -

THE LIFE OF


together-a power which was even beyond the reach
of Iadley's six-foot instrument.  The celebrated
Maclaurin compared the telescopes of Short with
those made by the best London artists; and so great
was their superiority, that his small telescopes were
invariably superior to larger ones from London. In
1742, after he had settled as an optician in the metropolis, he executed for Lord Thomas Spencer a reflecting telescope, twelve feet in focal length, for ~630;
in 1752, he completed one for the King of Spain, at
the expense of ~1200; and a short time before his
death, which took place in 1768, he finished the
speculaof the large telescope which was mounted
equatorially for the observatory of Edinburgh, by
his brother, Thomas Short, who was offered twelve
hundred guineas for it by the King of Denmark.
C Although the superiority of these instruments,
which were all of the Gregorian form, demonstrated
the value of the reflecting telescope, yet no skilful
hand had yet directed it to the heavens; and it was
reserved for Dr. Herschel to employ it as an instrument of discovery-to exhibit to the eyes of men new
worlds, and new systems; and to bring within the
grasp of his reason those remote regions of space to
which his imagination even had scarcely ventured to
extend its power. So early as 1774, he completed a
five-foot Newtonian reflector; and he afterwards executed no fewer than two hundred seven -feet, one hundred and fifty ten-feet, and eighty twenty-feet specula. In 1781, he began a reflector thirty feet long,
and having a speculum thirty-six inches in diameter;
and under the magnificent patronage of George III.
he completed, in 1789, his gigantic instrument, forty
feet long, with a speculum forty-nine and a half inches
in diameter. The genius and perseverance which
created instruments of such transcendant magnitude
were not likely to terminate with their construction.
In the examination of the starry heavens, the ulti



SIR ISAAC NEWTON.


AT,


mate object of his labours, Dr. Herschel exhibited the:
same exalted qualifications; and in a few years he
rose from the level of humble life to the enjoyment of
a name more glorious than that of the sages and warsriors of ancient times, and as immortal as the objects
with which it will be for ever associated. Nor was it
in the ardour of the spring of life that these triumphs
of reason were achieved. Dr. Herschel had reached
the middle of his course before his career of discovery
began; and it was in the autumn and winter of his
days that he reaped the full laurels of his glory. The
discovery of a new planet at the verge of the solar
system was the first trophy of his skill; and new
double and multiple stars, and new nebulae and groups
of celestial bodies, were added in thousands to the
system of the universe. The spring-tide of knowledge which was thus let in upon the human mind, continued for a while to spread its waves over Europe;
but when it sank to its ebb in England, there was no
other bark left upon the strand than that of the Deucalion of Science, whose home had been so long upon
the waters.
" During the life of Dr. Herschel, and during the
reign, and within the dominions of his royal patron,
four new planets were added to the solar system, but
they were detected by telescopes of ordinary power;
and, we venture to state, that since the reign of
George III. no attempt has been made to keep up
the continuity of Dr. Herschel's discoveries.
" Mr. Herschel, his distinguished son, has indeed
completed more than one telescope of considerable
size;-Mr. Ramage, of Aberdeen, has executed reflectors rivalling almost those of Slough;-and Lord
Oxmanstown, an Irish nobleman of high promise, is
now engaged on an instrument of great size. But
what avails the enthusiasm and the efforts of individual minds in the intellectual rivalry of nations
When the proud science pines in obscurity, blighted:




48


THE LIFE OF


by the absence of royal favour, and of the nation'
sympathy;-when its chivalry fall unwept and unhonoured;-how can it sustain the conflict against
the honoured and marshalled genius of foreign lands?"
Newton's great discoveries in the science of optics
formed the principal subjects of his lectures in the
University of Cambridge during the years 1669,
1670, and 1671, and his new theory of light and
colours was explained, with a clearness arising from
perfect knowledge, to the satisfaction of a crowded
and admiring audience; yet it is a singular circumstance that these discoveries should not have become
public through the conversation or correspondence of
his pupils. The Royal Society had acquired no
knowledge of them till the beginning of 1672, and
his reputation in that body was founded chiefly on his
reflecting telescope. On the 23rd of December, 1671,
the celebrated Dr. Seth Ward, Lord Bishop of
Sarum, who was the author of several able works on
astronomy, and had filled the astronomical chair at
Oxford, proposed Mr. Newton as a Fellow of the
Royal Society. The satisfaction which he derived
from this circumstance appears to have been considerable; and in a letter to Mr. Oldenburg, of the 6th of
January, he says, "I am very sensible of the honour
done me by the Bishop of Sarum in proposing me a
candidate; and which, I hope, will be further conferred upon me by my election; and if so, I shall
endeavour to testify my gratitude, by communicating
what my poor and solitary endeavours can effect
towards the promoting your philosophical designs."
His election accordingly took place on the 11th of
January, the same day on which the Society agreed
to transmit a drawing and description of his reflecting
telescope to Mr. Huygens at Paris. The notice of his
election, and the thanks of the Society for the communication of his telescope, were conveyed in the same
letter, with an assurance that the society "would




SIR ISAAC NEWTON.             49
take care that all right should be done him in the
matter of this invention."  In his next letter to Mr.
Oldenburg, written on the 18th of January, he
announces his optical discoveries in the following remarkable manner:-" I desire that in your next letter
you would inform me for what time the society continue their weekly meetings; because if they continue them for any time, I am purposing them, to be
considered of and examined, an account of a philosophical discovery which induced me to the making of
the said telescope; and I doubt not but will prove
much more grateful than the communication of that
instrument; being in my judgment the oddest, if
not the most considerable, detection which hath
hitherto been made in the operations of nature."
This '" considerable detection" was the discovery of
the different refrangibility of the rays of light which
we have already explained, and which led to theo construction of his reflecting telescope.  It was communicated to the Royal Society in a letter to Mr.
Oldenburg, dated February 6th, and excited, as
might have been expected, the greatest interest
among the members of that distingished body. The
" solemn thanks" of the meeting were ordered to be
transmitted to its author for his c" very ingenious discourse."  A strong desire was expressed to have it
immediately printed, both for the purpose of having
it well examined and considered by philosophers, and
for "securing the considerable notices thereof to the
author against the arrogation of others," and Dr.
Seth Ward, Bishop of Sarum, Mr. Boyle, and Dr.
Hooke, were desired by the Society to peruse and
consider it, and to bring in a report upon it.
It is reputed that Isaac Newton was at this period
so poor that he was compelled to apply for a dispensation from the usual payment of one shilling weekly,
which is contributed by each member towards the
D




50


THE LIFE OF'


expenses of the Royal Society. He had no income
but what he derived from his college and his professorship, the produce of his small estate being absorbed
in supporting his mother and her family. His personal wishes, however, were so moderate, that he never
could regret the want of money, except in as much as
it limited his purchases of books and scientifical
instruments, and restricted his power of relieving the
distresses of others.
The kindness of the Royal Society in admitting
him as a member, and the anxiety which they had
already evinced for his reputation, excited on the part
of Newton a corresponding feeling, and he gladly
accepted of their proposal to publish his discourse in
the monthly numbers in which the Tansactions of
the Society were then given to the world. In a letter
to Mr. Oldenburg, dated February 10th, he says, "It
was an esteem of the Royal Society for most candid and able judges in philosophical matters, encouraged me to present them with that discourse of light
and colours, which since they have so favourably accepted of, I do earnestly desire you to return them
my cordial thanks.   I before thought it a great
honour to be made a member of that honourable
body; but I am now more sensible of the advantages; for, believe me, sir, I do not only esteem it a
duty to concur with you in the promotion of real
knowledge; but a great privilege, that, instead of
exposing discourses to a prejudicial and common multitude, (by which means many truths have been baffled and lost;) I may, with freedom, apply myself to
so judicious and impartial an assembly. As to the
printing of that letter, I am satisfied in their judgment, or else I should have thought it too straight
and narrow for public view. I designed it only to
to those that know how to improve upon hints of
things; and, therefore, to spare tediousness, omitted
many such remarks and experimepts as might be col



SIR ISAAC NEWTON.


51


lected by considering the assigned laws of refractions;
some of which, I believe, with the generality of men,
would yet be almost as taking as any I have described.  But yet, since the Royal Society have
thought it fit to appear publicly, I leave it to their
pleasure: and, perhaps, to supply the aforesaid defects,
I may send you some more of the experiments to
second it (if it be so thought fit) in the ensuing
Transactions."
In following the order which Newton himself
adopted, we have endeavoured to give an account of
the leading doctrine of the different refrangibility of
light, and of the various attempts to improve the
reflecting telescope which that discovery suggested.
We shall now, therefore, further endeavour to make
the reader acquainted with the discoveries respecting
colours, which he at this time communicated to the
Royal Society of London.
Having determined, by experiments which we have
already described, that a beam of white light, as
emitted from the sun, consisted of seven different colours, which possess different degrees of refrangibility;
he measured the relative extent of the coloured spaces
on the wall, and found them to have the proportions
according to their different degrees of refrangibility;
the prismatic spectrum is nothing more than an elongated image of the sun produced by the rays of the
sun being separated in different degrees from their original direction, the red being refracted least, and the
violet most powerfully.
If we consider light as consisting of minute particles of matter, we may form some notion of its decomposition by the prism from the following popular illustration.  "If we take steel filings of seven different
degrees of fineness and mix them together, there are
two ways in which we may conceive the mass to be
decomposed, or, what is the same thing, all the different kinds of filings separated from each other. By




52


THE LIFE OF


means of seven sieves of different degrees of fine.
ness, and so made that the finest will just transmit the
finest powder and detain all the rest, while the next in
fineness transmits the two finest powders and detains
all the rest, and so on, it is obvious that all the powders may be completely separated from each other. If
we again mix all the steel filings, and laying them upon
a table, hold high above them a flat bar magnet, so that
more of the filings are attracted, then if we bring the
magnet nearer and nearer, we shall come to a point
where the finest filings are drawn up to it. These
being removed, and the magnet brought nearer still,
the next finest powder will be attracted, and so on till
we have thus drawn out of the mass all the powders in
a separate state.  We may conceive the bar magnet to
be inclined to the surface of the steel filings, and so
moved over the mass, that at the end nearest to them
the heaviest or coarsest will be attracted, and all the
remotest and the finest or lighter filings, while the rest
are attracted to intermediate points, so that the seven
different filings are not only separated but are found
adhering in separate patches to the surface of the flat
magnet.   The first of these methods with the sieves
may represent the process of decomposing light by
which certain rays of white light are absorbed, or stifled, or stopped in passing through bodies, while certain rays are transmitted. The second method may represent the process of decomposing light by refraction,
or by the attraction of certain rays further from their
original direction than other rays, and the different
patches of filings upon the flat magnet may represent
the spaces on the spectrum.
When a beam of light is decomposed into the seven
different colours of the spectrum, every particular colour, when once separated from the rest, is not susceptible of any change, or farther decomposition, whether
it is refracted through prisms or reflected from mirrors.
It may become fainter or brighter, but Newton never




SIR ISAAC NEWTON.


53


could, by any process, alter its colour or its refrangibility.
Among the various bodies which act upon light, it is
conceivable that there might have been some which
acted least upon the violet rays and most upon the red
rays. Newton found, however, that this never took
place; but that the same degree of refrangibility always belonged to the same colour to the same degree
of refrangibility.
Having thus determined that the seven different colours of the spectrum were original or simple, he was
led to the conclusion that whiteness, or white light, is
a compound of all the seven colours of the spectrum,
in the proportions in which they are represented on the
wall. In order to prove this, or what is called the
recomposition of white light out of the seven colours,
he employed three different methods.
When the beam was separated into its elementary
colours by the prism, he received the colours upon
another prism, held either close to the first or a little
behind it, and by the opposite refraction of this prism
they were all refracted back into a beam of white
light, which formed a white circular image on the wall,.
similar to what took place before any of the prisms
were placed in its way.
The other method of recomposing white light consisted in making the spectrum fall upon a lens at some
distance from it. When a sheet of white paper was held
behind the lens and removed to a proper distance, the
colours were ail refracted into a circular spot, and so
blended as to reproduce light so perfectly white as not
to differ sensibly from the direct light of the sun.
The last method he adopted of recomposing white
light was one more suited to common apprehensions.
It consisted in attempting to compound a white by
mixing the coloured powders used by painters. He
was aware that such colours, from their very nature,
could not compose a pure white; but even this imper



54


THIE LIFE OF


fection in the experiment he removed by an ingenious
device. He accordingly mixed one part of red lead,
four parts of blue bise, and a proper proportion of orpiment and verdigris. This mixture was dun, like
wood newly cut, or like the human skin.  He now
took one-third of the mixture and rubbed it thickly on
the floor of his room, when the sun shone upon it
through the opened casement, and beside it, in the
shadow, he laid a piece of white paper of the same
size. "Then going from them" he says, "to the distance of twelve or eighteen feet, so that I could not
discern the unevenness of the surface of the powder,
nor the little shadows let fall from the gritty particles
thereof; the powder appeared intensely white, so as to
transcend even the paper itself in whiteness." By adjusting the relative illumination of the powders and
the paper, he was able to make them both appear of
the very same degree of whiteness.  "For," says he,
"when I was trying this, a friend coming to visit me,
I stopped him at the door, and before I told him what
the colours were, or what I was doing, I asked him
which of the two whites were the best, and wherein
they differed? And after he had, at that distance,
viewed them well, he answered that they were both
good whites, and that he could not say which was
best, nor wherein their colour differed."  For this
reason Newton inferred that perfect whiteness may be
compounded of different colours.
As all various shades of colour which appear in the
material world can be imitated by intercepting certain
rays in the spectrum, and uniting all the rest, and as
bodies always appear of the same colour as the light
in which they are placed, he concluded, that the colours of natural bodies are not qualities inherent in
the bodies themselves, but arise from the disposition
of the particles of each body to stop or absorb certain
rays, and thus to reflect more copiously the rays which
are not thus absorbed.




SIR ISAAC NEWTON.


55


No sooner were these discoveries given to the world
than they were opposed with a degree of virulence
and ignorance which have rarely been combined in
scientific controversy.  Unfortunately for Newton,
the Royal Society at that time contained very few
individuals of pre-eminent talents, capable of appreciating the truth of his valuable discoveries, and of
protecting him against the malevolent shafts of his
envious and ignorant assailants. This eminent body,
while they held his labours in the highest esteem,
were still of opinion that his discoveries were fair subjects of discussion, and their secretary accordingly
communicated to him all the the papers which were
written in opposition to his views. The first of these
was by a Jesuit named Ignatius Pardies, Professor of
Mathematics, at Clermont, who pretended that the
elongation of the sun's image arose from the unequal
incidence of the different rays on the first face of the
prism, although Newton had demonstrated to a certainty in his own discourse that this was not the case.
In April, 1672, Newton transmitted to Oldenburg a
decisive reply to the animadversions of Pardies; but,
unwilling to be vanquished, this disciple of Descartes
took up a fresh position, and maintained that the
elongation of the spectrum might be explained by the
diffusion of light on the hypothesis of Grimaldi, or by
the diffusion of undulations on the hypothesis of
Hook. Newton again replied to these feeble reasonings; but contented himself with repeating his origin
nal experiments, and confirming them by more popular arguments, apparently better suited to the comprehension of Pardies, as the vanquished Jesuit wisely
quitted the field.
Another combatant soon sprung up in the person of
one Francis Linus, a physician in Liege, who, on the
6th of October, 1674, addressed a letter to a friend
in London, containing animadversions on Newton's
doctrine of colours. He boldly affirmed, that in




6            THE LIFE OF
perfectly clear sky, the image of the sun made by a
prism is never elongated, and that the spectrum observed by Newton was not formed by the true sunbeams, but by rays proceeding from some bright cloud.
In support of these assertions, he appeals to frequently
repeated experiments on the refractions and the reflexions of light which he had exhibited thirty years
before to Sir Kenelm  Digby, who took notes upon
them; and he unblushingly states, that if Newton had
used the same industry as he did, he would never
have " taken so impossible a task in hand, as to explain the difference between the length and breadth of
the spectrum by the received laws of refraction."
When this letter was shown to Newton, he considered
it below his notice, and refused to answer it; but a
letter was sent to Linus referring him to the answer
given by Mr, Newton to Pardies, and assuring him
that the experiments on the spectrum were made at
a time when there was no bright cloud in the
heavens. This reply, however, did not satisfy the
Dutch experimentalist, and he addressed another
letter to his friend in London, on the 25th of
February, 1675, in which he gravely attempted to
prove that the experiment of Newton was not made
in a clear day; that the prism was not close to the
hole; and that the length of the speculum was not
perpendicular or parallel to the length of the prism.
Such assertions could not but irritate even the patient
mind of Newton.    He several times declined the
earnest request of Mr. Oldenburg to answer these observations; he observes, that as the dispute referred
to'matters of fact, it could only be decided before
competent witnesses, and he referred to the testimony
of those who had seen his experiments. The entreaties of Oldenburg, however, prevailed over his
own better judgment; and " lest Mr. Linus should
make more stir," this illustrious philosopher was
compelled to draw up a long and explanatory reply to




SIR ISAAC NEWTON.


57


reasonings which he considered utterly contemptible,
and to assertions, altogether without foundation.
This answer, dated November 13th, 1675, would
scarcely have been perused by Linus, who died on the
15th of December, when his pupil Mr. Gascoigne
took up the cause, and declared that Linus had shown
to various persons in Liege his experiment, which
proved the spectrum to be circular, and that Newton
could not be more confident on his side than they
were on the other.  He admitted, however, that the
different results might arise from different ways of
placing the prism. Pleased with the " handsome genius of Mr. Gascoigne's letter," Newton replied to it,
and suggested that the spectrum seen by Linus may
have been the circular eye formed by one reflection,
or, what he thought more probable, the circular one
formed by two refractions, and one intervening reflexion from the base of the prism, which would be
colouredif the prismwas not an isosceles one. This suggestion appears to have enlightened the Dutch philosophers. Mr. Gascoigne having no conveniences for
making the experiments pointed out by Newton, requested Mr. Lucas of Liege to perform them in his
own house. This ingenious gentleman, whose letter
gave evident satisfaction to Newton; and deserves
the highest praise, confirmed the leading results of
the English philosopher; but though the refractiug
angle of his prism was 60 degrees, and the refractions
equal, he never could obtain a spectrum whose length
was more than from three to three and a half times its
'treadth, while Newton found the length to be five
times its breadth.  In Newton's reply he direets the
attention of his correspondent principally to this point
of difference.  He repeated his measures with each
of the three angles of three different prisms, and he
affirmed that Mr. Lucas might "' make sure to find
the image as long or longer than he had yet done,'
by taking a prism with plain surfaces, and with an




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angle of 66 or 67 degress.  He admitted that the
smallness of the angle in Mr. Lucas's prism, viz, 60
degrees, did not account for the shortness of the spectrum which he obtained with it; and he observed in
one of his own prisms that the length of the image
was greater in proportion to the refracting angle than
it should have been; an effect which he ascribes to
its having a refractive power.  Newton speaks with
singular positiveness on this subject.  " For I know,"
says he,  " that Mr. Lucas's observations  cannot
hold where the refracting angle of the prism is full
60 degrees, and the day is clear, and the full length
of the colours is measured, and the breadth of
the image answers to the sun's diameter: and
seeing I am well assured of the truth and exactness of my own observations, I shall be unwilling to be diverted by any other experiments
from   having a  fair end made of this in the
firt place."  There can be no doubt that the prism
made use of by Lucas had actually a less dispersive
power than that of Newton: and had the Dutch
philosopher measured its refractive powers instead of
uessing it, or had Newton been less confident than
e really was, that all other prisms must give a speec
tum of the same length as his in relation to its refrating angle and its index of refraction, the inventicn of the achromatic telescope would have been the
necessary result.  The objections of Lucas, howvev
forced our philosopher to make experiments which he
had never before thought of-to measure accurately
the length of the spectrum with different prisms of
d   rent angles and different refractive powers; anA
had Lucas maintained his position with greater ostinacy, he would have conferred a distinguished favour
pon science, and would have rewarded Newton for
all the vexation which had sprung from the disagree
able discussion of his optical experiments.
Suoh was the termination of Newton's disputes with




SIR ISAAC NEWTON.             59
the Dutch philosophers, and there is every reason to
believe that it cost him more trouble to detect the
origin of his adversaries' mistakes, than to establish
the important truths which they had attempted to
overturn.
Harrassing as such a controversy must have been
to a philosopher like Newton, yet it did not touch
those deep-seated feelings which characterize the noble
and generous soul. No rival jealousy yet embittered
the arguments of his opponents;-no charges of plagiarism were yet directed against his personal character.
These aggravations of scientific controversy, however,
were yet in store for him; and the dispute which he
was called to maintain with Hooke and Huygens was
painfully increased by the personality and jealousy
with which it was conducted.
Dr. Robert Hooke was about seven years older than
Newton, observes the biographer of Newton, and was
one of the ninety-eight original or unelected members
of the Royal Society of London. He possessed great
-versatility of talent, yet, though his genius was of the
most original cast, and his acquirements extensive, he
had not devoted himself with fixed purpose to any
particular branch of knowledge. His numerous and
ingenious inventions, of which it is impossible to speak
in terms of too tnuch praise, gave to his studies a
practical turn which unfitted him for that patient
labour and investigation which physical researches so
imperiously demand. The subjects of light, however,
and of gravitation, appear to have deeply occupied his
thoughts before Newton appeared in the field, and
there can be but little doubt that he had made considerable progress in both of these inquiries. With a
mind less divergent in its pursuits, and more endowed
with patience of thought, he might successfully have
unveiled the mysteries in which both these subjects
were enveloped, and pre-occupied the intellectual
throne which was destined for his rival; but the in
**:




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firm state of his health; the peevishness of temper
which this occasioned; the number of unfinished inventions from which he looked both for fortune and
fame; and, above all, his extravagant love of reputation, distracted and broke down the energies of his
powerful intellect. In the more extensive inquiries of
Newton, he often recognised his own incompleted
speculations; and when he saw others reaping that
glorious harvest for which he considered he had prepared the ground, and of which he had sown the
seed, it was not easy for him to suppress the
deep mortification which Newton's success inspired.
In the history of science, as in all other history, it is
a difficult matter to adjust the rival claims of competitors, when the one was allowed to have completed
what the other had begun. He who commences an
inquiry and proclaims the results to the world, often
goes much further than he has announced, and, pushing his speculations into the very heart of the subject,
frequently submits them to the ear of friendship.
From the pedestal of his published labours his rival
begins his researches, and brings them to a successful
issue; while he has, in fact, done nothing more than
completed and demonstrated the imperfect speculations
of his predecessor. To the world, and to himself, he
is in the position of the principal discoverer; but there
is still some apology for his rival when he brings forward his unpublished labours; and some excuse for
the exercise of personal feeling, when he measures the
speed of his rival by his own proximity to the goal.
The conduct of Dr. HIooke would have been viewed
with some such feeling, had not his arrogance on other
occasions checked the natural current of our sympathy. When Newton presented his reflecting telescope to the Royal Society, Dr. Hooke not only criticised
the instrument with undue severity, but announced
that he possessed an infallible method of perfecting all
kinds of optical instruments, so that "whatever almost




SIR ISAAC NEWTON.


61


hath been in notion or imagination, or desired in
optics, may be performed with great facility and
truth."
Hooke had been strongly impressed with the belief,
that light consisted in the undulations of a highly
elastic medium pervading all bodies; and, guided by
his experimental investigation of the phenomena of
diffraction, he had even announced the great principle
of interference, which has performed such an important part in modern science.   Regarding himself,
therefore, as in possession of the true theory of light,
he examined the discoveries of Newton in their relation to his own speculative views, and finding that
their author was disposed to consider that element as
consisting of material particles, he did not hesitate to
reject doctrines which he believed to be incompatible
with truth. Dr. Hooke was too accurate an observer,
not to admit the general correctness of Newton's observations. He allowed the existence of different
refractions, the unchangeableness of the simple colours,
and the production of white light by the union of all
the colours of the spectrum; but he confidently
maintained that the different refractions arose from
the splitting and rarefying of ethereal pulses, and
that there are only two colours in nature, viz: red
and violet, which produce by their mixture all the
rest, and which are themselves formed by two sides
of a split pulse or undulation.
In reply to these observations, Newton wrote an
able letter to Mr. Oldenburg, dated June 11th, 1762,
in which he examined with great boldness and force
of argument, the various objections of Dr. Hooke,
and maintained the truth of his doctrine of colours, as
independent of the two hypotheses respecting the
origin and production of light. He acknowledged his
own partiality to the doctrine of the materiality of
light; he pointed out the defects of the undulatory
theory; he brought forward new     experiments i










620


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confirmation of his former results; and he refuted the
opinions of his opponent, respecting the [existence of
only two simple colours. No reply was made to the
powerful arguments of Newton, which our limits
prohibit us from giving in full, and Dr. Hooke contented himself with laying before the society, his
curious and interesting observations on soap bubbles,
and of plates of air, and in pursuing his experiments
on the diffraction of light.
Mr. Newton had no sooner silenced this most
powerful of his opponents, than he was again called
into the field to defend his discoveries against a new
enemy. Christian Huygens, an eminent mathematician and natural philosopher, who, like Dr. Hooke,
had maintained the undulatory theory of light, transmitted to Mr. Oldenburg various animadversions on
the Newtonian doctrine, but though his knowledge of
optics was most extensive, yet his objections were
nearly as groundless as his less-enlightened countryman. Attached to his own hypothesis respecting the
nature of light, namely to the system of undulation,
he seems like Hooke, to have regarded the discoveries
of Newton, as calculated to overturn it, but his
prncipal objections related to the composition of
colours, and particularly of white light, which he
alleged could be obtained from the union of two
colours, YELLOW and BLUE. To this and similar
objections Newton replied, that the colours in question
were not simple yellows and blues, but were compound colours, in which, together, all the colours of
the spectrum were themselves blended; and though
he evinced some strong traces of feeling at being again
called upon to answer such frivolous objections, yet
his respect for Huygens induced him to enter with
patience on a fresh development of his doctrine.
Hnygens felt the reproof which the tone of this
anwer so gently conveyed, and in writing to Oldenburg, he made use of the words, that Mr. Newton




SIR ISAAC NEWTON.


ea


" maintained his doctrine with some concern."  To
this Newton replied, " As for Mr. Huygens' expression, I confess it was a little ungrateful to me, to meet
with objections which had been answered before,
without having the least reason given me why those
were insufficient." But though IIuygens appears in
this controversy as a rash objector to the Newtonian
doctrine, it was afterwards the fate of Newton to play
a similar part against the Dutch philosopher, when
he published his beautiful law of double refraction in
Iceland spar, founded on the finest experimental analysis of the phenomena, though presented as a result
of the undulatory system.   Newton unhesitatingly
rejected it, and substituted for it another law entirely
inconsistent with the experiments of Huygens, and
with those of all succeeding philosophers.
Even the calm temper of Newton was ruffled on
account of these controversies; the satisfaction of
humbling all his antagonists was not a sufficient compensation for the disturbance of his tranquillity. In
his letter to Oldenburg, containing his first reply to
Huygens, he says-" I intend to be no farther solicit- -
ous about matters of philosophy. And, therefore, I
hope you will not take it ill if you find me never doing
anything more in that kind; or rather, that you will
favour me in my determination, by preventing, so far
as you can conveniently, any objections or other philosophical letters that may concern me."  In a subsequent letter to the same gentleman, he says-" I had
some thoughts of writing a further discourse about
Colours, to be read at one of your assemblies; but
find it yet against the grain to put pen to paper any
more on that subject:" and in a letter to Leibnitz,
dated December 9th, 1675, he observes-" I was so
persecuted with discussions arising from the publication of my theory of light, that I blamed my own;
imprudence for parting with so substantial a blessing
a my quiet to run after a shadow."




64


THE LIEE OF


CHAPTER III.
Hall invents the Achromatic Telescope. Principles of it explained.
Re-invented by Dolland, and Improved by future Artists. Blair's
Achromatic Telescope. Mistakes in Newton's Analysis of the Spec.
trum. Structure of the Spectrum. Colours of thin Plates. Newton
determines the law of their production. His Theory of fits of easy
reflexion and transmission.  Colours of thick Plates.  Newton's
Theory of the Colours of Natural Bodies explained.
THERE is no fact in the history of science more singular than that Newton should have concluded that
all bodies produced spectra of equal length, or separated the red and violet rays to equal distances when
the refraction of the mean rays was the same.     This
opinion, unsupported by experiments, and not even
sanctioned by any theoretical views, seems to have
been impressed firmly upon his mind with all the force
of a self-evident proposition. Even the shortness of
the spectrum, observed by his opponent at Liege, did
not rouse him to further inquiry; and when, under the
influence of this blind conviction, he pronounced the
improvement of the refracting telescope to be desperate, he checked for a long time the progress of this
branch of science, and furnished to future philosophers
a lesson which cannot be too deeply studied.
In 1729, about two years after the death of Sir
Isaac Newton, an individual unknown to the scientific
world broke the spell in which the subject of the
spectrum had been so long and so singularly bound.
Mr. Chester More Hall, of More Hall, in Essex, while
studying the mechanism of the human eye, was led to
suppose that telescopes might be improved by a combination of lenses of different refractive powers, and
he actually completed several object glasses upon this




SIR ISAAC NEWTON.


65


principle. We are not informed of the steps by which
he arrived at such a construction: but it is certain
that he must have made a discovery which had escaped
the sagacity of Newton-that prisms made of different
kinds of glass produced different degrees of separation
of the red and violet rays, or gave spectra of different
lengths when the refraction of the middle ray of the
spectrum was the same.
In order to explain how such a property led Mr.
Hall to the construction of a telescope without colour,
or an achromatic telescope, let us take a lens of crown
or plate glass, whose focal length is about twelve
inches.  When the sun's rays fall upon it the red will
be refracted more than the yellow, and the yellow
than the violet. If we now place behind it a concave
lens of the same glass and of the same focus or curvature, it will be found both by experiment, and by
drawing the refracted rays, according to the rules
given in elementary works, that the concave glass
will refract the rays free of all colour; but as these
rays will be parallel, the two lenses will not have a
focus, and consequently cannot form an image so as to
be used as the object glass of a telescope. This is obvious from another consideration; for since the curvatures of the convex and concave lenses are the same,
the two put together will be exactly the same as if
they were formed out of a single piece of glass,
having parallel surfaces like a watch glass, so that
the parallel rays of light will pass on in the same
direction affected by equal and opposite refractions as
in a piece of plane glass.
NoW   since the convex lens separated the white
light into its component coloured rays, the extreme
violet and the extreme red, it follows that a similar
concave lens of the same glass is capable of uniting
the violet and the red into white light.    Consequently, if we take a concave lens of the same or of a.,.  Id  *  E:     *  *  f;;




6             THE LIPE OF
greater refractive power than the convex one, and
having the power of uniting rays farther separated
than the violet and the red are, a less concavity in
the other lens will be sufficient to unite the violet and
red rays into a white ray; but as the one lens is now
less concave than the other is convex, the concvity
will predominate, and the uncoloured rays will no
longer be parallel, but will converge to some point
where they will form a colourless or achromatic image
of the sun.
The effect now described may be obtained by
making the convex lens of crown or of plate glass, and
the concave lens of flint glass. If the concave lens
has a greater refractive power than the convex, which
is always the case, the only effect of it will be to
make the rays converge to a focus more remote, or to
render a less curvature necessary in the concave lens.
Such is the principle of the achromatic telescope
invented by Mr. Hall. This ingenious gentleman
employed working opticians to grind his lenses, and he
furnished them with the radii of the surfaces, which
were adjusted to correct the aberrations of figure as
well as of colour. His invention, therefore, was not
an accidental combination of a convex and a concave
lens of different glass, which might have been made
merely for experiment; it was a matter of deep
study; and was a complete achromatic telescope,
founded on a thorough knowledge of the different
dispersive powers of crown and flint glass. It is a
curious circumstance, however, in the history of the
telescope, that this invention was actually lost. This
gentleman never published any account of his labours,
keeping them secret, no doubt, till he should be able
to present his instrument in a more perfect form to
the public; and it was till John Dolland had discovered the property of light upon which the instru.
ment depends, and had actually constructed some
very fine telescopes, that the previous labours of Mr.




SIR ISAAC NEWTON.
Hall were made public.     From   this period the
achromatic telescope underwent gradual improvement, and by the successive labours of several philosophers, it has become one of the most valuable
instruments in physical science.
Although the achromatic telescope, as constructed
by Dolland, was founded on the principle that the
spectra formed by crown and flint glass differed only
in their relative lengths, when the refraction of the
mean ray was the same, yet by a more minute examination of the best instruments it was found that
they exhibited white or luminous objects tinged on
one side with a green fringe, and on the other with.one of a claret colour. These colours, which did not
arise from any defect of skill in the artist, were discovered to arise from a difference in the extent of the
coloured spaces in two equal spectra formed by crown
and flint glass. This property was called the irratiot.,
aliy of the coloured spaces, and the uncorrected
colours which remain when the primary spectrum of
the crown glass was corrected by the primary spectrum
of the flint glass, were called the secondary or residual
spectrum. By a happy contrivance, which our limits
prohibit us from describing, the celebrated Dr. Blair
succeeded in correcting this secondary spectrum, or in
removing the green and claret coloured fringes which
appeared in the best telescopes previously, and to this
contrivance he gave the name of the Aplanatic
Telescope.
But, while these remarkable properties of the prismatic spectrum, as formed by different bodies, were
overlooked by Newton, he committed some considerable mistakes in his examination of the spectrum,
which was under his own immediate examination.
It does not appear to have occurred to him, that the
relations of the coloured spaces must be greatly modi.
fled by the angular magnitude of the sun or the luminos body, or aperture from which the spectrum is




B8


TIlE LIFE OP0


obtained; and, misled by an apparent analogy be.,
tween the length of the coloured spaces and the divisions of a musical chord, he adopted the latter, as
representing the proportion of the coloured spaces in
every beam of white light. "This result," says Newton in his Optics, " was obtained by an assistant
whose eyes were more critical than mine, and who,
by right lines drawn across the spectrum, noted the
confines of the colours. And this operation being
divers times repeated, both on the same and on several papers, I found that the observations agreed well
enough with one another." Had two other observers,
one situated in Mercury, and the other in Jupiter,
studied the prismatic spectrum of the sun by the same
instruments, and with the same sagacity as Newton,
it is evident that they would have obtained very different results. On account of the apparent magnitude
of the sun in Mercury, the observer there would obtain a spectrum entirely without green, having red,
orange, and yellow at one end, the white in the
middle, and terminated at the other end with blue and
violet. The observer in Jupiter would, on the contrary, have obtained a spectrum in which the colours
were much more condensed. On the planet Saturn, a
spectrum exactly similar would have been obtained,
notwithstanding the greater diminution of the sun's
apparent diameter. It may now be asked, which of
all these spectra are we to consider as exhibiting the
number, and arrangement, and extent of the coloured
spaces proper to be adopted as the true analysis of a
solar ray.
The spectrum of Newton has surely no claim to our
notice merely because it was observed on the surface
of the earth. The spectrum obtained in Mercury affords no analysis at all of the incident beam, the
colours being almost all compound and not homogeneous, and that of Newton is liable to the same objection. Had Newton examined his spectrum under th




SIR ISAAC NEWTON.


69


very same circumstances in winter and in summer, he
would have found the analysis of the beam more complete in summer, on account of the diminution of the
sun's diameter; and, therefore, we are entitled to say,
that neither the number nor the extent of the coloured
spaces, as given by Newton, are those which belong
to homogeneous and uncompounded light.
The spectrum obtained in Jupiter and Saturn is the
only one where the analysis is complete, as it is incapable of having its character altered by any further
diminution of the sun's diameter. Hence we are
forced to conclude, not only that the number and extent of the primitive homogeneous colours, given by
Newton, are incorrect; but that if he -had attempted
to analyse some of the primitive tints in the spectrum,
he would have found them decidedly composed of
heterogeneous rays.  There is one consequence of
these observations which is somewhat interesting. A
rainbow formed in summer when the sun's diameter is
least, must have its colours more condensed and homogeneous than in winter, when the size of its disc is a
maximum, and when the upper or under limb of the
sun is eclipsed, a rainbow formed at that time will
lose entirely the yellow rays, and have the green and
the red in perfect contact. For the same reason, a
rainbow formed in Venus and Mercury will be destitute of green rays, and have a brilliant bow of white
light separating two coloured arches, while in Mars,
Jupiter, Saturn, and the Georgian planet, the bow
will exhibit only four homogeneous colours.
From his analysis of the solar spectrum, Newton
concluded, "that to the same degree of refrangibility
ever belonged the same colour, and to the same
colour ever belonged the same degree of refrangibility;"
and from this he inferred, that red, orange, yellow,
green, blue, indigo, and violet, were primary and
simple colours. He admitted, indeed, that "the same
colours in specie, with those primary ones, may be




7                 THE LIFE O
also produced by composition.  For a mixture of
yellow and blue makes green, and of red and yellow
makes orange;" but such compound colours were
easily distinguished from the simple colours of the
spectrum by the circumstance, that they are always
capable of being resolved by the action of the prismr
into the two colours which compose them.
This view of the composition of the spectrum might
have long remained unchallenged, had we not been
able to apply to it a new mode of analysis. Though
we cannot separate the green rays of the spectrum
into yellow and blue by the refraction of prisms, yet
if we possessed any substance which had a specific
attraction for blue rays, and which stopped them in
their course, and allowed the yellow rays to pass, we
should thus analyse the green as effectually as if they
were separated by refraction. The substance which
possesses this property is a purplish blue glass, similar
to that of which finger-glasses are made. When we
view through a piece of this glass, about the twentieth
part of an inch thick, a brilliant prismatic spectrum,
we find that it has exercised a most extraordinary
absorptive action on the different colours which compose it. The red part of the spectrum is divided into
two red spaces, separated by an interval entirely
devoid of light. Next to the inner red space comes
a space of bright yellow, separated from the red by a
visible interval. After the yellow comes the green,
with an obscure space between them, then follows the
blue and the violet, the last of which has suffered little
or no diminution. Now it is very obvious, that in this
experiment the blue glass has actually absorbed the
red rays, which, when mixed with the yellow on one
side, constituted green, so that the insulation of the
yellow rays thus effected, and the disappearance of the
orange, and of the greater part of the green light,
proves beyond a doubt that the orange and green
colours in the spectrum are compound colours, the




SIR ISAAC NE1BWTON.


71


former consisting of red and yellow rays, and the latter
of yellow and blue rays of the very same refrangibility.
If we compare the two red spaces of the spectrum
seen through the blue glass with the red space seen
without the blue glass, it will be obvious that the red
has experienced such an alteration in its tint by the
action of the blue glass, as would be effected by the
absorption of a small portion of yellow rays; and from
this we conclude, that the red of the spectrum contains a slight tinge of yellow, and that the yellow
space extends over more than one-half of the spectrum,
including the red, orange, yellow, green, and blue
spaces.
" It has been found also," says a modern scientific
writer, "that red light exists in the yellow space,
and it is certain, that in the violet space, red light
exists in a state of combination with the blue rays.
From these and other facts, which it would be out of
place here to explain, I conclude, that the prismatic
spectrum consists of three different spectra, viz., red,
yellow, and blue, all having the same length, and all
overlapping each other. Hence, red, yellow, and blue
rays of the very same refrangibility co-exist at every
point of the spectrum; but the colour at any one
point will be that of the predominant ray, and will
depend upon the relative distance of the point from
the maximum ordinate curve which represents the
intensity of the light of each of the three spectra."
After explaining the structure of the spectrum by
means of a diagram, he proceeds, " At the red extremity of the spectrum, the pure red is scarcely
altered by the very slight intermixture of yellow and
blue. Farther on in the red space, the yellow makes
the red incline to scarlet.  It then exists in sufficient
quantity to form orange, and, as the red declines, the
yellow predominates over the feeble portion of red and
blue which are mixed with it. As the yellow dereases in intensity the increasing blue forms with it::: pr:A 00:;:, e::                       i 4400;:P000t~f;-.




72


THE LIFE OF


a good green, and the blue rising to its maximum
speedily overpowers the small portion of yellow and
red. When the blue becomes very faint, the red exhibits its influence in converting it into a violet, and
the yellow ceases to exercise a marked influence on
the tint. The influence of the red over the blue space
is scarcely perceptible, on account of the great intensity of the blue light; but we may easily conceive it
to reappear and form the violet light, not only from
the rapid decline of the blue light, but from the
greater influence of the red rays upon the retina.
" These views may perhaps be more clearly understood by supposing that a certain portion of white
light is actually formed at every point of the spectrum by the union of the requisite number of the
three coloured rays that exist at any point. The
white light thus formed will add to the brilliancy
without affecting the tint of the predominant colour.
In the violet space we may conceive the small portion
of yellow which exists there to form white light with
a part of the blue and a part of the red, so that the
remaining tint will be violet, composed of the blue
and the small remaining portion of red, mixed with
the white light. This white light will possess the remarkable property of not being susceptible of decomposition by the analysis of the prism, as it is composed of red, yellow, and blue rays of the very same
refrangibility. The insulation of this white light by
the absorption of the predominant colours I have
effected in the green, yellow, and red spaces, and by
the use of new absorbing media we may yet hope to
exhibit it in some of the other colours, particularly in
the brightest part of the blue space, where an obvious
approximation to it takes place.
Among the most important modenm discoveries
respecting the spectrum we must enumerate that of
fixed dark and coloured lines, which we owe to the
sagacity of Dr. Wollaston and Mr. Fraunhofer. Two




SIR ISAAC NEWTON.              73
or three of these lines were discovered by Dr. Wollaston, but nearly 600 have been detected by means of
the fine prisms and the magnificent apparatus of the
Bavarian optician. These lines are parallel to one
another, and perpendicular to the length of the spectrum. The largest occupy a space from five to ten
seconds in breadth. Sometimes they occur in welldefined lines, and at other times in groups; and in all
spectra formed from solar light, they preserve the
same order and intensity, and the same relative position to the coloured spaces, whatever be the nature of
the prism by which they are produced. Hence these
lines are fixed points, by which the relative dispersive
powers of different media may be ascertained with a
degree of accuracy hitherto unknown in this branch of
science. In the light of the fixed stars, and in that of
artificial flames, a different system of lines is produced,
and this system remains unaltered, whatever be the
nature of the prism by which the spectrum is formed.
The most important fixed lines in the spectrum
formed by light emitted from the sun, whether it is
reflected from the sky, the clouds or the moon, may
be easily seen by looking at a narrow slit in the window shutter of a dark room, through a hollow prism
formed of plates of parallel glass, and filled with any
fluid of a considerable despersive power. The slit
should not greatly exceed the twentieth of an inch,
and the eye should look through the thinnest edge of
the prism where there is the least thickness of fluid.
These lines I have found to be the boundaries of
spaces within which the rays have particular affinities
for particular bodies.
While Sir Isaac was examining the nature and
origin of colours as the component parts of white
light, his attention was directed to the curious subject
of the colour of thin plates, and to its application to
explain the colours of natural bodies. He communicated his earliest researches on the subject in his Dis



74


THE LIFE OP


course on Light and Colours, to the Royal Society, on
te 9th December, 1675, and they were read at subsequent meetings of that body. This discourse contained more particular details respecting the composition and decomposition of light, than he had previously
given in his letter to Mr. Oldenburg, and was eoneluded with nine propositions, showing how the colours
of thin transparent plates stand related to those of all
natural bodies.
The colours of thin plates appear to have been first
observed by the celebrated philosopher Mr. Boyle.
Dr. Hook who had lived with Mr. Boyle, as his assistant, afterwards studied them with some care, and
gave a correct account of the leading phenomena, as
exhibited in the coloured rings of soap bubbles, and
between plates of glass pressed together. He recognised that the colour depended upon some certain
thickness of the transparent plate, but he acknowledges that he had attempted in vain to discover the
relation between the thickness of the plate and the
colour which it produced.
Dr. Hooke succeeded in splitting a mineral substance called mica, into films of such extreme thinness
as to give brilliant colours. One plate, for example,
gave a yellow colour, another a blue colour, and the
two together a deep purple; but as plates which produced those colours were always so extremely thin —
less than the twelve thousandth part of an inch thick,
it was quite impracticable, by any contrivance yet discovered, to measure their thickness, and determine the
law according to what the colour varied with the
thickness of the film.  Newton surmounted this
difficulty by laying a double convex lens, the radius of
curvature of each side of which was fifty feet, upon
the flat surface of a plano-convex object glass where it
touched the plane surface, to a considerable thickness
at the circumference of the lens. When light was
allowed to fall upon the object glass, every different




SIR ISAAC NEWTON.


75


thickness of the plate of air between the object-glass
gave different colours, so that the point where the two
object-glasses touched one another was the centre of a
number of concentric coloured rings.  Now, as the
curvature of the object-glass was known, it was easy
to calculate the thickness of the plate of air at which
any particular colour appeared, and thus to determine
the law of the phenomena.
When the object-glasses are illuminated by white
light, the seven systems of rings, formed by all the
seven colours which compose white light, will be seen
at once. Had the rings in each colour been all of the
same diameter, they would all have formed brilliant
white rings, separated by dark intervals; but as they
have all different diameters, they will overlap one
another, producing rings of various colours by their
mixture. These colours, reckoning from the centre,
are as follows:1st Order.-Black, blue, white, yellow, orange,
red.
2nd Order.-Violet, blue, green, yellow, orange,
red.
3rd Order.-Purple, blue, green, yellow, red,
bluish-red.
4th Order.-Bluish-green, green, yellowish-green,
red.
5th Order.-Greenish-blue, red.
6th Order.-Greenish-blue, red.
Sir Isaac Newton deduces the phenomena thus
briefly described, that ingenious, though hypothetical
property of light, called its fits of easy reflexion and
transmission. This property consists in supposing
that every particle of light from its first discharge
from a luminous body possesses, at equally distant intervals, dispositions to be reflected from, and transmitted through, the surfaces of bodies upon which it
is incident. Hence if a particle of light reach a reflecting surface of glass when it is in its fit of relexian,




76            THE LIFE OF
or in its disposition to be reflected, it will yield
more readily to the reflecting force. Sir Isaac has
not ventured to inquire into the cause of this property, but we may form a very intelligible idea of it
by supposing that the particles of light have two attractive and two repulsive poles at the extremities of
two axis at right angles to each other, and that the
particles revolve round their axis, and at equi-distant
intervals, bring one or other of these axis into the
line of the direction in which the particle is moving.
If the attractive axis is in the line of the direction in
which the particle moves when it reaches the refracting surface, the particles will yield to the attractive
force of the medium, and be refracted and transmitted; but if the repulsive axis is in the direction of
the particle's motion when it reaches the surface, it
will yield to the repulsive force of the medium, and
be reflected from it.
If the thickness of the plate does not vary according to a regular law, but if, like a film of blown glass,
it has numerous inequalities, then the alternate fringes
of light and darkness will vary with the thickness of
the film, and throughout the whole length of each
fringe the thickness of the film will be the same.
We have supposed that the light employed is homogeneous. If it is white, then the differently coloured
fringes will form, by their superposition, a system of
fringes analogous to those seen between two objectglasses.
The same periodical colours which we have now
attempted to describe, as exhibited by thin plates,
were discovered by Newton in thick plates, and he
has explained them by means of the theory of fits;
but it would lead us far beyond our limits to enter
into any detail of his observations in this place, or to
give an account of the numerous and important additions which this branch of optics has received from the
discoveries of succeeding philosophers.
J




SIR ISAAC NEWTON.


77


If the objects of the material world had been illuminated with white light, observes the learned author
whom we have already noticed, all the particles of
which possessed the same degree of refrangibility, and
were equally acted upon by the bodies on which they
fall, all nature would have shone with a leaden hue,
and all the combinations of external objects, and all
the features of the human countenance, would have
exhibited no other variety but that which they possess
in a pencil sketch or a china-ink drawing. The rainbow itself would have dwindled into a narrow arch of
white light-the stars would have shone through a
grey sky-and the mantle of a wintry twilight would
have replaced the golden vesture of the rising and
setting sun. But He who has exhibited such matchless skill in the organization of material bodies, and
such exquisite taste in the forms upon which they are
modelled, has superadded that ethereal beauty which
enhances their more permanent qualities, and presents
them to us in the ever-varying colours of the spectrum.   Without this the foliage of vegetable life
might have filled the eye and. fostered the fruit which
it veils; but the youthful green of its spring would
have been blended with the dying yellow of its
autumn. Without this the diamond might have displayed to science the beauty of its forms, and yielded
to the arts its adamantine virtues; but it would have
ceased to shine in the chaplet of beauty, and to sparkle
in the diadem of princes. Without this the human
countenance might have expressed all the sympathies
of the heart; but "the purple light of love" would
not have risen on the cheek, nor the hectic flush been
the herald of its decay.
The gay colouring with which the Almighty has
decked the pale marble of nature, is not the result of
any quality inherent in the coloured body, or in the
particles by which it may be tinged, but is merely a
property of the light in which they happen to be
prop                                A




78:TE LIFE OF


placed. Newton was the first person who placed this
great truth in the clearest evidence. He found that
all bodies, whatever were their peculiar colours, exhibited these colours only in white light. When they
were illuminated by homogeneous red light, they appeared red, by homogeneous yellow light, yellow, and
so on;    their colours being most brisk and  ivid
under the influence of their own day-light colours."
The leaf of a plant, for example, appeared green in the
white light of day, because it had the property of
reflecting that light in greater abundance than any
other. When it was placed in homogeneous red light,
it could no longer appear green, because there was no
green light to reflect; but it reflected a portion of red
light, because there was some red in the compound
green which it had the property of reflecting. Had
the leaf originally reflected a pure homogeneous green,
unmixed with red, and reflected no white light from
its outer surface, it would have appeared quite black
in pure homogeneous red light, as this light does not
contain a single ray which the leaf was capable of
reflecting. Hence the colours of material bodies are
owing to the property which they possess of stopping
certain rays of white light, while they reflect or transmit to the eye the rest of the rays of which light is
composed.
So far the doctrine of Newton regarding colours is
capable of rigid demonstration; but its author was
not content with carrying it thus far: he sought to
- determine the manner in which particular rays are
stopped, while others are reflected or transmitted;
and the result of this profound inquiry was his theory
of the colours of natural bodies, which was communicated to the Royal Society on the 10th of February,
1675. This theory is, perhaps, the loftiest of all his
speculations; and though, as a physical generalization
it stands on a perishable basis, and must soon be
swept away in the progress of science, it yet bears




SIR ISAAC NEWTON..I


the deepest impress of the grasp of his powerful
intellect.
The principles upon which this theory is founded
are the following: —
1. Bodies that have the greatest refractive powers
reflect the greatest quantity of light; and at the conu
fines of equally refracting media there is no reflection,
2. The least particles of almost all natural bodies
are in some measure transparent.
3. Between the particles of bodies are many pores
or spaces, either empty or filled with media of less
density than the particles.
4. The particles of bodies and their pores, or the
spaces between the particles, have some definite size.
Upon these principles Newton explains the origin
of transparency, opacity, and colour.
Transparency he considers as arising from the particles and their intervals or pores being too small to
cause reflexion  at their common surfaces, so that all
the light which enters transparent bodies passes
through them without any portion of it being turned
from its path by reflexion.  If we could obtain, for
example, a film of mica, whose thickness does not
exceed two-thirds of the millionth part of an inch, all
the light which fell upon it would pass through it,
and none would be reflected. If this film was then
cut into fragments, a number of such fragments would
constitute a bundle, which would also transmit all the
light which fell upon it, and be perfectly transparent.
Opacity in bodies, he is of opinion, form an opposite cause, viz., when the parts of bodies are of such
a size as to be capable of reflecting the light which
falls upon them, in which case the light is "stopped
or stifled" by the multitude of reflexions.
The colours of natural bodies have, in the hypothesis of Newton, the same origin as the colours of
thin plates, their transparent particles, according to
their several sizes, reflecting rays of one colour, an




80                THE LIFE OF
transmitting those of another. "For if a thinned or
plated body which, being of an immense thickness,
appear all over of one uniform colour, should be slit
into threads, or broken into fragments of the same
thickness with the plate or film, every thread or fragment should keep its colour, and consequently a heap
of such threads should constitute a mass or powder
of the same colour which the plate exhibited before
it was broken: and the parts of all natural bodies
being like so many fragments of a plate, must, on the
same grounds, exhibit the same colour."
Such is the theory of the colours of natural bodies,
stated as clearly and briefly as we can. It has been
very generally admitted by philosophers, both of our
own and of other countries, and has been illustrated
and defended by a French philosopher of distinguished eminence. That this theory affords the true
explantion of certain colours, or, to speak more correctly, that certain colours in natural bodies are the
colours of thin plates, cannot be doubted; but it will
not be difficult to show that it is quite inapplicable to
that great class of phenomena which may be considered as representing the colours of natural bodies.
The first objection to the theory of Newton is the
entire absence of all reflected light from the particles
of transparent coloured media, such as coloured gems,
coloured glasses, and coloured fluids. This objection
was urged long ago by Mr. Delaval, a philosopher
of great repute, who placed coloured fluids on black
grounds, and never could perceive the least trace of
the reflected tints. Sir David Brewster repeated the
experiment with every precaution, and with every
variation that he could think of, and he considered it
as an established fact, that in such coloured bodies the
complementary reflected colour' cannot be rendered
visible. If the fluid, for example, be red, the green
light from which the red has been separated, ought to
appear either directly by looking into the coloured




SIRE ISAAC INEWYTON.


81


mass, or ought to be recognised by its influence in
modifying the light really reflected; but as it cannot
be seen, we must conclude that it has not been reflected, but has been destroyed by some other property
of the coloured body.
A similar objection may be drawn from the disappearance of the transmitted complementary colours,
in the leaves of plants and petals of flowers. It has
been ascertained from numerous experiments, that the
transmitted colour is invariably the same with the
reflected colour, and the same holds true with the
coloured juices expressed from them. The complementary tints are never seen, and when there has
been anything like an approximation of two tints, it
has been invariably found that it arose from there
being two coloured juices existing in different sides of
the leaf.
In the phenomena of the light transmitted by
coloured glasses, there are some peculiarities which
we think demonstrate that their colours are not those
of thin plates. The light, for example, transmitted
through a particular kind of blue glass, has a blue
colour of such a peculiar composition, that there is no
blue in any of the orders of colours in'thin plates
which has any resemblance to it. It is entirely destitute of the red rays which form the middle of the
red space in the spectrum; so that the particles on
which the colour depends must reflect the middle
red rays, and transmit those on each side of it-a
property which cannot be deduced from the doctrine
of Newton.
The explanation of opacity, as arising from a multitude of reflexions, is liable to the same objection
which we have urged against the explanation of
colour. In order to appreciate its weight, we must
distinguish opacity into two kinds, namely, the opacity
of wuiteness, and the opacity of blackness. Thow
F




82                 THE LIFE OF
bodies which possess the power of reflexion in the
highest degree, such as white metals, chalk, and
plaster of Paris, never reflect more than one half of
the light which falls upon them. The other half of
the incident light is, according to Newton, lost by a
multitude of reflexions. But how is it lost? Reflexion merely changes the direction of the particles
of light, so that they must again emerge from the
body, unless they are reflected into fixed returning
orbits, which detain them for ever in a state of motion within the body. In the case of black opacity,
such as that of coal, which reflects from its first
surface only onie twenty-fifth of the white light, the
difficulty is still greater, and we cannot conceive how
any system of interior reflexions could so completely
stifle 24-25ths of the whole incident light, without
some of it returning to the eye in a visible form.
In determining the constitution of bodies that produces transparency and blackness, the theory of
Newton encounters a difficulty which its author has
by no means surmounted. Transparency, as we have
already seen, arises from the "particles and their interstices being too small to cause reflexions in their
common surfaces," that is, they must be "less than
any of those which exhibit colours," or " less than is
requisite to reflect the white and very faint blue of
the first order." But this is the very same constitution
which produces blackness by reflexion, and in order
to explain the cause of blackness by transmission, or
black opacity, Newton is under the necessity of introducing a new principle.
" For the production of black," says he, " the corpuscles must be less than any of those which exhibit
colours. For at all greater sizes there is too much
light reflected to constitute this colour. But if they
be supposed a little less than is requisite to reflect the
white and very faint blue of the first order, they will
reflect so very little light as to appear intensely black,




SIR ISAAC NEWTON.


83


and yet may perhaps variously refract it to and fro
within themselves so long, until it happens to be
stifled and lost, by which means they will appear
black in all positions of the eye, without any transparency."  In the same paragraph, when speaking
of black bodies becoming hot, and burning sooner
than others, he says that their " effect may proceed
partly from the multitude of refractions in a little
room, and partly from the easy commotion of so very
small corpuscles."
This very remarkable pasage in his "Optics" exhibits, in a striking manner, the perplexity in which
our philosopher was involved by the difficulties of his
subject.  As the particles which produce blackness
by reflexion are necessarily so small as to exclude the
existence of any reflective forces, he cannot ascribe the
loss of the intromitted light, as he does in the case of
white opacity, to a "multitude of reflexions;" and,
therefore, he is compelled to have recourse to refracting forces to perform the same office. The reluctance
with which he avails himself of this expedient, is well
marked in the mode of expression which he adopts;
and it is almost certain that when he wrote the above
passage, he felt the full force of the objections to this
hypothesis, which cannot fail to present themselves
to every discriminating reader. As the size of the
particles which produce blackness are intermediate
between those which produce transparency and those
which produce colour, approaching closely to the latter,
it is difficult to conceive why they should refract the
intromitted light, while the greater and smaller particles, and even those almost of the same size, should
be destitute of that property. It is besides not easy
to understand how a refraction can take place within
bodies which shall stifle all the light, and prevent it
from emerging. Nay, we may admit the existence of
such refractions and yet understand how, by a com



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pensation in their direction, the refracted rays may all
emerge from the opaque body.
The force of these objections is tacitly recognized
in Pemberton's View of Sir Isaac Newton's Philosophy; and as Newton not only read and approved
of that work, but even perused a great part of it
along with its author, we may fairly consider the
opinion there stated to be his own.
"For producing black, the particles ought to be
smaller than for exhibiting any of the colours, viz., of
a size answering to the thickness of the (soap) bubble,
whereby reflecting little or no light it appears colourless; ' but yet they must not be too small,' for that
will make them transparent ' through deficiency of reflexions' in the inward parts of the body, sufficient to
stop the light from going through it; but they must
be of a size 'bordering upon that' disposed to reflect
the faint blue of the first order, which affords an evi-.
dent reason why blacks usually partake a little of that
colour." In this passage all idea of refraction has
been abandoned, and that precise degree of size is
assumed for the particles which leave a small power
of reflexion, which is deemed sufficient to prevent the
body from becoming transparent; that is, sufficient to
render it opaque or black.
The last objection which we shall state to this
theory is one to which we attach great weight, and,
as it is founded on discoveries and views which have
been published since the time of Newton, we venture
to believe, that, had he been aware of them, he would
never have proposed the theory which is now under
consideration.
When light falls upon a thin film so as to produce
the colours of thin plates, it follows, from Sir Isaac
Newton's theory of fits, that a portion of the light is,
as usual, reflected at the first surface, while the light
that forms the coloured image is that which is reflected
from the second surface, so that all the colours of thin




SIR ISAAC NEWTON.


85


plates are diluted with the white light reflected from
the first surface. Now, in the modern theory, which
ascribes the colours of thin plates to the interference
of the light reflected from the second surface, with
the light reflected from the first surface, the resulting tint arises from the combination of these two
pencils, and, consequently, there is no light reflected
from the first surface.  In like manner, when the
thickness of the film is such, that the two interfering
pencils completely destroy one another, and produce
black, there is not a ray of light reflected from the
first surface.  Here, then, we have a criterion for
deciding between the theory of fits and the theory of
interference; for if there is no white light reflected
from the first surface, the theory of fits must be rejected.  In a remarkable phenomenon of blackness
arising from minute fibres, there was no perceptible
reflexion from  the surface of the fibres; and M.
Fresnel describes an experiment made to determine
the same point, and states the result of it to have been
unequivocally in favour of the doctrine of interference.
In order to apply this important fact, let us take a
piece of coal, one of the blackest and most opaque of
all substances, and which does not reflect to the eye a
single ray out of those which enter its substance.
The size of its particles is so small, that they are incapable of reflecting light. When a number of these
particles are placed together, so as to form a surface,
and other particles behind them so as to form a solid,
they will not acquire by this process the power of reflexion; and, consequently, a piece of coal so composed should be destitute of the property of reflecting
light from its first surface.  But the reverse is the
case-light is abundantly reflected from the first surface of the coal, and, of course, its elementary particles must possess the same power.    Hence the




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blackness of coal must be ascribed to some other cause
than to the minuteness of its transparent atoms.
To transparent bodies this argument has a similar
application.  As their atoms are still less than those
of black bodies, their inability to reflect light is still
greater, and hence arises their transparency.  But
the particles forming the surface of such bodies do
reflect light, and, therefore, their transparency must
have another origin.
In the case of coloured bodies, too, the particles
forming their surfaces reflect white light like those of
all other bodies, so that these particles cannot produce
colour on the same principles as those of thin plates.
In many of those cases of colour which seem to depend upon the minuteness of the particles of the body,
the reflexion of white light may nevertheless be observed, but this will be found to arise from a thin
transparent film, behind which the colorific particles
are placed.




SIR ISAAC NEWTON.


sr


CHAPTER IY.
New Classification of Colours. Outline of a New Theory.  Newton's
Discoveries respecting the Inflexion or Diffraction of Light. Previous
Discoveries. Labours of succeeding Philosophers. New Theory of
Inflexion. Miscellaneous Optical Researches of Newton.  Experi.
ments on Refraction.  Conjecture respecting the Inflammability of
the Diamond. Law of Double Refraction.  Observations on the Po.
larization of Light. Newton's Theory of Light.  His " Optics."
Astronomical Discoveries.  Sketch of the History of Astronomy previous to the time of Newton.
WHATEVER      answer may be made to         the previous
objections, we think it will be admitted by all those
who have studied the subject most profoundly, that a
satisfactory theory of the colours of natural bodies
is still a desideratum in science.  How far we may be
able to approach it in the present state-of optics, the
reader will judge from the following views.
Colours may be arranged into seven classes, each
of which depends upon different principles.
1.   Transparent coloured fluids-transparent coloured gems-transparent coloured glasses-coloured
powders-and the colours of the leaves and flowers of
plants.
2.   Oxidations of metals-colours        of Labrador
feld-spar-colours of precious and hydrophanous opal,
and other opal essences-the colours of the feathers of
birds, of the wings of insects, and of the scales of
fishes.
8.   Superficial colours, as those of mother of pearl
and striated surfaces.
4. Opal essences and colours in composite crystals
having double refractions.




$8


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5. Colours from the absorption of common and
polarized light by double refracting crystals.
6. Colours at the surfaces of media of different
dispersive powers.
7. Colours at the surface of media in which the
reflecting forces extend to different distances, or follow
different laws.
The two first of these classes are the most important. The Newtonian theory appears to be strictly
applicable to the phenomena of the second class; but
those of the first class cannot, we conceive, be referred
to the same cause.
The rays of solar light possess several remarkable
physical properties: They heat-they illuminatethey promote chemical combination-they effect chemical decompositions-they impart magnetism to steelthey alter the colours of bodies-they communicate to
plants and flowers their peculiar colours, and are in
many cases necessary to the development of their
characteristic qualities. It is impossible to admit for
a moment that these varied effects are produced by a
mere mechanical action, or that they arise from the
agitation of the particles of bodies by the vibration of
ether which is considered to be the cause of light.
Whatever be the difficulties which attach to the
theory which supposes light to consist of material
particles, we are compelled, by its properties, to admit
that light acts as if it were material, and that enters
into combinations with bodies, in order to produce
the effects which we have enumerated.
When a beam of light falls upon a body, and the
'whole or a part of that which enters its substance totally disappears, we are entitled to say, that it is detained by some power exercised by the particles of the
body over the particles of light. When this light is
said to be lost by a multitude of reflexions or refractions, the statement is not only hypothetical, but it is
a hypothesis incompatible with optical principles.




SIR ISAAC NEWTON.              8^
That the light detained within bodies has been stopped
by the attractive force of the particles seems to be
highly probable, and the mind will not feel any repugnance to admit that the particles of all bodies,
whether solid, fluid, or aeriform, have a specified affinity for the particles of light.  Considering light,
therefore, as material, it is not difficult to comprehend
how it should, like other elementary substances, enter
into combination with bodies, and produce many
chemical and physical effects, but particularly the
phenomena of transparency, opacity, and colour.
In transparent colourless bodies, such as water and
glass, the intromitted light experiences a considerable
loss, because a certain number of its particles are attracted and detained by the atoms of the water and
glass, and the light which emerges is colourless, because the particles exercise a proportional action over
all the simple colours which compose white light.
When the transparent body has any decided colour,
such as those ennumerated in Class I., then the particles of the body have exercised a specific attraction
over those rays of white light which are complementary
to those which compose the colour of the transmitted
light. If the transparent body, for example, is red,
then its particles have detained the green rays which
entered into the incident light, or certain other rays,
which, with the red, are necessary to compose white
light. In compound bodies, like some of the artificial
glasses, the particles will attract and detain rays of
light of different colours, as may be seen by analysing
the transmitted light with a prism, which will exhibit
a spectrum deprived of all the rays which have been
detained. In black bodies the particles exercise a
powerful attraction over light, and detain all the intromitted rays.
When coloured bodies are opaque, so as to exhibit
their colours principally by reflexion, the light which
is reflected back to the observer has received its colour




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from transmission through part of the thickness of the
body, or, what is the same thing, the colour reflected
to the eye is complementary to that which has been
detained by the particles of the body while the light
is passing and re-passing through a thickness terminated by the reflecting surfaces; and as only part of
this light is reflected, as in the case of leaves and
fowers, the transmitted light must have the same
colour as the reflected light.
When coloured bodies exhibit two different colours
complementary to each other, the one seen by reflexion
and the other by transmission, it is then highly probable that the colours are those of thin plates, though
there are still other optical principles to which they
may be referred. As the particles of bodies, and the
medium which unites them, or, as the different atoms
of a compound body may have different dispersive
powers, while they exercise the same refractive force
ala; particular part of the spectrum, the rays for
which 'this compensation takes place will be transmitted, while. part of the complementary light is refeeted. Or in cases where the refractive and dispersive powers are the same, the reflective forces of the
particles may vary according to a different law, so that
at the separating surfaces either white or coloured
light may be reflected.
-I:  those cases of colour where the reflected and the
trimitted tints are not complementary, as in leaf
goli;where the former is yellow and the latter green;
inllf-silver, where they are white and blue, and in
certiia pieces of fir-wood, where the reflected light is
whitish yellow, and the transmitted light a brilliant
homogeneous red, we may explain the separation of
the colours either by the principles we have already
laid down, or by the doctrine of their plates. On the
first principle, the colour of the reflected light, which
is supposed to be the same as that of the transmitted
light,,will be modified by the law according to which




SIR ISAAC NEWTON.              91
the particles of the body attract differt rays out of
the beam of white light.  In pitch, forexample, the
blue rays are first absorbed, so that at small thicknesses the transmitted light is a fine yellow, while, by
the action of greater thickness, the yellow itself is
absorbed, and the transmitted light is a bright homogeneous red. Now, in leaf-gold the transmitted colour
of thinner films than we can obtain may be yellow,
and, consequently, the light reflected from the first
strata of interrupting faces will be yellow, and will
determine the predominate tint of the reflected light.
On the Newtonian doctrine Mr. Herschel has explained
it by saying " that the transmitted rays have traversed
the whole thickness of the medium, and therefore
undergo many more times the action of its atoms than
those reflected, especially those near the first surface
to which the brighter part of the reflected colour is
due."
The phonomena of the absorption of common and
polarized light, which have been described by Sir
David Brewster in the Philosophical Transactions,
throw considerable light on the subject of coloured
bodies. The relation of the absorbenVt.4ion to the
axis of double refraction, and Iconseqt.t   to the
poles of the molecules of the crystal, show:how the
particles of light attracted by the molecules of the
body will vary, both in their nature and nufber,
according to the direction in which they approach the
molecules; and explains how the colour of a body may
be changed, either temporarily or permanently, by
heat, according as it produces a temporary or a permanent change in the relative position of the moleetd.
This is not the proper place to enlarge on the aubject;
but we may be permitted to apply the ide- to the
curious experiment of M. Thenard, on phosphorus.
When this substance is rendered pure by roeated
distillation, it is transparent, and trandasmti:yelow
light; but when it is thrown in a melted sff  into




:; '                    '..; 8.,  '  4:
ArTHE              Ij49OF
ater, itirmestjeti   ack. When again melted,
resumes its^inal colour and transparency. According to the theory of Newton, we must suppose
that the atoms of the phosphorus have been diminished
in size by sudden cooling-an effect which it is not
easy to comprehend; but, according to the preceding
views, we mayosuppose that the atoms of the phospPus have been forced by sidden. cooling into relaftivesitions quite diffeteiC frormtthose which they
take when they sl6wly assume the solid state; and
their poles of maximum attraction, in place of being
turned to one another, are turned in different directions, and then allowed to exercise their full action in
attracting the intromitted light, and detaining it wholly
without the body. If this view of the matter be just,
we should expect that the specific gravity of the black
would exceed that of the yellow.
Before concluding this portion of our subject, there
is one topic peculiarly observing our notice, namely,
the change of colour produced in bodies by continued
exposure to light. The general effect of light is to
diminish or dilute the colours of bodies, and in many
cases to deprive them entirely of their colour. Now,
it is not easy to understand how repeated undulations
propagated through a body could diminish the size of
its particles, or how the same effect could be produced
by a multitude of reflexions from particle to particle.
But if light is attracted by the particles of bodies,
and combines with them, it is easy to conceive, that
when the molecules of a body have combined with a
great number of particles of a green colour, for example, their power of combination with others will be
diminished, and, consequently, the number of particles
of any colour absorbed or detained must diminish with
the time that the body has been exposed to the light;
that is, these particles must enter into the transmitted
and reflected pencils, and diminish the intensity of
their colour. If the body, for example, absorbs red




SIR ISAAC NEtON..
ight, and transmits and reflecgreethen, if the
quantity of absoibed.red light l  diminishedit will,i;
enter into the reflect6did tra'rnietted pencils4i/nd,
forming white light-b'yLtsztixture with a portiot-:of
the green rays, will actuitlr dilute them in the same
manner as if a portion of white light had been
added.
Although the discoveries of Sir Isaac Newton respecting the INFLEXION OF LIGHT were first published
in his OPTICS in 1704, yet there are many reasons to
conclude that they were made at a much earlier period.
He, indeed, informs us, in his preface to that great
work, that the third book, which contains these discoveries, "was put together out of scattered papers;"
and he adds at the end of his observations,4that " he
designed to repeat most of them with more care and
exactness, and to make some new ones for determining
the manner how the rays of light are bent in their
passage by bodies, for making the fringes of colour
with the dark lines between them. But I was then
interrupted, and cannot now think of taking these
things into consideration."  On the 18th of March,
1674, Dr. Robert Hooke had read a valuable paper
on the phenomena of diffraction; and, as Sir Isaac
makes not the slightest allusion to this work, it is the
more probable that his " scattered papers" had been
written previous to the communication of Dr. Hooke's
experiments.
The phenomena of the inflexion of light were first
discovered by Francis Maria Grimaldi, a learned Jesuit,
who has fully described them in a posthumous work,
published in 1665, two years after his death.
Having admitted a beam of the sun's light through
a small pin-hole in a piece of lead or card into a dark
chamber, he found that the light diverged from this
aperture in the form of a cone, and that the shadows
of allbodies placed in this light were not only larger
than might have been expected, but were surrounded




94                THE LIFE OF
with three  loured fringes, the nearest being the
widest, and  e most remote the narrowest. In strong
light he discovered analogous fringes within the shadows of bodies, which increased in number with the
breadth of the body, and became more distinct when
the shadow was received obliquely and at a greater
distance.  When two small apertures or pin-holes
were placed so near each other that the cones of light
formed by each of them intersected on another, Grimaldi observed, that a spot common to the circumference of each, or, which is the same thing, illuminated
by rays from each cone, was darker than the same
spot when illuminated by either of the cones separately;
and he announced this remarkable fact in the following apparently absurd proposition:-" That a body
actually illuminated may become more dark by adding
a light to that which it already receives."
Without being aware of what had been done by the
Italian philosopher, Dr. Hooke had been diligently
occupied with the same subject. In 1672, he communicated his first observations to the Royal Society, and
he then spoke of his paper as "containing the dis-.
covery of a new property of light not mentioned by
any optical writers before him." In his paper of 1764,
already mentioned, and which is, no doubt, the one to
which he alludes, he has not only described the leading phenomena of the inflexion, or the deflexion of
light, as he calls it, but he has distinctly announced
the doctrine of interference, which has performed so
conspicuous a part in the subsequent history of optics.
He thus announces this doctrine.  1st. That the same
rays of light falling upon the same point of an object
will turn into all sorts of colours by the various
inclinations of the object.   2nd.  That colours
begin to appear when two pulses of light are blended
so well and so near together that the sense takes them
for one.
Such was the state of the subject when Newton di



SIR ISAAC NEWTON.


95


rected to it his powers of acute and accurate observation.  His attention was turned only to the enlargement of the shadow, and to the three fringes which stirrounded it; and he begins his observations by ascribing the discovery of these facts to Grimaldi. After
taking exact measures of the diameter of a human
hair, and of the breadth of the fringes at different distances behind it, he discovered the remarkable fact
that these diameters and breadths were not proportional to the distances from the hair at which they
were measured. In order to explain this phenomena,
Newton supposed that the rays which passed the edge
of the hairs are deflected or turned aside from it, as if
by a repulsive force, the nearest rays suffering the
greatest, and those more remote a less degree of deflexion.
The explanation given by Sir Isaac of the coloured
fringes is less precise, and can be inferred only from
the two following queries.
1. " Do not the rays which differ in refrangibility
differ also in flexibility, and are they not by these different inflexions separated from one another, so as after
separation to make the colours in the three fringes above
described? And after what manner are they inflected
to make those fringes.
2. "Are not the rays of light in passing by the
edges and sides of bodies bent several times backwards and forwards with a motion like that of an
eel?  And do not the three fringes of light above
mentioned arise from three such bendings?"
The idea thus indistinctly thrown out in the preceding queries has been ingeniously interpreted by
Mr. Herschel, who supposes that the rays undergo
several bendings, and the particles of light are thrown
off at one or other of the points of contrary flexure,
according to the state of their fits or other circumstances. Those that are thrown outwards will produce as many caustics by their intersections as there




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are deflected rays, and each caustic, when received on
a screen at a distance, will depict on it the brightest
part of a maximum of a fringe.
In this unsatisfied state was the subject of the
inflexion of light left by Sir Isaac Newton.  His
inquiries were interrupted and never again renewed;
and though he himself found that the phenomena
were the same, "whether the hair was encompassed
with air or with any other pellucid substance," yet
this important result does not seem to have shaken
his conviction, that the phenomena had their origin
in the action of bodies upon light.
During two sets of experiments which Sir David
Brewster made on the inflexion of light, the first in
1798, and the second in 1812 and 1813, he was desirous of examining the influence of density and refractive power over the fringes produced by inflexion. He
compared the fringes formed by gold leaf with those
formed by masses of gold-and those produced by
films which gave the colours of thin plates with those
formed by masses of the same substance. He examined the influence of platinum, diamond, and cork,
in inflecting light, the effect of non-reflecting grooves
and spaces in polished metals, and of cylinders of
glass immersed in a mixture of oil of cassia and oil of
olives of the same refractive power, and, as the
fringes had the same magnitude and character under
all these circumstances, he concluded that they were
not produced by any force inherent in the bodies
themselves, but arose from a property of the light
itself, which always showed itself when light was
stopped in its progress.
Dr. Thomas Young, who had supported with considerable ingenuity and great force of argument the
undulatory theory of light, as maintained by Hooke
and Huygens, was the first who gave a plausible
explanation of the inflexion of light. By interposing
a small screen, and intercepting the rays that passed




SIR ISAAC NEWTON.


o9


near the hair, he was surprised to find that all the
fringes within the shadow disappeared. The same
effect took place when the screen intercepted the rays
on the other side; and hence he concluded, that the
rays on each side of the hair were necessary to the production of the inner fringes, and that the fringes were
produced by the interference of the rays that passed
on the one side of the hair with those that passed on
the other side. In order to account for the coloured
fringes without the shadow, Dr. Young conceived
that the rays which pass near the edge of the hair interfere with others, which he supposes may be reflected
after falling very obliquely upon its edge-a supposition which, if correct, would certainly produce fringes
very similar to those actually observed.
In pursuing these researches so successfully begun
by Dr. Young, M. Fresnel had the good fortune to
explain all the phenomena of inflexion by means of
undulatory doctrine combined with the principle of
interference.  In place of transmitting the light
through a small aperture, he caused it to diverge from
the focus of a deep convex lens, and, instead of receiving the shadow and its fringes upon a smooth
white surface as was done by Newton, he viewed
them directly with his eye through a lens placed
behind the shadow; and by means of a microscope
he was able to measure the dimensions of the fringes
with the greatest exactness. By this mode of observation he made the remarkable discovery, that the
inflexion of the light depended on the distance of the
inflecting body from the aperture or from the focus
of divergence, the fringes being observed to dilate as
the body approached that focus, and to contract as it
receded from it, their relative distances from each
other, and from the margin of the shadow continuing
invariable. In attempting to account for the formation of the exterior fringes, M. Fresuel found it necesG




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sary to reject the supposition of Dr. Young, that they
were owing to light reflected from the edge of a body.
He not only ascertained that the real place of the
fringe was the seventeenth hundredth of a millimetre
different from what it should be on that supposition,
but he found that the fringes preserved the same intensity of light, whether the inflecting body had a
round or a sharp edge, and even when the edge was
such as not to afford sufficient light for their production.  From  this difficulty the undulatory theory
speedily released him, and he was led by its indications to consider the exterior fringes as produced by
an infinite number of elementary waves of light
emanating from a primitive wave when partly interrupted by an opaque body.
The various phenomena of inflexion, which had so
long resisted every effort to generalize them, having
thus received so beautiful and satisfactory an explanation from the undulatory doctrine, they must of
course be regarded as affording to that doctrine the
most powerful support, while the Newtonian hypothesis of the materiality of light, is proportionally
thrown into the shade. It is impossible, indeed, even
for national partiality, to consider the views of Newton
as furnishing any explanation of the facts discovered
by Fresnel, and, as no attempt has been made by the
small, though able phalanx of his disciples, to stay the
decision with which, on this account at least, the doctrine of emission has been threatened;-we shall
venture to suggest some principles by which the refracting phenomena may perhaps be yet brought
within the poles of the Newtonian theory.
That the particles of light, like those of heat, are
endowed with a repulsive force, which prevents them
from accumulating, when in a state of condensation,
or when they are detained by the absorptive action of
opaque bodies, will be readily admitted. By this
power, a beam of light radiating from a luminous




SIR ISAAC NEWTON.              99
point, has, in every azimuth, the same degree of intensity at the same distance from its centre of divergence; but if we intercept a portion of such a beam by
an opaque body, the repulsive force of the light which
formerly occupied its shadow, is withdrawn, and consequentlythe rays which pass near the body, will be repelled into the shadow, and will form by their interference
with those similarly repelled on the other side, the
interior fringes, which are parallel to the edge of the
body. The rays which pass at a greater distance, will
in like manner be bent towards the body, but with
less force, and interfering with those rays which retain
their primitive direction, from the state of their fits,
or the position of their poles, they will form the exterior fringes. When the inflecting body is placed
near the point of divergence, the greater proximity of
the rays will produce a greater repulsive force, and
consequently, a greater inflexion of the passing light;
while the removal of the body from the point of divergence, will be accompanied with an increased
distance of the particles-an inferior repulsive force
and a feebler inflexion. As the phenomena of inflexion, considered under this aspect, arise from  a
property of the light itself, it follows that they will
remain invariable, whatever be their nature or density
of the body, or the form of the edge which acts upon
the passing rays.
Before concluding our account of Sir Isaac Newton's
optical discoveries, it is necessary to notice some of his
minor researches which, though of inferior importance
in the science of light, have exercised an influence over
the progress of discovery, or been associated with the
history of other branches of knowledge.
One of the most curious of these inquiries related
to the connection between the refractive powers and
the chemical composition of bodies. Having measured the refractive powers and the densities of twentytwo substances, he found that the forces which reflect




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THIE LIFE OF


and refract light are very nearly proportional to the
densities of the same bodies. In this law, howeveri
he noticed a remarkable exception in the case of unctuous and sulphureous bodies, such as camphor, olive
oil, linseed oil, spirits of turpentine, and diamond,
which have their refractive powers two or three times
greater in respect of their densities than the other substances in the table, while among themselves their refractive powers are proportional to their densities,
-without any considerable variation. Hence he concluded that diamond " is an unctuous substance coagulated,"-a sagacious prediction, which has been since
verified in the discoveries of modern chemistry. The
connection between a high degree of inflammability,
and a great refracting force, has been still more strongly
established by the high refractive power which has
been detected in phosphorus, and which was discovered
in hydrogen by M. M. Biot and Arago.
There is no part of the optical labours of Newtoi
which is less satisfactory than that which relates to
the double refraction of light. In 1690 Huygens published his admirable treatise on light, in which he has
given the law of double refraction in calcareous spar,
as deduced from his theory of light, and as confirmed
by direct experiment. Viewing it probably as a theoretical deduction, Newton seems to have regarded it
as incorrect; and though he has given Huygens the
credit of describing the phenomena more correctly than
Bartholinus, yet, without assigning any reason, he rejected the law of the Dutch philosopher, and substituted another its place.  These observations of Sir
Isaac form the subject of the twenty-fifth and twentysixth queries at the end of his Optics, which was published fourteen years after the appearance of Huygen's
work. The law adopted by Newton is not accompanied with any of the experiments from which it was
deduced; and though he has given it without expressing any doubt of its accuracy, it is, nevertheless




SIR ISAAC NEWTON.


101


eutirely incompatible with observation, and has been
rejected by all succeeding philosophers.
In his speculations respecting the successive disappearance and re-appearance of two of the four images
which are formed when a luminous object is viewed
through two rhombs of calcareous spar, one of which
is made to revolve upon the other, Newton has been
more successful. He concluded from these phenomena
that every ray of light has two opposite sides originally
endued with the property, on which the universal
refraction depends, and other two opposite sides not
endued with that property, and he suggested it as a
subject for further inquiry, whether there are not more
properties of light by which the sides of the rays differ,
and are distinguished from one anothor. This is the
first occasion on which the idea of polarity in the rays
of light has been suggested.
From the various optical inquiries in which Newton was engaged he was strongly impressed with the
belief that light consists of small material particles
emitted from shining substances, and that these particles could again be combined into solid matter, so
that " gross bodies and light were convertible into one
another." He conceived also that the particles of solid
bodies and of light exerted a mutual action upon each
other, the former being agitated aud heated by the
latter, and the latter being attracted and repelled by
the former, with forces depending on the inertia of
the luminous particles. These forces he regarded as
insensible at all measurable distances, and he conceived
that the distances between the particles of bodies was
very small when compared with the extent of their
sphere of attraction and repulsion.
With the exception of Hooke, Huygens, and Euler,
almost all the contemporaries and successors of Newton maintained the doctrine of the materiality of light.
It was first successfully assailed by Dr. Thomas
Young, and since that time it has been shaken to its




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foundation by those great discoveries which have illustrated the commencement of the present century.
The undulatory theory which has triumphed in its
turn, is still subject to grave difficulties, and we fear
another century must elapse before a final decision can
be pronounced on this long disputed question.
The most important of the optical discoveries of
Newton, of which we have given a general history,
were communicated to the Royal Society in detached
papers; but the numerous disputes in which they had
involved their author, made him hesitate about the
publishing of his other discoveries. Although he had
drawn up a connected view of his labours, under the
title of " Optics, or a Treatise on the Reflexions,
Refractions, Inflexions, and Colours of Light," yet
he formed the resolution of not publishing this work
during the life of Hooke, by whose rival jealousy his
tranquillity had been so frequently interrupted.
IHooke, however, died in 1702, and the Optics of
Newton appeared in English in 1704. Dr. Samuel
Clark proposed a Latin edition of it, which accordingly
appeared in 1706, and he was generously presented by
Sir Isaac with ~500, (as a gift of ~100 each for his
five children,) as a token of the approbation and gratitude of the author. Both the English and Latin
editions have been frequently reprinted both in England and on the Continent, and there perhaps never
has been a work of profound science so widely circulated.
From the optical labours of Sir Isaac Newton, we
will now proceed to his astronomical discoveries-i
those transcendant deductions of human reason by
which he has secured to himself an immortal name,
and vindicated the intellectual dignity of his species.
Pre-eminent as his triumphs have been, it would be
unjust to affirm that they were achieved by himself
alone. The torch of many a preceding age had thrown
its light into the strongholds of the material universe,




SIR ISAAC NEWTON.


103


and the grasp of many a powerful hand had pulled
down the strongest of its defences. An alliance, indeed, of many kindred spirits had been long struggling
in this great cause, and Newton was only the leader
of this glorious band-the fortunate general who won
the victory, and therefore wears its laurels.
The history of science presents us with no example
or an individual mind throwing itself far in advance
of its contemporaries.  It is only in the career of
crime and ambition that reckless man takes the start
of his species, and, uncurbed by moral and religious
restraint, erects an unholy dynasty upon the ruins of
ancient and venerable institutions. The achievements
of intellectual power, though often begun by one mind
and completed by another, have ever been the results
of combined exertions. Slow in their growth, they
gradually approximate to a more perfect condition;the variety in the phenomena of nature call forth a
variety of intellectual gifts;-the powers of analysis
and combination are applied to the humbler labours
of observation and experiment, and in the ordeal of
rival inquiry truth is finally purified from error. How
different is it with those systems which the imagination rears-those theories of wild import which are
directed against the consciences and hopes of man.
The fatal upas tree distils its poison in the spring as
well as in the autumn of its growth, but the fruit
which sustains life must have its bud prepared before
the approach of winter, its blossom expanded in the
spring, and its juices elaborated by the light and the
heat of the summer and the autumnal sun.
In the century which preceeded the birth of Newton, the science of astronomy advanced with the most
rapid strides.  Emerging from the darkness of the
middle ages, the human mind seemed to rejoice in its
new-born strength, and to apply itself with elastic
vigour to unfold the mechanism of the heavens. The
labours of Hipparchus and Ptolemy had indeed fur



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nished many important epochs and supplied many
valuable data; but the cumbrous appendages of cycles
and epicycles with which they explained the stations
and retrogadations of the planets, and the vulgar
prejudice which a false interpretation of Scripture had
excited against a belief in the motion of the earth,
rendered it difficult even for great minds to escape
from the trammels of authority, and appeal to the
simplicity of nature.
The generous and noble-minded sovereign of Castile,
Alphonso, had long before proscribed the rude expedients of his predecessors; and when he declared that.
if the heavens were thus constituted, he could have
given the Deity good advice, he must not only have
felt the absurdity of the prevailing system, but must
have obtained some foresight of a more simple arrangement. But neither he nor the astronomers whom he
so liberally patronised seem to have established a:
better system, and it was left to Copernicus to enjoy
the dignity of being the restorer of astronomy.
This eminent man, a native of Thorn, in Prussia,
following his father's profession, began his career as a
Doctor of Medicine, but an accidental attendance on
the mathematical lectures of Brudzevius excited a love
for astronomy, which became the ruling passion of his
life. Quitting a profession uncongenial to such pursuits, he went to Bologna to study astronomy under
Dominic Maria, and after having enjoyed the friendship and instruction of that able philosopher, he
established himself at Rome in the humble capacity of
a teacher of mathematics.  Here he made many
astronomical observations which served him as the
basis of future researches; but an event soon occurred,
which, though it interrupted for a time his important
studies, placed him in a situation for pursuing them
with increased zeal. The death of one of the canons
enabled his uncle, who was Bishop of Ermeland, to
appoint him to a canonry in the chapter of Frauen-u




SIR ISAAC NEWTON.


105


berg, where, in a house situated on the brow of a
mountain he continued in peaceful seclusion, to carry
on his astronomical observations. During his residence at Rome his talents had been so well appreciated, that the Bishop of Fossombrona, who presided
over the council for reforming the calendar, solicited
the aid of Copernicus in this desirable undertaking
At first he entered warmly into the views of the
council, and charged himself with the determination of
the length of the year and of the month, and of the
other motions of the sun and moon that seemed to be
required; but he found the task too irksome, and
probably felt that it would interfere with those interesting discoveries which had already begun to dawn
upon his mind.
Copernicus is said to have commenced his inquiries
by a historical examination of the opinions of ancient
authors on the system of the universe; but it is more
likely that he sought for the authority of their great
names to countenance his peculiar views, and that he
was more desirous to present his own theory as one
that he had received, rather than as one which he had
invented. His mind had been long imbued with the
idea, that simplicity and harmony should characterize
the arrangements of the planetary system, and, in the
complication and disorder which reigned in the hypothesis of Ptolemy, he saw insuperable objections to its
being regarded as a representation of nature. In the
opinions of the Egyptian sages, in those of Pythagoras,
Philolaus, Aristarchus, and Nicetas, he recognised his
own earliest conviction that the earth was not the
centre of the universe; but he appears to have considered it as still possible that our globe might perform some function in the system more important
than that of the other planets: and his attention was
much occupied with the speculation of Martianus
Capella, who placed the sun between Mars and the
Moon, and made Mercury and Venus revolve round




106               THE LIFE OF
him as a centre; and with the system of Apollonius
Pergoeus, who made all the planets revolve round the
sun, while the sun and moon were carried round the
earth in the centre of the universe. The examination,
however, of these hypotheses gradually dispelled the
difficulties with which the subject was beset, and
after the labours of more than thirty years, he was
permitted to see the true system of the heavens. The
sun he considered as immoveable in the centre of the
system, while the earth revolved between the orbits of
Venus and Mars, and produced by its rotation about
its axis all the diurnal phenomena of the celestial
sphere. The precession of the equinox was thus referred to a slight motion of the earth's axis, and the
stations and the retrogadations of the planets were
the necessary consequence of their own motions combined with that of the earth about the sun. These
remarkable views were supported by numerous astronomical observations; and, in 1530, Copernicus brought
to a close his immortal work on the Revolutions of
the Heavenly Bodies.
But while we admire the genius which triumphed
over so many difficulties, we cannot fail to commend the
extraordinary prudence with which he ushered his
new system into the world. Aware of the prejudices,
and even of the hostility with which such a system
would be received, he determined neither to startle the
one nor provoke the other. He allowed his opinions
to circulate in the slow current of personal communication. The points of opposition which they presented
to established doctrines were gradually worn down,
and they insinuated themselves into reception among
to ecclesiastical circles by the very reluctance of their
author to bring them into notice, In the year 1534,
Cardinal Schonberg, Bishop of Capua, and Gyse,
Bishop of Culm, exerted all their influence to induce
Copernicus to lay his system before the world; but he
resisted their solicitations; and it was not till 1539




SIR ISAAC NEWTON.


107


than an accidental circumstance contributed to alter his
resolution. George Rheticus, Professor of Mathematics at Wirtenberg, having heard of the successful labours of Copernicus, resigned his chair and proceeded
to Frauenberg to make himself master of his discoveries.  This zealous disciple prevailed upon his
master to permit the publication of his system; and
they seem to have arranged a plan for giving it to the
world without alarming the vigilance of the church, or
startling the prejudices of individuals. Under the disguise of a student of mathematics, Rheticus published
in 1540 an account of the manuscript volume of
Copernicus. This pamphlet was received without any
disapprobation, and its author was encouraged to reprint it at Basle in 1541, with his own name. The
success of these publications, and the flattering manner
in which the new astronomy was received by several
eminent writers, induced Copernicus to place his
manuscripts in the hands of Rheticus. It was accordingly printed at the expense of Cardinal Schonberg,
and appeared at Nuremberg, in 1543. Its illustrious
author, however, did not live to peruse it. A complete copy was handed to him in his last moments,
and he saw and touched it a few hours before his
death. This great work was dedicated to the Holy
Pontiff, in order, as Copernicus himself says, that the
authority of the head of the church might silence the
calumnies of individuals who had attacked his views
by arguments drawn from religion. Thus introduced,
the Copernican system met with no ecclesiastical opposition, and gradually made its way in spite of the
ignorance and prejudice of the age.
Among the astronomers who preceded Newton and
provided the materials of his philosophy, the name of
Tycho Brahe merits a conspicuous place. Descended
from an ancient Swedish family, he was born at
Knudstorp, in Norway, in 1546, three years after the
death of Copernicus. The great eclipse of the sun,




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which happened on the 26th of August, 1560, while
he was at the university of Copenhagen, attracted his
notice; and when he found that all its phenomena had
been accurately predicted, he was seized with the most
irresistible passion to acquire the knowledge of a
science so infallible in its results. Destined for the
profession of the law, his friends discouraged the pursuit which now engrossed his thoughts, and such were
the reproaches, and even persecutions to which he was
exposed, that he quitted his country with the design
of travelling through Germany. At the very commencement of his journey, however, an event occurred
in which the impetuosity of his temper had nearly
cost him his life. At a wedding-feast in Rostock, a
questionable point in geometry involved him in a dispute with a Danish nobleman of the same temperament as himself, and the two mathematicians resolved
to settle the difference by the sword. Tycho, however, seems to have shared worst in the conflict, for he
lost the greater part of his nose, and was forced to
supply the deficiency by a substitute of gold, silver,
and wax, so skilfully made that it could scarcely be
distinguished from nature. During his stay at Augsburg he inspired the burgomaster of the city, Peter
Htainzell, with a love of astronomy. This public
spirited citizen erected an excellent observatory at his
own expense, and here Tycho began that distinguished
career which has placed him in the first rank of practical astronomers.
Upon his return to Copenhagen, in 1570, he was
received with every mark of respect. The king invited him to court, and persons of all ranks harassed
him with their attentions. At Herritzvold, near the
place of his birth, the house of his maternal uncle
afforded him a retreat from the gaieties of the capital,
and he was there offered every accommodation for the
prosecution of his astronomical studies. Here, however, the passion of love and the pursuits of alchemy




SIR ISAAC NEWTON.


109


distracted his thoughts; but though the peasant-girl
of whom he was enamoured was of easier attainment
than the philosopher's stone, the marriage produced an
open quarrel with his relations, lhich became sb violent, that the royal authority was necessary to effect a
reconciliation. In the tranquillity of domestic happiness Tycho resumed his study of the heavens; and,
in 1573 he enjoyed the singular good fortune of observing, through all its variations, the new star in the
constellation, Cassiopeia, which appeared with such
extraordinary splendour as to be visible in the daytime, and which gradually disappeared in the following
year.
Dissatisfied with his residence in Denmark, Tycho
resolved to settle in some distant country; and having
travelled as far as Venice in search of a suitable abode,
he at at last fixed upon Basle, in Switzerland. The
King of Denmark, however, had learned his intention
from the Prince of Hesse; and when Tycho returned
to Copenhagen to remove his family and his instruments, his sovereign announced to him his resolution
to detain him in his kingdom. He presented him
with the canonry of Roschild, with an income of two
thousand crowns yearly. To this he added a pension
of one thousand crowns; and he promised to give
him the island of Huen, with a complete observatory
erected under his own eye. This generous offer was
instantly accepted.  The celebrated observatory of
Uranibourg was established at the expense of ~20,000;
and in this magnificent retreat Tycho continued for
twenty-one years to enrich astronomy with the most
valuable observations. Admiring disciples crowded
to this sanctuary of the sciences to acquire the
knowledge of the heavens; and kings* and princes
* When James I. went to Denmark to visit his future spouse, the
daughter of Frederic II., he spent a week under the roof of Tycho.Besides making some considerable presents, and composing a set of Latin
verses in favour of the astronomer, he gave him his royal license for the
publieation of his works in England,




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felt themselves honoured by becoming the guests of
the great astronomer of the age.
One of the principal discoveries of Tycho was that
of the inequalities of the moon's motion, called the
Variation. He detected also the annual equation
which affects the place of her apogee and nodes, and
he determined the greatest and the least inclination of
the lunar orbit. His observations on the plantes were
numerous and precise, and have formed the data of the
the present generalizations in astronomy. Though
thus skilful in the observation of phenomena, his
mind was little suited to investigate their cause; and
it was probably owing to this defect that he rejected
the system of Copernicus. The vanity of giving his
own name to another system was not likely to actuate
a mind such as his; and it is more probable that
he was led to adopt the immobility of the earth,
and to make the sun, with all his attendant planets,
circulate round it, from the great difficulty which still
presented itself by comparing the apparent diameter
of the stars with the annual parallax of the earth's
orbit.
The death of Frederic II., in 1588, proved a severe
calamity to Tycho, and to the science which he cultivated. During the first years of the minority of
Christian IV., the regency continued the royal patronage to the Observatory of Uranibourg; and in
1592, the young king paid a visit of some days to
Tycho, and left him a gold chain in token of his favour.  The astronomer, however, had made himself
enemies at court, and the envy of his high reputation
had probably added fresh malignity to the irritation of
personal feelings. Under the ministry of Walchendorf, a name for ever odious to science, Tycho's pension was stopped; he was even, in 1597, deprived of
the canonry of Roschild, and was thus forced, with
his wife and children, to seek an asylum in a foreign
land. His friend, Henry Rautzan, of Wansbeok,




SIR ISAAC NEWTON.!ll


under whose roof he found a hospitable shelter, was
fortunately acquainted with the Emperor Rodolph II.,
who, to his love of science, added a passion for
alchemy and astrology. The reputation of the astronomer having already reached the imperial ear, the
recommendation of Rantzau was scarcely necessary to
insure him his warmest friendship. Invited by the
emperor, he repaired, in 1599, to Prague, where he
met with the warmest reception. A pension of three
thousand crowns was immediately settled upon him,
and a commodious observatory erected for his use in
the vicinity of that city. Here the exiled astronomer
renewed with delight his interrupted labours, and the
gratitude which he cherished for the favour increased
the satisfaction which he felt in having so unexpectedly found a resting place for approaching age. These
prospects of latter days were enhanced by the good
fortune of receiving two such men as Kepler and Longomontanus for his pupils: but the fallacy of human
anticipation was here, as in so many other cases,
strikingly displayed. Tycho was not aware of the inroads which both his labours and his disappointments
had made upon his constitution. Though surrounded
with affectionate friends and admiring disciples, he was
still an exile in a foreign land. Though his country
had been base in its ingratitude, it was yet the land
which he loved-the scene of his earliest affections —
the theatre of his scientific glory. These feelings continually preyed upon his mind, and his insulted spirit
was ever hovering among his native mountains. In
this condition he was attacked with a disease of the
most painful kind-being dining at the house of a lord
named Rosenberg, lie had drank more than usual, and
not wishing to disturb the company he remained with
them and retained his urine, notwithstanding the
pressing necessity to the contrary, in consequence of
which he was seized with the disorder which terminated his life in twelve days afterwards. He saw




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that death was approaching, and implored his pupils
to persevere in their scientific labours. He conversed
with Kepler on some of the most profound points of
astronomy, and withl these secular occupations he
mingled frequent acts of piety and devotion. In
this happy condition he expired on the 24th of October, 1601, without pain, at the age of fifty-five, unquestionably the unfortunate victim of the councils of
Christian IV.
Notwithstanding the accessions which astronomy
had received from the labours of Copernicus and
Tycho Brahe, no progress was yet made in developing
the general laws of the system, and scarcely an idea
had been formed of the power by which the planets
were retained in their orbits. The labours of assiduous
observers had supplied the materials for this purpose,
and Kepler arose to lay the foundations of physical
astronomy.
John Kepler was born at Wiel, in Wirtenberg, in
1571. He was educated for the church, and discharged even some of the clerical functions; but his
devotion to science withdrew him from the study of
theology. Having received mathematical instruction
from the celebrated Maestlinus, he had made such
progress in the science, that he was invited in 1594 to
fill the mathematical chair of Gratz in Styria. Endowed with a fertile imagination, his mind was ever
intent upon subtle and ingenious speculations. In the
year 1596, he published his peculiar views in a work
on the Harmonies and Analogies of Nature. In this
singular production, he attempts to solve what he calls
the great cosmographical mystery of the admirable
proportion of the planetary orbits; and by means of
the six regular geometrical solids, he endeavours to
assign a reason why there are six planets; and why
the dimensions of their orbits, and the time of their
periodical revolutions, were such as Copernicus had
found them. If a cube, for example, was inserted in




SIR ISAAC NEWTON.            11
a sphere, of which Saturn's orbit was one of the great
circles, it would, he supposed, touch by its six planes
the lesser sphere of Jupiter; and, in like manner, he
proposes to determine, by the aid of the other geometrical solids, the magnitude of the spheres of the other
planets. A copy of this work was presented by its
author to Tycho Brahe, who had been too long versed
in the severe realities of observation to attach any
value to such wild theories. He advised his young
friend " first to lay a solid foundation for his views by
actual observation, and then, by ascending from these,
to strive to reach the causes of things;" and there is
reason to think, that, by the aid of the whole Baconian philosophy thus compressed by anticipation
into a single sentence, he abandoned for a while his
visionary inquiries.
Inl the year 1598, Kepler suffered persecution for
his religious principles, and was compelled to quit
Gratz; but though he was recalled by the States of
Styria, he felt his situation insecure, and accepted of a
pressing invitation from Tycho Brahe to settle at
Prague, and assist him in his calculations. Having
arrived in Bohemia in 1O00, he was introduced by his
friends to the Emperor Rodolph, from whom he ever
afterwards received the kindest attention.  On the
death of Tycho in 1601, he was appointed mathematician to the emperor, a situation in which he was
continued during the successive reigns of Matthias and
Ferdinand; but what was of more importance to
science, he was put in possession of the valuable collection of Tycho's observations. These observations
were remarkably numerous; and as the orbit of Mars
was more oval than that of any of the other planets,
they were peculiarly suitable for determining its real
form. The notions of harmony and symmetry in the
construction of the solar system, which had filled the
mind of Kepler, naturally led him to believe that the
*. i




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planets revolved with an uniform motion in circular
orbits. So firm, indeed, was this conviction, that he
made several attempts to represent the observations of
Tycho by this hypothesis. The deviations were too
great to be ascribed to errors of observation; and in
trying various other curves he was led to the discovery, that Mars revolved round the sun in an eliptical
orbit, in one of the foci of which the sun itself was
placed.  The same observations enabled him to determine the dimensions of the planet's orbit; and by comparing together the times in which Mars passed over
different portions of its orbit, he found that they were
to one another as the areas described by the lines
drawn from the centre of the planet to the centre of
the sun, or, in more technical terms, that the radius
vector describes equal arcs in equal times.  These two
remarkable discoveries, the first that were ever made
in physical astronomy, were extended to all the other
planets of the system, and were communicated to the
world in 1609, in his " Commentaries on the Motions
of the Planet Mars, as deduced from the Observations
of Tycho Brahe."
Although Kepler was conducted to these great laws
by the patient examination of well-established facts,
his ima gination was ever hurrying him among the
wilds of conjecture.  Convinced that tlhe mean distances of the planets from the sun bore to one another
some mysterious relation, he not only compared them
with the regular geometrical solids, but also with the
intervals of musical tones; an idea which the ancient
Pythagoreans had suggested, and which had been
adopted by Archimedes himself.  All these comparisons were fruitless; and Kepler was about to abandon an inquiry of about seventeen years' duration,
when on the 8th of March, 1618, he conceived the
idea of comparing the powers of the different numbers
which express the planetary distances, in place of the
aumbers themselves.   He compared the squares and




SIR ISAAC NEWTON.


115


the cubes of the distances with the same powers of
the periodic times; nay, he tried even the squares of
the times with the cubes of the distances; but his
hurry and impatience led him into an error of calculation, and he rejected this law as having no existence
in nature! On the 15th May, his mind again re.verted to the same notion, and upon making the calculations anew, and free from error, he discovered the
great law, that the squares of the periodic times of
any two planets are to one another as the cubes of
their distances from the sun. Enchanted with this
unexpected result, he could scarcely trust his calculations; and, to use his own language, he at first believed that he was dreaming, and had taken for
granted the very truth of which he was in search.
This brilliant discovery was given to the world in
1619 in his " IHarmony of the World," a work dedicated to James VI. of Scotland. Thus were established what have been termed the three laws of
Kepler-the motion of the planets in elliptical orbits
-the proportionality between the areas described and
their times of description-and the relations between
the squares of the periodic times and the cubes of the
distances.
The relation of the movements of the planets to the
sun, as the general centre of all their orbits, could not
fail to suggest to Kepler, that some power resided in
that luminary by which these various motions were
produced; and he went so far as to conjecture, that
this power diminishes as the square of the distance of
the body on which it was exerted; but he immediately rejects this law, and prefers that of the simple
distance. In his work on Mars, he speaks of a gravity as a mutual and corporeal affection between
similar bodies.  He maintained that the tides were
occasioned by the moon's attraction, and that the irregularities of the lunar motions, as detected by Tycho
Brahe, were owing to the joint actions of the sun and




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the earth; but the relation between gravity, as exhibited on the earth's surface, and as conducting the
planets in their orbits, required more patience of
thought than he could command, and was accordingly
left for the exercise of higher powers.
The misery in which Kepler lived forms a painful
contrast with the services which he performed to science. The pension on which he subsisted was always
in arrears, and, though the three emperors whose
reigns he adorned, directed their ministers to be more
punctual in its payments, the disobedience of their
commands was a source of continued vexation to the
astronomer.' When he retired to Sagan, in Silesia,
to spend in retirement the remainder of his days, his
pecuniary difficulties became still more harassing.
Necessity at last compelled him to apply personally
for the arrears which were due; and he accordingly
set out in 1630, for Ratisbon; but in consequence of
the great fatigue which so long a journey on horseback produced, he was seized with a fever, which
carried him off, on the 30th of November, 1630, in
the fifty-ninth year of his age.
While Kepler was laying4the foundation of physical astronomy, Galileo was busily employed in extending the boundaries of the solar system. This distinguished philosopher was born at Pisa, in 1564.
He was the son of a Florentine nobleman, and was,educated for the medical profession; but a passion for
geometry took possession of his mind, and called forth
all his powers. Without the aid of a master he studied the writings of Euclid and of Archimedes, and
such were his acquirements, that he was appointed
by the Grand Duke of Tuscany to the Mathematical
chair of Pisa, in the twenty fifth year of his age.
His opposition to the Aristotelian philosophy gained
him many enemies, and at the end of three years he
quitted Pisa, and accepted of an invitation to the
Professorship of Mathematics at Padua.  Here he




SIR ISAAC NEWTON.


117


continued for eighteen years adorning the university
by his name, and diffusing around him a taste for the
physical sciences. With the exception of some contrivances of inferior importance, Galileo had distinguished himself by no discovery till he had reached
the forty-fifth year of his age. In the year 1609,
the same year in which Kepler published his celebrated commentary on Mars, Galileo paid a visit to
Venice, where he heard, in the course of conversation,
that a Dutchman, of the name of Jansens had constructed and presented to Prince Maurice, an instrument through which he saw distant objects magnified
and rendered more distinct, as if they had been
brought nearer to the observer. This report was
credited by some, and disbelieved by others; but, in
the course of a few days, Galileo received a letter
from a friend in Paris, which placed beyond a doubt
the existence of such an instrument. The idea instantly
took possession of his mind as one of the utmost
importance to science; and so thoroughly was he
acquainted with the properties of lenses, that he not
only discovered the principle of its construction, but
was able to complete a telescope for his own use.
Into one end of a leaden tube he fitted a spectacleglass, plane on one side and convex on the other, and
in the other end he placed another spectacle-glass,
concave on one side and plane on the other. He then
applied his eye to the concave glass, and saw objects
"pretty large and pretty near him."  They appeared
three times nearer, and nine times larger in surface,
than to the naked eye. He soon after made anotler,
which represented objects above sixty times larger;
and sparing neither labour nor expense, he finally
constructed an instrument so excellent, as "to show
things almost a thousand times larger, and above
thirty times nearer to the naked eye."
There is perhaps no invention that science has
presented to man so extraordinary in its nature, and




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so boundless in its influence, as that of the telescope.
To the uninstructed mind, the power of seeing an
object at the incredible distance of a thousand miles,
as large and nearly as distinct as if it was brought
within a mile of the observer, must seem almost miraculous; and to the philosopher, even, who thoroughly comprehends the principles upon which it
acts, it must ever appear one of the most elegant
applications of science. To have been the first astronomer in whose hands such a gift was placed, was a
preference to which Galileo owed much of his future
fame.
No sooner had he completed his telescope than he
applied it to the heavens, and on the 7th of January,
1608, the first day of its use, he saw, round Jupiter
three bright little stars lying in a line parallel to the
ecliptic, two to the east, and one to the west of the
planet. Regarding them as ordinary stars, he never
thought of estimating their distances.  On the following day, when he accidentally directed his telescope to Jupiter, he was surprised to see the three
stars to the west of the planet.  To produce this
effect it was requisite that the motion of Jupiter
should be direct, though, according to calculation, it
was actually retrograde.  In this dilemma he waited
with impatience for the evening of the 9th, but unfortunately the sky was covered with clouds.  On
the 10th he saw only two stars to the east-a circumstance which he was no longer able to explain by the
motion of Jupiter.  lie was therefore compelled to
ascribe the change to the stars themselves; and upon
repeating his observations on the 11th he no longer
doubted that he had discovered three planets revolving
round Jupiter.  On the 13th of January he for the
first time saw the fourth satellite.
This discovery, though of the utmost importance in
itself, derived an additional value from the light
which it threw on the true system of the universe.




SIR ISAAC NEWTON.


11 W


While the earth was the only planet enlightened by
a moon, it might naturally be supposed that it alone
was habitable, and was therefore entitled to the preeminence of occupying the centre of the system; but
the discovery of four moons round a much larger
planet deprived this argument of its force, and created
a new analogy between the earth and the other planets.
When Kepler received the " Sidereal Messenger,"
the work in which Galileo announced his discovery in
1610, he perused it with the deepest interest; and
while it confirmed and extended his substantial discoveries, it dispelled at the same time some of those
harmonic dreams which    still hovered among his
thoughts.  In the " Dissertation" which he published
on the discovery of Galileo, he expresses his hope
that satellites will be discovered round Saturn and
Mars-he conjectures that Jupiter has a motion of
rotation about his axis-and states his surprise, that,
after what hasbeen written on the subject of telescopes
by Baptista Porta, they had not been earlier introduced into observatories.
In continuing his observations Galileo applied his
telescope to Venus, and in 1610 he discovered the
phases of that planet, which exhibited to him the
various forms of the waxing and waning moon. This
fact established beyond a doubt that the planet revolved round the sun, and thus gave an additional
blow to the Ptolemaic system. In his observations
on the sun Galileo discovered his spots, and deduced
from them the rotation of the central luminary. He
observed that the body of Saturn had handles attached
to it, but he was unable to detect the form of its ring,
or render visible its minute satellites. On the surface
of the moon he discovered her mountains and vallies,
and determined the curious fact of her libration, in
virtue of which parts of the margin of her disc occasionally appear and disappear. In the Milky Way he
descried numerous minute stars which the unassisted.




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eye was unable to perceive; and as the largest fixed
stars, in place of being magnified by the telescope, became actually minute brilliant points, he inferred their
immense distance as rendered necessary by the Copernican hypothesis. All his discoveries, indeed, furnished fresh arguments in favour of the new system; and
the order of the planets, and their relation to a central
sun, may now be considered as established by incontrovertible evidence.
While Galileo was occupied with these noble pursuits at Pisa, to which he had been recalled in 1611,
his generous patron Cosmo II., Grand Duke of Tuscany, invited him to Florence, that he might pursue
with uninterrupted leisure his astronomical observations, and carry on his correspondence with the German astronomers.   His fame had now resounded
through all Europe;-the strongholds of prejudice and
ignorance were unbarred;-and the most obstinate
adherents of ancient systems acknowledged the meridian
power of the day star of science. Galileo was ambitious of propagating the great truths which he contributed so powerfully to establish. He never doubted
that they would be received with gratitude by allby the philosopher as the consummation of the greatest efforts of human genius-and by the Christian as
the most transcendant displays of Almighty power.
But he had mistaken the disposition of his species, and
the character of the age. That same system of the
heavens which had been discovered by the humble
ecclesiastic of Frauenberg, which had been patronised
by the kindness of a bishop, and published at the expense of a cardinal, and which the pope himself had
sanctioned by the warmest reception, was, after the
lapse of a hundred years, doomed to the most violent
opposition, as subversive of the doctrines of the Christian faith. On no former occasion has the human
mind exhibited such a fatal relapsento intolerance.,The age itself had improved in lb;lit  e per



SIR ISAAC NEWTON.


121


secuted doctrines themselves had become more deserving of reception;-the light of the Reformed faith had
driven the Roman Catholics from some of their most
obnoxious positions; and yet, under all these circumstances, the Church of Rome unfurled her banner of
persecution against the pride of Italy-against the
ornament of his species, and against truths immutable
and eternal.
In consequence of complaints laid before the Holy
Inquisition, Galileo was summoned to appear at Rome,
in 1615, to answer for the heretical opinions which he
had promulgated. He was charged with "maintaining as true the false doctrine held by many, that the
sun was immoveable in the centre of the world, and
that the earth revolved with a diurnal motion;-with
having certain disciples to whom he taught the same
doctrine;-with keeping up a correspondence on the
subject with several German mathematicians;-with
having published letters on the solar spots, in which
he explained the same doctrine as true;-and with
having glossed over, with a false interpretation, the
passages of Scripture which were urged against it."
The consideration of these charges came before a
meeting of the Inquisition which assembled on the
25th of February, 1616, and the court declaring their
disposition to deal gently with the prisoner, pronounced the following decree:-" That the Cardinal
Bellarmine should enjoin Galileo to renounce entirely
the above recited false opinions; that on his refusal to
do so, he should be commanded by the commissary of
the Inquisition to abandon the said doctrine, and to
cease to teach and defend it; and that if he did not
obey this command, he should be thrown into prison."
On the 26th of February, Galileo appeared before
Cardinal Bellarmine, and after receiving from him a
gentle admonition, he was commanded by the commissary, in the presence of a notary and witnesses, to
desist altogether from his erroneous opinions; and it




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was declared to be unlawful for him in future to teach
them in any way whatever, whether orally or in his
writings. To these commands Galileo promised obedience, and was dismissed from the Inquisition.
The mildness of this sentence was no doubt partly
owing to the influence of the Grand Duke of Tuscany, and other persons of rank and power at the
Papal Court, who took a deep interest in the issue of
the trial. Dreading, however, that so light a punishment might not have the effect of putting down the
obnoxious doctrines, the Inquisition issued a decree
denouncing the new opinions as false, and contrary to
the sacred writings, and prohibiting the sale of every
book in which they should be mentioned.
Thus liberated from his persecutors, Galileo returned to Florence, where he pursued his studies with
his wonted diligence and ardour. The recantation of
his astronomical opinions was so formal and unreserved, that ordinary prudence, if not a sense of per-.
sonal honour, should have restrained him from unnecessarily bringing them before the world. No anathema was pronounced against his scientific discoveries; no interdict was laid upon the free exercise of
his genius. He was prohibited merely from teaching
a doctrine which the Church of Rome considered as
injurious to its faith. We might have expected,
therefore, that a philosopher, conspicuous in the eyes of
the world, would have respected the prejudices, however base, of an institution whose decrees formed part
of the law of the land, and which possessed the
power of life and death within the limits of its jurisdiction.  Galileo, however, thought otherwise. A
sense of degradation seems to have urged him to retaliate; and before six years had elapsed, he began to
compose his " Cosmical System, or Dialogues on the
two greatest Systems in the World, the Ptolomean
and the Copernican," the concealed object of which is
to establish the opinions which he had promised to




SIR ISAAC NEWTON.


123


abandon. In this work, the subject is discussed by
three speakers, Sagredo, Salviatus, and Simplicius, a
peripatetic philosopher, who defends the system of
Ptolemy with much skill against the overwhelming
arguments of the rival disputants. Galileo hoped to
escape notice by this indirect mode of propagating the
new system, and he obtained permission to publish his
work, which appeared at Florence, in 1632.
The Inquisition did not immediately summon
Galileo to their presence. Nearly a year elapsed
before they gave any indications of their design; and,
according to their own statement, they did not even
take the subject into consideration till they saw that
the obnoxious tenets were every day gaining ground,
in consequence of the publication of the Dialogues.
They then submitted the work to a careful examination, and having found it to be a direct violation of
the injunction which had been formerly intimated to
its author, they again cited him before their tribunal,
in 1633. The venerable sage, now in his seventieth
year, was thus compelled to repair to Rome; and
when he arrived, he was committed to the apartments
of the Fiscal of the Inquisition. The unchangeable
friendship, however, of the Grand Duke of Tuscany
obtained a remission of this severity, and Galileo was
allowed to reside at the house of the Tuscan ambassador, during the two months which the trial occupied.
When brought before the Inquisition, and examined
on oath, he acknowledged that the Dialogues were
written by himself, and that he obtained permission to
publish them, without notifying to the person who
gave it that he had been prohibited from holding, defending, or teaching the heretical opinions. He confessed also that the Dialogues were composed in such  *
a manner, that the arguments in favour of the Coper.
nican system, though given as partly false, were yet
managed in such a manner, that they were more likely
to confirm than overturn its doctrines; but that this




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error, which was not intentional, arose from the natural desire of making an ingenious defence of false
propositions, and of opinions that had the semblance
of probability.
After receiving these confessions and excuses, the
Inquisition allowed Galileo a proper time for giving
in his defence; but this seems to have consisted
solely in bringing forward a certificate from Cardinal
Bellarmine, which made no allusion to the promise
under which Galileo had come, never to defend, nor
teach in any way whatever, the Copernican doctrines.
The court held this defence to be an aggravation of
the crime rather than excuse for it, and proceeded to
pronounce a sentence which will be ever memorable
in the history of the human mind.
Invoking the name of our Saviour, they declare,
that Galileo had made himself liable to the suspicion
of heresy, by believing the doctrine, contrary to
Scripture, that the sun was the centre of the earth's
orbit, and did not move from east to west; and by
defending as probable the opinion, that the earth
moved, and was not the centre of the world; and
that he had thus incurred all the censures and
penalties which were enacted by the church against
such offences;-but that he should be absolved from
these penalties, provided he sincerely abjured and
cursed all the errors and heresies contained in the
formula of the church, which should be submitted to
him. That so grave and pernicious a crime should
not pass altogether unpunished, that he might become
more cautious in future, and be an example to others
to abstain from such offences, they decreed that his
Dialogues should be prohibited by a formal edict, that
he should be condemned to the prison of the Inquisition during pleasure, and that during the three following years, he should recite once a week the seven
penitentiary psalms.
This sentence was subscribed by seven cardinals;




SIR ISAAC NEWTON.


125


and on the 22nd of June, 1633, Galileo signed an
abjuration, humiliating to himself and degrading to
philosophy. At the age of seventy, on his bended
knees, and with his right hand resting on the holy
Evangelists, did this patriarch of science avow his
present and his past belief in all the dogmas of the
Romish Church, abandon as false and heretical the
doctrine of the earth's motion and of the sun's immobility, and pledge himself to denounce to the Inquisition any other person who was even suspected of
heresy.  He abjured, cursed, and detested, those
eternal and immutable truths which the Almighty
had permitted him to be the first to establish. What
a mortifying picture of moral depravity and intellectual weakness! If the unholy zeal of the assembly
of Cardinals has been branded with infamy, what
must we think of the venerable sage whose gray hairs
were entwined   with the chaplet of immortality,
quailing under the fear of man, and sacrificing the
convictions of his conscience, and the deductions of his
reason, at the altar of a base superstition? Had
Galileo but added the courage of the martyr to the
wisdom of the sage-had he carried the glance of his
indignant eye round the circle of his judges-had he
lifted his hands to heaven, and called the living God
to witness the truth and immortality of his opinions,
the bigotry of his enemies would have been disarmed,
and science would have enjoyed a memorable triumph.
The great truths of the Copernican system, instead
of being considered as heretical, had been actually
adopted by many pious members of the Roman
Church, and even some of its dignitaries did not
scruple to defend it openly. Previous to the fir:::t
persecution of Galileo in 1615, a Neapolitan noble:
man, Vincenzio Caraffa, a person equally distinguished by his piety and birth, had solicited Paul
Anthony Foscarinus, a learned Carmelite monk, to
illustrate and defend the new system of the universe.




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With this request the ecclesiastic speedily complied;
and in the pamphlet which he completed on the 6th
of January, 1615, he defends the Copernican system
with much boldness and ingenuity; he reconciles the
various passages of Scripture with the new doctrine,
and he expresses the hope that such an attempt, now
made for the first time, will prove agreeable to the
philosophers, but particularly to those very learned
men, Galileo Galilei, John Kepler, and all the members of the Lyncean Academy, who, he believes,
entertain the same opinion. This remarkable production, written from the convent of the Carmelites
at Naples, is dedicated to the very reverend Sebastian Fantoni, general of the order of Carmelites, and
was published at Florence, with the sanction of the
ecclesiastical authorities in 1630, three years before
the second persecution of Galileo.
It would be interesting to know the state of public
feeling in Italy when Galileo was doomed to the
prisons of the Inquisition.  No appeal seems to have
been made against so cruel a sentence, and neither in
remonstrance nor in derision does an individual voice
seem to have been raised. The master of the spirits
of the age looked with sullen indifference on the persecution of exalted genius; and Galileo lay in chains
deserted and unpitied. This unrebuked triumph of
his enemies was perhaps favourable to the object of
their vengeance.  Resistance might have heightened
the rigour f a sentenc'ivwhich submission seems to
have alleviated. The i:nterference of some eminent
individuals of Rome, among whom we have no doubt
that the Grand Duke of Tuscany was the most influential, induced the Pope not only to shorten the
period, but to soften the rigour of Galileo's imprisonment. From the dungeon of the Inquisition, where
he had remained only four days, he was removed to
the ambassador's palace; and when his health began
to suffer, he was permitted to leave Rome; and would




SIR ISAAC NEWTON.


127


have been allowed to return to Florence, but as the
plague raged in that city, he was sent to the residence
of the Archbishop Piccolimini, where he carried on
and completed his valuable investigations respecting
the resistance of solids.  Here he continued five
months, when, in consequence of the disappearance of
the plague at Florence, he was allowed to retire to his
villa at Bellosguardo, and afterwards to that of Arcetri, in the vicinity of Florence.
Though Galileo was now, to a certain degree, liberated from the power of man, yet the afflicting dispensations of Providence began to fall thickly around him.
No sooner had he retired to Arcetri, than his favourite
daughter was seized with a dangerous illness, which
quickly terminated in her death. He was himself
attacked with a complication of disorders, and the
most oppressive melancholy; and though he solicited
permission to repair to Florence for medical assistance,
yet this was denied him. In 1631, however, the Pope
permitted him to pay a visit to Florence, and his
friend, Father Castelli, was allowed to visit him,
attended by an officer of the Inquisition. But this
indulgence was soon withdrawn, and at the end of a
few months he was ordered to return to Arcetri. The
sight of his right eye had begun to fail him in 1636;
in 1637, his left eye was similarly attacked, so that in a
few months he was affected with total and incurable
blindness. Before this calamity had supervened, he
had noticed the curious phenomenon of the moon's
libration, in  consequence of which, parts of her
visible disc that are exposed to view at one time are
withdrawn at another.  He succeeded in explaining
two of the causes of this curious phenomenon, viz., the
different distances of the observer from the line joining
the centre of the earth and themoon, which producesthe
diurnal libration, and the unequal motion of the moon
in her orbit, which produces the libration in longitude.
It was left, however, to Helvetius to discover the










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libration in latitude, which arises from the inclination
of her axis being a little less than a right angle to the
ecliptic; and Lagrange to discover the spheroidal
libration, or that which arises from the action of the
earth upon the lunar spheroid.
The sorrows with which Galileo was now beset,
seem to have disarmed the severity of the Inquisition.
He was freely permitted to enjoy the society of his
friends, who now thronged around him to express
their respect and their sympathy. The Grand Duke
of Tuscany was his frequent visitor, and Gassendi, Deodati, and our celebrated countryman, Milton, went to
Italy for the purpose of visiting him. He entertained
his friends with the warmest hospitality, and though
simple and abstemious in his diet, yet he was fond of
good wine, and seems even in his best days to have
paid particular attention to the excellence of his
cellar.
Although Galileo had nearly lost his hearing as
well as sight, yet his intellectual faculties remained
unimpaired; and while his mind was occupied in
considering the force of percussion, he was seized with
fever and palpitation of the heart, which after two
months' illness, terminated his life on the 8th of
January, 1642.
Among the predecessors of Newton in astronomical
research we must not omit the names of, Bouillaud,
Borelli, and Dr. Hooke. Bouillaud, the author of
several valuable astronomical works, was a native of
France, and has derived more reputation from a single
sentence in his " Astronomica," published in 1645,
than from all the rest of his labours. He was not a
believer in the doctrine of attraction; but in speaking
of that power as the cause of planetary motions, he remarks, "that if attraction existed, it would decrease
as the square of the distance."  The influence was
still more distinctly developed by Borelli, a Neapolitan
philosopher, who, in 1666, published a work on the




SIR ISAAC NEWTON.


129


satellites of Jupiter. In this work he maintains, that
all the planets perform their motions round the sun
according to a general law; that the satellites of Jupiter
and Saturn move round their primary planets in the
same manner as the meon does round the earth, and
that they all revolve round the sun, which is the only
source of any virtue, and that this virtue attaches
them, and unites them so that they cannot recede from
their centre of action.
Dr. Hooke seems to have devoted much of his attention to the cause of the planetary motions.  On the
21st March, 1666, he read to the Royal Society an
account of a series of experiments for determining if
bodies experience any deviation in their weight at
different distances from the centre of the earth.  His
experiments were by no means satisfactory to himself,
and hence he was led to the ingenious idea of measuring the force of gravity, by observing, at different
altitudes, the rate of a pendulum clock. About two
months afterwards, he exhibited to the Society an approximate representation of the forces which maintain
the planets in their orbits, in the paths described by a
circular pendulum  impelled with different degrees of
force; but though this experiment illustrated the production of a curvilinear motion, by combining a tangcntial force with a central force of attraction, yet it
vwas only an illustration, and could not lead to the
true cause of the planetary motions.  Eight years
after, however, he resumed the subject, and published
a dissertation, entitled "an attempt to prove the motion of the earth from observation;" 'which has been
considered as a remarkable production by the philosophers of every country.:




130


THE LIFE OP


CHAPTER V.
Newton's first speculations on Gravity. He discovers the true law of
Gravity and the cause of the Planetary Motions. His principles of
Natural Philosophy. His " Principia" appears in 1687. Account of
it and the Discoveries it contains. They meet with great opposition.
The reception of the Newtonian Philosophy. Doctrine of Infinite
Quantities. Discovers the Binomial Theorem. Doctrine of Fluxions.
His Mathematical Tracts. His Universal Arithmetic. Account of the
celebrated Controversy respecting the Invention of Fluxions.
WHEN the plague had driven Newton from Cambridge,
in 166, he was sitting alone in the garden at Woolsthorpe, and reflecting on the nature of gravity, that
remarkable power which causes all bodies to descend
to the centre of the earth. As this power is not found
to suffer any sensible diminution at the greatest distance from the earth's centre to which we can reach,
being as powerful at the summit of the highest mountain as at the bottom of the deepest mine, he conceived
it highly probable that it must extend much farther
than was usually supposed. No sooner had this happy
conjecture occurred to his mind than he considered
what would be the effect of its extending as far as the
moon.    That her motion must be influenced by such a
power, he did not for a moment doubt; and a little
reflection convinced him that it might be sufficient for
retaining that luminary in her orbit round the earth.
Though the force of gravity suffers no sensible diminution at those small distances frJ-ifie'ielr'th's centre
at which   we can place ourselves, yet he thought
it very possible that, at the distance of the moon, it
might differ much in stirength from what it is on the
earth.   In order to for   some estimate of the degree
of its diminution, lhe -considered that if the moon be




SIR ISAAC NEWTON.


131


retained in her orbit by the force of gravity, the primary planets must also be carried round the sun by
the same power; and by comparing the periods of the
different planets, with their distances from the sun, he
found that if they were retained in their orbits by any
power like gravity, its force must decrease in the duplicate proportion, or as the squares of their distances
from the sun. In drawing this conclusion, he supposed
the planets to move in orbits perfectly circular, and
having the sun in their centre. Having thus obtained
the law of the force by which the planets were drawn
to the sun, his next object was to ascertain if such a
force emanating from the earth, and directed to the
moon, was sufficient, when diminished iirthe duplicate ratio of the distance, to retain her in her orbit.
In performing this calculation, it was necessary to
compare the space through which heavy bodies fall in
a second of time at a given distance from the earth,
viz., at its surface, with the space through which the
moon, as it were, falls to the earth in a second of time
while revolving in a circular orbit. Being at a distance from books when he made this computation, he
adopted the common estimate of the earth's diameter,
then in use among geographers and navigators, and
each degree of latitude contained 60 English miles.
In this way he found that the force which retains the
moon in her orbit, as deduced from the force which
occasions the fall of heavy bodies to the earth's surface, was one-sixth greater than what is actually
observed in her circular orbit. This difference threw
a doubt upon all his speculations; but unwilling to
abandon what seemed to be otherwise so plausible, he
endeavoured to account for the difference of the two
forces, by supposing that some other cause must have
been united with the force of gravity in producing
so great a velocity of the moon in her circular orbit.
As this new cause, however, was beyond the reach of
observation, he discontinued all further inquiries into




A    132


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the subject, and concealed from his friends the speculations in which he had been employed.
After his return to Cambridge his attention was
occupied with those optical discoveries which we
have already noticed; but he had no sooner brought
them to a close than his mind reverted to the subject
of the planetary motions. Upon the death of Oldenburg, in 1678, Doctor Hooke was appointed secretary to the Royal Society; and as this distinguished
body. had requested the opinion of Newton about the
system of physical astronomy, he addressed a letter
to the secretary, on the 28th of November, 1679, in
which he proposed a direct experiment for verifying
the motion of the earth, namely, by observing whether
or not bodies that fall from a considerable height descend in a vertical direction, for if the earth were at
rest, the body would describe a vertical line, whereas
if it revolved round its axis, the falling body must deviate from  the vertical line towards the east. The
Royal Society attached great value to this idea, and
appointed Dr. Hooke to put it to the test of experiment. Being thus led to consider the subject more
attentively, he wrote to Newton, that where ever the
direction of gravity was oblique to the axis on which
the earth revolved, that is, in every part of the earth
except the equator, falling bodies should approach to
the equator, and the deviation from the vertical, in
place of being exactly to the east, as Newton maintained, should be to the south-east of the point from
which the body began to move. Newton acknowledged that this conclusion was correct in theory, and
)r. Hooke is said to have given an experimental demonstration of it before the Royal Society, in 1679.
Newton had erroneously concluded, that the path of
the falling body would be a spiral; but Dr. Hooke,
on the same occasion oa which he made the preceding
experiment, read a paper to the Society in which he
proved that the path of the body would be an eccn



SIR ISAAC NEWTON.


134 i


tric ellipse in the vacuo, and an elliptic spiral, if the
body moved in a resisting medium.
This correction of Newton's error, and the discovery
that a projectile would move in an elliptical orbit when
under the influence of a force varying in the inverse
ratio of the square of the distance, led Newton to
discover "the theorem by which he afterwards examined the ellipses," and to demonstrate the celebrated
proposition, that a planet acted upon by an attractive
force varying inversely as the squares of the distances, will describe an elliptical orbit in one of whose
foci the attractive force resides.
But though Newton had thus discovered the true
cause of all the celestial motions, he did not yet possess
any evidence that such a force actually resided in the
sun and planets. The failure of his former attempt,
to identify the law  of falling bodies, at the earthy
surface, with that which guided the moon in her orbit,
threw a doubt over all his speculations, and prevented
him from giving any account of them to the public.
An accident, however, of a very interesting nature,
induced him to resume his former inquiries, and enabled him to bring them to a close. In June, 1682,
when he was attending a meeting of the Royal Society
of London, the measurement of a degree of meridian,
executed by M. Picard, became the subject of conversation. Newton took a memorandum of the result
obtained by the French astronomer, and having ideduced from it the diameter of the earth, he immediately resumed his former calculations, and began to
repeat it with these new data, In the progress of the
calculation, he saw that the result which he had formerly
expected, was- likely to be produced, and he was
thrown into such a state of nervous irritability, that
he was unable to carry it on. In this state of mind,
he entrusted it to one of his friends, and he had the
high satisfaction of finding his former views amply
realized. The force of gravity which regulated the fall
~:;. i




134               THE LIFE OF
of bodies at the earth's surface, when diminished as
the square of the moon's distance from the earth, was
found to be almost exactly equal to the centrifugal
force of the moon, as deduced from her observed distance and velocity.
The influence of such a result upon such a mind
may be more easily conceived than described. The
whole material universe was spread out before him;the sun with all his attending planets-the planets
with all their satellites-the comets wheeling in every
direction in their eccentric orbits, and the systems of
the fixed stars stretching to the remotest limits of
space. All the varied and complicated movements of
the heavens, in short, must have been at once presented
to his mind as the necessary result of that law which
he had established in reference to the earth and the
moon.
After extending this law to the other bodies of the
system, he composed a series of propositions on the
motion of the primary planets about the sun, which
were sent to London about the end of 1683, and
were soon afterwards communicated to the Royal
Society.
About this period other philosophers had been
occupied with the same subject.   Sir Christopher
Wren had many years before endeavoured to explain
the planetary motions " by the composition of a descent
towards the sun, and an impressed motion; but he
at length gave it over, not finding the means of doing
it. In January, 1684, Dr. Halley had concluded that
the centrepital force decreased in the reciprocal proportion of the squares of the distances, and having one
day met Sir Christopher Wren and Dr. Hooke, the
latter affirmed that he had demonstrated upon that
principle all the laws of the celestial motions. Dr.
Halley confessed that his attempts were unsuccessful,
and Sir Christopher, in order to encourage the inquiry,
offered to present a book of forty shillings value, to




SIR ISAAC NEWTON.


135


either of the two philosophers who should, in the space
of two months, bring him a convincing demonstration
of it. Hooke persisted in the declaration, that he
possessed the method, but avowed it to be his intention
to conceal it for some time.
In August, 1684, Dr. Halley went to Cambridge
for the express purpose of consulting Newton on this
interesting subject. Newton assured him that he
had brought this demonstration to perfection, and
promised him a copy of it. This copy was received
in November, by the Doctor, who made a second
visit to Cambridge, in order to induce its author
to have it inserted in the register-book of the
Royal Society.  On the 10th   of December, Dr.
Halley intimated to the Society, that they had
seen at Cambridge Mr. Newton's treatise, " De Motu
Corporum," which he had promised to send to the
Society to be entered upon their register; and Dr.
Halley was desired to unite with Mr. Paget, Master
of the Mathematical School in Christ's Hospital, in
reminding Mr. Newton of his promise, " for securing
the invention to himself, till such time as he can be at
leisure to publish it." On the 25th of February the
secretary communicated a letter from Mr. Newton, in
which he expresses his willingness " to enter in the
register his notions about motion, and his intentions to
fit them suddenly for the press." The progress of his
work was interrupted, however, by a visit of some
weeks which he made in Lincolnshire; but he proceeded with such diligence on his return, that he was
able to transmit the manuscript to London before the
end of April. This manuscript, entitled Philosophiae
Naturalis Principia Mathematica, and dedicated to the
Society, was presented by Dr. Vincent on the 28th of
April, 1686, when Sir John Hoskins, the vice-president, and the particular friend of Dr. Hooke, was in
the chair. Dr. Vincent passed a just encomium on
the novelty and dignity of the subject; and another
\a: '::
<e           *;' 0  0 ':fff  '!';;* 0.0;  0 '*; '   '




136              THE LIFE OF
member added, that " Mr. Newton had carried the
thing so far, that there was no more to be added."
Dr. Hooke took offence at these remarks, and blamed
Sir John for not having mentioned " what he had
discovered to him;" but the vice-president did not
recollect any such communication, and the consequence
was, that " these two, who, till then, were inseparable
cronies, have since scarcely seen one another, and are
utterly fallen out."  After the breaking up of the
meeting the Society adjourned to the coffee-house,
when Dr. Hooke stated, that he not only had made
the same discovery, but had given the first hint of it
to Newton.
An account of these proceedings was communicated
to Newton through two different channels. In a letter dated May 22nd, Dr. Halley wrote to him, " that
Dr. Hooke has some pretensions upon the invention of
the rule of the decrease of gravity being reciprocally
at the squares of the distances from the centre. He
says you had the notion from him, though he owns the
demonstration of the curves generated thereby to be
wholly your own. How much of this is so, you know
best, as likewise what you have to do in this matter.
Only Mr. Hooke seems to expect you would make
some mention of him in the preface, which it is possible you may see reason to prefix."
This communication from Dr. Halley induced our
author, on the 20th of June, to address a long letter
to him, in which he gives a minute and able refutation
of Hooke's claims; but before this letter was despatched, another correspondent, who had received his
information from one of the members who had been
present, informed Newton, " that Hooke made a great
stir, pretending that he had all from him, and desiring
they would see that he had justice done him."  This
fresh charge seems to have ruffled the tranquillity of
Newton; and he accordingly added an angry and satirical postscript, in which he treats Hooke with very:: \:




SIR ISAAC NEWTON.            137'
little ceremony, and goes so far as to conjecture that
he might have acquired his knowledge of the law from
a letter of his own to Huygens, directed to Oldenburg,
and dated January 14th, 1672-3.   " My letter to
Hugenius was directed to Mr. Oldenburg, who used
to keep the originals.  His papers came into Mr.
Hooke's possession, Mr. Hooke, knowing my hand,
might have the curiosity to look into that letter, and
there take the notion of comparing the forces of the
planets arising from their circular motion; and so
what he wrote to me afterwards about the rate of
gravity might be nothing but the fruit of my own
garden."
In replying to this letter, Dr. Halley assured him
that Hooke's " manner of claiming the discovery had
been represented to him in worse colours than it ought,
and that he neither made public application to the
Society for justice, nor pretended that you had all
from him."  The effect of this assurance was to make
Newton regret that he had written the angry postscript to his letter; and in replying to Halley, he not
only expressed his regret, but recounts the different
new ideas which he had acquired from Hooke's correspondence, and suggests it as the best method of
(c compromising the present dispute," to add a scholium, in which Wren, Hooke, and Halley are acknowledged to have independently deduced the law of
gravity from the second law of Kepler.
At the meeting at which the manuscript of the
' Principia" was presented to the Royal Society, it
was agreed that the printing of it should be referred
to the Council, that a letter of thanks should be
written to its author; and at a meeting of the Council
it was resolved that the work should be printed at the
Society's expense, and that Dr. Halley should superintend it while going through the press. These resolutions were communicated by Dr. Halley, and in
Newton's reply he makes the following observations:




188


THE LIFE OF


cc The proof you sent me I like very well. I designed
the whole to consist of three books; the second was
finished last summer, being short, and only wants
transcribing, and drawing the cuts fairly. Some new
propositions I have since thought on, which I can as
well let alone. The third wants the theory of comets.
In autumn last I spent two months in calculation to
no purpose for want of a good method, which made
me afterwards return to the first book, and enlarge it
with diverse propositions, some relating to comets,
others to other things found out last winter. The
third I now design to suppress. Philosophy is such
an impertinently letigious lady that a man had as good
be engaged in law-suits as have to do with her. I
found it so formerly, and now I can no sooner come
near her again but she gives me warning. The two
first books without the third, will not so well bear the
title of "Philosophie Naturalis Principia Mathematica;" and therefore I had altered it to this, "De
Motu   Corporum  Libri duo."   But after second
thoughts I retain the former title. 'Twill help the
sale of the book, which I ought not to diminish now
'tis yours."
In replying to this letter, Dr. Halley regrets that
Newton's tranquillity should have been thus disturbed
by envious rivals; and implores him in the name of
the Society not to suppress the third book. He says
"c I must again beg you not to let your resentment run
so high as to deprive us of your third book, wherein
your applications of your mathematical doctrine to the
theory of comets, and several curious experiments
which, as I guess by what you write ought to compose
it, will undoubtedly render it acceptable to those who
will call themselves philosophers without mathematics,
which are much the greater number."
To these solicitations Newton seems to have
readily yielded. His second book was sent to the
Society and presented on the 2nd March, 1686-7.




SIR ISAAC NEWTON.


139


The third book was also transmitted, and presented on
the 6th April, and the whole work was completed
and published in May, 1687.
Such is a brief account of the publication of a work
which is memorable not only in the annals of one
science or of one country, but which will form an
epoch in the history of the world, and will ever be
regarded as the brightest page in the records of human
reason.
The " Principia" consists of three books. The two
first, which occupy three fourths of the work, are entitled, "On the Motion of Bodies;" and the third
bears the title, " On the System of the World."  The
first and second books contain the mathematical Principles of Philosophy viz., the laws and conditions of
motions and forces; and they are illustrated with
several philosophical scholia which treat of some of the
most general and best established points in philosophy,
such as the density and resistance of bodies, spaces
void of matter, and the motion of sound and light.
The object of the third book is to deduce from these
principles the constitution of the system of the world;
and this book has been drawn up in as popular a style
as posssible, in order that it may be generally read.
The great discovery which characterises the Principia is that of the principle of universal gravitation, as
deduced from the motion of the moon, and from the
three great facts or laws discovered by Kepler. This
principle is "' that every particle of matter is attracted
by, or gravitated to, every other particle of matter
with a force inversely proportional to the squares of
their distances."
From  the first law  of Kepler, namely, the proportionality of the areas to the times of their description, Newton inferred that the force which kept the
planet in its orbit was always directed to the sun;
and from the second law of Kepler, that every
planet moves in an ellipse with the sun in one of its




14'0


THE LIFB OF


foci, he drew the still more general inference, that the
force by which the planet moves round that focus
varies inversely as the square of its distance from the
focus.  As this law was true in the motion of satellites round their primary planets, Newton deduced
the equality of gravity in all the heavenly bodies towards the sun, upon the supposition that they are
equally distant from its centre, and in the case of terrestrial bodies, he succeeded in verifying this truth
by numerous and accurate experiments.
By taking a more general view of the subject,
Newton demonstrated that a conic section was the
only curve in which a body could move when acted
upon by a force varying inversely as the square of the
distance; and he established the conditions depending
on the velocity and the primitive positioh of the
body, which were requisite to make it describe a circular, an elliptical, a parabolic, or a hyperbolic orbit.
Notwithstanding the generality and importance of
these results, it still remained to be determined
whether the focus resided in the centres of the
planets, or belonged to each individual particle of
which they were composed. Newton removed this
uncertainty by demonstrating, that, if a spherical
body acts upon a distant body with a force varying
as the distance of this body from the centre of the
sphere, the same effect will be produced, as if each
of its particles acted upon the distant body according
to the same law.   And hence it follows that the
spheres, whether they are of uniform diversity, or
consist of concentric layers, with densities varying
according to any law whatever, will act upon each
other in the same manner as if their force resided in
their centres alone. But as the bodies of the solar
system are very nearly spherical, they will act upon
one another, and upon bodies placed on their surface,
as if they were so many centres of attraction; and
therefore we obtain the law of gravity which subsists




SIR ISAAC NEWTON.


141


between spherical bodies, namely, that one sphere
will act upon another with a force directly proportioned to the quantity of matter, and inversely as the
square of the distance between the centres of the
spheres. From the equality of action and reaction,
to which no exception can be found, Newton concluded that the sun gravitated to the planets, and the
planets to their satellites; and the earth itself to the
stone which falls upon its surface, and, consequently,
that the two mutually gravitating bodies approached
to one another with velocities inversely proportional
to their quantities of matter.
Having established this universal law, Newton was
enabled not only to determine the weight which the
same body would have at the surface of the sun and
the planets, but even to calculate the quantity of
matter in the sun, and in all the planets that had
satellites, and even to determine the density or
specific gravity of the matter of which they were
composed. In this way he found that the weight of
the same body would be twenty-three times greater
at the surface of the sun than at the surface of the
earth, and that the density of the earth was four times
greater than that of the sun, the planets increasing in
density as they receded from the centre of the
system.
If the peculiar genius of Newton has been displayed in his investigation of the law of universal
gravitation, it shines with no less lustre in the patience
and sagacity with which he traced the consequences
of this fertile principle.
The discovery of the spheroidal form of Jupiter by
Cassini had probably directed the attention of Newton to the determination of its cause, and consequently to the investigation of the true figure of the
earth. The spheroidal form of the planets had been
ascribed by Copernicus to the gravity, or natural appetency of their parts; but upon considering the




142


THE LIFE OF


earth as a body revolving upon its axis, Newton
quickly saw that the figure arising from the mutual
attraction of its parts must be modified by another
force arising from its volition. When a body revolves
upon an axis, the velocity of rotation increases from
the poles, where it is nothing, to the equator, where
Itis a maximum. In consequence of this velocity,
the bodies on the earth's surface have a tendency to fly
off from it, and this tendency increases with the velocity. Hence arises a centrifugal force which acts in
combination with the force of gravity, and which
Newton found to be the 289th part of the force of
gravity at the equator, and decreasing, as the cosine
of the latitude, from the equator to the poles. The
great predominance of gravity over the centrifugal
force prevents the latter from carrying off any bodies
from the earth's surface, but the weight of all bodies
is diminished by the centrifugal force, so that the
weight of any body is greater at the poles than it is
at the equator. If we now suppose the waters at the
pole to communicate with those of the equator by
means of a canal, one branch of which goes from the
pole to the centre of the earth, and the other from the
centre of the earth to the equator, then the polar
branch of the canal will be heavier than the equatorial
branch, in consequence of its weight not being diminished by the centrifugal force; and, therefore that
the two columns may be in equilibrio, and the equatorial one may be lengthened. Newton found that
the length of the polar must be to that of the equatorial canal as 229 to 230, or that the earth's polar
radius must be seventeen miles less than its equatorial
radius —that is, that the figure of the earth is an oblate spheroid, formed by the revolution of an ellipse
round its lesser axis. Hence it follows that the intensity of gravity at any point of the earth's surface
is in the inverse ratio of the distance of that point
from the centre, and, consequently, that it diminishes




SIR ISAAC NEWTON.


143


from the equator to the poles-a result which he confirmed by the fact, that clocks required to have their
pendulums shortened in order to beat true time, when
carried from Europe towards the equator.
The next subject to which Newton applied the
principle of gravity was the tides of the ocean. The
philosophers of all ages had recognised the connection
between the phenomena of the tides, and the position
of the moon. The College of Jesuits, at Coimbra,
and subsequently Antonio de Dominis and Kepler,
distinctly referred the tides to the attraction of the
earth by the moon; but so imperfect was the explanation which was thus given of the phenomenon, that
Galileo ridiculed the idea of lunar attraction, and
substituted for it a fallacious explanation of his own.
That the moon is the principal cause of the tides, is
obvious from the well-known fact, that it is highwater at any given place about the time when she is
in the meridian of that place; and that the sun performs a secondary part in their production may be
proved from the circumstance, that the highest tides
take place when the sun, the moon, and the earth are
in the same straight line-that is, when the force of
the sun conspires with that of the moon; and that
the lowest tides take place when the lines drawn from
the sun and moon to the earth are at right angles to
each other-that is, when the force of the sun acts in
opposition to that of the moon. The most perplexing
phenomenon in the tides of the ocean, and one which
is still a stumbling-block to persons slightly acquainted
with the theory of attraction, is the existence of high
water on the side of the earth opposite to the moon,
as well as on the side next the moon. To maintain
that the attraction of the moon at the same instant
draws the waters of the ocean towards herself, and
lso draws them    from  the earth in an opposite
direction, seems, at first sight paradoxical; but
the  difficulty vanishes  when  we  consider the






I
I,




144


THE LIFE OF


earth, or rather the centre of the earth, and the
water on each side of it as three distinct bodies
placed at different distances from the moon, and
consequently attracted with forces inversely proportional to the squares of their distances. The water
nearest the moon will be much more powerfully attracted than the centre of the earth, and the centre of
the earth more powerfully attracted than the water
farthest from the moon. The consequence of this must
be, that the waters nearest the moon will be drawn
away from the centre of the earth, and will consequently rise from their level, while the centre of the
earth will be drawn away from the waters opposite the
moon, which will, as it were, be left behind, and consequently be in the same situation as if they were
raised from the earth in a direction opposite to that
in which they are attracted by the moon. Hence the
effect of the moon's motion upon the earth is to draw
its fluid parts into the form of an oblong spheroid, the
axis of which passes through the moon. As the action of the sun will produce the very same effect,
though in a smaller degree, the tide at any place will
depend on the relative position of these two spheroids,
and will be always equal either to the sum or to the
difference of the effects of the two luminaries. At
the time of new and full moon the two spheroids will
have their axis coincident, and the height of the tide,
which will then be a spring one, will be equal to the
sum of the elevations produced in each spheroid considered separately, while at the first and third quarters
the axis of the spheroids will be at right angles to each
other, and the height of the tide, which will then be
a neap one, will be equal to the difference of the elevations produced in each separate spheroid. By comparing the spring and neap tides, Newton found that
the force with which the moon acted upon the waters
of the earth was to that with which the sun acted
upon them as 4.48 to 1; that the force of the moon




SIR ISAAC NEWTON.            145
produced a tide of 8.63 feet, that of the sun of 1.93
feet; and both of them combined, one of 10 feet and a
half French measure,-a result which in the open sea
does not deviate much from observation. Having thus
ascertained the force of the moon upon the waters of
our globe, he found that the quantity of matter in the
moon was to that in the earth as 1 to 40, and the
density of the moon to that of the earth as 11 to 9.
The motions of the moon, so much within the reach
of our own observation, presented a fine field for'the
application of the theory of universal gravitation.
The irregularities exhibited in the lunar motions had
been known in the time of Hipparchus and Ptolemy.
Tycho Brahe had discovered the great inequality called
the variation, amounting to 37 minutes, and depending
on the alternate acceleration and retardation of the
moon in every quarter of a revolution, and he had also
ascertained the existence of the annual equation. Of
these two inequalities Newton gave a most satisfactory
explanation. The action of the sun upon the moon
may be always resolved into two, one acting in the
direction of the line joining the moon and the earth,
and consequently tending to increase or diminish the
moon's gravity to the earth, and the other in a direction at right angles to this, and consequently tending
to accelerate or retard the motion in her orbit. Now,
it was found by Newton that this last force was reduced to nothing, or vanished at the syzigies or quadratures, so that at these four points the moon described
areas proportionable to the times. The instant, however, that the moon quits these positions, the force under consideration, which we may call the tangential
force, begins, and it reaches its maximum in the four
octants. The force, therefore, compounded of these
two elements of the solar force, or the diagonal of the
parallelogram which they form, is no longer directed
to the earth's centre, but deviates from it at a maxiK::f. S —f/




14Q


TE, LME OFr


mtum about 30 minutes, and therefore affects the angular motion of the moon, the motion being accelerated
in passing from the quadratures to the syzigies, and
retarded in passing from the syzigies to the quadratures. Hence the velocity is in its mean state in the
octants, a maximum in the syzigies, and a minimum in
the quadratures.
Upon considering the influence of the solar force in
diminishing or increasing the moon's gravity to the
earth, Newton saw that her distance and her periodic
time must from this cause be subject to change, and in
this way he accounted for the annual equation observed by Brahe. By the application of similar principles, he explained the cause of the motion of the apsides, or of the greater axis of the moon's orbit, which
has an angular progressive motion of three degrees
four minutes nearly in the course of one lunation, and
he showed that the retrogadation of the nodes, amounting to three minutes ten seconds daily, arose from one
of the elements of the solar force being exerted in the
plane of the ecliptic, and thus cause the line of the
nodes, or the intersection of these two planes, to move
in a direction opposite to that of the moon. The
lunar theory thus blocked out by Newton, required for
its completion the labours of another century. The
imperfections of the fluxionary calculus prevented him
from explaining the other inequalities of the moon's
motions, and it was reserved to Euler, D'Alembert,
Clairant, Mayer, and Laplace to bring the lunar tables
to a high degree of perfection, and to enable the navigator to determine his longitude at sea with a degree
of precision which the most sanguine astronomer could
scarcely have anticipated.
By the consideration of the retrogade motion of
the moon's nodes, Newton was led to discover the
cause of the remarkable phenomenon of the procession
of the equinoctial points which moved fifty seconds
annually, and completed the circuit of the heavens in. A




SIR ISAAC NEWTON.


147


25,920 years. Kepler declared himself unable to
assign any cause for this motion, and we do not think
any other person ever made the attempt. From the
spheroidal form of the earth, it may regarded as a
sphere with a spheroidal ring surrounding its equator,
one half of the ring being above the plane of the
ecliptic, and the other half below. Considering this
excess of matter as a system of satellites adhering to
the earth's surface, Newton saw that the combined
actions of the sun and moon upon these satellites
tended to produce a retrogadation with the nodes of
the circles which they described in their diurnal rotation, and that the sum of all the tendencies being
communicated to the whole mass of the planet, ought
to produce a slow retrogadation of the equinoxial
points. The effect produced by the motion of the
sun he found to be forty seconds, and that produced
by the action of the moon ten seconds.
Although there could be little doubt that the
comets were retained in their orbits by the same laws
which regulated the motions of the planets, yet it
was difficult to put this opinion to the test of observation. The visibility of comets only in a small part
of their orbits rendered it difficult to ascertain their
distance and periodic time, and as their periods were
probably of great length, it was impossible to correct
approximate results by repeated observation.  Nowton, however, removed this difficulty, by showing
how to determine the orbits of a comet, namely, the
form and position of the orbit, and the periodic time,
by three observations. By applying this method to
the comet of 1680, he calculated the elements of its
orbit, and from the agreement of the computed places
with those which were observed, he justly inferred
that the motion of comets were regulated by the same
laws as those of the planetary bodies. This result
Was one of great importance; for as the comets enter
or system in every possible direction, and at all an



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gles with the ecliptic; and, as a great part of their
orbits extend far beyond the limits of the solar system, it demonstrated the existence of gravity in spaces
far removed beyond the planet, and proved that the
law of the inverse ratio of the squares of the distance
was true in every possible direction, and at very
remote distances from the centre of our system.
Such is a brief view of the leading discoveries
which the " Principia" first announced to the world.
The grandeur of the subjects of which it treats, the
beautiful simplicity which it unfolds, the clear and
concise reasoning by which that system is explained,
and the irresistible evidence by which it is supported,
might liave insured it the warmest admiration of contemporary mathematicians, and the most welcome
reception in all the schools of philosophy throughout
Europe. This, however, is not the way in which
great truths are generally received.  Though the
astronomical discoveries of Newton were not assailed
by the class of ignorant pretenders who attacked his
optical writings, yet they were everywhere resisted by
the errors and prejudices which had taken a deep hold
even of the strongest minds. And, notwithstanding
a few examples that might be quoted, we must admit the truth of the remark of Voltaire, that "though
Newton survived the publication of the 'Principia'
more than forty years, yet at the time of his death,
he had not above twenty followers out of England."
With regard to the progress of the Newtonian
philosophy in Great Britain, some difference of
opinion has been entertained.  Professor Playfair
gives the following account of it. "In the universities of England, though the Aristotelian physics had
made an obstinate resistance, they had been supplanted by the Cartesian, which became firmly established about the time.when their foundation began
to be sapped by the general progress of science, and
particularly by the discoveries of Newton. For more




SIR ISAAC NEWTON.


149


than thirty years after the publication of these discoveries, the system of vortices kept its ground, and a
translation from the French into Latin of the Physics
of Rohault-a work entirely Cartesian, continued at
Cambridge to be the text for philosophical instruction.
About the year 1718, a new and more elegant translation of the same book was published by Dr. Samuel
Clarke, with the addition of notes, in which that profound and ingenious writer explained the views of
Newton on the principal objects of discussion, so that
the notes contained virtually a refutation of the text;
they did so, however, only virtually, all appearance of
argument and controversy being carefully avoided.
Whether this escaped the notice of the learned
Doctor or not, is uncertain; but the new translation,
from its better Latinity, and the name of the editor,
was readily admitted to all the academical honours
which the old one had enjoyed.  Thus the stratagem
of Dr. Clarke completely succeeded; the tutor might
predict from the text, but the pupil would sometimes
look into the notes, and error is never so sure of being.
exposed, as when the truth is placed close to it, side
by side, without anything to alarm  prejudice, or
awaken from its lethargy the dread of innovation.
Thus, therefore, the Newtonian philosophy first.
entered the university of Cambridge under the protection of the Cartesian." To this passage thelearned professor adds the following as a note.
"The universities of St. Andrews and Edinburgh
were, I believe, the first in Britain where the Newtonian philosophy was made the subject of the academical prelictions. For this distinction they are indebted to James and David Gregory, thejfirst in some
respects the rival, but both the friends of Newton.
Whiston bewails, in the anguish of his heart, the difference, in this respect, between those universities and
his own. David Gregory taught in Edinburgh for
several years prior to 1690, when he removed to




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Oxford; and Whiston says, ' he had already caused
several of his scholars to keep acts, as we call them,
upon several branches of the Newtonian philosophy,
while we, at Cambridge, poor wretches, were ignominiously studying the fictitious hypothesis of the
Cartesians.' I do not, however, mean to say, that
from this date the Cartesian philosophy was expelled
from these universities; the Physics of Rohault were
still in use as a text-book-at least occasionally, to a
much later 'period than this, and a great deal, no
doubt, depended on the character of the individual.
Professor Keill introduced the Newtonian philosophy
in his lectures at Oxford in 1697; but the instructions of the tutors, which constitute the real and efficient system of the university were not cast into the
mould till long afterwards."  Mr. Dugald Stewart,
adopting the same view of the subject, has stated, "That
the philosophy of Newton was publicly taught by
David Gregory at Edinburgh, and by his brother
James Gregory, at St. Andrews, before it was able to
supplant the vortices of Descartes, in the very university of which Newton was a member. It was in the
Scottish universities that the philosophy of Locke, as
well as that of Newton, was first adopted as a branch
of academical education."
Anxious as we should have been to have awarded
to Scotland the honour of having first adopted the
Newtonian philosophy, yet a regard for historical truth
compels us to take a different view of the subject. It
is well known that Sir Isaac Newton delivered
lectures on his own philosophy from the Lucasian
chair before the publication of the Principia; and in
the very page of Whiston's Life quoted by Professor
Playfair, he informs us that he had heard him read
such lectures in the public schools, though at that
time he did not at all understand them. Newton continued to lecture till 1699, and occasionally, we presume, till 1703, when Whiston became his successr,




SIR ISAAC XEWEFTON.


151


having been appointed his deputy in 1699. In both
of these capacities Whiston delivered in the public
schools a course of lectures on astronomy, and a course
of physico-mathematical lectures, in which the mathematical philosophy of Newton was explained and
demonstrated; and both these courses were published,
the one in 1707, and the other in 1710, " for the use
of the young men in the university."  In 1707, the
celebrated blind mathematician, Nicholas Saunderson,
took up his residence in Christ's College, without
being admitted a member of that body. The society
not only allotted to him apartments, but gave him the
free use of their library. With the consent of Whiston he delivered a course of lectures " On the Principia, Optics, and Universal Arithmetic of Newton"
and the popularity of these lectures was so great that
Sir Isaac corresponded on the subject of them with
their author; and on the ejection of Whiston from
Lucasian chair in 1711, Saunderson was appointed
his successor, and contined to teach the Newtonian
philosophy till his death in 1739.
One of the most strenuous supporters of the Newtonian philosophy was Dr. Langton. In 1709-10,
when he was proctor of the college, instead of appointing a moderator, he discharged the office himself, and
devoted his most active exertions to the promotion of
mathematical knowledge. Previous to this, he had
even published a paper of questions on the Newtonian
philosophy, which appear to have been used as theses
for disputations; and such was his ardour and learning that they greatly contributed to the popularity of
his college. Between 1706 and 1716, the celebrated
Roger Cotes, the friend and disciple of Newton, filled
the Plumian chair of astronomy and experimental
philosophy at Cambridge.   During this period he
edited the second edition of the Principia, which he
enriched with an admirable preface, and thus contribted by his writings as well as by his lectures, to




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advance the philosophy of his master. About the
same time, the celebrated Dr. Bentley, who first made
known the philosophy of his friend to the readers of
general literature, filled the high office of Master of
Trinity College, and could not have failed to have
exerted his utmost influence in propagating doctrines
which he so greatly admired. Had any opposition
been offered to the introduction of the true system of
the universe, the talents and influence of these individuals would have immediately suppressed it; but
no such opposition seems to have been made; and
though there may have been individuals at Cambridge, ignorant of mathematical science, who adhered to the system of Descartes, and studied the
physics of Rohault, yet it is probable that similar
persons existed in the Scottish universities; and we
cannot regard their adherence to error as disproving
the general fact, that the philosophy of Newton was
quickly introduced into all the universities of Great
Britain.
Dr. John Keill was the first person who publicly
taught natural philosophy by experiments. Desaguliers informs us that this author "laid down very
simple propositions, which he proved by experiments,
till he had instructed his auditors in the laws of
motion, the principles of hydrostatics and optics, and
some of the chief propositions of Sir Isaac Newton,
concerning light and colours. He began these courses
in Oxford about the year 1704 or 1705, and in that
way introduced the love of the Newtonian philosophy."
When Dr. Keill left the university, Desaguliers began to teach the Newtonion philosophy by experiments. He commenced his lectures at Harthall in
Oxford, in 1710, and delivered upwards of one hundred and twenty courses; and when he went to settle
in London in 1713, he informs us that he found "the
Newtonian philosophygenerally received among persons
of all ranks and professions, and even among the ladies




SIR ISAAC NEWTON.


153


by the help of experiments." Such were the steps by
which the philosophy of Newton was established in
Great Britain; and long before his death Sir Isaac
enjoyed the high satisfaction of seeing his doctrine
triumphant in his native land.
Previous to the time of Newton, the doctrine of
infinite quantities had been the subject of the most
anxious study. The ancients made the first step in
this curious inquiry by a rude, though ingenious, attempt to determine the area of curves. The method
of exhaustions which was used for this purpose consisted in finding a given rectilinear area to which the
inscribed and circumscribed polygonal figures continually approached by increasing the number of their
sides. This area was obviously the area of a curve,
and in the case of the parabola it was found by Archimedes to be two-thirds of the area formed by multiplying the ordinate by the abscissa. Although the
synthetical demonstration of the results was perfectly
conclusive, yet the method itself was limited and imperfect. The celebrated Pappus of Alexandria followed Archimedes in the same inquiries, and in his
demonstration of the property of the centre of gravity
of a plane figure, by which we may determine the
solid formed by its revolution, he has shadowed forth
the discoveries of later times.
In his curious tract on Stareometry, published in
1615, Kepler made some advances in the doctrine of
infinitesimals. Prompted to the task by a dispute
with the seller of some casks of wine, he studied the
measurement of solids formed by the revolution of a
curve round any line whatever. In solving some of
the simplest of these problems, he conceived a circle
to be formed of an infinite number of triangles having
all their vortices in the centre, and their infinitely
small bases in the circumference of the circle, and by
thus rendering familiar the idea of quantities infinitely
great and infinitely small, he gave an impulse to than




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branch of mathematics. The failure of Kepler, too,
in solving some of the more difficult of the problems
which he himself proposed, roused the attention of
geometers, and seems particularly to have attracted
the notice of Cavaleri.
This ingenious mathematician was born at Milan in
1598, and was Professor of Geometry at Bologna. In
his method of Indivisibles, which was published in
1635, he considered a line as composed of an infinite
number of points, a surface of an infinite number of
lines, and a solid of an infinite number of surfaces;
and he lays it down as an axiom, that the infinite
sums of such lines and surfaces have the same ratio
when compared with the linear or superficial unit, as
the surfaces and solids which are to be determined.
As it is not true that an infinite number of infinitely
small points can make a line, or an infinite number of
infinitely small lines a surface, Pascal removed this
verbal difficulty by considering a line as composed of
an infinite number of infinitely short lines, a surface
as composed of an infinite number of infinitely narrow
parallelograms, and a solid of infinitely thin solids.
Bat, independent of this correction, the conclusions
deduced by Cavaleri are rigorously true, and his method of ascertaining the ratios of areas and solids to
one another, and the theorems which he deduced from
it, may be considered as forming an era in mathematics.
By the application of this method, Roberval and
Toricelli showed that the area of the cycloid is three
times that of its generating circle, and the former
extended the method of Cavaleri to the case where
the powers of the terms of the arithmetical progression
to be summed were fractional.
I  applying the doctrine of infinitely small quantiies to determine the tangents of curves, and the
naxima and minima of their ordinates, both Roberval and Fermat  a ade a near aproach to the invems




SIR ISAAC NEWTON.


155


tion of Fluxions-so near indeed, that both Lagrange
and Laplace have pronounced the latter to be the true
inventor of the differential calculus.
The labours of Peter Fermat, a counsellor of the
parliament of Thoulouse, approached still nearer to
the fluxionary calculus. In his method of determining
the maxima and minima of the ordinates of curves, he
substitutes x - e for the independent variable x in
the function which is to beeome a maximum, and as
these two expressions should be equal when e becomes infinitely small or o, he frees this equation from
surds and radicals, and after dividing the whole by e e
is made = o, and the equation for the maximum is thus
obtained.  Upon a similar principle he founded his
method of drawing tangents to curves. But though
the methods thus used by Fermat are in principle the
same with those which connect the theory of tangents
and of maxima with the analytical method of exhibiting the differential calculus, yet it is a singular
example of national partiality, to consider the inventor of these methods as the inventor of the method of
fluxions.
The discoveries of Fermat were improved and simplified by Hudde, Huygens, and Barrow, and by the
publication of the " Arithmetic of Infinites" by Dr.
Wallis, Savilian Professor of Geometry at Oxford,
mathematicians were conducted to the very entrance
of a new and untrodden field of discovery. This dis.
tinguished author had effected the quadrature of all
curves whose ordinates can be expressed by any direct
integral powers; and though he had extended his
conclusions to the cases where the ordinates are expressed by the inverse or fractional powers, yet he
failed in its application. Nicolas Mercator (Kauff
surmounted the difficulty by which Wallis had beae
baffed, by the continued division of the numerator by
the denominator to infinity, and the applying Walliia
method to the resulting positive powers. In Atds




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he obtained, in 1667, the first general quadrature of
the hyperbola, and, at the same time, gave the regular development of a function in series.
In order to obtain the quadrature of the circle, Dr.
Wallis considered that if the equations of the curves
of which he had given the quadrature were arranged
in a series, beginning with the most simple, these
areas would form  another series. I-e saw also that
the equation of the ciecle was intermediate between
the first and second terms of the first series, or between the equation of a straight line and that of a parabola, and hence he concluded, that by interpolating
a term betwen the first and second term of the second
series, he would obtain the area of the circle. In pursuing this singularly beautiful thought, Dr. Wallis
did not succeed in obtaining the indefinite quadrature
of the circle, because he did not employ general exponents; but he was led to express the entire area of
the circle by a fraction, the numerator and the denominator of which are each obtained by the multiplication of a certain series of numbers.
Such was the state of this branch of mathematical
science when Newton, at an early age, directed his
attentionto it. At the commencement of his mathematical studies, when the works of Dr. Wallis fell into
his hands, he was led to consider how he could interpolate the general values of the areas in the second
series of that mathematician.  With this view he investigated the mathematical law of the co-efficients of
the series, and obtained a general method of interpolating not only the series above referred to, but also
other series. These were the first steps taken by Newton; and, as he himself informs us, in his letter to the
secretary of the Royal Society, October 24, 1676, they
would have entirely escaped from his memory, if he had
not a few weeks before found the notes which he had
made upon the subject. When he had obtained this
method, it occurred to him that the very same process




SIR ISAAC NEWTON.


157


was applicable to the ordinates, and by following out
this idea, he discovered the general method of reducing
radical quantities, composed of several terms into infinite series, and was thus led to the discovery of the
celebrated "Binomial Theorem."   He now entirely
neglected his methods of interpolation, and employed
that theorem alone as the easiest and most direct method for the quadratures of curves, and in the solution of many questions which had not even been attempted by the most skilful mathematicians.
After having applied the Binomial theorem to the
rectification of curves, and to the determination of the
surfaces and contents of solids, and the position of their
centres of gravity, he discovered the general principle
of deducing the areas of curves from the ordinate, by
considering the area as a nascent quality increasing by
continual fluxion in the proportion of the length of the
ordinate, and supposing the abscissa to increase uniformly in proportion to the time. In imitation of
Calverius, he called the momentary increment of a
line a point, though it is not a geometrical point, but
an infinitely short line; and the momentary increment
of an area or surface he called a line, though it is not
a geometrical line, but an infinitely narrow space. By
thus regarding lines as generated by the motion of
points, surfaces by the motions of lines, and solids by
the motion of sarfaces, and by considering that the
ordinates, abscissare, &c., of curves thus formed, vary
according to a regular law depending on the equation
of the curve, he deduces from this equation the velocities with which these quantities are generated; and
by the rules of infinite series he obtains the ultimate
value of the quantity required. To the velocities with
which every line or quantity is generated, Newton
gave the name of Fluxions, and to the lines or quantities themselves that of Fluents. This method contitutes the doctrine of fluxions which Newton had
invented previous to 1666, when the breaking out of




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the plague at Cambridge drove him from that city,
aad turned his attention to other subjects.
But though Newton had not communicated this
great invention to any of his friends, he composed his
treatise "Analysis per equationes numero terminorum
mfinitas," in which the principle of fluxions and its
numerous applications are clearly pointed out. In the
month of June, 1669, he communicated this work to
Dr. Barrow, who mentions it in a letter to Mr. Collins, dated the 20th June, 1699, as the production of
a friend of his residing at Cambridge, who possesses a
fine genius for such inquiries. On the 31st of July
he transmitted the work to Collins; and having received his approbation of it, he informs him that the
name of the author was Newton, a fellow of his own
college, and a young man who had only two years
before taken his degree of M.A. Collins took a copy
of this treatise, and returned the original to Dr. Barrow; and this copy having been found among Collins's
papers by his friend Mr. William Jones, and compared
with the original manuscript borrowed from Newton,
it was published with the consent of Newton in 1711,
nearly half a century after it was written.
Though the discoveries contained in this treatise
were not at first given to the world, yet they were
made generally known to mathematicians by the correspondence of Collins, who communicated them to
James Gregory; to Bertel and Vernon, in France;
to Sluisius, in Holland; to Borelli, in Italy; and to
Strode, Townsend, and Oldenburgh, in letters dated
between,1669 and 1672.
Hitherto the method of fluxions was known only to
the friends of Newton and their correspondents; but
in the first edition of the " Principia," which appeared
in 1687, he published, for the first time, the funda
mental principle of the fiuxionary calculus, in the
second lemma of the second book. No information,
however,; is here given respecting the algorithm, or




SIR 1SARI4  NEWTON.


150


notation of the calculus, and it was not till 1693 that
it was communicated to the mathematical world in
the second volume of Dr. Wallis's works, which were
published in that year. This information was extracted from two letters written by Newton, in 1i62.
Some time in the year 1672, Newton had undertaken to publish an edition of Kinckhuysen's Algebra,
with notes and additions. He therefore drew up a
treatise, entitled " A Method of Fluxions," which he
proposed as an introduction to that work; but the
fear of being involved in disputes about this new discovery, or perhaps the wish to render it more complete, or to have the sole advantage of employing it in
his physical researches, induced him to abandon this
design. At a later period of his life he again resolved
to give it to the world; but it did not appear till after
his death, when it was translated into English, and
published in.1736, with a commentary by Mr. John
Colson, Professor of Mathematics in Cambridge.
To the first of Newton's Optics, which appeared in
1704, there were added two mathematical treatises,
" entitled " Tractatus duo de speciebus et magnitudine
figurarum curvilinearum," the one bearing the title of
" Tractatus de Quadratura Curvarum," and the other
" Enumeratio linearum tertii ordinis." The first contains an explanation of the doctrine of fluxions, and
of its application to the quadrature of curves; and
the second a classification of seventy-two curves of the
third order, with an account of their properties. The
reason for publishing these two tracts in his Optics (in
the subsequent editions of which they are omitted) is
thus stated in the advertisement:-" In a letter written to M. Leibnitz, in tie year 1679, and published
by Dr. Wallis, I mentioned a method by which I had
found some general theorems about squaring curvilinear figures on comparing them with the conic sections,
or other the simplest figures with which they might be
compared. And some years ago I lent out a manu




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script containing such theorems; and having since
met with some things copied out of it, I have on this
occasion made it public, prefixing to it an introduction, and joining a scholium concerning that method.
And I have joined with it another small tract concerning the curvilineal figures of the second kind,
which was also written many years ago, and made
known to some friends, who have solicited the making
it public."
In the year 1707, Mr. Whiston published the algebraical lectures which Newton had, during nine years,
delivered at Cambridge, under the title of " Arithmetica Universalis, sive de Compositione et Resolutione Arithmetica Liber." It is not known how Mr.
Whiston obtained possession of this work; but it is
stated by one of the editors of the English edition,
that " Mr. Whiston, thinking it a pity that so noble
and useful a work should be doomed to a college confinement, obtained leave to make it public." It was
soon after translated into English by Mr. Ralphson;
and a second edition of it, with improvements by the
author, was published at London in 1712 by Dr.
Machin, then secretary to the Royal Society. With
the view  of stimulating mathematicians to write
annotations on this admirable work, the celebrated
S'Gravesande published a tract entitled " Specimen
Commentarii in Arithmeticam Universalemr;" and
Maclaurin's Algebra seems to have been drawn up in
consequence of this appeal.
Among the mathematical works of Newton, we
must not omit to enumerate a small tract entitled
"Methodus Differentialis," which was published with
his consent in 1711. It consists of six propositions,
f    which contain a method of drawing a parabolic curve
through any given number of points, and which was
useful for constructing tables by the interpolation of
series, and for solving problems depending the quadrature of curves.




SIR ISAAC NEWTON.


161


Another mathematical treatise of Newton's was
published for the first time in 1779, in Dr. Horsley's
edition of his works. It is entitled " Artis Analyticae
Specimina, vel Geometria Analytica." In editing this
work, which occupies about one hundred and thirty
quarto pages, Dr. Horsley used three manuscripts, one
of which was in the handwriting of the author; another,
written in an unknown hand, was given by Mr. William
Jones to the Hon. Charles Cavendish; and a third,
copied from this by Mr. James Wilson, the editor of
Robins's works, was given to Dr. Horsley by Mr.
John Nourse, bookseller to the king. Dr. Horsley
has divided it into twelve chapters, which treat of
infinite series; of the reduction of affected equations;
of the specious resolution of equations; of the doctrine of fluxions; of maxima and minima; of drawing
tangents to curves; of the radius of curvature; of the
quadrature of curves; of the area of curves which
are comparable with the conic sections; of the construction of mechanical problems, and on finding the
lengths of curves.
In enumerating the mathematical works of Sir Isaac
Newton, we must not overlook his solutions of the
celebrated problems proposed by Bernouilli and Leibnitz. On the Kalends of January, 1697, John Bernouilli addressed a letter to the most distinguished
mathematicians in Europe, challenging them to solve
the two following problems:
1. To determine the curve like connecting two
given points which are at different distances from the
horizon, and not in the same vertical line, along
which a body passing by its own gravity, and beginning to move at the upper point, shall descend to the
lower point in the shortest time possible.
2. To find a curve line of this property, that the
two segments of a right line drawn from a given point
through the curve, being raised to any given power,
L




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and taken together, may make everywhere the same
sum.
On the day after receiving these problems, Newton
addressed to the President of the Royal Society a solution of them both.  He announced that the curve
required in the first problem must be a cycloid, and
he gave a method of determining it. He' solved also
the second problem, and he showed that by the same
method other curves might be formed which shall cut
off three or more segments having the like proportions.
Leibnitz, who wda struck with the beauty of the
problem, requested the author, who had allowed six
months for its solution, to extend the period to double
that time.  This delay was readily granted, and solutions were obtained from Newton, Leibnitz, and the
Marquis de L'Hopital; and although that of Newton,
yet Bernouilli recognised in it his powerful mind, " as
the lion is known by his claw."
The last mathematical effort of Sir Isaac was made
with his usual success in solving a problem which
Leibnitz proposed in 1716, in a letter to the Abbe
Conty, " for the purpose of feeling the pulse of the
English analysts," as he expressed it. The object of
this problem was to determine the curve which should
cut at right angles an infinity of curves of a given nature, but expressible by the same equation. Newton
received this problem about five o'clock in the afternoon, and though the problem was extremely difficult,
and he himself much fatigued at the time, yet he
finished the solution of it before he went to bed.
Such is a short account of the mathematical writings
of Newton, not one of which as is reported, were voluntarily communicated to the world by himself. The
publication of his "Universal Arithmetic," is said to have
been a breach of confidence on the part of Whiston;
and however this may be, it was, as is evident, an
unfinished work never designed for the public.  The
in consequence of plagiarisms front the manuscripts of




SIR ISAAC A4EWTON.. publication of his " Quadrature of Curves," and of his
"Enumeration of Curve Lines," was rendered necessary
_them which he had lent to his friends, and the rest of
his analytical writings did not appear till after his
death. It is impossible to penetrate into the motives
by which Sir Isaac was on these occasions actuated.
If his object was to keep possession of his discoveries
till he had brought them to a higher degree of perfection, we may approve of the propriety, though
we can by no means admire the prudence of such &
step. If he wished to retain to himself his own
methods, iu order that he alone might have the advantage of them, in prosecuting his inquiries, we
cannot reconcile so selfish a measure with that openness and generosity of character which marked the
whole of our author's life. If he withheld his labours
from the world in order to avoid the disputes and contentions to which they might give rise,'he adopted
the very worst method of securing his tranquillity.
That this was the leading motive under which he
acted, there can be little doubt. The early delay in
the publication of his method of fluxions, after the
breaking out of the plague at Cambridge, was probably owing to his not having completed the algorithm
of that calculus; but no apology can be made for the
imprudence of withholding it any longer from the
public. Had he published this noble discovery even
previous to 1623, when his great rival had not even,
entered upon these studies which led him to the
same method, he would have secured to himself the
undivided honour of the invention; and Leibnitz
could have aspired to no other fame but that of an improver of the doctrine of fluxions.  But he unfortunately acted otherwise. He announced to his friends
that he possessed a method of great generality and
power; he communicated to them a general account
of its principles and applications; and the information which was thus conveyed directed theatta




164


THE LIE OFP


of mathematicians to subjects to which they might not
otherwise have applied their powers. In this way, the
discoveries which he had previously made, were made
subsequently by others; and Leibnitz, in place of
appearing in the theatre of science as the disciple and
follower of Newton, stood forth with all the dignity
of a rival; and, by the early publication of his discoveries, had nearly placed himself on the throne which
Newton was destined to ascend.
A  brief account of the dispute between Newton.
and Leibnitz, respecting the invention of fluxions, is all
that we can admit here from the popular nature of our
volume.
In the beginning of 1673, Leibnitz came to London
in the suite of the Duke of Hanover, ernd he became
acquainted with the great men who then adorned the
capital of the British Empire.  Among these was
Oldenburg, a fellow countryman, who was the secretary to the Royal Society. About the beginning of
March in the same year, Leibnitz went to Paris, where,
with the assistance of Huygens, he devoted himself
to the study of the higher geometry. In the month
of July he renewed his correspondence with Oldenburg,
and he communicated to him some of the discoveries
which he had made relative to a series, particularly
the series for a circular arc in terms of the tangent,
Oldenburg informed him in return of the discoveries
of Newton and Gregory on series; and in 1676,
Newton communicated to him, through 91denburg, a
letter of fifteen closely printed quarto pages, containing many of his analytical discoveries, and stating,.
that he possessed a general method of drawing tangents, which he thought it necessary to conceal in
two sentences of transposed characters.
In this letter neither the method of fluxions nor any
of its principles are communicated, but the superiority
of the method over all others is so full described, that
Leibnitz could scarcely fail to discover that Newtoa




SIR ISAAC NEWTON.           165
Possessed that secret of which geometers had so long
been in quest.
' Had Leibnitz, at the time of receiving this letter,
been entirely ignorant of his own differential method,
the information thus conveyed to him by Newton
could not fail to stimulate his curiosity, and excite
his mighty efforts to obtain possession of so great a
secret. That this new method was intimately connected with the subject of series was clearly indicated
by Newton; and as Leibnitz was deeply versed in
this branch of analysis, it is far from improbable that
a mind of such strength and acuteness might attain his
object by direct investigation. That this was the
case may be inferred from his letter to Oldenburg,
(to be communicated by Mr. Newton), of the 21st of
June, 1677, where he mentions he had for some time
been in possession of a method of drawing tangents
more general than that of Sluisius, namely, by the
differences of ordinates. He then proceeds with the
utmost frankness to explain the method, which was
no other than the differential calculus. He describes
the algorithm which he had adopted, the formation of
differential equations, and the application of the calculus to various geometrical analytical questions. No
answer seems to have been returned to this letter,
either by Newton or Oldenburg, and with the exception of a short letter from Leibnitz to Oldenburg,
12th of July, 1677, no farther correspondence seems
to have taken place. This may be accounted for by
the death of Oldenburg in the month of August,
when the two rivals pursued their researches with all
the zest which the greatness of the subject was so
well calculated to inspire.
In the hands of Leibnitz the different calculus made
rapid progress. In the Acea Eruditorum, which was
published at Leipsic, in November, 1684, he gave the
first account of it, describing its algorithm in the same
manner as he had done in his letter to Oldenburg, and




6t^                THE LIfE OF
pointing out its application to the drawing of tangents
and the determination of maxima and minima. He
makes a remote reference [to the similar caleulus of
Newton, but lays no claim  to the sole invention of
the differential method. In the same work for June,
1686, he resumes the subject, and when Newton had
not published a single word upon fluxions, and had
not even made known his notation, the differential
calculus was making rapid advances on the continent;
and in the hands of the brothers, Bernouilli, bad
proved the means of solving some of the most important and difficult problems.
The silence of Newton was at last broken, and in
the second lemma of the second book of the Principia,
he explained the fundamental principle of the fluxionary calculus. His explanation, which was very short,
concluded with the following scholium. " In a correspondence which took place about ten years ago between that very skilful geometer, G. G. Leibnitz,
and myself, I announced to him that I possessed a
method of determining   maxima    and  minima, of
drawing tangents, and of performing similar operations
which was equally applicable to rational and irrational
quantities, and concealed the same in transposed letters
involving this sentence "(data equatione quoterneque
fluentes quantitates involvente fluxiones invenire et
vice versa.)" This illustrious man replied that he had
also fallen on a method of the same kind, and he communicated to me his method which scarcely differed
from mine except in the notation, and in the idea of
the generation  of quantities."   This   celebrated
scholium, which is so often referred to in the present
controversy, has, in our opinion, been much misapprehended. While Biot considers it as " eternalizing the
rights of Leibnitz by recognising them in the Principia," Professor Playfair regards it as containing " a
highly favourable opinion on the subject of the dispoveries of Leibnitz." To us it appears to be nothing




SIR ISAAC NEWTON.           16T
nore than the simple statement of the fact, that the
method communicated by Leibnitz was nearly the
same as his own; and this much he might have said
whether he believed that Leibnitz had seen the
fluxionary calculus among the papers of Collins, or
was the independent inventor of his own. It is more
than probable, indeed, that when Newton wrote this
scholium, he regarded Leibnitz as a second inventor;
but when he found that Leibnitz and his friends had
shown a willingness to believe, and had even ventured
to throw out the suspicion, that he himself had borrowed the doctrine of fluxions from the differential
calculus, he seems to have altered the opinion which
he had formed of his rival, and to have been willing in
his turn to retort the charge.
This change of opinion was brought about by a
change of circumstances over which he had no control.  Duillier, a Swiss mathematician, resident in
London, communicated to the Royal Society in 1699,
a paper on the line of quickest descent, which contains
the following observations:-" Compelled by the evidence of facts, I hold Newton to have been the first
inventor of this calculus, and the earliest by several
years; and whether Leibnitz, the ' second inventor,'
has borrowed any thing from the other, I would prefer to my own judgment that of those who have seen
the letters and other copies of the same manuscripts of
Newton."   This imprudent remark, which by no
means amounts to a charge of plagiarism, for Leibnitz
is actually designated the 'second inventor,' may be
considered as showing that the English mathematicians
had been cherishing suspicions unfavourable to Leibnitz,
and there can be no doubt that a feeling had long prevailed that this mathematician either had, or might
have, seen among the papers of Collins the Analysis
per Equationes &c., which contained the principles of
the fluxionary method. Leibnitz replied to the remark of Duillier with much good feeling. He appealed




168               THE LIFE OF
to the facts as exhibited in his correspondence with
Oldenburg; he referred to Newton's scholium  as a
testimony in his favour, and, without disputing or acknowledging the priority of Newton's claim, he asserted his own right to the invention of the differential
calculus. Duillier transmitted a reply to the " Leipsic
Acts;" but the editor refused to insert it. The dispute therefore terminated, and the feelings of the concluding parties continued for some time in a state of repose, though ready to break out on the slightest provocation.
When Newton's Optics was published, in 1704,
accompanied by his treatise on the Quadrature of
Curves, and his Enumeration of lines of the third
order, the editor of the Leipsic Acts (who Newton
supposed to be Leibnitz himself) took occasion to
review the first of these tracts.  After giving an
imperfect analysis of its contents, he compared the
method of fluxions with the differential calctilus, and,
in a sentence of some ambiguity, he states that Newton employed fluxions in place of the differences of
Leibnitz, and made use of them in his Principia in
the same manner as Fabri, in his Synopsis of Geometry, had substituted progressive motion in place of
the indivesibles of Cavaleri.  As Fabri, therefore,
was not the inventor of the method which is here
referred to, but borrowed it from Cavaleri, and only
changed the mode of its expression, there can be no
doubt that the artful insinuation contained in the
above passage was intended to convey the impression
that Newton had stole his method of fluxions from
Leibnitz. The indirect character of this attack, in
place of mitigating its severity, renders it doubly
odious; and we are persuaded that no candid reader
can peruse the passage without a strong conviction
that 'it justifies the indignant feelings which it excited
among the English philosophers. If Leibnitz was
the author of the review, or if he was in.any way a




SIR ISAAC NEWTON.


169


party to it, he merited the full measure of rebuke
which was dealt out to him by the friends of Newton,
and deserved those severe reprisals which doubtless
embittered the rest of his days. He who dared to
accuse a man like Newton, or, indeed, any man
holding a fair character in society, with the crime of
plagiarism, placed himself without the pale of the
ordinary courtesies of life, and deserved to have the
same charge thrown back upon himself.
Dr. Keill, as the representative of Newton's friends,
could not brook this base attack upon his countryman.   In a letter inserted in the Philosophical
Transactions, for 1708, he maintained that Newton
was, beyond the possibility of a doubt, the first inventor of fluxions. He referred for a direct proof of
this, to his letters published by Wallis; and he asserted that the same calculus was afterwards published by Leibnitz, the name and the notation being
changed. If we are to consider this passage as retorting the charge of plagiarism upon Leibnitz, we
must admit that the mode of its expression is neither
so coarse nor so insidious as that which is used by the
writer of the Leipsic Acts. In a letter to Hans
Sloane, in March, 1711, Leibnitz complained to the
Royal Society of the treatment he had received. He
expressed his conviction that Keill had erred more
from rashness of judgment than from any improper
motive, and that he did not regard the imputation as
a calumny; and he requested that the Society would
oblige Mr. Keill to disown publicly the injurious
sense which his words might bear. When this letter
was read, Mr. Keill justified himself to Sir Isaac
and the other members, by showing them the obnoxious review of the Quadrature of Curves in the
Leipsic Acts. They all agreed in attaching the same
injurious meaning to the passage which we formerly
quoted, and authorised Keill to explain and defend
his statement. He accordingly addressed a letter to
0.         S S   V X,*  g




170


tn LISFE OP


Sir Hans Sloane, which was read to the Society, 24th
of May, 1711, and a copy of which was ordered to be
sent to Leibnitz.  In this letter he declares that he
never meant to state that Leibnitz knew either the
name of Newton's method or the form   of notation,
and that the real meaning of the passage was " that
Newton was the first inventor of fluxions or of the
differential calculus, and that he had given in two
letters to Oldenburg, which had been transmitted to
Leibnitz, indications of it sufficiently intelligible to an
acute mind, from which Leibnitz derived, or at least
might derive the principles of his calculus."
The charge of plagiarism which Leibnitz thought
was implied in the former letter of his antangonist is
here greatly modified, if not altogether denied. Keill
expresses only an opinion that the letter seen by
Leibnitz  contained  intelligible indications of the
fluxionary calculus. Even if this opinion was correct, it is no proof that Leibnitz either saw these
indications or availed himself of them, or if he did
perceive them, it might have been in consequence of
his having previously been in possession of the differential calculus, or having enjoyed some distant
view of it. Leibnitz should therefore, have accepted
of this explanation of Kiell's, and allowed the dispute
to terminate here; for no ingenuity on his part could
affect an opinion which any other person, as well as
Keill was entitled to maintain.
Leibnitz, however, thought otherwise, and wrote a
letter to Sir Hans Sloane, which excited new feelings,
and involved him in new embarrassments. Insensible
to the mitigation which had been kindly impressed
upon the supposed charge against his honour, he alleges that Keill had attacked his candour and sincerity
more openly than before;-that he acted without any
authority from Sir Isaac Newton, who was the party
most interested; —and that it was in vain to justify
his proceedings by referring to the provocation in the




SIR ISAAC NEWTON.


171


Leipsic Acts, because in that journal, "no injustice
had been done to any party, as every one had received
only his due." He styled Keill as an upstart, and
totally unqualified to judge of the case; he called
upon the members of the society to silence his unjust
clamours, which he was certain was contrary to the
opinion of Sir Isaac himself, who was perfectly acquainted with all the facts, and who, he had no doubt,
would willingly give his opinion on the matter.
This letter was, without doubt, the cause of all the
rancour which so speedily followed, and it placed his
antagonist in a new and more favourable position. It
was not true that Keill acted without the authority of
Newton, because Keill's letter was approved of, and
transmitted by the Royal Soeiety, of which Newton,
at the time, was president, and therefore became the
act of that body. The obnoxious part, however, of
Leibnitz's letter consisted in his appropriating to himself the opinions of the reviewer in the Leipsic Acts,
by declaring that in a review which charged Newton
with plagiarism, every person had got what was his
due. The controversy was now changed in every
feature. Leibnitz places himself in the position of the
person who had first disturbed the tranquillity of
science by maligning its most brilliant ornament; and
the Royal Society was compelled to throw all the
light they could upon a transaction which had exposed
their respected president to so vile a charge. The
Society, likewise, had become a party to the question,
by their approbation and transmission of Keill's letter,
and were on that account bound to vindicate the step
they had taken.
When Leibnitz's letter was read, Keill appealed to
the Society for the proofs of what he had advanced;
Sir Isaac also expressed his displeasure at the obnoxious passage in the Leipsic Review, and at the
defence of it by Leibnitz; and he left it to the members to act as they thought proper. A committee




172


THE LIFE OP


was therefore appointed, who were instructed to examine the registers of the Society, to inquire into the
dispute, and to produce such documents as they should
find, and report their own opinions on the case. The
committee produced the following report:
"We have consulted the letters and letter-books in
the custody of the Royal Society, and those found
among the papers of Mr. John Collins, dated between
the years 1669 and 1677, inclusive; and showed them
to such as knew and avouched the hands of Mr. Barrow, Mr. Collins, Mr. Oldenburg, and Mr. Leibnitz;
and compared those of Mr. Gregory with one another,
and with some of them taken in the hand of Mr.
Collins; and have extracted from them what relates
to the matter referred to us; all which extracts herewith delivered to you, we believe to be genuine and
authentic. And by these letters and papers we find,
" 1. That Mr. Leibnitz was in London in the beginning of the year 1673; and went thence, in or
about March, to Paris, where he kept a correspondence with Mr. Collins, by means of Mr. Oldenburg,
till about September, 1676, and then returned by
London and Amsterdam to Hanover; and that Mr.
Collins was very free in communicating, to able mathematicians, what he had received from Mr. Newton
and Mr. Gregory.
"2. That when Mr. Leibnitz was the first time
in London, he contended for the invention of another
differential method, properly so called; and notwithstanding that he was shown by Dr. Pell, that it was
Newton's method, persisted in maintaining it to be his
own invention, by reason that he had found it by himself, without knowing what Newton had done before,
and had much improved it. And we find no mention of his having any other differential method than
Newton's, before his letter of the 21st of June, 1677,
which was a year after a copy of Mr. Newton's letter: an*
f  d;  of t;  d  f  f  0   S: 0   0 f   S   0  f  A:   0   0   \ f:.<




SIR ISAAC NEWTON.


173


had been sent to Paris to be communicated to him;
and above four years after, Mr. Collins began to
communicate that letter to his correspondent; in
which letter the method of fluxions was sufficiently
described to any intelligent person.
"3. That by Mr. Newton's letter of the 13th of
June, 1676, it appears that he had the method of
fluxions above five years before the writings of that
letter. And by his "Analysis pre JEquationes numero
Terminorum Infinitas," communicated by Dr. Barrow
to Mr. Collins, in July, 1669, we find that he had invented the method before that time.
"4. That the differential method is one and the
same with the method of fluxions, excepting the name
and mode of notation; Mr. Leibnitz calling these
quantities differences, which Mr. Newton calls moments or fluxions; and marking them with the letter
d-a mark not used by Mr. Newton.
" And therefore we take the proper question to be,
not who invented this or that method, but who was
the first inventor of the method. And we believe,
that those whio have reputed Mr. Leibnitz the first
inventor knew little or nothing of his correspondence
with Mr. Collins and Mr. Oldenburg long before; nor
of Mr. Newton's having that method above fifteen
years before Mr. Leibnitz began to publish it in the
"Acta Eruditortum" of Leipsic.
For which reason we reckon Mr. Newton the first
inventor, and are of opinion, that Mr. Keill, in asserting the same, has been no ways injurious to Mr.
Leibnitz. And we submit to the judgment of the
Society whether the extract and papers now presented
to you, together with what is extant to the same purpose, in Dr. Wallis's third volume, may not deserve
to be made public."
This report being read, the Society without a dissenting voice, ordered the collection of letters and
manuscripts to be printed, under the superintendence




174


THE LIFE OF


of Dr. Halley, Mr. Jones, and Mr. Machin. Complete
copies of it, under the title of " Commercium Epistolicum  D. Johannis Collins et aliorum  de analysi
promata," were laid before the Society on the 8th of
January, 1713, and Sir Isaac Newton as president,
ordered a copy to be delivered to each member of the
Committee, to examine it before its publication.
Leibnitz received information of the appearance of
this publication when he was at Vienna, and, as he
expresses himself, " being satisfied that it must contain 'malicious falsehoods,' I did not think proper to
send for it by post, but wrote to M. Bernouilli to
give me his sentiments. M. Bernouilli wrote me a
letter, dated at Basle, June 7th, 1713, in which he
said, 'that it appeared probable that Sir Isaac Newton had formed his calculus after having seen mine.' "
This letter was published by a friend of Leibnitz,
with reflections, in a loose sheet, entitled " Charta
Volans," and dated July 29th, 1713.  It was widely
circulated without either the name of the author,
printer, or place of publication, and was communicated to the " Journal Literaire" by another friend of
Leibnitz, who added remarks of his own, and stated
that when Newton published the Principia in 1687,
" he did not understand the true differential method;
and that he took his fluxions from Leibnitz."
In this state of the controversy, Mr. Chamberlayne
conceived the design of reconciling these two distinguished philosophers; and in a letter, dated April
28th, 1714, he addressed himself to Leibnitz, who
was still at Vienna. In his reply to this letter,
Leibnitz declared that he had given no occasion for
the dispute; " That Newton procured a book to be
published, which was written purposely to discredit
him, and sent it to Germany as in the name of the
Society;" and he also stated, "that there was room
to doubt whether Newton knew his invention before
he had it of him,' Mr. Chamberlayne communicated.1 \ }
~-f* *,f0.: 00 *ff.- 0 in!1 *




SIR ISAAC NEWTON.


175


this letter to Sir Isaac Newton, who replied, that
Leibnitz had attacked his reputation, in 1705, by intimating that he had borrowed from him the method
of fluxions; and that if Mr. Collins would point out to
him anything in which he had injured Mr. Leibnitz,
he would give him satisfaction; that he would not retract things which he had known to be true; and that
he believed that the Royal Society had done no injustice by the publication of the Commercium Epistoli.
cum.
The Royal Society, having learned that Leibnitz
complained of their having condemned him, inserted a
declaration in their Journals on the 20th of May,
1714, that they did not pretend that the report of
their committee should pass for a decision of the
Society. Mr. Chamberlayne sent a copy of this to
Leibnitz, along with Sir Isaac's letter, and Dr. Keill's
answer to the papers inserted in the " Journal Literaire." After perusing these documents, Leibnitz
replied:-" that Sir Isaac's letter was written with
very little civility; that he was not in a humour to
put himself in a passion against such people; that
there were other letters among those of Oldenburg
and Collins which should have been published; and
that on his return to Hanover, he would be able to
publish a ' Commercium Epistolicum,' which would
be of service to the History of Learning."  When
this letter was read to the Royal Society, Sir Isaac
remarked, that the last part of it injuriously accused
the Society of having made a partial selection of papers for their publication; that he did not interfere in
any way in the publishing of the "Commercium
Epistolicum," and had even withheld from the comnaittee two letters, one from Leibnitz in 1693, and
another from  Wallis in 1695, which were highly
favourable to his claim. He stated that he did not
tiok it proper for Mr. Leibnitz, himself, but that, if
he hd letters to produce in his favour, that they
4>




176


THE LIFE OF


might be published in the Philosophical Transactions,
or in Germany.
About this time the Abbe Conti, a noble Venetian,
came to England. He was a correspondent of Leibnitz, and in a letter, which he had received soon after
his arrival, he enters upon his dispute with Newton.
He charges the English " with wishing to pass for
almost the only inventors."  He declared "that Bernouilli has judged right in saying that Newton did
not possess before him the infinitessimal characteristic
and algorithm."  He remarks that Newton preceded
him only in series; and he confesses that during his
second visit to England, " Collins showed him part of
his correspondence," or, as he afterwards expresses it,
he saw " some of the letters of Newton at Mr. Collins's." He then attacks Sir Isaac's philosophy, particularly his opinions about gravity and vacuum, the
intervention of God for the preservation of his creatures; and he accuses him of reviving the occult qualities of the schools. But the most remarkable passage in this letter is the following:- "I am a great
friend of experimental philosophy, but Newton deviates much from it, ' when he pretends that all matter
is heavy,' or that each particle of matter attracts every
other particle."
The above letter to the Abbe Conti was generally
shown in London, and came to be much talked of at
court, in consequence of Leibnitz having been counsellor to the Elector of Hanover, when that prince
ascended the throne of England. Many persons of
distinction urged Newton to reply to Leibnitz's letter,
but he declined. One day, however, the king inquired when Sir Isaac Newton's answer to Leibnitz
would appear; and when Sir Isaac was informed
of this, he addressed a long reply to the Abbe Conti.
This letter written with dignified severity, is a complete refutation of the allegations of his adversary;aqd the following passage deserve~ to be quoted, as
I fin X,;;,,:0;  ff~f  tS~f000D0;  As 0:  0 \SS; f   t   fS  f: t s?-f  f0 f.




SIR ISAAC NEWTON.


177


connected with that branch of the dispute which relates to Leibnitz's having seen part of Newton's letters
to Mr. Collins. " He complains of the committee of
the Royal Society, as if they had acted partially in
omitting what made against me; but he fails in proving the accusation. For he instances in a paragraph
concerning my ignorance, pretending that they omitted
it, and yet you will find it in the Commercium Epistolicum, p. 547, lines 2, 3, and I am not ashamed of
it. He saith that he saw this paragraph in the hands
of Mr. Collins when he was in London the second
time, that is in October, 1676. It is in my letter of
the 24th of October, 1676, and therefore he then saw
the letter. And in that and some other letters writ
before that time, I described my method of fluxions;
and in the same letter I described also two general
methodA of series, one of which is now claimed from
me by Mr. Leibnitz." The letter concludes with the
following paragraph: "But as he has lately attacked
me with an accusation which amounts to plagiary, if
he goes on to accuse me, it lies upon him by the laws
of all nations to prove his accusations, on pain
of being accounted guilty of calumny.  He hath
hitherto written letters to his correspondents full of
affirmations, complaints, and reflections, without proving any thing. But he is the aggressor, and it lies
upon him to prove the charge."
In transmitting this letter to Leibnitz, the Abbe
Conti informed him tlat he had himself read with great
attention, and without prejudice, the Commercium
Epistolicum, and the little piece that contains the extract; that he had also seen at the Royal Society the original papers of the Commercium Epistolicum, and some
other original pieces relating to it. "From all this."
he says, " I infer, that, if all digressions are cut off,
the only point is, whether Sir Isaac Newton had the
method of fluxions or infinitesimals before you, or
-qf,,,., 1.':  ^ ^.,,fAsbNCt




178


THE LIFE OF


whether you had it before him. You published it
first, it is true, but you have owned also that Sir
Isaac Newton had given many hints of it in his letters
to Mr. Oldenburg and others. This is proved very
largely in the Commercium, and in the extract of it,
What answer do you give? This is still wanting to
the'public, in order to form an exact judgment of the
affair." The Abbe adds, that Leibnitz's own friends
waited for his answer with great impatience, and that
they were of opinion that he could not refuse answering, if not Dr. Keill, at least Sir Isaac Newton, who
had given him a challenge in express terms.
Leibnitz was not long in complying with his request. He addressed a letter to the Abbe Conti,
9th April, 1716, but he sent it through M. Ramond,
at Paris, to communicate it to others. When -it was
received by the Abbe, Newton wrote observations
upon it, which were communicated only to some of his
friends, and which, while he placed his defence on the
most impregnable basis, at the same time threw
much light on the early history of his mathematical
discoveries.
The death of Leibnitz on the 14th November, 1716,
put an end to this controversy, and Newton some
time afterwards published the correspondence with
the Abbe Conti, which had hitherto been only
privately circulated among the friends of the disputants.
Iif,viewing this controversy, at this distance of
time, itis not difficult to form a correct estimate of
the conduct and claims cf the two rival philosophers.
It has been decided by the unanimous verdict of all
nations, that Newton invented fluxions at least ten
years before Leibnitz. Some of the letters of Newton
which bore reference to this great discovery were
perused by the German mathematician, according t6
his own confession; but there is no evidence that he
S,  '




SIR ISAAC NEWTON.


179


borrowed his differential calculus from these letters.
Newton was therefore the first inventor, and Leibnitz
the second. It was impossible that the former could
have been a plagiarist; but it was possible for the
latter.
Although an attempt has been since made to place
the conduct of Leibnitz on the same level with thtt of
Newton, yet the circumstances of the case will by no
means justify such a comparison. The conduct of
Newton was at all times dignified and just. He knew
his rights and he boldly claimed them. Conscious of
his integrity, he spurned with indignation the charge
of plagiarism with which an ungenerous rival had so
falsely branded him; and if there is one step in his
whole procedure which posterity can blame, it is his
omission in the third edition of the Principia, of the
references to the differential calculus of Leibnitz. This
omission, however, was perfectly just. The scholium
which he had left out was a mere historical statement
of the fact, that the German mathematician had sent
him a method which was the same as his own, and
when he found that this simple assertion had been
held by Leibnitz and others as a recognition of his in-.
dependent claim to the invention, he was bound either
to omit it altogether, or to enter into explanations
which might have involved him in a new controversy.
The conduct of Leibnitz was different. That he was
the aggressor no one can deny. That he first dared
to accuse Newton of plagiarism, and that he frequently
referred to it has been sufficiently apparent: and when
arguments failed him he had recourse to threats. All
this is now matter of history; and we may find some
apology for it in his excited feelings, and in the insinuations which were occasionally thrown out against
the originality of his discovery; but for other parts of
his conduct we seek in vain for an excuse. When he
assailed the philosophy in his letters to the A,:e
'. ^*00S




180              THE LIFE OF
Conti, he exhibited perhaps only the petty feelings
of a rival; but when he ventured to caluminate that
great man in his correspondence with the Princess of
Wales; when he dared to represent the philosophy of
Newton as physically false, and as dangerous to religion; and when he founded these accusations on
passages in the Principia and the Optics, glowing with
all the fervour of genuine piety, he cast a blot upon his
own name, which all his talents as a philosopher, and
all his virtues as a man, will never be able to efface.
~~


sZ


1,




SIR ISAAC NEWTON.


181


CHAPTER VI.
The privileges of the University attacked by James II. Newton chosen
one of the delegates to resist this encroachment. Elected a member of
the Convention Parliament. Burning of his manuscript. Supposed
derangement of mind. Refutation of the statement. Friendship between Newton and Charles Montague. Newton appointed Master of
the Mint. Newton elected Associate of the Academy of Sciences.
Member for Cambridge. President of the Royal Society. Queen
Anne confers upon him the honour of Knighthood.
AN event now occurred which drew Newton from
his studies and placed him upon the theatre of public
life. James II., desirous of re-establishing the Roman Catholic faith in its former supremacy, had begun
to assail the rights and privileges of his Protestant
subjects.  Among other tyrannical acts, he sent his
letter of mandamus to the University of Cambridge
to order Father Francis, an illiterate Benedictine
monk, to be received as Master of Arts, and to enjoy
all the privileges of this degree, without taking the
oaths of allegiance and supremacy. The University
at once perceived the consequences which might arise
from such a measure.     Independent of the encroachment upon their vested rights which such an order involved, it was evident that the highest interests of
the University were endangered, and that Roman Catholics might soon become a majority in the convocation. They, therefore, unanimously refused to pay the
least attention to the royal mandate, and this they
did with a firmness of purpose which greatly irritated the regal despot.  He reiterated his commands,
and accompanied them    with the severest threatenings
in case of disobedience. The Catholics were not idle
in supporting the views of the sovereign. The ho



182


THE LIFE OF


norary degree of M.A., which conveys no civil rights
to its possessor, having been, upon one occasion given
to the secretary of the ambassador from Morocco, it
was triumphantly blazoned forth that the members
of the University of Cambridge had a greater respect
for an infidel than for a Roman Catholic, and were
more obsequious to the Mohammedan ambassador than
to their lawful sovereign.  Though this reasoning
might impose upon the ignorant, it produced but
little effect upon the members of the University. A
few weak-minded individuals, however, were disposed
to yield a reluctant consent to the tyrant's wishes.
The% proposed to confer the degree, but at the same
time to resolve that it should not be regarded as a
precedent in future. To this it was replied, that the
very act of submission in one case would be a stronger
argument for continuing the practise than any such
resolution would be against its repetition. The University, therefore, remained firm in their original decision. The Vice-Chancellor was summoned before
the ecclesiastical commission to answer for this act of
contempt. Newton was among the number of those
who most strenuously resisted the command of the
sovereign, and he was consequently chosen one of the
nine delegates who were appointed to defend the independence of the University. These delegates appeared before the High Court. They maintained that
not a single precedent could be found to justify
so extraordinary a measure; and they showed that
Charles II. had, under similar circumstances, been
pleased to withdraw his mandamus. This representation had its full weight, and the king was compelled
to abandon his design.
The part which Newton had taken in this affair, and
the character which he now held in the scientific
world, induced his friends to propose him as Member
of Parliament for the university.  He was accordingly
elected in 1688, though by a majority of only five,




SIR ISAAC NEWTON.             183
and he sat in the convention Parliament till its dissolution. In the years 1688 and 1689, Newton was for
the greater portion of the time absent from Cambridge,
owing to his attendance in parliament; but it appears
from the books of the university that from 1690 to
1695, he was seldom absent, and must, therefore, we
presume, have renounced his parliamentary duties.
During his residence in the metropolis he must have
experienced the inadequacy of his finances to the new
circumstances in which he was placed, and it is probable that this was the cause of his confining himself to
Cambridge. His income was certainly limited, and
but little suited to the generosity of his disposition.
Demands were, no doubt, made upon it by some of his
less wealthy relatives; and there is every reason to
believe, that he himself, as well as his influential
friends, had been looking forward to some act of
liberality on the part of the government.
An event, however, occurred, which will ever form
an epoch in the history of this distinguished philosopher; and it is a most singular fact that this incident
was for more than a century unknown to his own
countrymen, and was only accidentally brought to light
by the examination of the various manuscripts belonging to Iuygens. This event has been magnified into
a temporary aberration of mind, which is said to
have arisen from a cause scarcely adequate to its production.
One winter morning while he was attending divine
service in the chapel of the university, he had left in
his study a favourite little dog called Diamond. Upon
returning from his devotions he found that this animal
had overturned a lighted candle on his desk, which set
fire to several papers on which he had recorded the reaults of some optical experiments. These papers are
said to have contained the labours of many year% and
it has been stated that when the philosopher discovered the magnitude of his loss, he exclaimed  Oh, Dia



184               THE LIFE OF
mond, Diamond, little do you know the mischief you
have done me!" It is a curious circumstance that
Newton never refers to the experiments which he is
said to have lost on this occasion, and Mr. Conduit,
the husband of his favourite niece, makes no allusion
to the accident itself. The distress, however, which it
occasioned, is said to have been so deep as to affect
even the mighty powers of his understanding.
This extraordinary effect was first communicated to
the world in the life of Newton by M. Biot, who says
he received the following account of it from the celebrated M. Van Swinden:
" There is among the manuscripts of the celebrated
Huygens, a small journal in folio, in which he used to
note down different occurrences. The following extract is written by Huygens himself, with whose handwriting I am well acquainted, having had occasion to
peruse several of his manuscripts and autograph letters. " On the 29th of May, 1694, M. Colin, a Scotsman, informed me that, 18 months ago, the illustrious
geometer, Isaac Newton, had become insane, either in
consequence of his too intense application to his studies,
or from excessive grief at having lost, by fire, his chemical laboratory and several manuscripts. When he
came to the Archbishop of Cambridge, he made some
observations which indicated an alienation of mind.
He was immediately taken care of by his friends, who
confined him to his house and applied remedies, by
means of which he had now so far recovered his health
that he began to understand the Principia." Huygens
mentioned this circumstance to Leibnitz in a letter,
dated June 8th, 1694, to which Leibnitz replies on the
23rd, " I am very glad that I received information of
the cure of Mr. Newton at the same time that I first
heard of his illness, which doubtless must have bee
very alarming. ' It is to men like you and him, Sir,
that I wish a long life.'"
The first announcement of the preceeding statement




SIR ISAAC NETON.


185


created a great sensation among the friends and ad-*
mirers of Newton. They could not easily be made to
believe in the prostration of that intellectual strength
which had unbarred the strongholds of the universe.
The unbroken equanimity of Newton's mind, the purity
of his moral character, his temperate and even abstemious life, his ardent and unaffected piety, and the
weakness of his imaginative powers, all indicated a
mind which was not likely to be overset by any affliction to which it could be exposed. The loss of a few
experimental records could never have disturbed the
equilibrium of a mind like his. If they were the records of discoveries, the discoveries themselves, indestructible, would have been afterwards given to the
world. If they were merely the details of experimental results, a little time could have easily reproduced
them. Had these records contained the first fruits of
early genius-of obscure talent, on which fame had not
yet shed its rays, we might suppose that the first blight
of such early ambition would have unsettled the
stability of an untried mind.   But Newton was
satiated with fame. His mightiest discoveries were
completed, and diffused over all Europe, and he must
have felt himself placed on the loftiest pinnacle of
earthly ambition. The incredulity which such views
could not fail to encourage, was increased bythe
novelty of the information. No English biographer
had ever alluded to the existence of such a malady.
History and tradition were alike silent, and it was not
easy to believe that the Lucasian Professor of Mathematics at Cambridge, a member of the English parliament, and the most celebrated philosopher in Europe
could have lost his reason without the distressing fact
being known to his own countrymen.
But if the friends of Newton were surprised by
the nature of the intelligence, they were distressed at
the view which was taken of it by foreign philos6o
phers.  While one maintained that the intellectual




186               TEE LIFE OF
exertions of Newton had terminated with the publication of the Principia, and that the derangement of
his mind was the cause of his abandoning the science,
others indirectly questioned the sincerity of his religious opinions, and ascribed to the aberration of his
mind, those Theological pursuits which gilded his
declining years. "But the fact," says Biot, "of the
derangement of his intellect, whatever may have been
the cause of it, will explain why, after the publication of
the Principia, in 1687, Newton, though only forty-five
years of age, never more published a new work on any
branch of science, but contented himself with giving to
the world those which he had composed long before
that epoch, confining himself to the completion of those
parts which might require development. We may
also remark, that even these developments appear,
always, to be derived from experiments and observations formerly made, such as the additions to the
second edition of the Principia, published in 1713, the
experiments on thick plates, those on diffraction, and
the chemical queries placed at the end of the Optics
in 1704; for in giving an account of these experi
ments, Newton distinctly says, that they were taken
from ancient manuscripts which he had formerly composed; and he adds, that though he felt the necessity
of extending them, on reading them more perfectly,
he was not able to resolve to do this, these matters
being no longer in his way. Thus it appears that
though he had recovered his health sufficiently to understand all his researches, and even in some cases, to
make additions to them, and useful alterations, as
apears from the second edition of the Principia, for
which he kept up a very active mathematical correspondence with Mr. Cotes, yet he did not wish to
undertake new labours in those departments of science
where he had done so much, and where he distincty
saw what remained to be done." Under the influence
of thesame opinion, Mr. Biot finds "it extreely




SIR ISAAC NEWTON.


187


probable that his dissertation on the scale of heat,
was written before the fire in his laboratory;" he
describes Newton's conduct respecting the longitude
bill as " almost puerile on so solemn an occasion, and
one which might lead to the strongest conclusions,
particularly if we refer it to the fatal accident which
Newton had suffered in 1695."
The celebrated Marquis de la Place viewed the illness of our philosopher in a light more painful to his
friends.  He strenuously maintained that he never
recovered the vigour of his intellect, and he was persuaded that Newton's theological inquiries did not
commence till after that afflicting period of his life.
He even commissioned Professor Gautier, of Geneva,
to make inquiries on this particular subject during his
visit to England, as if it concerned the interests of
truth and justice, to show that Newton became a
Christian and a theological writer, only after the decay of his strength and the eclipse of his reason.
Such having been the consequences of the disclosure
of Newton's illness by the manuscript of Huygens,
Sir David Brewster considered it to be a sacred duty
to the memory of that distinguished individual, to the
feelings of his countrymen, and to the interests of
Christianity itself, to inquire into the nature and history of that indisposition which appears to have been
so much misrepresented and misapplied. From the
ignorance of so extraordinary an event, which has prevailed for such a long period in England, it might
have been urged with some plausibility, that Huygens
had mistaken the real import of the information that
was conveyed to him; or that the individual from
whom he received it had propagated an idle and a
groundless rumour. But we are fortunately not confined to this very reasonable mode of defence. There
still exists at Cambridge a rmanuscript journal written
b  Mr. Abraham de la Pryme, who was a student in
the niversity while Newton was a Fellow of Trinity




188


THE LIFE OF


This MS. is entitled " Ephemeris Vitae, or Diary of
my own Life, containing an account likewise of the
most observable and remarkable things that I have
taken notice of from my youth up hitherto."  Mr.
Pryme was born in 1671, and begins his diary in 1685.
This manuscript is in the possession of hisj collateral
descendant, George Pryme, Esq.; Professor of Political
Economy at Cambridge, from whom Sir David Brewster obtained the following extract:"1692, February 3rd.-What I heard to-day I
must relate. There is one Mr. Newton, (whom I
have very oft seen,) Fellow of Trinity College, that is
mighty famous for his learning, being a most excellent
mathematician, philosopher, divine, &c. He has been
Fellow of the Royal Society these many years; and
amongst other very learned books and tracts he's
written one upon the mathematical principles of philosophy, which has got him a mighty name, he having
received, especially from Scotland, abundance of congratulatory letters for the same; but of all the books
that he ever wrote, there was one of colours and light,
established upon thousands of experiments which he
had been twenty years of making, and which had cost
him many hundred of pounds. This book, which lie
valued so much, and which he so much talked of, had
the ill luck to perish, and be utterly lost just when
the learned author was almost at putting a conclusion
at the same, after this manner: In a winter's morning,
leaving it amongst his other papers on his study table
whilst he went to chapel, the candle, which he had
unfortunately left burning there too, catched hold by
some means of other papers and they fired the aforesaid book, and utterly consumed it and several other
valuable writings; and which is most wonderful, did
no further mischief. But when Mr. Newton came
from chapel, and had seen what was done, every one
thought he would have run mad, he was so troubled
thereat, that he was not himself for a monthl ifter.'.:     X




SIR ISAAC NEWTON.


189


A long account of this, his system of light and colours,
you may find in the Transactions of the Royal Society,
which he had sent up to them long before this sadmischance happened unto him."
From this extract we are enabled to fix the approximate date of the accident by which Newton lost his
papers. It must have been previous to the 3rd of
January, 1692, a month before the date of the extract;
but if we fix it by the dates in Huygen s manuscript,
we should place it about the 29th of November, 1692,
eighteen months previous to the conversation between
Collins and Huygens. The manner in which Mr.
Pryme refers to Newton's state of mind is that which
is daily used when we speak of the loss of tranquillity
which arises from the ordinary afflictions of life; and
the meaning of the passage amounts to nothing more
than that Newton was very much troubled by the
destruction of his papers, and did not recover his
serenity, and return to his usual occupations for more
f'tan a month.  The very phrase that every person
t,ought he would have run mad, is in itself a sufficient
l:oof that no such melancholy effect was produced;
ac.ld, whatever degree of indisposition may be implied
in the expression " he was not himself for a month
after," we are entitled to infer that one month was the
period of its duration, and that, previous to the 3rd of
February, 1692, the date of Mr. Pryme's memorandum, " Newton was himself again."
These facts and dates cannot be reconciled with
those in Huygens's manuscript. It appears from that
document, that, so late as May, 1694, Newton had
only so far recovered his health as to begin again to
understand the Principia.  His supposed malady,
thererefore, was in force from the 3rd of January, 1692,
till the month of May, 1694,-a period of more than
two years. Now, it is a most important circumstance,
which M. Biot must have known, that in the very
middle of this period Newton wrote his four celebrated




190


TE LIFE OF


letters to Dr. Bentley on the Existence of a Deity,letters which evince a power of thought and a serenity
of mind absolutely incompatible even with the slightest
aberration of his intellect. No man can peruse these
letters without the conviction that their author possessed his full vigour of reason, and was capable of
understanding the most profound parts of his writings.
The first of these letters was written on the 10th
December, 1692, the second on the 17th January,
1693. His mind was therefore strong and vigorous
during the composition of these letters, and as they
were written at the express request of Dr. Bentley,
who had been appointed to deliver the lecture founded
by Mr. Boyle for vindicating the fundamental principles of Natural and Revealed Religion, we must consider such a request as showing his opinion of the
strength and originality of his friend's mental powers.
In 1692, Newton, at the request of Dr. Wallis,
transmitted to him the first proposition of his book on
quadratures, with examples of it in first, second, and
third fluxions. These examples were written in consequence of an application from his friend; and the
author of the review of the Commercium Epistolicum,
in which this fact is quoted, draws the conclusion, that
he had not at that time forgotten his method of second
fluxions. It appears also from the second book of
the Optics, that in the month of June, 1692, he had
been occupied with the subject of halos, and had
made accurate observations both on the colours and
the diameters of the rings in a halo which he had then
seen round the sun.
But, though these facts stand in direct contradiction
to the statement recorded by Huygens, the reader will
be naturally anxious to know the real nature and ex*
tent of the indisposition to which it refers. The following letters written by Newton himself to Mr. Pepys,
Secretary to the Admiralty, and Mr. Millington, of
Magdalene College, Cambridge, wil throw much light




SIR ISAAC NEWTON.


19t


upon the subject. Lord Braybrooke published these
letters in the Life of Pepys.
As will be presently seen, Newton had fallen into a
bad state of health some time in 1692, in consequence
of which both his sleep and his appetite were greatly
affected. About the middle of September, 1693, he
had been kept awake for five successive nights by this
nervous disorder, and in this condition he wrote the
following letter to Mr. Pepys:"September 13, 1693.
" SIR,
"Some time after Mr. Millington had delivered
your message, he pressed me to see you the next time
I went to London.   I was averse; but upon his
pressing consented, before I considered what I did, for
I am extremely troubled at the embroilment I am in,
and have neither ate nor slept well this twelvemonth,
nor have my former consistency of mind. I never
designed to get anything by your interest, nor by
King James's favour, but am now sensible that I must
withdraw from your acquaintance, and see neither you
nor the rest of my friends any more, if I may but
leave them quietly. I beg your pardon for saying I
would see you again, and rest your most humble and
most obedient servant,
"Is. NEWTON."
From this letter it is evident that his complaint had
continued for a twelvemonth, and during that period
neither ate nor slept well, nor enjoyed his frmer consisteney of mind. It is not easy tb understand exactly
what is meant by this phrase; but whatever may be
its import, it is certain that he was in a state of mind
so sound as to enable him to compose his four famous
letters to Bentley, all of which were written in the
course of the twelvemonth here referred to.
On receiving this letter, Mr. Pepys appears to hav A
s.'.:::a:..^:                                 A  000:00 - _
00< S -~~l0:~:7000..i;  -} '.




192


THE LIFE OF


written to his friend, Mr. Millington, to inquire after
Mr. Newton's health; but the inquiry having been
made in a vague manner, an answer equally vague
was returned. Mr. Pepys, however, who seems to
have been deeply anxious respecting Newton's health,
addressed the following more explicit letter to Mr.
Millington:" September 26th, 1693.
" SIR,
"After acknowledging your many old favours,'
give me leave to do it a little more particularly upon
occasion of the new one conveyed to me by my nephew
Jackson. Though, at the same time, I must acknowledge myself not at the ease I would be glad to be at
in reference to the excellent Mr. Newton, concerning
whom (methinks) your answer labours under the same
kind of restraint which (to tell you the truth) my asking did. For I was loth at first dash to tell you, that
I had lately received a letter from him so surprising
to me for the inconsistency of every part of it as to be
put into great disorder by it, from the concernment I
have for him, lest it should arise from that which,
of all mankind, I should least dread from him and
most lament-I mean a discomposure in head, or
mind, or both. Let me, therefore, beg of you, Sir,
having now told you the true ground of the trouble
I lately gave you, to let me know the very truth of
the matter, as far at least as comes within your knowledge. For I own too great an esteem for Mr. Newton, as for a public good, to be able to let any doubt
in me of this kind concerning him be a moment uncleared, where I can have any hopes of helping it.-I
am, with great truth and respect, Dear Sir, your most
humble and most affectionate servant,
"S. PEPYS."
/S  *....
~:,:, ~dc: T f




SIR ISAAC NEWTON.           193
Mr. Millington made the following reply:<' Coll. Magd. Camb.,
" Sept. 30th, 1693.
" HONOR'D SIR,
Coming home from a journey on the 28th instant,
at night, I met with your letter, which you were
pleased to honour me with of the 26th. I am much
troubled I was not at home in time for the post, that
I might as soon as possible put you out of your
generous payne that you are in for the worthy Mr.
Newton. I was, I must confess, very much surprised
at the inquiry you were pleased to make by your
nephew about the message that Mr. Newton made
the ground of his letter to you, for I was very sure I
never either received from you or delivered to him any
such; and therefore I went immediately to wayt upon
him, with a design to discourse him about the matter,
but he was out of town, and since I have not seen
him, till upon the 28th I met him at Huntingdon,
where, upon his own accord, and before I had time to
ask him any questions, he told me that he had writt
to you a very odd letter, at which he was much concerned; and added, that it was in a distemper that
much seized his head, and that it kept him awake for
above five nights together, which upon occasion he
desired I would represent to you, and beg your pardon, he being very much ashamed he should be so
rude to a person for whom he hath so great an honour.
tie is now very well, and, though I fear he is under
some small degree of melancholy, yet I think there is
no reason to suspect that it hath at all touched his
understanding, and I hope never will; and so I am
sure all ought to wish who love learning or the honour
of our nation, ' which it is a sign how much it is
looked after, when such a person as Mr. Newton lyes
so neglected by those in power.' And thus, honoured




104


THE LIFE OF


sir, I have made you acquainted with all I know of
the cause of such inconsistencys in the letter of so
excellent a person; and I hope it will remove the
doubts and fears you are, with so much compassion
and publicness of spirit, pleased to entertain about
Mr. Newton; but if I should have been wanting in
anything tending to the more full satisfaction, I shall,
upon the least notice, endeavour to amend it with all
gratitude and truth.-Honored Sir, your most faithfull and most obedient servant,
"JOH. MILLINGTON."
That this information was perfectly satisfactory to
Mr. Pepys appears from the following letter:"October 3rd, 1693.
"Sir,
" You have delivered me from a fear that indeed
gave me much trouble, and from my very heart I
thank you for it-an evil to Mr. Newton being what
every good man must feel for his own sake as well as
his. God grant it may stop there. And for the kind
reflection hee has since made upon his letter to mee,
I dare not take upon mee to judge what answer I
should make him to it, or whether any or no; and
therefore pray that you will bee pleased either to
bestow on mee what directions you see fitt for my own
guidance towards him in it, or to say to him in my
name but your own pleasure, whatever you may think
may be most welcome to him upon it, and most expressive of my regard and affectionate esteem of him,
and concernment. Dear Sir, your most humble and
most faithful servant,
' S. PEPYS."
It does not appear from the memoirs of Mr. Pepys,
whether he ever returned any answer to the "odd
letter" of Mr. Newton, which occasioned this cor



SIR ISAAC NEWTON.           195
respondence; but we there find that in less than two
months after the date of the preceding letter, an opportunity presented itself of introducing to him a Mr.
Smith, who wished to have his opinion on some problem in the doctrine of chances. This letter from Mr.
Pepys is dated November 22nd, 1693. Sir Isaac replied to it on the 26th November, and wrote to Pepys
aggain on the 16th December: and in both these letters he enters fully into the discussion of the mathematical question which had been submitted to his
judgment.
It is obvious, from Mr. Newton's letter to Mr.
Pepys, that the subject of receiving some favour from
the government had been a matter of anxiety with
himself, and of discussion among his friends. Mr.
Millington was no doubt alluding to this anxiety,
when he represents Newton as an honour to the nation, and expresses his surprise " that such a person
should be so neglected by those in power." And we
find the same subject distinctly referred to in two
letters written to Mr. Locke during the preceding
year. In one of these he says, "Being fully convinced that Mr. Montague, upon an old grudge, which
I thought had been worn out, has been false to me, I
have done with him, and intend to sit still, unless my
Lord Monmouth be still my friend."  Mr. Locke appears to have assured him of the continued friendship
of this nobleman, and Newton still referring to the
same topic remarks, "I am  very glad Lord Monmouth is still my friend, but intend not to give his
lordship any further trouble. My inclinations are to
sit still." In a later letter to Mr. Locke, dated September, 1693, which is given below, he asks his
pardon for saying or thinking that there was a
design to sell him an office. In these letters Newton
no doubt referred to some appointment in London
which he was solicitous to obtain, and which Mr.
Montague and his other friends may have failed in




196:          TTHE LIFE OF
^     procuring. This opinion is confirmed by the letter of
Mr. Montague, announcing to him his appointment to
r    the wardenship of the Mint, in which he says that he
E    can at last give him good proof of his friendship.
In the same month in which Newton wrote to Mr.
Pepys, we find him in correspondence with Mr. Locke.
Displeased with his opinions respecting innate ideas,
he had rashly stated that they struck at the root of
all morality, and that he regarded the author of such
doctrines as a Hobbist. Upon reconsidering their opinions, he addressed the following remarkable letter to
Mr. Locke, written only three days after his " odd
letter" to Mr. Pepys, and consequently during the
illness under which he then laboured:"SIR,
"Being of opinion that you endeavoured to embroil me with women, and by other means, I was
so much affected with it, that when I was told you
were sickly, and would not live, I answered, 'twere
better if you were dead.' I desire you will forgive
me this uncharitableness; for I am now satisfied that
what you have done is just, and I beg your pardon for
having hard thoughts of you for it, and for representing that you struck at the root of morality, in a principle you laid down in your book of ideas, and designed
to pursue in another book, and that I took you for a
Hobbist. I beg your pardon also for saying or thinking that there was a design to sell me an office, or to
embroil me.-I am your most humble and unfortunate
servant,
"Is. NEWTON."
"At the Bull, in Shoreditch, London,
September 16th, 1693."
To this letter Locke returned the following answer,
so nobly distinguished by philosophical magnanimity
and Christian charity:



SIR ISAAC NEVTON.           197
" Oates, Oct. 5th, 1693.
"SIR,
" I have been, ever since I first knew you, so entirely and sincerely your friend, and I thought you so
much mine, that I could not have believed what you
tell me of yourself, had I had it from anybody else.
And though I cannot but be mightily troubled that
you should have had so many wrong and unjust
thoughts of me, yet next to the return of good offices,
such as from a sincere good will I had ever done you,
I receive your acknowledgment of the contrary as the
kindest thing you have done me, since it gives me
hopes I had not lost a friend I so much valued.After what your letter expressss, I shall not need to
say anything to justify myself to you. I shall always
think your own reflection on my carriage, both to you
and to all mankind, will sufficiently do that. Instead
of that, give me leave to assure you, that I am more
ready to forgive you than you can be to desire it; and
I do it so freely and fully, that I wish for nothing
more than the opportunity to convince you that I
truly love and esteem you, and that I have the same
good will for you as if nothing of this had happened.
To confirm this to you more fully, I should be glad to
meet you anywhere, and the rather, because the conelusion of your letter makes me apprehend it would
not be wholly useless to you. But whether you think
it fit or not, I leave wholly to you. I shall always be
ready to serve you to my utmost, in any way you shall
like, and shall only need your commands or permission
to do it.
"My book is going to Dress for a second edition;
and, though I can answer for the design with which I
write it, yet, since you have so opportunely given me
notice of what you have said of it, I should take it as
a favour if you would point out to me the places that
gave occasion to that censure, that by explaining my-,




198


THE LIFE OF


self better, I may avoid being mistaken by others, or
unawares doing the least prejudice to truth or virtue.
I am sure you are so much a friend to them both, that,
were you none to me, I could expect this from you.
But I cannot doubt that you would do a great deal
more than this for my sake, who, after all, have all
the concern of a friend for you, wish you extremely
well, and am, without compliment, &c."
Newton made the following reply to this friendly
epistle:"Cambridge, Oct. 5th, 1693.
SIR,
"The last winter, by sleeping too often by my fire,
I got an ill habit of sleeping; and a distemper, which
this summer has been epidemical, put me farther out
of order, so that when I wrote to you, I had not slept
an hour a night for a fortnight together, and for five
days together not a wink. I remember I wrote to
you, but what I said of your book I remember not.
If you please to send me a transcript of that passage I
will give you an account of it if I can.-I am your
most humble servant,
Is. NEWTON."
Although the first of these epistles shows the
existence of a nervous irritability which could not fail
to arise from the reasons assigned, yet it is evident
that its author was in full possession of his mental
powers. The answer of Mr. Locke is obviously
written upon that supposition; and it is worthy of
remark, that the celebrated Dugald Stewart, who first
presented a portion of these letters to the publicq
never imagined for a moment that Newton was labouring under any mental alienation; and no man could
be a better judge.
The notion entertained by Laplace, that Newton
devoted his [attention to theology only in the latter
*  * -..




SIR ISAAC NEWTON.


199


part of his life, may be considered as deriving some
countenance from the fact, that the celebrated general
scholium, at the end of the second edition of the
Principia, published in 1713, did not appear in the
first edition of that work. This argument has been
ably denied by Dr. J. C. Gregory, of Edinburgh, on
the authority of a manuscript of Newton, which
seems to have been transmitted to his ancestor, Dr.
David Gregory, between the years 1687 and 1698.
This manuscript which consists of twelve folio pages
in Newton's handwriting, contains, in the form of
additions, and scholia to some propositions in the third
book of the Principia, an account of the opinions of
the ancient philosophers on gravitation and motion,
and on natural theology, with various quotations
from their works. Attached to this manuscript are
three very curious paragraphs. The two first appear
to have been the original draught of the general
scholium already referred to; and the third relates to
the subject of an ethereal medium, respecting which
he maintains an opinion diametrically opposite to that
which he afterwards published at the end of his
Optics. Dr. Gregory concludes his account of this
manuscript in the following words:-" I do not know
whether it is true, as stated by Huygens, ' Newtonium incidisse, in Phrenitim;' but I think every
gentleman who examines this manuscript will be of
opinion that he must have thoroughly recovered from
his phrenitis before he wrote either the Commentary
on the Opinions of the Ancients, or the Sketch of his
own Theological and Philosophical Opinions which it
contains."
In the middle of the year 1694, about the time
*Newton is pronounced to be beginning to understand
the Principia, we find him occupied with the difficult
and profound subject of the lunar theory. In order to
procure observations for verifying the equations which
he had deduced from the theory of gravity, he




200


THE LIFE OF


paid a visit to Mr. Flamstead, at the Royal Observatory of Greenwich, on the 1st September, 1694, when
he received from him a series of lunar observations.
On the 7th October he wrote to Flamstead that he
had compared the observations with his theory, and
had satisfied himself that by both together "the
moon's theory may be reduced to a good degree of
exactness, perhaps to the exactness of two or three
minutes."  He wrote to him again on the 24th of
October, and the correspondence was continued for
about four years, Newton making constant application for observations, to compare with his theory of
the planetary motions; while Flamstead, not sufficiently aware of the importance of the inquiry, received
his requests as if they were idle intrusions in which
the interests of science were but slightly concerned.
In one of his letters to Newton, he says, " Upon
hearing occasionally that you had sent a letter to Dr.
Wallis about the parallax of the fixed stars to be
printed, and that you had mentioned me therein with
respect to the theory of the moon, I was concerned
to be publicly brought upon the stage about what,
perhaps, will never be fitted for the public, and thereby
the world put into expectation of what perhaps they
are never likely to have. I do not love to be printed
upon every occasion, much less to be dunned by
foreigners about mathematical things, or to be thought
by your own people to be trifling away my time when
I should be about the king's business.
In receiving the details which we have now
given respecting the health and occupations of Newton,
from the commencement of 1692 till 1695, it is impossible to come to any other conclusion than that he
possessed a sound mind, and was quite capable oi
pursuing his mathematical, his metaphysical, and, his
astronomical inquiries. During the period of bodily
indisposition, his mind, though in a state of nervous
irritability, and disturbed by want of rest, was capable




SIR ISAAC NEWTON.


201


of putting forth its highest powers. At the request
of Dr. Wallis, he drew up an example of one of his
propositions on the quadrature of curves in second
fluxions. At the desire of Dr. Bentley, he composed
his profound and beautiful letters on the existence of
the Deity. He was requested by Locke to reconsider
his opinions on the subject of innate ideas; and we
find him grappling with the difficulties of the lunar
theory.
But with all these proofs of a vigorous mind, a diminution of his mental powers has been rashly inferred
from the cessation of his great discoveries, and from
his unwillingness to enter upon new investigations.
The facts, however, here assumed, are as incorrect as
the inference drawn from them. The ambition of
fame is a youthful passion which is softened, if not
subdued by age. Success diminishes its ardour, and
early pre-eminence often extinguishes it. Before the
middle period of his life, Newton was invested with
all the insignia of immortality; but endowed with a
native humility of mind, and animated with those
hopes which teach us to form a moderate estimate of
human greatness, he was satisfied with the laurels
which he had won, and he sought only to perfect and
complete his labours. His mind was principally bent
on the improvement of his Principia; buthe occasionally diverged into new fields of scientific research,-he
solved problems of great difficulty, which had been
proposed to try his strength-and he devoted much
time to profound inquiries in chronology and theological
literature.
The powers of his mind were therefore in full requisition; and when we take into our consideration
That he was called to the discharge of high official functions which forced him into public life, and compelled
to direct his genius into new channels,-we can scarcely
be surprised that he ceased to produce any original
wrks on abstract science. In the direction of the




V,






202


THE LIEZ OF


affairs of the Mint, and of the Royal Society, to which
we shall now follow him, he found ample occupation
for his time, while he devoted the leisure of his declining years to those exalted studies in which philosophy
yields to the supremacy of faith, and hope administers
to the aspirations of genius.
We have hitherto viewed Newton as a faithful
philosopher leading a life of seclusion within the walls
of a college, and either engaged in the duties of his
professorship, or occupied in mathematical and scientific inquiries. He had now reached the fifty-third
year of his age, and while those of his own standing at
the university had been receiving high appointments in
the church, or more lucrative offices under the government, he still remained without any mark of the respect
or gratitude of his country. All Europe, it is true, had, been offering incense to his name, andEnglishmenthemselves boasted of him as the pride of their country, and
the ornament of mankind, but he was left in comparative
poverty; so much was this the case indeed, that the
council of the Royal Society excused him from making
the usual payment of one shilling weekly, " on account
of his low circumstances, as he represented." He had
no other income than the salary of his professorship,
and the trifling rental of his paternal inheritance.
Such disregard of the greatest genius, dignified by the
most exemplary virtue, could only have taken place in
England, and we should have been ready to have
ascribed this carelessness to the turbulence of the age
in which he lived, had we not seen, in the history of
another century, that the successive governments which
preside over the destinies of Britian, have never been
able to feel or to recognize the true nobility of soul,
while the people of the country are reduced to a state
of misery and privation, on account of the enormous
sums granted for the support of the aristocracy, who
never have done, nor, in all likelihood, ever will do
an action worthy of being handed down to posterity;:it




SIR ISAAC NEWTON.


203


but these are the men-and women too,-whom the
British government delights to honour.
Among his friends of Cambridge Newton had the
honour of numbering Charles Montague, grandson of
the Earl of Manchester, a young man of high promise, and every way worthy of his friendship.
Though devoted to literary pursuits, and twenty years
younger than Newton, he cherished for thephilosopher
all the veneration of a disciple, and his affection gathered new strength as he rose to the highest honours
and offices of the state.  In the year 1684, we find
him co-operating with Newton in the establishment
of a Philosophical Society at Cambridge, but though
both of them had made personal application to different individuals to become members, yet the plan failed
as Newton expresses it from the want of persons willing to try useful experiments.
Mr. Montague sat along with Newton in the Convention Parliament, and such were the powers he displayed in that assembly, as a public speaker, that he
was appointed a commissioner of the treasury, and
soon afterwards a privy councillor. In these situations
his talents and knowledge of business were highly
conspicuous, and in 1694, he was appointed Chancellor of the Exchequer.  The current coin of the
kingdom having been much adulterated and debased,
one of his earliest designs was to recoin it, and to restore it to its intrinsic value. This scheme, however,
met with great opposition, being characterised as a
wild project, unsuited to a period when the nation was
engaged in war, as highly injurious to the interests of
commerce, and as likely to sap the foundation of the
government. But he had studied the subject too deeply,
and had entrenched himself behind opinions too impartial and too well founded, to be driven from a measure
which the best interests of his country seemed to require.
The persons whom Mr. Montague had consulted










204              THE LIFE OF
about the re-coinage, were Newton, Locke, and IIalley,
and in consequence of Mr. Overton, the warden of the
Mint, having been appointed a Commissioner of Customs, he embraced the opportunity which was thus
offered, of serving his friend and his country, by recommending Newton to that important office. The
notice of his appointment was conveyed to Newton in
the following letter:London, 19th March, 1693.
" SIR,
' I am very glad that, at last, I can give you a
good proof of my friendship, and the esteem the king
has of your merit. Mr. Overton, the Warden of the
Mint, is made one of the Commissioners of the Customs, and the king has promised me to make Mr.
Newton Warden of the Mint. The office is the most
proper for you. 'Tis the chief office in the Mint, 'tis
worth five or six hundred pounds per annum, and has
not too much business to require more attendance than
you can spare. I desire you will come up as soon as
you can, and I will take care of your warrant in the
meantime.   Let me see you as soon as you come to
town, that I may carry you to kiss the king's hand.
I believe you may have a lodging near me.
"I am, &c., &c.
"CHARLES MONTAGUE."
In this new situation the mathematical and chemical knowledge of Newton was of great service to the
nation, and he became eminently useful in carrying on
the re.coinage, which was completed in the space of
two years. In the year 1699, he was promoted to the
Mastership of the Mint, —a situation which was worth
~1500 per annum, and which he held during the remainder of his life. While he was yet Master of the
Mint, he wrote an official report on the coinage which
was published; and he likewise drew up a table of




SIR ISAAC NEWTON.


205


essays of foreign coins, which was printed at the end
of Dr. Arbuthnot's Tables of Ancient Coins, Weights,
and Measures, and appeared in 1727.
Newton retained his professorship at Cambridge till
his promotion to the Mastership in 1699, when he ap.
pointed Mr. Whiston to be his deputy, with all the
emoluments of the office; and when he resigned the
chair in 1703, he succeeded in getting him nominated
his successor.
The appointment of Newton to the Mastership of
the Mint must have been peculiarly gratifying to the
members of the Royal Society, and it was probably
from a feeling of gratitude to Mr. Montague, more
than from a regard for his talents, that this able statesman was unanimously elected president of that learned
body. This office he held for three years, and Newton
had the satisfaction of addressing to him his solution of
the celebrated problems proposed by John Bernouilli.
Charles Montague was created Earl of Halifax in
1700; and after the death of his first wife he conceived an ardent attachment for the niece of Newton,
who was the widow of Colonel Barton. This lady
was young, gay, and beautiful, and though she did not
escape the censures of the world, she was regarded by
all who knew her as a woman of the strictest honour
and virtue. What were the causes which prevented
her union with the Earl of Halifax, we have no means
of knowing, but so great was the esteem and affection
which he bore her, that in his will in which he left
~100 to Mr. Newton, he bequeathed to Mrs. Barton
a very large portion of his fortune. This distinguished
statesman died in 1715, in the fifty-fourth year of his
age.  Himself, a poet and an elegant writer, he was the
liberal patron of genius, and he numbered among his
intimate friends Congreve, Halley, Prior, Tickel,
Steele, and Pope. His conduct to Newton will be for
ever remembered in the annals of science. The sages
at every nation and of every age will pronounce with




i:


Y




206


THE LIEB OF


affection the name of Charles Montague, and the persecuted science of England will continue to deplore
that he was the first and the last English minister who
honoured genius by his friendship and rewarded it by
his patronage.
The elevation of Mr. Newton to the highest offi
in the mint, was followed by other marks of honur.
The Royal Academy of Sciences at Paris having been
empowered by a New Charter, granted in 1699, to admit a very small number of foreign associates, Newton
was elected a member of that distinguished body. In
the year 1701, on the assembling of a new parliament
he was re-elected one of the members for the University of Cambridge. In 1703, he was chosen President
of the Royal Society of London, to which office he was
annually re-elected during the twenty-five remaining
years of his life. On the 16th of April, 1705, when
Queen Anne was living at the royal residence of Newmarket, she went with Prince George of Denmark,
and the rest of the court to visit the University of
Cambridge. After the meeting of the Regia Consilia,
her majesty held a court at Trinity Lodge, the residence of Dr. Bentley then master of Trinity, where
the honour of knighthood was conferred upon Mr.
Newton, Mr. John Ellis, the vice-chancellor, and Mr.
James Montague, the university counsel.
On the dissolution of the parliament, which took
place in 1705, Sir Isaac was again a candidate for the
representation of the university, but notwithstanding
the recent expression of the royal favour, he lost his
election by a very great majority. There were four
candidates, of whom the highest had 182 votes, while
Sir Isaac, the lowest, had only 117. This singular
result was perhaps owing to the loss of that personal
influence which his residence in the university could
not fail to command, though it is more probable that
the ministry preferred the candidates of a more obseqious character, and that the electors looked for




Y, -


SIR ISAAC NEWTON.             207
advantages which Newton was not able to procure for
them.
Although the first edition of the Principia had been
for some time sold off, and copies had become scarce,
yet Sir Isaac's attention was so much occupied with
his professional avocations, that he could not find
leisure for preparing a new edition. Dr. Bentley, who
had frequently urged him to undertake the task, at
last succeeded by engaging Roger Cotes, Plumian
Professor of Astronomy at Cambridge, to superintend
its publication at the university press. In June, 1709,
Sir Isaac committed this important trust to his young
friend; and about the middle of July, he promised to
send him in the course of a fortnight, his own revised
copy of the work. Business, however, seems to have
intervened and that gentleman was obliged to remind
Sir Isaac of his promise, which he did in the following
letter:Cambridge, Aug. 18th, 1709.
" SIR,
' The earnest desire I have to see a new edition of
your "Principia," makes me somewhat impatient till
we receive your copy of it, which you were pleased
to promise me about the middle of last month you
would send down in about a fortnight's time.  I hope
you will pardon me for this uneasiness, from which I
cannot free myself, and for giving you this trouble to
let you know it.  I have been so much obliged by
yourself and your book, that (I desire you to believe
me,) I think myself bound in gratitude to take all
the care that I properly can that it shall be correct.
Your obliged servant,          "ROGER COTES."
" For Sir Isaac Newton, at his house,
in Jermyn Street, near St. James's
Church, Westminster."
This was the commencement of that lengthened




208


THE LIFE OP


correspondence, consisting of nearly three hundred
letters, in which Sir Isaac and Mr. Cotes discussed
the various improvements which were thought necessary in a new edition of the Principia. The revised
copy was forthwith sent to Cambridge, and Mr.
Cotes gladly undertook the labour of superintending
the printing of it.
When the work was ready for publication, Mr.
Cotes expressed a wish that Dr. Bentley should write
a preface to it, but it was the opinion both of Sir
Isaac and the Doctor, that the preface should come
from the pen of Mr. Cotes himself. This he engaged
to do; but previous to writing it he addressed the
following letter to Dr. Bentley, in order to learn
from  Sir Isaac the particular view with which it
should be written.
" March 10th, 1712-13.; SIR,
"I received what you wrote to me in Sir Isaac's
letter. I will set about the index in a day or two.
As for the preface, I should be glad to know from
Sir Isaac with what view he thinks proper to have it
written.  You know    the book has been received
abroad with some disadvantage, and the cause of it
may be easily guessedgat. Tlhe " Commercium Epistolicum," lately published by order of the Royal
Society, gives such indubitable proofs of Mr. Leibnitz's want of candour, that I shall not scruple in the
least to speak out the full truth of the matter, if it
be thought convenient. There are some pieces of his
looking this way, which deserve a censure, as his
" Tentamen de motuum    caelestium causis."  If Sir
Isaac is willing that something of this nature may be
done, I should be glad if, whilst I am making the
index, he would consider of it, and put down a few
notes of what he thinks most material to be insisted on.
This I say upon supposition that I write the preface




SIR ISAAC NEWTON.


20to


myself. But I think it will be much more advisable
that you, or he, or both of you, should write it
whilst you are in town. You may depend upon it
I will own it, and defend it as well as I can, if hereafter there should be occasion. I am, Sir, &c.
We have no means of learning the instructions
which were given to Mr. Cotes; but it appears from
the preface itself that Sir Isaac had prohibited any
personal reference to the conduct of Leibnitz.
In the year 1714 several captains and owners of
merchant vessels petitioned the House of Commons
to consider the propriety of bringing in a bill to reward inventions for promoting the discovery of the
longitude at sea. A committee was appointed to investigate the subject, and Mr. Ditton and Mr.
Whiston, having thought of a new method of finding
the longitude, submitted it to the committee.  Four
members of the Royal Society viz., Sir Isaac Newton,
Dr. Halley, Mr. Cotes, and Dr. Clarke, were examined on the subject, along with Messrs. Ditton and
Whiston. The three last of these philosophers stated
their opinions verbally.  Mr. Cotes considered 'the
proposed scheme as correct in theory and on shore,
and both he and Dr. Halley were of opinion that expensive experiments would be requisite. Newton,
when caHled upon for his opinion, read the following
memorandum, which is worthy of being recorded:" For determining the longitude at sea there have
been several projects, true in theory, but difficult to
execute.
" 1. One is by a watch to keep time exactly; but
by reason of the motion of the ship, the variation
of heat and cold, wet or dry, and the difference of
gravity in different latitudes, such a watch hath not
yet been made.
"2. Another is by the eclipses of Jupiter's..;;   1'1




210


TE- LIFE OF


satellites; but, by reason of the length of telescopes
wequisite to observe them, and the motion of a ship at
sea, those eclipses cannot yet be there observed.
" 3. A third is by the place of the moon; but her
theory is not yet exact for that purpose; it is exact
enough to determine the longitude within two or three
degrees, but not within a degree.
" 4. A fourth is Mr. Ditton's project, and this is
rather for keeping an account of the longitude at sea
than for finding it, if at any time it should be lost,
as it may easily be in cloudy weather. How far this
is practicable, and with what charge, they that are
killed in sea affairs are best able to judge.  In sailing by this method, whenever they are to pass over
very deep seas, they must sail due east or west; they
must first sail into the latitude of the next place to
which they are going beyond it, and then keep due
east or west, till they come at that place. In the
three first three ways there must be a watch regulated
by a spring, and rectified every visible sunrise and
sunset, to tell the hour of the day or night. In the
fourth way such a watch is not necessary. In the
first way there must be two watches, this and the other
above mentioned. In any of the three first ways, it
may be of some service to find the longitude within a
degree, and of much more service to find it withi
forty minutes, or half a degree if it may be, and the
success may deserve rewards accordingly.   In the
fourth way, it is easier to enable seamen to know their
distance and bearing from the shore, 40, 60, or 80
miles off, than to cross the seas; and some part of
the reward may be given, when the first is performed
on the coast of Great Britain, for the safety of ships
coming home: and the rest, when seamen shall be
enabled to sail to an assigned remote harbour without
losing their longitude if it may be."
The committee brought up their report on the 11th
of June, and recommended that a bill should be intro



SIR ISAAC NWTON.


21t


duced into parliament for the purpose of rewarding
inventions or discoveries connected with the determination of the longitude.  The bill passed the
House of Commons on the 3rd of July, and was
agreed to by the Lords on the 8th of the same month.
Mr. Whiston, in giving an account of this transaction, in his " Longitude Discovered," states that nobody understood Sir Isaac's paper, and that after
sitting down he obstinately kept silence, though he
was much pressed to explain himself more distinctly.
At last seeing that the scheme was likely to be rejected, Whiston ventured to say that Sir Isaac did
not wish to explain more through fear of compromising himself, but that he really approved of the
plan. Sir Isaac, he goes on to say, repeated every
word that he had said. This is the part of Newton's
conduct which M. Biot has described as puerile, and
tending to confirm the fact of the aberration of his
intellect in 1693."  We must be satisfied with the
correctness of Whiston's statement before we can admit such a censure. The paper read by Newton is
perfectly plain, and we may easily understand how he
might have approved of Mr. Ditton's plan as ingenios and practicable under particular circumstance;
though he did not think it of that paramount importance which would have authorized the House of
Commons to distinguish it by a parliamentary reward. The conflict between public duty and a dis
position to promote the interests of Messrs. Whiston
and Ditton, was undoubtedly the cause of that embarrassment of manner which the former of these
mathematicians has so ungratefully brought before
the public.
~:,::~




212


THE LIFE OF


CHAPTER VII.
Respect in which Newton is held at the court of George I.  The
Princess of Wales delighted with his conversation. She obtains a
manuscript copy of his system of Chronology. She allows the Abbe
Conti to take a copy of it on the promise of secrecy. He publishes
it surreptitiously in French. Sir Isaac's defence of his system.
Theological studies of Sir Isaac. Origin of Newton's Theological
studies. Analogy between the Book of Nature and that of Revelation. Minor Discoveries of Newton. His Reflecting Sextant.
Reflecting Microscope. Prismatic Reflector. His method of varying
the Magnifying power of Newtonian Telescopes. His Experiments on
Impressions on the Retina.
SIR ISAAC NEWTON became an object of interest at
the British court on the accession of George I., to the
throne of these dominions in 1714. His high situation under government-his splendid reputation-his
spotless character-and      above all,   his   unaffected
piety, attracted the attention of the Princess of
Wales. This lady who possessed a highly cultivated
mind, derived the greatest pleasure from conversing
with Newton and corresponding with Leibnitz. In
all her difficulties she applied to Sir Isaac, from whom
she received that information and assistance which
she had elsewhere sought in vain; and she was frequently heard to declare that she considered herself
as fortunate in living at a period which enabled her to
enjoy the conversation of so great a genius.          But
while Newton was thus esteemed by the house of
Hanover, Leibnitz, his great rival, endeavoured to
weaken and undermine his influence. In his correspondence with the princess he represented the Newtonian philosophy as, not only physically false, but as
injurious to the interests of religion. He asserted that
natural religion was rapidly declining in England, and




SIR ISAAC NEWTON.


218


he supported this assertion by referring to the works
of Locke, and to the beautiful and pious sentiments
contained in the 28th query at the end of the Optics.
He represented the principles of these great men as
precisely the same with those of the materialists, and
thus endeavoured to degrade the character of English
philosophers.
These attacks of Leibnitz became subjects of conversation at court, and when they reached the ear of
the king, his majesty expressed his expectation that
Sir Isaac would draw up a reply. He accordingly
entered the lists on the mathematical part of the controversy, and left the philosophical part of it to Dr.
Clarke, who was more than a match for the German
philosopher. The correspondence which ensued was
carefully perused by the princess, and from the estimation in which Sir Isaac continued to be held we
may infer that the views of the English philosopher
were not very remote from her own.
One day, when Sir Isaac was conversing with her
royal highness on some portion of ancient history, he
was led to mention to her,. and to explain, his new
system of chronology which he composed during his
residence at Cambridge, when he was in the habit, as
he himself expresses it, "of refreshing himself with
history and chronology when he was weary with
other studies." The princess was so much pleased
with this ingenious system, that she afterwards sent
a message by the Abbe Conti to Sir Isaac, requesting
him to speak with her, and she, when he came,
earnestly entreated him to favour her with a copy of
the interesting work which contained his system of
chronology. Sir Isaac informed her, that it existed
merely in separate papers, which were not only in a
state of confusion, but which contained a very imperfect view of the subject, and he promised, in a few
days to draw up an abstract of it for her own private




214               THE LIFE OF
use, and on the condition that it should not be communicated to any other person whatever. Some time
after the princess received the manuscript, she requested that the Abbe Conti might be allowed to
have a copy of it. Sir Isaac granted this request, and
the Abbe was informed that he received a copy of
the manuscript with Sir Isaac's permission, at the
princess's request, and that it was to be kept secret.
The manuscript which was thus confidingly put into
the hands of a foreigner, was entitled "A short
Chronicle from the first Memory of Things in Europe
to the Conquest of Persia by Alexander the Great."
It consists of about twenty four quarto printed pages,
with an introduction of four pages, in which Sir Isaac
states that he " does not pretend to be exact to a
year, that there may errors of five or ten years, and
sometimes twenty, but not much above."
The Abbe Conti kept his promise of secresy so
long as he remained in. England, but he no sooner
reached Paris, than he communicated it to M. Freret,
a learned antiquarian, who not only translated it, but
drew up observations upon it for the purpose of refuting some of its principal results. Sir Isaac was
unacquainted with this transaction till he was informed of it by the French bookseller, M. Cavalier,
in whose hands it had been placed, who requested his
leave to publish it, and charged one of his friends in
London to procure Sir Isaac's answer, which was
speedily given as follows:"I remember that I wrote a Chronological Index
for a particular friend, on condition that it should not
be communicated. As I have not seen the manuscript which you have under my name, I know not
whether it be the same. That which I wrote was not
all done with design to publish it. I intend not to
meddle with that which hath been given you under
d.-0SSS.X\...i.X$;  f:0:ft:00:f f:0.v\::0:: Ads.  At   of::;  t::0S:;0  f; at:;D::,: t:0\ff'   0 of'




SIR ISAAC NEWTON.


21s


my name, nor to give any consent to the publishing of
it. I am your very humble servant.
" Is. NEWTON."
London, May 27th, 1725, O.S.
Before this letter was written, M. Cavalier had
received the royal sanction for printing the work;
and when it was completed he sent a copy of it in a
present to Sir Isaac, who received it on the 11t
November, 1725. It was entitled " Abrege de Chronogie de M. Le Chevalier Newton, fait par lui-meme,
et traduit sur le manuscript Anglais," and was accompanied with observations by M. Freret, the object of
which was to contradict the leading points of the
system. An advertisement was prefixed to it, in
which M. Cavalier defends himself for publishing it
without the author's permission, on the ground that
he had written three letters to obtain his consent, ana
had declared that he would take Sir Isaac's silence as
a tacit permission. When Sir Isaac received this
work, he drew up a paper entitled " Remarks on the
Observations made on a Chronological Index of Sir
Isaac Newton, translated into French by the Observator, and published at Paris."  These remarks were
published in the 33rd volume of the Philosophical
Transactions for 1725. He gives a complete history
of the transaction; charges the Abbe Conti with deceit, and blames M. Cavalier for having asked his
permission to publish the translation without sending
him a copy for his perusal, without acquainting him
with the name of the translator, and without announcing his intention of publishing along with it a refutation
of the original. The observations made by the trans1ltor against the conclusions deduced by the author
were founded on an imperfect knowledge of Sir Isaac's
system; and they are so plausible that Dr. Halley
onfes     that he was at first prejudiced in favour of




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the observations, taking the calculations for granted,
and not having seen the original.
To all the observations of Freret, Sir Isaac returned
an explicit answer.  This presumptuous antiquary
had ventured to state at the end of his observations,
"that he believed he had stated enough concerning the
epochs of the Argonauts, and the length of generations,
to make people cautious about the rest; for these are
the two foundations of all this new system of chronology." He founds his arguments against the epochs
of the Argonauts, as fixed by our author, on the supposition that Sir Isaac places the vernal equinox at
the time of the Argonautic expedition in the middle of
the sign of Aries, whereas Sir Isaac places it in the
middle of the constellation-a point corresponding with
the middle of the back of Aries, or eight degrees
from the first star of Aries. This position of the colure is assigned on the authority of Eudoxus, as given
by Hipparchus, who says that the colure passed over
the back of Aries. Setting out with this mistake,
M. Freret concludes that the Argonautic expedition
took place 532 years earlier than Sir Isaac allowed.
His second objection relates to the length of generations, which he asserts is made in this new system
only 18 or 20 years. On the contrary, Sir Isaac
reckons a generation at 33 years, or 3 generations at
100; and it was the length of the reigns of kings that
he made 18 or 20 years. This deduction he founds
on the reigns of 64 French kings. Now the ancient
Greeks and Egyptians reckoned the length of a reign
equal to that of a generation; and it was by correcting this mistake, and adopting a measure founded on
fact, that Sir Isaac placed the Argonautic expedition
44 years after the death of Solomon, and fixed some
of the other points of his system.
Sir Isaac's answer to these objections called into
the field a fresh antagonist, Father Souciet, who published no fewer than five dissertations on the new




SIR ISAAC NEWTON.


217


chronology. These dissertations were written in a
style disgraceful to a scholar; and the friends of Sir
Isaac being afraid that the manner in which his system was attacked, would be more hurtful to his feelings than the arguments themselves, prevailed upon a
friend to draw up an abstract of Souciet's objections,
stripped of their offensive language. The perusal of
these arguments only convinced Sir Isaac of the
shameful ignorance of their author; and he was induced to read the original work, which only confirmed
him in opinion.
In consequence of these attacks and discussions,
Sir Isaac was prevailed upon, in order to set the matter at rest, to prepare his larger work for publication.
He had nearly completed it at the time of his death,
and it was published in 1728, under the title of
"The Chronology of Ancient Kingdoms amended, to
which is prefixed, a Short Chronicle from the first
memory of Things in Europe, to the Conquest of
Persia, by Alexander the Great." It was dedicated
to the Queen, by Mr. Conduit, and consists of six
chapters; 1. On the Chronology of the Greeks; 2.
Of the Empire of Egypt; 3. Of the Assyrian Empire; 4. Of the two contemporary Empires of the
Babylonians and Afedes; 5. A   Description of the
Temple of Solomon; 6. Of the Empire of the Persians. The sixth chapter was not copied out with
the other five, which makes it doubtful whether it
was intended for publication or not, but as it was
found among his papers, and appeared to be a continuation of the same work, it was thought proper by
the friends of the deceased author to add it to the
other five chapters.
After the death of Newton, Dr. Halley, who had
not yet seen the larger work, felt himself called upon,
both as astronomer-royal and as the personal friend
of the author, to reply to the first and last dissertation of Father Souciet, which were chiefly astronomi



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al; and in two papers printed in the 34th and 35th
volumes of the Philosophical Transactions, he has
done this in a most convincing and learned argument,
showing the tptal incapacity of Souciet for the task
which he had so zealously undertaken.
Among the supporters of the views of Newton, we
may enumerate Dr. Reid, Nauze, and some other
writers; and among its opponents who were far more
numerous, M. Freret, who left at his death a posthumous work on the subject, M. Fourmond, Mr. A.
Bedford, Dr. Shuckford, Dr. Middleton, Whiston,
and M. Delambre. The object of Fourmond is to
show the uncertainty of the astronomical argument,
arising on the one hand from the vague account of the
ancient sphere as given by Hipparchus; and, on the
other, from the extreme rudeness of ancient astronomical
observations. Delambre has taken a similar view of
the subject. He regards the observations of ancient
astronomers as too incorrect to form the basis of a
ystem of chronology; and he maintains, that if we
admit the accuracy of the details in the sphere of
Eudoxus, and suppose them all to belong to the same
epoch, all the stars which it contains ought at that
epoch to be found in the place where they are marked,
and we might thence verify the accuracy, and ascertain the state of the observations. It follows, however, from such an examination, that the sphere would
indicate almost as many different epochs as it contains
stars. Some of them even had not, in the time of
Eudoxus, arrived at the position weiaih had been for a
long time attributed to them, and will not even reach
it for 300 years to come, and on this account he considers it impossible to deduce any chronological conlusions from such a rude mass of errors.
But however well founded these observations may
be, we heartily concur in the opinion of M. Danou
"that they are not sufficient to establish a new system, and we must regard the system of Newton, asa
great fact in the history of chronological science, and




SIR ISAAC NZWTON.


219


as confirming the observation of Varro, the stage of
history does not commence till the first Olympiad."
While upon this part of our subject, we must not
forget to enumerate, among the chronological writings
of Sir Isaac Newton, his " Letter to a person of distinction, who had desired his opinion of the learned
Bishop Lloyd's hypothesis of the most ancient year."
This hypothesis was sent by the Bishop of Worcester
to Dr. Prideaux. Sir Isaac says, that it is filled with
many excellent observations on the ancient year; but
he does not find it proved that any ancient nations
used a year of 12 months and 360 days, without
correcting it from time to time by the luminaries, to
make the months keep to the course of the moon, and
the year to the course of the sun, and returns of the
seasons and fruits of the earth." After examining the
years of all the nations of antiquity, he concludes,
" that no other years are to be met with among the
ancients, but such as were either luni-solar, or solar
or lunar, or the calendars of these years. A practical
year," he adds," of 360 days, " is none of these.The beginning of such a year would have run round
the four seasons in seventy years; and such a notable
revolution would have been mentioned in history, and
is not to be asserted without proving it."
We will now turn our attention to the history of
the theological studies of Sir Isaac Newton, which
must ever be regarded as one of the most interesting portions of his life. That he who among all
the individuals of his species possessed the highest'
intellectual powers, was not only a learned and profound divine, but a firm believer in the great doctrines
of religion, is one of the proudest triumphs of the
Christian faith. Had he distinguished himself only
by an external respect for the offices and duties of
religion, and had he left merely in his last words an
acknowledgment of his faith, his piety might hve
been ascribed to the decay or the extinctio of his










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transcenda powers.   But Isaac Newton had been a
Christia       his early youth, and though never intendedAW     a preacher of the gospel, yet he interchanged the study of the Scriptures with that of the
laws of tle material universe; and from the examination of the works of the Creator, he found it to be no
abrupt transition to investigate the revelation of his
will, and to calculate the immortal destinies of mankind.
But when the religious professions of Sir Isaac
Newton could not be ascribed to an ambition of popularity, to the influence of weak health, or to the force
of professional impulse, it became necessary for the
apostles of infidelity to refer it to some extraordinary
cause. His supposed aberration of intellect was therefore eagerly seized upon by some as a plausible origin
for his religious principles: while others, without any
view of supporting the cause of scepticism, ascribed
his theological researches to the habits of the age in
which he lived, and to a desire of promoting(political
freedom, by turning against the abettors of despotism
those powerful weapons which the Holy Scriptures
supplied. The anxiety of Laplace to refer his religious writings to a late period of his life, seems to have
also been felt by Biot, who has gone so far as to fix
the date of one of his most important works, and
thus to establish the erroneous suspicions of his
colleague.
In his observations on Sir Isaac's "' Historical Account of two notable Corruptions of the Scriptures,"
he says, " From  the nature of the subject, and from
certain indications which Newton seems to give at the
beginning of his dissertation, we may conjecture with
probability that he composed it at the time when the
errors of Whiston, and a work of Dr. Clarke on the
same subject, drew upon them the attacks of all
the theologians of England, which would place the
date between the years 1712 and 1719. It would




SIR ISAAC NEWTON.


221


then be truly a prodigy to remark, that a man
of from seventy-two to seventy-five years of age was
able to compose, rapidly, as he leads us to 1believe,
so extensive a piece of sacred criticism, of literary
history, and even of bibliography, where an erudition
the most vast, the most varied, and the most ready,
always supports an argument well arranged and powerfully combined.  *   *     At this epoch of the
life of Newton, the reading of religious books had
become one of his most habitual occupations; and
after he had performed the duties of his office, they
formed, along with the conversation of his friends, his
principal amusement. He had then almost ceased to
care for the sciences; and as we have already remarked, since the fatal epoch of 1693, he gave to the
world only three really new scientific productions."
M. Biot has, however, adopted 1712-19 as the date
of this critical dissertation, notwithstanding the prodigy which it involves;-it is regarded as the composition of a man of seventy-two or seventy-five;-the
reading of religious books is stated to have become one
of his most habitual occupations, and such reading to
have been one of his principal amusements;-and all
this is associated with " the fatal epoch of 1693," as
if his illness at that time had been the cause of his
abandoning science and betaking himself to theology.
Carrying on the same views, Mr. Biot asks, in reference to Sir Isaac's works on Prophecy, " How a mind
of the character and force of Newton's, so habituated
to the severity of mathematical considerations, so
exercised in the observation of real phenomena, and
so well aware of the conditions by which truth is to
be discovered, could put together such a number of
conjectures without noticing the extreme improbability of his interpretations from the infinite number
of arbitrary postulates on which he has founded
them?" We would apply the same question to the
reasoning by which Biot fixes the date of the critical




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dissertation; and we would ask how so eminent a
philosopher could hazard such frivolous conjectures
upon a subject on which he had not a single fact to
guide his inquiries. The obvious tendency, though
not the design of the conclusion at which he arrives,
is injurious to the memory of Sir Isaac, as well as to
the interests of religion; and these considerations
might have checked the temerity of speculation even
if it had been founded on better data. The Newtonian interpretation of the Prophecies, and especially
that part which Biot characterizes as unhappily
stamped with the spirit of prejudice, has been adopted
by men of the soundest and most unprejudiced minds;
and, in addition to the moral and historical evidence
by which it is supported, it may yet be exhibited in
all the fullness of demonstration. But the speculation
of Biot respecting the date of Newton's theological
works was never maintained by any other person than
himself, and is capable of being disproved by the most
incontrovertible evidence.
We have previously seen in the extract from Mr.
Pryme's manuscript journal, that before the year
1692, when a shade is supposed to have obscured his
powerful mind, Newton was well known as an "e excellent divine"-a character which it was impossible
he could have acquired without the attention of many
years to theological researches; but important as this
argument would have been, we are fortunately not left
to so general a defence. The correspondence of Newton with Locke, published by Lord King, places it
beyond the possibility of a doubt that he had begun
his researches respecting the prophecies before the
year 1691-before the 49th year of his age, and previoue to " the fatal epoch of 1693."  That he had
previously discussed this interesting subject is evident
from the following letter to his friend:



SIR ISA-A NEWTON.


228


" Cambrdge, Feb. 7th, 190-91
SIR,
"I am sorry your journey proved to so little purpose, though it delivered you from the trouble of the
company the day after. You have obliged me by
mentioning me to my friend at London, and I mus
thank both you and my Lady Masham for your civilities at Oates, and for not thinking that I made a long
stay there. I hope we shall meet again in due time,
and then I should be glad to have your judgment upon
some of my mystical fancies.  The Son of Man;
Dan. vii., I take to be the same with the Word of
God upon the White Horse in Heaven, Apoc. xii., for
both are to rule the nations with a rod of iron; but
whence are you certain that the Ancient of Days is
Christ? Does Christ any where sit upon the throne?
If Sir Francis Masham be at Oates, present, I pray
my service to him with his lady, Mrs. Cudworth and
Mrs. Masham. Dr. Covel is not in Cambridge.-I
am your affectionate and humble servant,
"C Is. NEWTON."
"Know you the meaning of Dan. x. 21. There
is none that holdeth with me in these things, but
Mich. the Prince."
Having thus determined the date of those investigations which constitute his " Observations on the
Prophecies of Holy Writ," particularly the prophecies
of Daniel and the Apocalypse, we shall proceed to fix
the latest date of his " historical account of two notable
cornmptions of the Scripture, in a letter to a friend."
This work seems to have been a very early production of'Newton's. It was written in the form of a
letter to Mr. Locke, and at the time, Sir Isaac appears
to have been anxious for its publication. Afraid,
however, of being again led into a controversy, and
dreading the intolerance to which he might be exposed,




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he requested his friend, who was at that time intending to proceed to Holland, to get it translated into
French, and published on the continent. Having
abandoned his design of visiting Holland, Locke
transmitted the manuscript, without the author's name,
to his learned correspondent, M. Le Clerc, in Holland;
and it appears from a letter of Le Clerc to Mr. Locke,
that he had received the manuscript previous to April
11th, 1691. M. Le Clerc, however, delayed taking
any steps regarding its publication for a long time;
and it was till the 20th of January, 1692, that he announced to Locke, his intention of publishing the tract
in Latin. When this plan   was communicated to
Newton, he became alarmed at the risk of detection,
and resolved to stop the publication.  This resolution
he intimated to Mr. Locke in the following letter:"Cambridge, Feb. 16th, 1691-2.
SIR,
"Your former letters came not to my hand, but
this I have. I was of opinion my papers had lain
still, and am sorry to hear there is news about them.
Let me entreat you to stop their translation and impression so soon as you can; for I design to suppress
them. If your friend hath been at any pains and
charge, I will repay it, and gratify him. I am very
glad my Lord Monmouth is still my friend, but intend
not to give his lordship and you any farther trouble.
My intentions are to sit still. I am to beg his lordship's pardon for pressing into his company the last
time I saw him, and had not done it, but that Mr.
Paulin pressed me into the room. Miracles, of odod
credit, continued in the church for about two or three
hundred years.  Gregorius Thaumaturgus had his
name from thence, and was one of the latest who was
eminent for that gift; but of their number and frequency I am  not able to give you a just account.
The history of those ages is very imperfect. Mr.




SIR ISAAC NEWTON.


225


Paulin told me you had writ for some of Mr. Boyle's
red earth, and by that I know you had the receipt.
"Your most affectionate and obedient servant,
Is. NEWTON."
We have here positive evidence that this celebrated
treatise which M. Biot asserts to have been written
between the years 1712 and 1719, was actually in the
hands of Le Clerc in Holland, at least twenty-one
years previously, viz, April, 1691; and consequently
before the time of its author's supposed insanity.
Mr. Locke lost no time in obeying the request of
Newton, and Le Clerc instantly stopped the publication
of the letter; but, as he had never understood who
was the author, he deposited the manuscript, which
was in the handwriting of Locke, in the library of the
Remonstrants, where it was afterwards found, and
was published at London, in 1754, under the title of
" Two Letters from Sir Isaac Newton to M. Le Clerc"
-a form which had never been given to it by its
author. The copy thus published was very imperfect,
as it wanted both the beginning and the end, and erroneous in many places; but Dr. Horsley has published a genuine edition, which is ip the form of a
single letter to a friend, and was printed from a manuscript in the handwriting of Sir Isaac Newton, in the
possession of the Rev. Dr. Ekins, Dean of Carlisle.
Having thus determined the dates of the principal
theological writings of Sir Isaac, with as mulch accuracy as possible, we shall now proceed to give somn
account of their contents.
"The Observations on the prophecies of Daniel, and
the Apocalypse of St. John" were published in
London, in 1733, in one quarto volume. The work is
divided into two parts, the first of which treats of the
Prophecies of Daniel, and the second of the Apocalyps of St. John. It begins with an account of the




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different books which compose the Old Testament, and,
as the author considers Daniel to be the most distinct
in the order of time, and the easiest to be understood,
he makes him the king to all the prophetic books in
those matters which relate to the last time. He next
considers the figurative language of the prophets, which
he regards as taken "from the analogy between the
world natural, and an empire or kingdom considered
was a world political;" the heavens, and the things
therein, the inferior people; and the lowest parts of
the earth the most miserable of the people. The sun
is put for the whole race of kings, the moon for the
body of the common people, and the stars for subordinate princes and rulers. In the earth, the dry land
and the waters are put for the people of several nations. Animals and vegetables are also put for the
people of several regions. When a beast or man is
put for a kingdom, his parts and qualities are put for
the analogous parts and qualities of the kindom; and
when a man is taken in a mystical sense, his qualities
are often signified by his actions, and by the circumstances and things about him.   In applying these
principles he commences with the vision of the image
composed of four different metals. This image he considers as representing a body of four great nations
which should reign in succession over the earth, viz.,
the people of Babylonia, the Persians, the Greeks, and
the Romans, while the stone cut out without hands is
a nw kingdom which should arise after the four, conquer all those nations, become very great, and continue to the end of time.
The vision of the four beasts is the prophecy oithe
four empires repeated, with several new editions. The
lion with eagle's wings was the kingdom of Babylon
and Media, which overthrew the Assyrian power.
The beast like a bear was the Persian empire, and its
three ribs were the kingdoms of Sardis, Babylon, and
Egypt. The third beast, like a leopard was the Greek
* 4'




SIR ISAAC NEWTON.


227


empire, and its four heads and four wings were the
kingdoms of Cassander, Lysimachus, Ptolemy, and
and Seleucus. The fourth beast, with its great iron
teeth was the Roman empire, and its ten horns were
the ten kingdoms into which it was broken in the reign
of Theodosius the Great.
In the fifth chapter the author treats of the kingdoms represented by the feet of the image composed of
iron and clay which did not stick to one another, and
which were of different strength. These were the
Gothic tribes called Ostrogoths, Visigoths, Vandals,
Gepidae, Lombards, Burgundians, Alans, &c., all of
whom had the same manners and customs, and spoke
the same language, and who, about 416 years before
Christ, were all quietly settled in several kingdoms
within the empire, not only by conquest, but by grants
of the Emperor.
In the sixth chapter Sir Isaac treats of the ten kingdoms represented by the ten horns of the fourth beast,
into which the western empire became divided about
the time when Rome was besieged and taken by the
Goths. These kingdoms were
1. The kingdom of the Vandals and Alans in Spain
and Africa.
2. The kingdom of Suevians in Spain.
3. The kingdom of the Visigoths.
4. The kingdom of the Alans in Gaul.
5. The kingdom of the Burgundians.
6. The kingdom of the Franks.
7. The kingdom of the Britons.
8. The kingdom of the Huns.
9. The kingdom of the Lombards.
10. The kingdom of Ravenna.
Some of these kingdoms at length fell and new
ones sprung up; but whatever was their subsequent




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number, they still retain the name of the ten kings
from their first number.
The eleventh horn of Daniel's fourth beast is shown
in the seventh chapter to be the Church of Rome in its
triple character of a seer, a prophet, and a king, and
its power to change times and laws is copiously illustrated in the eighth chapter.
In the ninth chapter our author treats of the kingdom represented in Daniel by the ram and the hegoat, the ram indicating the kingdom of the Medes
and Persians from the beginning of the four empires,
and the he-goat the kingdom of the Greeks to the end
of them.
The prophecy of the seventy weeks, which had
hitherto been restricted to the first coming of our Saviour, is shown to be a prediction of all the main
periods relating to the coming of the Messiah, the
times of his birth and death, the time of his rejection
by the Jews, the duration of the Jewish war, by
which he caused the city and sanctuary to be destroyed, and the time of his second coming.
In the eleventh chapter our author treats, with
great sagacity and acuteness, of the time of our Saviour's birth and passion-a subject which had exceedingly perplexed all preceding commentators.
After explaining in the twelfth chapter the last
prophecy of Daniel, viz., that of the scripture of truth,
which he considers as a commentary on the vision of
the ram and he-goat, he proceeds in the thirteenth
chapter to the prophecy of the king who did according
to his will, and magnified himself above every god,
and honoured Mahuzzims, and regarded not the desire
of women. He shows that the Greek empire, after
the division of the Roman empire into the Greek and
Latin empires, became the king who in matters of
religion did according to his will, and in legislation
exalted and magnified himself above every god.
In the second part of the work on the Apocalypse of




SIR ISAAC NEWTON.


229


St. John, Sir Isaac treats, 1st, of the time when the
prophecy was written, which he conceives to have
been during John's exile in Patmos, and before the
epistles to the Hebrews and to Peter were composed,
which in his opinion have a reference to the Apocalypse; 2ndly, of the scene of the vision, and the revelation which the Apocalypse has to the book of the
law of Moses and to the worship of God in the temple;
and, 3rdly, of the relation which the Apocalypse has
to the prophecies of Daniel, and of the subject of the
prophecy itself.
Sir Isaac Newton regards the prophecies of the Old
and New Testament not as given to gratify men's
curiosity, by enabling them to foreknow things, but
that, after they were fulfilled, they might be interpreted by the event, and afford convincing arguments
that the world is governed by Providence. He considers that there is so much of this prophecy already
fulfilled, as to afford to the diligent student sufficient
instances of God's Providence; and he adds, that
" amongst the interpreters of the last age there is
scarce one of note who hath not made some discovery worth knowing, and thence it seems one may
gather that God is about opening these mysteries.
The success of others put me upon considering it, and
if I have done anything which may be useful to following writers, I have my design."
Such is a brief abstract of this truly valuable and
ingenious work, which is characterised throughout by
great learning, and marked with the sagacity of its
distinguished author. The same qualities of his gifted
mind are equally conspicuous in his "Historical
Account of Two Notable Corruptions of Scripture."
This praiseworthy treatise relates to two texts in
the Epistles of St. John and St. Paul. The first of
these is in 1 John v. 7:-" For there are three that
bear record in heaven, the Father, the Son, and the
Holy Ghost, and these three are one."  This text he




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considers as a gross corruption of Scripture, which
had its origin among the Latins, who interpreted the
Spirit, Water, and Blood, to be Father, Son, and Holy
Ghost, in order to prove them one. With the same
view Jerome inserted the Trinity in express words in
his version. The Latins marked his variations in the
margins of their books; and in the twelfth and following centuries, when the disputations of the schoolmen were at their height, the variation began to creep
into the text in transcribing. After the invention of
printing, it crept out of the Latin into the printed
Greek, contrary to the authority of all the Greek
manuscripts and ancient versions; and from the
Venetian press it went soon after to Greece. After
proving these positions, Sir Isaac gives the following
paraphrase of this remarkable passage:"' Who is he that overcometh the world, but he
that believeth that Jesus is the Son of God,' that Son
spoken of in the Psalms, where he saith, 'thou art
my Son, this day have I begotten thee.' ' This is he
that,' after the Jews had long expected him, came,
first in a mortal body, by baptism of water, and then
in an immortal one, by shedding his blood upon the
cross and rising again from the dead; 'not by water
only, but by water and blood;' being the Son of God
as well by his resurrection from the dead (Acts xiii. 33)
as by his supernatural birth of the virgin (Luke i. 35).
'And it is the Spirit' also that, together with the
water and blood, 'beareth witness' to the truth of his
coming; 'because the Spirit is truth;' and so a fit
and unexceptionable witness, ' For there are three
that bear record' of his coming; ' the Spirit,' which
he promised to send, and which was since shed forth
upon us in the form of cloven tongues, and in various
gifts; ' the' baptism of 'water,' wherein God testified
'this is my beloved Son;' 'and the' shedding of his
'blood,' accompanied with his resurrection, whereby
he became the most faithful martyr, or witness, of this
truth. CAnd these three,' the Spirit, the baptism,




SIR ISAAC NEWTON.              2
and passion of Christ, 'agree in' witnessing ' one' and
the same thing, (namely, that the Son of God is
come;) and therefore their evidence is strong: for the
law requires but two consenting witnesses, and here
we have three: ' and if we receive the witness of menD'
the threefold 'witness of God,' which he bare of his
Son, by declaring at his baptism, 'this is my beloved
Son;' by raising him from the dead, and by pouring
out his Spirit on us, 'is greater;' and, therefore, ought
to be more readily received."
While the Latin Church was corrupting the preceding text, the Greek Church was doing the same to
St. Paul's 1st Epistle to Timothy, iii. 16 —" Great is
the Mystery of Godliness, God manifest in the Flesh."
According to Sir Isaac, after proving by a learned and
ingenious examination of ancient manuscripts that this
has been altered from the original, he concludes that
the reading should be, " Great is the Mystery of Godliness, who (namely, our Saviour) was manifest in the
flesh."
As this ingenious dissertation had the effect of depriving the zealous defenders of the doctrine of the
Trinity of the aid of two leading texts, Sir Isaac
Newton has been regarded as an Anti-trinitarian;
but such a conclusion is not warranted by anything
he has published. Even Mr. Biot has remarked,
"' that there is absolutely nothing in the writings of
Newton to justify, or even to authorise, the idea that
he was an Anti-trinitarian."  Sir Isaac himself distinctly warns his readers, that his object was solely to
purge the truth of things spurious."  For our own
part, we are disposed to think that he declares his
belief in the doctrine of the Trinity, when he says,
" In the eastern nations, and for a long time in the
Western, the faith subsisted without this text; and it
is rather a danger to religion, than an advantage to
make it now lean upon a bruised reed. There cannot
be better service done to the truth, than to purge it




2a2


3  THE LIFE OF


of things spurious; and, therefore, knowing your
prudence and calmness of temper, I am confident I
shall not offend you by telling you my mind plainly;
especially since it is no article of faith, no point of
discipline, nothing but a criticism concerning a text
of scripture which I am going to write about." The
word faith in this passage cannot mean faith in the
scriptures in general, but faith in the particular doctrine of the Trinity; for it is this article of faith only
to which Sir Isaac refers, when he deprecates its
leaning on a bruised reed. But whatever may be the
meaning of this passage, we know that Newton
greatly offended Mr. Whiston for having represented
him as an Arian; and so much did he resent the conduct of his friend in ascribing to him heretical opinions,
that he prevented him from being elected a Fellow
of the Royal Society while he was President.
The only other religious works which were composed by Sir Isaac Newton were his " Lexicon Propheticum," to which was added a Dissertation on the
sacred cubit of the Jews, and " Four Letters addressed to Dr. Bentley, containing some arguments in
proof of a Deity."
The Lexicon Propheticum was left incomplete, and
has never been published; but the Latin Dissertation
which was appended to it, was published in 1737,
among the Miscellaneous Works of Mr. John Greaves,
In this treatise he proves that the ancient cubit was
about twenty-six and a half Roman unciae.
Upon the death of the Honourable Robert Boyle,
on the 30th December, 1691, it was found by a
codicil to his will, that he had left the sum of ~50
per annum for the purpose of establishing a lecture-.
ship, in which eight discourses were to be preached
annually in one of the churches of the metropolis, in
illustration of the evidences of Christianity, and in
opposition to the wide-spreading principles of infidelity. Dr. Bentley, though at that time a very




SIR ISAAC NEWTON.


13$


young man, was appointed to preach the first course
of sermons; and the manner in which he discharged
this important duty gave the highest satisfaction, not
only to the trustees of the lectureship, but to the public in general. In the first six lectures the DoAr
exposed the folly of atheism even in reference to the
present life, and derived powerful arguments for the
existence of a Supreme Being from the faculties of the
soul, and the structure and functions of the human
frame. In order to complete his plan, he proposed to
devote his seventh and eighth lectures to the demonstration of a divine Providence from the physical constitution of the universe, as established in the Principia.
In order to qualify himself for this task, he received
from Newton written directions respecting a list of
books necessary to be perused previous to the study
of that work; and having made himself master of the
system which it contained, he applied it with irresistible force of argument to establish the existence of
an overruling mind. Previous to the publication of
these lectures, Bentley encountered a difficulty which
he was not able to solve, and he prudently transmitted
to Sir Isaac during 1692 a series of queries on the
subject.  This difficulty occurred in an argument
urged by Lucretius, to prove the eternity of the world
from a hypothesis of deriving the frame of it by
mechanical principles from matter endowed with an
innate power of gravity, and evenlyscattered throughout the heavens.   Sir Isaac with great pleasure
entered upon the consideration of the subject, and returned his sentiments to Dr. Bentley in the four
letters which we have already noticed in the preceding
chapter. j
In the first of these letters, dated December 10th,
1692, Sir Isaac mentions that when he wrote his
treatise about our system, namely, the Third Book of
the Prncipia, "he had an eye upon such principles
as might work with considering men for the belief




2I4               THEl LIfE OF
of a deity, and he expressed his happiness that it has
been found useful for that purpose. In answering the
fst query of Dr. Bentley, the exact import of which
we do not know, he states that if matter were evenly
diffused through a finite space, and endowed with
innate gravity, it would fall down into the middle of
the space, and form one great spherical mass; but if
it were diffused through an infinite space, some of it
would collect into one mass, and some into another,
so as to form an infinite number of great masses. In
this manner the sun and stars might be formed if the
matter were of a lucid nature. But he thinks it inexplicable by natural causes, and to be ascribed to the
counsel and contrivance of a voluntary agent, that the
matter should divide itself into two sorts, part of it
composing a shining body like the sun, and part an
opaque body like the planets. Had a natural and
blind cause, without continuance and design, placed
the earth in the centre of the moon's orbit, and
Jupiter in the centre of his system of satellites, and the
sun in the centre of the planetary system, the sun
would have been a body like Jupiter and the earth,
that is without light and heat, and consequently he
knows no reason why there is only one body qualified
to give light and heat to all the rest, but because the
author of the system thought it convenient, and becuse one was sufficient to warm and enlighten all the
rest.
To the second query of Dr. Bentley he replies that
the motions which the planets now have could not
spring from any natural cause alone, but were impressed by an intelligent agent. " To make such a
system with all its motions, required a cause which
understood, and compared together the quantities of
matter in the several bodies of the sun and planets,
and the gravitating powers resulting from itece, the
several distances of the primary planets  the sun,
and of the secondary ones from Saturn,  per, and




SIR ISAAC NEWTON.


2235  -1


the Earth, and the velocities with which those planed
could revolve about those quantities of matter in thi
central bodies; and to compare and adjust all thes
things together in so great a variety of bodies, argues
that cause to be not blind andfortuitous, but very well
skilled in mechanics and geometry."
In the second letter, 17th Jan., 1692-3, he admits that
the spherical mass formed by the aggregation of the par.
tiles would effect the figure of the space in which the
matter was diffused, provided the matter descends directly downwards to that body, and the body has no
diurnal rotations; but he states that by earthquakes
loosening the parts of this solid, the protuberance
might sink a little by the weight, and the mass by degrees approach a sperical figure. He then proceeds to
correct an error of Dr. Bentley's in supposing that all
infinites are equal. He admits that gravity might put
the planets in motion, but he maintains that, without
the Divine power, it could never give them such a circulating motion as they have about the sun, because a
proper quantity of a transverse motion is necessary for
this purpose; and he concludes that he is compelled
to ascribe the frame of this system to an intelligent
agent.
The third letter contains, opinions confirming or cor
recting several positions which Dr. Bentley had laid
down, and he concludes it with a curious examination
of the opinion of Plato, that the motion of the pla
is such as if they had all been created by God in
region very remote from our system, and let fall from
thence towards the sun, their falling motion being
turned aside into a traverse one whenever they arrived
at their several orbits. Sir Isaac shows that there is
no common place such as that conjectured by Plato,
provided the gravitating power of the sun remains
conat; but that Plato's affirmation is true if we
suppise    gavitating power of the sun to be doubled at that  oment of time when they all arrive at




836              'THE LIFE OF
their several orbits. " If we suppose," he says, "the
gravity of all the planets towards the sun to be of such
a quantity as it really is, and that the motions of the
planets are turned upwards, every planet will ascend
to twice its height from the sun. Saturn will ascend
till he be twice as high from the sun as he is at preset, and no higher; Jupiter will ascend as high again
as he is at present, that is, a little above the orb of
Saturn; Mercury will ascend to twice his present
height, that is, to the orb of Venus; and so of the rest;
and then, by falling down again from the places to
which they ascended, they will arise again at their several orbs with the same velocities they had at first,
and with which they now revolve.
" But if so soon as their motions by which they revolve are turned upwards, the gravitating power of
the sun, by which their descent is perpetually retarded,
be diminished by one half, they will now ascend perpetually, and all of them, at all equal distances from
the sun, will be equally swift. Mercury, when he arrives at the orb of Venus, will be as swift as Venus;
and he and Venus, when they arrive at the orb of the
earth, and so of the rest.  If they begin all of them
to ascend at once, and ascend in the same line, they
will consequently, in ascending, become nearer and
nearer together, and their motions will constantly approach to an equality, and become at length slower
-than any motion assignable.  Suppose, therefore, that
they ascended till they were almost contiguous, and
their motions inconsiderably little, and that all their
motions were at the same moment of time, turned
back again, or, which comes almost to the same thing,
that they were only deprived of their motions, and
let fall at that time, they would all at once arrive at
their several orbs, each with the velo    had at
first; and if their motions were then tu deways,
and at the same time the gravitating;of te
eun doubled, that it might be strong A t   to retain




SIR ISAAC NEWTON.


237


them in their orbs, they would revolve in them as before their ascent. But if the gravitating power of the
sun was not doubled, they would go away from their
orbs into the highest heavens in parabolical lines."
In the fourth letter, he states that the hypothesis
that matter is at first evenly diffused through the
universe, is in his opinion inconsistent with the hypothesis of innate gravity without a supernatural power
to reconcile them, and therefore it infers a Deity;
" For if there be innate gravity," he says, "it is impossibre now for the matter of the earth and all the
planets and stars to fly up from them, and become
evenly spread throughout all the heavens without a
supernatural power."
These letters, of which we have endeavoured to give
a brief summary, will repay the most attentive perusal
by the philosopher as well as the divine. They are
written with much perspicuity of language, and great
power of thought, and they contain results which incontestibly prove that their author was fully master of
his noblest faculties, and comprehended the profoundest
parts of his own writings.
The logical acuteness, the varied erudition, and the
absolute freedom from all prejudice which shine
throughout the theological writings of Newton, might
have protected them from the charge of having been
written in his old age, and at a time when a failure of
mind was supposed to have unfitted him for his mathematical studies. But it is fortunate for his reputation,
as well as for the interests of Christianity, that we
have been able to prove the falsity of such base insinuations, and to produce the most undoubted evidence that
allthe theological writings of Newton were composed
when        al powers were in their greatest vigour,
a      the crisis of that bodily indisposition which
is  p       ",some to have affected his reason. The
abSle         r. Bentley were even written in the
maiddle ef     rod twhen want of sleep and appetite




238


THE LIVE OF


had disturbed the serenity of his mind, which is a
sufficient proof that this disturbance never affected the
higher functions of his understanding.
When a mind of great and acknowledged power
irst directs its energies to the study of the material
universe, no indications of order attract his notice, and
no proofs of design call forth his admiration. In the
tarry firmament he sees no bodies of stupendous magnitude, and no distances of immeasurable span. The
two great luminaries appear vastly inferior in magnitude to many objects around him, and the greatest
distances in the heavens seem even inferior to those
which his own eye can embrace on the surface of the
earth. The planets, when observed with care, are
seen to have a motion among the fixed stars, and to
vary in their magnitude and distances, but these
changes appear to follow no law. Sometimes they
move to the east, sometimes to the west, sometimes
towards the north, and sometimes towards the south,
and at other times they are absolutely stationary. No
system, in short, appears, and no general law seems
to direct their motions. By the observations and inquiries of astronomers, however, during successive
ages, a regular system has been recognised in this
chaos of moving bodies, and the magnitudes, distances,
and revolution of every planet which composes it has
been determined with the most extraordinary accuracy.
Minds fitted and prepared for this species of inquiry
are capable of understanding the great variety of evidence by which the truth of the planetary system is
established; but thousands of individuals, who are
even distinguished in other branches of knowledge, are
incapable of such researches, and view with a sceptical
eye the great and irrefragable truths of astr.i y.
That the sun is stationary in the oe     f our
system-that the earth moves round thtain     and
round its own axis-that the earth is          n
miles in diameter, and the sun one huni  andt ten




SIR ISAAC NBWTOn.
times as large; that the earth's orbit is one hundred
and ninety millions of miles in breadth; and that if
this immense space were filled with light, it would
appear only like a luminous point at the nearest fixed
star-are positions absolutely unintelligible and incredible to all who have not carefully studied the subject.  To millions of mankind, then, the Great Book
of Nature is absolutely sealed, though it is in theo
power of all to unfold its pages, and to peruse thoseglowing passages which proclaim the power and
wisdom of its Almighty Author.
The Book of Revelation exhibits to us the same
peculiarities as that of Nature. To the ordinary eye
it presents no immediate indication of its divine
origin. Events apparently insignificant-supernatural
interferences seemingly unnecessary-doctrines almost
contradictory-and prophecies nearly unintelligible of
moral and physical evil-the prediction of a Messiah
-- the actual advent of our Saviour-his instructionhis miracles-his death-his resurrection-and the
subsequent propagation of his religion by the unlettered fishermen of Galilee, are each a stumblingblock to the wisdom of this world. The youthful
and vigorous mind when first called upon to peruse
the sacred writings, turns from them with disappointment. It recognizes in them no profound science-no
secular wisdom-no divine eloquence-no disclosure of
Nature's secrets-no direct impress of an Almighty
hand. Bnt though the system of revealed truth
which this book contains is like that of the universe
concealed from common observation, yet the labourzs
of centuries have established its divine origin, and developed in all its order and beauty the great plan of
human restoration.  In the chaos of its incidents, we
discover the whole history of our species, whether it is
delieated in events that are past, or shadowed forth
ia those hic are to come,-from the creation of man
a4d the   g  of evil, to the extinction of hi earthly




240


THE LIFE OP


dynasty, and the commencement of his immortal
career.
The antiquity and authenticity of the books which
comprise the sacred canon-the fulfilment of its prophecies-the miraculous works of its founder-his
death and resurrection, have been demonstrated to all
who are capable of appreciating the force of historical
evidence; and in the poetical and prose writings of
the inspired authors, we discover a system of doctrine,
and a code of morality traced in characters as distinct
and legible as the most unerring truths in the material world. False systems of religion have indeed
been deduced from the Scriptures, as false systems of
the universe have sprung from the study of the Book
of Nature; but the very prevalence of a false system
proves the existence of one that is true; and though
the two classes of facts necessarily depend on different
kinds of evidence, yet we have no hesitation in saying
that the Copernican system is not more demonstrably
true than the system of theological truth contained in
the Bible. If men of high powers, then, are still found,
who are insensible to the evidence which sustains the
system of the universe, need we wonder that there are
others whose minds are shut against the clear evidence which entrenches the strongholds of our faith.
If such, then, is the character of the Christian
faith, we need not be surprised that it was embraced
and expounded by such a genius as Sir Isaac Newton.
Cherishing its doctrines, and leaning on its promises,
he felt it his duty, as it was his pleasure, to apply to,
it that intellectual strength which had successfully
surmounted the difficulties of the material universe.
The fame which that success procured him, he could
not but feel to be the breath of popular applause
which administered only to his personal feelings; but
the investigation of the sacred mysteries, while it prepared his own mind for its final destiny was calculated to promote the spiritual interests of millions,




SIR ISAAC NEWTON.               241
This noble impulse he did not hesitate to obey, and by
thus uniting philosophy with religion, he dissolved the
league which genius had formed with scepticism, and
added to the host of witnesses the brightest name of
ahcient or modern times.
Having thus given an account of the principal
labours of Sir Isaac Newton, we consider it our
duty to notice several of his minor discoveries and
inventions, which could not properly be introduced
earlier.
The most important of these, perhaps, are his
chemical researches, which he seems to have pursued
with more or less diligence from the time when he
first witnessed the practical operations of chemistry
during his residence at the apothecary's at Grantham.
His first chemical experiments were, in all likelihood,
made on the alloys of metals, for the purpose of
obtaining a good metallic composition for the specula
of reflecting telescopes. In his paper on thin plates,
he treats of the combination of solids and fluids; but
he enters more largely on these and other subjects in
the queries published at the end of his Optics.
One of his most important chemical treatises is his
Tabula quantitatum   et graduum  caloris, which was
published in the Philosophical Transactions. This
short paper contains a comparative scale of temperature from that of melting ice to that of a small kitchen
coal fire.  The following are the principal points of
the scale, the intermediate degrees of heat having
been determined with great care.
Degrees   Equal Parts
of heat.    of heat.
0          0    Freezing point of water.
1          12   Blood heat.
24       Heat of melting wax.
3         48   Melting point of equal parts of tin and bismutkh
4-         96   Melting point of lead..5        19X   Heat of a small coal fire,
ant....:.     X.. S  -,.  D:  -  *  1:




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The first column of this table contains the degrees
of heat in arithmetical progression; and the second
contains the degrees of heat in geometrical progression, the second degree being twice as great as the
first, and so on. It is obvious from the above table,
that the heat at which equal parts of tin and bismuth
melt is four times greater than that of blood heat, the
heat of melting lead eight times greater; and the heat
of a small coal fire sixteen times greater.
This table was constructed by the help of a thermometer, and of red hot iron.   By the former he
measured all heats as far as that of melting tin; and
by the latter he measured all the higher heats. For
the heat which heated iron loses in a given time is as
the total heat of the iron; and therefore, if the times of
cooling are taken equal, the heats will be in a geometrical progression, and may therefore be easily formed
by a table of logarithms.
He found by a thermometer constructed with linseed oil, that if the oil, when the thermometer was
placed in melting snow, occupied a space of 1000
parts, the same oil, rarefied with one degree of heat,
or that of the human body, occupied a space of 10,256;
in the heat of water beginning to boil, a space of
10,705; in the heat of water boiling violently,
10,725; in the heat of melted tin beginning to cool,
and putting on the consistency of an amalgam 11,516,
and when the tin had become solid 11,496. Hence
the oil was rarefied in the ratio of 40 to 39 by the
heat of the human body; of 15 to 14 by the heat of
boiling water; of 15 to 13 in the heat of melting tin
beginning to solidify; and of 23 to 20 in the same
tin'when solid. The rarefaction of air was with the
same heat, ten times greater than that of oil; and the
rarefaction of oil fifteen times greater than that of
spirit of wine. By making the heat of oil proportioned to its rarefaction, and by calling the heat of the
human body 12 parts, we obtain the heat of water




SIR ISAAC NEWTON.


243


beginning to boil, 33; of water boiling violently, 34;
of melted tin beginning to solidify, 72; and of the
same become solid, 70.
Sir Isaac then heated a sufficiently thick piece of
iron till it was red hot; and having fixed it in a
cold place, when the wind blew uniformly, he put
upon it small pieces of different metals and other fusible bodies, and noted the times of cooling, till all the
particles having lost their fluidity grew cold, and the
heat of the iron was equal to that of the human body.
Then, by assuming that the excesses of the heats of
the iron and of the solidified particles of metal, above
the heat of the atmosphere, were in geometrical progression when the times were in arithmetical progression, all the heats were obtained. The iron was placed
in a current of air, in order that the air heated by the
iron might always be carried away by the wind, and
that cold air might replace it with a uniform motion;
for thus equal parts of the air were heated in equal
times, and received a heat proportional to that of the
iron. But the heats thus found had the same ratio to
one another with the heats found by the thermometer;
and hence he was right in assuming, that the rarefactions of the oil were proportional to its heats.
Another short chemical treatise by Sir Isaac Newton
has been published by Dr. Horsley. It is entitled
"De Natura Acidorum," but is principally occupied
with a number of brief opinions on chemical subjects.
This paper was written later than 1687, as it bears a
reference to the " Principia;" and the most important
facts which it contains seems to have been more distinctly reproduced in the queries at the end of the
Optics.
The most important of these queries relate to fire,
flame, and electric attractions, and as they were revised in the year 1716.and 1717, they may be regaded as containing the most matured opinions of
their author. Fire he regards as a body heated so hot




244


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as to emit light copiously, and flame as a vapour, fume,
or exhalation, heated so hot as to shine. In his long
query on elective attractions he considers the small
particles of bodies as acting upon one another at distances so minute as to escape observation. When salt
of tartar deliquesces, he supposes that this arises from
an attraction between the saline particles and the
aqueous particles held in solution in the atmosphere,
and to the same attraction he ascribes it that the water
will not distil from the salt of tartar without great
heat. For the same reason sulphuric acid attracts
water powerfully, and parts with it with great difficulty.  When this attractive force becomes very
powerful, as in the union between sulphuric acid and
water, so as to make the particles "coalesce with
violence," and rush towards one another with an accelerated motion, heat is produced by the mixture of
the two fluids. In like manner, he explains the production of flame from the mixture of cold fluids-the
action of fulminating powders,-the combination of
iron filings with sulphur,-and all the other chemical
phenomena of precipitation, combination, solution, and
crystallization, and the mechanical phenomena of cohesion and capillary attraction. He ascribes hot springs,
volcanoes, fire-damps, mineral coruscations, earthquakes, hot suffocating exhalations, hurricanes, lightning, thunder, fiery meteors, subterraneous explosions,
land-slips, ebullitions of the sea, and water-spouts, to
sulphureous steams abounding in the bowels of the
earth, and fermenting with minerals, or escaping into
the atmosphere, when they ferment with acid vapours
fitted to promote fermentation.
In explaining the structure of solid bodies, Sir Isaac
is of opinion "that the smallest particles of matter
may cohere by the strongest attractions and compose
bigger particles whose virtue is still weaker; and so
on for divers successions, until the progression ends in
the biggest particles on which the operations 'ia




SIR ISAAC NEWTON.


245


chemistry, and the colours of natural bodies, depend,
and which, by adhering, compose bodies of a sensible
magnitude. If the body is compact, and bends or yields
inward to pression, without any sliding of its parts, it is
hard and elastic, returning to its figure with a force rising from the mutual attraction of its parts. If the parts
slide upon one another, the body is malleable or soft.
If they slip easily, and are of a fit size to be agitated
by heat, and the heat is big enough to keep them in
agitation, the body is fluid; and if it be apt to stick
to things, it is humid; and the drops of every fluid
affect a round figure by the mutual attraction of their
parts, as the globe of the earth and sea affects a round
figure, by the mutual attraction of its parts by
gravity."
Sir Isaac then supposes that, as the attractive force
of bodies can but reach to a small distance from
them, " a repulsive virtue ought to succeed;" and he
considers such a virtue as following the reflexion of
the rays of light, the rays being repelled by the immediate contact of the reflecting body, and also from
the emission of light, the ray, as soon as it is shaken
off from a shining body by the vibrating motion of the
parts of the body getting beyond the reach of attraction, and being driven away with exceeding great
velocity by the force of reflexion.
Many of the chemical views which Newton thus
published in the form of queries, were illustrated and
confirmed by Stephen Hall, in his book on " Vegetable
Statics," a work which contains the germ of some of
the most valuable discoveries in modern chemistry.
Although there is little reason to suppose that Sir
Isaac Newton was a believer in the doctrines of
alchemy, yet we are informed, by the Rev. Mr. Law,
that he had been a diligent student of Jacob Behmen's
writings, and that there were found among his papers
copious extracts from them. He also states that Sir
Isaac, together with Dr. Newton, his relation, in the




246


THRE LIFE OF


earlier part of his life, set up furnaces, and were for
several months in quest of the philosopher's tincture.
Sir Isaac communicated to the Royal Society a
paper entitled, " An Hypothesis explaining properties
of Light," in which he, for the first time, introduces his
opinions respecting ether, and employs them to explain the nature of light and the cause of gravity." He was induced to do this," he says, "because he
had observed the heads of some great virtuosos to run
much upon hypotheses, and he therefere gave one
which he was obliged to consider as the most probable,
if he were inclined to adopt one.
This hypothesis seems to have been afterwards a
subject of discussion between him and Mr. Boyle, to
whom he promised to communicate his opinion more
fully in writing. He accordingly addressed to him a
long letter, in which he explains his views respecting
ether, and employs them to account for the refraction
of light-the cohesion of two polished pieces of metal
in an exhausted receiver-the adhesion of quicksilver
to glass tubes-the cohesion of the parts of all bodies
-the cause of filtration-the phenomena of capillary
attraction-the action of menstrua on bodies-the
transmutation of gross compact substances into aerial
ones-and the cause of gravity. From the language
used in this paper, we should be led to suppose that
Newton had entirely forgotten that he had formerly
treated the general subject of ether, and applied it to
the explanation of gravity. " I shall set down," he
says, " one conjecture more which came into my mind
now as I was writing this letter; it is about the cause
of gravity," which he goes on to explain; and he concludes by saying that " he has so little fancy to things
of this nature, that, had not your encouragement
moved me to it, I should never, I think, thus far have
set pen to paper about them."
These opinions, however, about the existence of
ether, Newton seems to have subsequently reaouned;




SIR ISAAC NEWTON.


214


for in the manuscript, which we mentioned already
as being in the possession of Dr. J. C. Gregory,
which was written previous to 1702, he states, that
ether is neither obvious to our senses, nor supported
by any argument, but is a gratuitous assumption
which, if we are to trust to reason and to our senses,
must be banished from the nature of things; and he
goes on to establish, by various arguments, the validity
of this opinion. This renunciation of his former hypothesis probably arose from his having examined more
carefully some of the phenomena which he endeayoured to explain by it. Those of capillary attraction,
for example, he had ascribed to the other " standing
rarer in the very sensible cavities of the capillary
tubes than without them;" whereas he afterwards
discovered their true cause, and ascribed them to the
reciprocal attraction of the tube and the fluid. But,
however, this may be, there can be no doubt that he
resumed his early opinions before the publication of his
" Optics," which may be considered as containing his
views upon this subject.
The queries which contain these opinions are the
18th,-24th, all of which appeared for the first time in
the second English edition of the Optics. If a body
is either heated or loses it heat when placed in vacuo,
he ascribes the conveyance of heat in both cases " to
the vibration of a much subtiler medium than air',
and he considers this medium as the same with that
by which light is refracted and reflected, and by whose
vibrations light communicates heat to bodies and is
put into fits of easy reflexion and transmission.
This ethereal medium, according to Sir Isaac, isexceedingly more rare and more elastic than air. It
pervades all bodies, and is expanded through all the
heavens. It is much rarer within the dense bodies of
the sun, stars, planets, and comets, than in the celestial spaces between them, and also more rare within
gs water, &c., than in the free and open sac0




4                  THE LIFE OF
void of air and other grosser bodies. In passing out
of glass, water, &c. and other dense bodies, into
empty space, it grows denser and denser by degrees,
and this gradual condensation extends to some distance
from the bodies.  Owing to its great elasticity, and,
consequently its efforts to spread in all directions, it
presses against itself, and, consequently, against the
solid particles of bodies, so as to make them continually approach one another, the body being impelled
from the denser parts of the medium towards the rarer
with all that power which we call gravity.
In employing this medium to explain the nature of
light, Newton does not suppose that light is nothing
more than the impression of those undulations on the
retina. He regards light as a peculiar substance composed  of heterogeneous particles thrown off  with
great velocity, and in all directions, from luminous
bodies; and he supposes that these particles while
passing through the ether excite in it vibrations or
pulses which accelerate or retard the particles of light,
and thus throw them into their alternate fits of easy
-reflexion and transmission.
Hence, if a ray of light falls upon a transparent
body, in which the ether consists of strata of variable
density, the particles of light acted upon by the
vibrations which they create will be urged with an
accelerated velocity in entering the body, while their
velocity will be retarded in quitting it. In this manner he conceives the phenomena of refraction to be
produced, and he shows how in such a case the refraction would be regulated by the law of the sines.
In order that the ethereal medium may produce the
lfts of easy reflexion and transmission, he conceives
that its vibrations must be swifter than light. He
-computes its elasticity to be four hundred and ninety
billion times greater than that of air in proportion to
its density, and about six hundred million times
wmore rare than water, from which he infers that the




SIR ISAAC NEWTON.             249
resistance whith it would oppose to the motion of the
planets would not be sensible in ten thousand years.
He considers that the functions of vision and hearing
may be performed chiefly by the vibrations of this
medium, executed in the bottom of the eye, or in the
auditory nerve by the rays of light, and propagated
through the solid, pellucid, and uniform capillamenta
of the optic or auditory nerves into the place of sensation; and he is of opinion that animal motion may be
performed by the vibrations of the same medium,
excited in the brain by the power of the will, and
propagated from thence by the solid, pellucid, and
uniform capillamenta of the nerves into the muscles
for contracting and dilating them.
In the registers of the Royal Society there exist several letters on the excitation of electricity, which were
occasioned by an experiment of this kind having been
mentioned in Sir Isaac's hypothesis of light.  The
Society had ordered the experiment to be tried at their
meeting on the 16th December, 1675; but in order to
secure its success, Mr. Oldenburg, the secretary wrote
to Newton for a more particular account of it. Sir Isaac
being " thus put upon recollecting himself a little farther about it," remembers that he made the experiment with a glass fixed at the distance of one third of
an inch from one end of a brass hoop, and only oneeighth of an inch from the other. Small pieces of thin
paper were then laid upon the table; when the glass
was laid above them and rubbed, the pieces of paper
leapt from  one part of the glass to the other, and
twirled about in the air. Notwithstanding the explicit account of the experiment, it entirely failed at the
Royal Society, and the secretary was desired to request the loan of Sir Isaac's apparatus, and to inquire
whether or not he had secured the papers from being
removed by the air, which might have somewhere got
in. Sir Isaac, in his answer, recommended to the Society to rub the glass " with stuff whose threads may




250


THE LIFE OF


rake its surface, and, if that will not do,*to rub it with
the fingers' ends to and fro, and kldock them as often
upon the glass." The directions enabled the Society
to succeed with the experiment, by using a scrubbing
brush of hog's bristles, and the help of a knife made
with whalebone.
Among the minor inventions of Sir Isaac Newton,
we must not omit his reflecting instrument for observing the moon's distance from the fixed stars at
sea. The description of this instrument was commuicated by Dr. Halley, in the year 1700; but, either
from having mislaid the manuscript, or from attaching
no value to the invention, he did not communicate it
to the Royal Society, and it remained among his papers
till after his death, in the year 1742, when it was
published in the Philosophical Transactions.
" By this instrument," says Sir Isaac, "the dis* tance of the moon from any fixed star is thus observed:
— view the star through the perspicil by the direct
light, and the moon by the reflexed, (or on the contrary); and tuirn the index till the star touch the
limb of the moon, and the index shall show on the
brass limb of the instrument the distance of the star
from the moon's limb; and though the instrument
shake by the motion of the ship at sea, yet the moon
and star will shake together as if they did really
touch one another in the heavens; so that an observation may be made as exactly at sea as at land.
"And by the same instrument may be observed
exactly the altitudes of the moon and stars, by bringing them to the horizon; and thereby the latitude and
times of observation may be determined more exactly
than by the ways now in use.
In the time of the observation if the instrument
move angularly about the axis of the telescope, the
star will move in a tangent of the moon's limb or of
the horizon; but the observation may, notwithstaning, be made exactly by noting when the line, de



SIR ISAAC NEWTON.


25It


scribed by thI star, is a tangent to the moon's limb
or to the horizon.
"To make the instrument useful, the telescope ought
to take in a large angle; and, to make the observation
true, let the star touch the moon's limb, not on the
outside, but on the inside."
This ingenious contrivance is obviously the same invention as that which Mr. Hadley produced in 1731,
and which, under the name of Hadley's Quadrant,
has been of so great service in navigation. The merit
of its first invention must therefore be transferred to
Sir Isaac Newton.
In the year 1672, Newton communicated to Oldenburg his design for a microscope, which he considered
to be as capable of improvement as the telescope, and
perhaps more so, because it requires only one speeuhlm; and in another letter to the same gentleman, in
the same year, he suggests another improvement in
microscopes, which is to " illuminate the object in a
darkened room with the light of any convenient colour not too much compounded, for by that
means the microscope will, with distinctness, beau a
deeper charge and larger aperture, especially if its
construction be such as I may hereafter describe.
Among the minor and detached labours of Sir Isaea
Newton, we must mention his curious experiments on
the action of light upon the retina. Locke seems to
have wished his opinion respecting a fact stated in
Boyle's Book on Colours, and in a letter from Cambridge, dated January 30th, 1691, he communicated
to his friend the following very remarkable observations made by himself:" The observation you mention in Mr. BoylWs
Book of Colours, I once made upon myself with the
hazard of my eyes. The manner was this:-I looked
a very little while upon the sun in the looking-glass
with my right eye, and then turned my eyes into a
dark corner of my chamber and winked to obsere




252


THE LIFE OF


the impression made, and the circles ofecolours which
encompassed it, and how they decayed by degrees,
and at last vanished. This I repeated a second and a
third time. At the third time when I saw the phantasm of light and colours about it were almost vanished,
intending my fancy upon them to see their last appearance, I found to my amazement that they began to
return, and by little and little become as lively and
vivid as when I had newly looked upon the sun. But
when I ceased to intend my fancy upon them, they
vanished again. After this I found, that, as often
as I went into the dark, and intended my mind upon
them, as when a man looks earnestly to see anything
which is difficult to be seen, I could make the phantasm return without looking any more upon the sun;
and the oftener I made it return, the more easily I
could make it return again.  And at length, by repeating this without looking any more upon the sun,
I made such an impression on my eye that if I looked
*upon the clouds, or a book, or any bright object, I
saw upon it a round bright spot of light like the sun,
and which is still stranger, though I looked upon the
sun with my right eye only, and not with my left,
yet my fancy began to make an impression upon my
left eye, as well as upon my right. For if I shut my
right eye or looked upon a book or the clouds with
my left eye I could see the spectrum of the sun almost
as plain as with my right eye, if I did but intend my
fancy a little while upon it; for at first, if I shut
my right eye, and looked with my left, the spectrum
of the sun did not appear till I intended my fancy
upon it; but by repeating, this appeared more easily.
And now, in a few hours time, I had brought my
eyes to such pass, that I could look upon no bright
object with either eye but I saw the sun before me,
so that I durst neither write nor read; but to recover
the use of my eyes, shut myself up in my chamber
made dark, for three days together, and used all




SIR ISAAC NEWTON.


258


means to divert my imagination from the sun. For if
I thought upon him I presently saw his picture,
though I was in the dark.  But by keeping in the
dark and employing my mind about other things, I
began in three or four days to have some use of my
eyes again; and by forbearing to look upon bright
objects recovered them pretty well, though not so well
but that for some months after the spectrum of the
sun began to return as often as I began to meditate
upon the phenomenas even though I lay in bed at
midnight with my curtains drawn.  But now I have
been very well for many years, though I am apt to
think, if I durst venture my eyes, I could still make
the'phantasm return by the power of my fancy. This
story I tell you to let you understand, that in the
observations related by Mr. Boyle, the man's fancy
probably concurred with the impression made by the
sun's light, to produce that plantasm of the sun which
he constantly saw in bright objects.  And so your
question about the cause of this phantasm involves
another about the power of fancy which, I must confess, is too hard a knot for me to untie. To place
this effect in a constant motion is hard; because the
sun ought then to appear perpetually.  It seems
rather to consist in a disposition of the sensorum to
move the imagination strongly, and to be easily moved
both by imagination and by the light, as often as
bright objects are looked upon."
These observations possess in many respects a high
degree of interest.  The fact of the transmission of
the impression from the retina of the one eye to that
of the other, is particularly important; and it deserves
to be remarked as a singular coincidence that Dr.
Brewster had occasion to observe, and to describe the
same phenomena long before'the observations of Sir
Iaac were communicated to the scientific world.




M54


TE - LIFE OF


CHAPTER VIII.
ewton's acquaintance with Dr. Pemberton, who edits the third edition
of the " Principia."  Sir Isaac's first attack of ill health. His recovery.  Is again taken ill.  His death. His Funeral. A medal
struck in honour of him. Division of his property. Permanence of
Newton's reputation. Character of his Genius. His social character.
Simplicity of his character. Religious and moral character.  Hospitalit and mode of life. His absence. Personal appearance. Memorial.
ABOUT the year 1722, Newton, was desirous of publishing a third edition of his Principia, and the premature death of Mr. Cotes, who had superintended.
the second edition, having deprived him of his valuable assistance, he was fortunate enough to become
acquainted with Dr. Pemberton, a young and accomplished physician, who had cultivated mathematical
learning with considerable success.     M. Poleni, an
emiment Professor in the university of Padua, having
endeavoured, on the authority of a new experiment,
to overturn the common opinion respecting the force
* of bodies in motion, and to establish that of Leibnitz
in its place, Dr. Pemberton transmitted to Dr. Mead,
a demonstration of its inaccuracy. Dr. Mead communicated this paper to Sir Isaac, who not only
highly approved of it, but added a demonstration of
his own, drawn from another consideration of the
subject; and this was printed without his name, as a
postscript to Pemberton's paper, when it appeared in
te Philosophical Transactions in 1722.
Ia a short time after the commencement of their
acquaintance, Sir Isaac engaged Dr. Pemberton to
superintend the new    edition of the Principia.    In
discharging this duty the doctor had occasion to make




SIR ISAAC NCWTON.


25


may remarks on this work, which the author always
received with the utmost good-nature, and the third
edition appeared with numerous alterations in 1726.
On the occasions upon which Pemberton had personal
intercourse with Sir Isaac, and which were necessarily
numerous, he endeavoured to learn his opinions on
various mathematical subjects, and to obtain some
historical information respecting his inventions ana
discoveries.  Sir Isaac entered freely into all these
topics; and during the conversations which took
place, and while they were reading together Dr. Pemberton's popular account of Sir Isaac's discoveries, he
obtained the most satisfactory evidence, that though
his memory was much decayed, yet he was fully able
to understand his own writings.
During the last twenty years of Newton's life,
which he spent in London, the charge of his domestic
concerns devolved upon his beautiful and accomplished
niece, Mrs. Catherine Barton, the widow of Colonel
Barton, for whom, as we already observed, the Earl
of Halifax had conceived the warmest affection.
This lady, who had been educated at the expense of
her uncle, married Mr. Conduit, and continued to
reside with her husband in Sir Isaac's house till the
time of his death.
In the year 1722, when he had reached the
eightieth year of his age, he was seized with an incontinence of urine, which was ascribed to stone in the
bladder, and was considered incurable. By means of
a strict regime, however, and other precautions, he
was enabled to alleviate his complaint, and to procure
long intervals of ease. At this time, he gave up the
Use of his carriage, and always went out in a chair.
Re declined all invitations to dinner, and at his own
house he had only small parties. In his diet he was
extremely temperate. Though he took a little butcher's meat, yet the principal articles of his food were
broth, vegetables, and fruit, of which he always ate




256


THE LIFE OF


very heartily. In spite of all his precautions, however, he experienced a return of his old complaint,
and in August, 1724, he passed a stone, the size of an
ordinary pea, which came away in two pieces, the one
at the distance of two days from the other. After
some months of tolerable good health, he was seized
in January, 1725, with a violent cough and inflammation of the lungs; and, in consequence of this
attack, he was prevailed upon with some difficulty,
to take up his residence at Kensington, where his
health experienced a decided improvement.    In
February, 1725, he was attacked in both his feet,
with a fit of the gout, of which he had felt slight
symptoms a few years before, and the effect of this
new complaint was to produce a great and beneficial
change in his general health. On the 7th of March,
when his head was clearer and his memory stronger
than his nephew had known it for a long time, he
entered into a long conversation on various subjects,
particularly in astronomy.  He' explained to Mr.
Conduit how comets might be formed out of the light
of vapours discharged from the sun, and the fixed
stars as the centres of systems. He conceived that
these luminaries were replenished by the same comets
being again returned to them; and upon this principle he explained the extraordinary lights which
were seen among the fixed stars by Hipparchus,
Tycho, Brahe, and Kepler's disciples, and which he
supposed to arise from the additional fuel which they
received.
We here give this conversation as originally copied
from Mr. Conduit's handwriting. It is entitled
"A remarkable and curious conversation between
Sir Isaac Newton and Mr. Conduit.
"I was on Sunday night, the 7th of March, 1724-5,
at Kensington, with Sir Isaac Newton, in his lodgings,
just after he was come out of a fit of the gout, which
he had had in both his feet; for the first time in the




SIR ISAAC NEWTON.


257


eighty-third year of his age. He was better after it,
and his head clearer, and memory stronger, than I had
known them for some time. He then repeated to me
by way of discourse, very distinctly, though rather in
answer to my queries than in one continued narration,
what he had often hinted to me before, viz., that it
was his conjecture (he would affirm nothing,) that
there was a sort of revolution in the heavenly bodies;
that the vapours and light omitted by the sun, which
had their sediment as water, and other matter had
gathered themselves by degrees into a body and attracted more matter from the planets, and at last
made a secondary planet (viz. one of those that go
round another planet) and then by gathering to them,
and attracting more matter, became a primary planet;
and then by increasing still became a comet, which
after several revolutions, by coming nearer and nearer
to the sun, had all its volatile parts condensed, and
became a matter fit to recruit and replenish the sun
(which must waste by the constant heat and light it
emitted) as a faggot would this fire if put into it,
(we were sitting by a wood fire) and that that would
probably be the effect of the comet of 1680, sooner or
later, for, by the observations made upon it, it appeared, before it came near the sun, with a tail only
two or three degrees long; but by the heat it contracted in going so near the sun, it seemed to have a
tail of thirty or forty degrees when it went from it;
that he could not say when this comet would drop
into the sun; it might perhaps have five or six revolutions more first, but whenever it did, it would so
much increase the heat of the sun that this earth
would be burnt, and no animals could live. That he
took the three phenomena seen by Hipparchus, Tycho
Brahe, and Kepler's disciples to have been of this
kind, for he could not otherwise account for an extraordinary light as those were, appearing all at once: E




258


THE LIFE OF


among the fixed stars (all which he took to be suns enlightening other planets as our sun does ours) as big as
Mercury or Venus seems to us, and gradually diminishing for sixteen months, and then sinking into
nothing. He seemed to doubt whether there were
not intelligent beings superior to us who superintended
these revolutions of the heavenly bodies by the direction of the Supreme Being. He appeared also to be
very clearly of opinion that the inhabitants of this
world were of a short date, and alleged as one reason
for that opinion, that all arts, as letters, ships, printing, needle, &c., were discovered with in the memory
of history, which could not have happened if the
world had Ben eternal; and that there were visible
marks of ruin upon it which could not be effected by
a flood only.
"(When I asked him how this earth could have
been re-peopled if ever it had undergone the same fate
it was threatened with hereafter by the comet of 1680,
he answered, that required the power of a Creator.
He said he took all the planets to be composed of the
same matter with this earth, viz., earth, water, stones,
&c., but variously concocted.
" I asked him why he would not publish his conjectures as conjectures, and instanced that Kepler had
communicated his; and though he had not gone near
so far as Kepler, yet Kepler's guesses were so just
and happy, that they had been proved and demonstrated by him."
"His answer was, ' I do not deal in conjectures.'"
"But upon my talking to him about the four obs0vations that had been made of the comet of 1680,
a4574 years' distance, and asking him the'particular
fimes, he opened his 'Principia' which laid on the
table, and shewed me the particular periods, viz., 1st
the Julium Sidus, in the time of Justinia, in 1106,
and in 1680."
"And I, observing that he said there of that comet




SIR ISAAC NEWTON.


259


'incidet in corpus solis,' and in the next paragraph
adds, 'stellae fixae refici possurit,' told him I thought
he owned there what we had been talking about, viz.,
that the comet would drop into the sun, and that fixed
stars were recruited and replenished by comets when
they dropt into them, and, consequently, that the sun
would be recruited too; and asked him why he would
not own as freely what he thought of the sun as well
as what he thought of the fixed stars."
" He said, 'that concerned us more;' and laughing,
added, 'that he had said enough for people to know
his meaning.'".Notwithstanding the improvement which his health
had experienced, his indisposition was still sufficiently
severe to prevent him from discharging his duties at
the Mint; and, as his deputy was at the same time
confined with the dropsy, he was desirous, in 1725, of
resigning his office in favour of Mr. Conduit. Difficulties were probably experienced in making this
arrangement, but his nephew discharged for him all
the duties of his office; and during the last year of
his life he hardly ever went to the Mint.
But, though every kind of motion was calculated to
aggravate his complaint, and though he had derived
from absolute rest, and from the air at Kensington,
the highest benefit, yet great difficulty was experienced
in preventing him from occasionally going to town.
Feeling himself able for the journey, he went to
London on Tuesday, the 28th of February, 1727, to
preside at a meeting of the Royal Society. On the
following day Mr. Conduit considered him better than
he had been for many years, and Sir Isaac was hi'.
slf so sensible of this improvement in his health, t*h
he assured his nephew, that on the Sunday precedi
h had slept from eleven o'clock at night till e
oeclock next morning without waking. He had unaen
gone great fatigue, however, in attending the r: a




6U0                THE LIFE OF.of 'the Royal Society, and in paying and receiving
visits, and the consequence of this was a violent return
of his former complaint. He returned to Kensington
on Saturday, the 4th of March, and was attended by
Dr. Mead and Dr. Cheselden, who pronounced his
disease to be stone, and held out no hopes of his recovery. From the time of his last journey to London
he had experienced violent fits of pain with very short
intermissions; and though the drops of sweat run
flown his face during these severe paroxysms, yet he
never uttered a cry or a complaint, or displayed the
least marks of peevishness or impatience; but during
the short intervals of relief which occurred, he smiled
and conversed with his usual gaiety and cheerfulness.
On Wednesday, the 15th of March, he seemed a little
better; and slight, though groundless, hopes were
entertained of his recovery. On the morning of Saturday, the 18th, he read the newspapers, and carried on
a pretty long conversation with Dr. Mead, when all
his senses and faculties were strong and vigorous; but
at six o'clock of the same evening he became insensible,
and he continued in that state during the whole of
Sunday, and till Monday the 20th, when he expired
between one and two o'clock in the morning, in the
eighty-fifth year of his age.
His remains were removed to London, and on Tuesday, the 28th of March, they lay in state in the Jerusalem Chambers, and were thence conveyed to Westminster Abbey, where they were buried near the
entrance into the choir on the left hand. The pall
was supported by the Lord High Chancellor, the
Dukes of Roxburgh and Montrose, and the Earls of
Pembroke, Sussex, and Macclesfield, who were Fellows
of the Royal Society. The Honourable Sir Michael
Newton+, Knight of the Bath, was chief mourner, and
was followed by some other relations, and several distinguished characters who had been intimately ac



SIR ISAAC NEWTON.


261


quainted with the deceased. The funeral service was
performed by the Bishop of Rochester, attended by
the prebend and choir.
Sensible of the high honour which they derived
from their connection with so distinguished a philosopher, the relations of Sir Isaac Newton who inherited
his personal estate, agreed to devote ~500 to the
erection of a monument to his memory, and the Dean
and Chapter of Westminster appropriated for it a place
in the most conspicuous part of the Abbey, which had
been frequently refused to the greatest of the English
nobility. This monument was erected in 1731. On
the front of a sarcophagus resting on a pedestal, are
sculptured, in basso-relievo, youths bearing in their
hands the emblems of Sir Isaac's principal discoveries.
One carries a prism, another a reflecting telescope, a
third is weighing the sun and planets with a steelyard, a fourth is employed about a furnace, and two
others are loaded with money newly coined. On the
sarcophagus is placed the figure of Sir Isaac, in a recumbent position, with his elbow resting on several of
his works. Two youths stand before him with a
scroll, on which is drawn a remarkable diagram relative to the solar system, and above that is a converging
series. Behind the sarcophagus is a pyramid, from
the middle of which rises a globe in mezzo-relievo,
upon which several of the constellations are drawn, in
order to show the path of the comet of 1681, whose
period Sir Isaac had determined, and also the position
of the solstitial colure mentioned by Hipparchus, and
by means of which Sir Isaac had, in his Chronology,
fixed the time of the Argonautic expedition. A figure
of Astronomy, as Queen of the Sciences, sits weeping
on the globe, with a sceptre in her hand, and a star
surmounts the summit of the pyramid. The following epitaph is inscribed on the monument:)




962


THE LIFE OP


Hie situs est
ISAAcUS NEWTON, Eques Auratus,
Qui animi vi prope divina
Planetorum Motus, Figuras,
Cometarum semitas, Oceanique.Estus,
Sua Mathesi facem preferente,
Primus demonstravit.
Radiorum Lucis dissimilitudines,
Quas nemo antea vel suspicatus erat, pervestigavit
Naturae, Antiquitates, S. Scripturse,
Sedulus, sagax, fidus Interpres,
Dei Opt. Max. Majestatem philosophia asserust,
Evangelii simplicitatem moribus expressit.
Libi gratulentur Mortales, tale tantumque extitisse,
HUMANI GENERfS DECUS.
Natus xxv. Decemb. MDCXLII. Obiit. xx. Mar.
MDCCXXVII.
Of which the following is a literal translation:Here lies
Sir Isaac Newton, Knight,
Who, by a vigour of mind almost supernatural,
First demonstrated
The Motions and Figures of the Planets,
The Paths of the Comets, and the Tides of the Ocean.
He diligently investigated
The different refrangibilities of the Rays of Light,
And the properties of the Colours to which they give rise.
An assiduous, Sagacious, and Faithful Interpreter
Of Nature, Antiquity, and the Holy Scriptures,
He asserted in his Philosophy the Majesty of God,
And exhibited in his conduct the simplicity of the Gospel.
Let Mortals rejoice
That there has existed such and so great
AN ORNAMENT OF HUMAN NATURE.
Born 25th December, 1642. Died 20th March, 1727.
In the beginning of 1731, a medal was struck at the
Tower, in honour of Sir Isaac          Newton.      It had on
one side the head of the philosopher, with the motto,
"Felix cognoscere causas," and on the reverse a figure
representing the Mathematics.
On the 4th February, 1755, a magnificent fulllength statue of Sir Isaac Newton in white marble,
was erected in the antechapel of Trinity College.            He
is represented standing on a pedestal in a loose gown,




SIR ISAAC NEWTON..                263
holding a prism, and looking upwards with an exn
pression of the deepest thought. On the pedestal is
the following inscription:Qui genus humanum ingenio superavit.
Who surpassed all men in genius.
This statue, executed by Roubilliac, was erected
at the expense of Dr. Robert Smith, the author of the
"Compleat    System    of Optics," and   Professor of
Astronomy and Experimental Philosophy at Cambridge.-It has been     thus described by a modern
poet:Hark! where the organ, full and clear,
With loud hosannahs charms the ear;
Behold, a prism within his hands,
Absorbed with thoughtgreat Newton stands;
Such was his brow and looks serene,
His serious gait and musing mien,
When taught on eagle wings to fly,
He traced the wonders of the sky;
The chambers of the sun explored,
Where tints of thousand hues were stored.
Dr. Smith likewise bequeathed the sum of ~500
for executing a painting on glass, for the window at
the south end of Trinity College, Cambridge. The
subject represents the presentation of Sir Isaac Newton to his Majesty, who is seated under a canopy with
a laurel chaplet in his hand, and attended by the
British Minerva, apparently advising him to reward
merit in the person of the great philosopher. Below
the throne, the Lord Chancellor Bacon is preparing to
register the reward about to be conferred upon Sir
Isaac.  The original drawing of this ridiculous picture was executed by Cipriani, and cost one hundred
guineas.
The personal estate of Sir Isaac Newton, which was
worth about ~32,000, was divided among the eight
grandchildren of his mother, by the Rev. Mr. Smith.
''~...! -




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The family estates of Woolsthorpe and Sustern, he
bequeathed to John Newton, the heir-at-law, whose
great-grangather was Sir Isaac's uncle. This gentlemah does not appear to have placed any great value
on the bequest, for, a few years afterwards, he sold
them to Mr. Turner; of Stoke Rocheford. A short
time before his death, Sir Isaac gave away an estate
in Berkshire, to the sons and daughter of a brother of
his niece, Mrs. Conduit, who, in consequence of their
father dying before Sir Isaac, had no share in the personal estate; and he also gave an estate of the same
value, which he purchased at Kensington, to Catherine,
the only daughter of Mr. Conduit, who afterwards
married Mr. Wallop, the eldest son of Lord Lymington. Sir Isaac was succeeded as Master and Warden
in the Mint by his nephew, John Conduit, Esq., who
wrote a treatise on the gold and silver coin, and who
died in 1737, leaving behind him his wife and daughter, the former of whom died in 1739, in the fifty-ninth
year of her age.
Such was the latter end of Sir Isaac Newton, and
such were the laurels which were dedicated to his
memory. Many discoveries have, since his day, been
added to science; but astonishing as these discoveries
are, they have not obliterated the minutest of his
labours, and have served only to brighten the halo
which encircles his name.   The achievements of
genius, like the source from which they spring, are
indestructible. Acts of legislation and deeds of war
may confer a high celebrity, but the reputation which
they bring is only local and transient; and while they
are hailed by the nation which they benefit, they are
reprobated by the people whom they ruin or enslave.
The labours of science on the contrary bear along with
them no counterpart of evil. They are the liberal
bequests of great minds to every individual of their
race, and wherever they are welcomed and honoured,








SIR ISAAC NEWTON.


265


they become the solace of private life, and the ornament and bulwark of the commonwealth.
The importance of Sir Isaac Newton's discoveries
has been sufficiently exhibited in the preceding pages.
The peculiar character of his genius, and the method
which he pursued in his inquiries, can only be gathered
from an attentive perusal of his works, and from the
history of his individual labours. Were we to judge
of the qualities of his mind from the early age at
which he made his principal discoveries, and from the
rapidity of their succession, we should be led to
ascribe to him that quickness of penetration, and that
exuberance of invention, which is more characteristic
of poetical than philosophical genius. But we must
bear in mind that Newton was placed in the most
favourable circumstances for the development of his
powers. The flower of his youth, and the vigour of
his manhood, were entirely devoted to science. No
injudicious guardian controlled his ruling passion, and
no ungenial studies or professional toils interrupted
the continuity of his pursuits. His discoveries, therefore, were the fruit of persevering and unbroken study;
and he himself declared, that whatever service he had
done to the public was not owing to any extraordinary
sagacity, but solely to industry and patient thought.
Initiated early into the abstractions of Geometry,
he was deeply imbued with her cautious spirit; and if
his acquisitions were not made with the rapidity of intuition, they were at least firmly secured; and the
grasp which lie took of his subject was proportional
to the mental labour which it had exhausted. Overlooking what was trivial, and separating what was
extraneous, he bore down with instinctive sagacity on
the prominences of his subject; and having thus
grappled with its difficulties, he never failed to entrench himself in its strongholds.
To the highest powers of invention, Newton added
what so seldom accompanies them-the talent of sim



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plifying and communicating his profoundest speculations. This valuable faculty characterises all his
writings. In the economy of her distributions, Nature is seldom thus lavish of her intellectual gifts. —
The inspired genius which creates is rarely conferred
along with the matured judgment which combines;
and yet, without the exertion of both, the fabric of
human wisdom could never have been reared. Though
a ray from heaven kindled the vestal fire, yet an
humble priesthood was required to keep alive the
flame.
The method of investigating truth by observation
and experiment, so successfully pursued in the Principia, has been ascribed by more than one modern
writer of celebrity to Lord Bacon, and Sir Isaac
Newton is represented as having owed all his discoveries to the application of the principles of that distinguished writer. One of the greatest admirers of
I4ord Bacon has gone so far as to characterise him as
a philosopher who has had no rival in the times which
are past, and as likely to have none in those which are
to come. In a eulogy so overstrained as this, we feel
that the language of panegyric has passed into that of
idolatry; and we are desirous of weighing the force
of arguments which tend to depose Newton from the
high-priesthood of nature, and to unsettle the proud
destinies of Copernicus, Galileo, and Kepler.
That Bacon was a man of powerful genius, and endowed with varied and profound talent-the most
skilful logician-the most nervous and eloquent writer
of the age which he adorned, are points which we
have not the hardihood to deny. The study of ancient
systems had early impressed him with the conviction
that experiment and observation were the only sure
gides in physical inquiries; and, ignorant though he
was of the methods, the principles, and the details of
the mathematical sciences, his ambition prompted him
to aim at the construction of an artificial system by




SIR ISAAC NEWTON.


2W


which the laws of nature might be investigated, and
which might direct the inquiries of philosophers in
all future ages. The necessity of experimental research, and of advancing gradually from the study of
facts to the determination of their cause, though the
groundwork of Bacon's method, is a doctrine which
was not only inculcated, but successfully followed by
preceding philosophers. In a letter from Tycho Brahe
to Kepler, this industrious astronomer urges his pupil
" to lay a solid foundation for his views by actual observation, and then by ascending from these, to strive
to reach the causes of things;" and it was no doubt
under the influence of this advice that Kepler submitted his wildest fancies to the test of observation,
and was conducted to his most splendid discoveries.The reasonings of Copernicus, who preceded Bacon by
more than a century, were all founded upon the most
legitimate induction. Dr. Gilbert had exhibited, in
his treatise on the magnet, the most perfect specimens
of physical research. Leonardo da Vinci had described, in the clearest manner, the proper method of
philosophic investigation; and the whole scientific
career of Galileo was one continued example of the
most sagacious application of observation and experiment to the discovery of general laws. The names
of Paracelsus, Helmont, and Cardan have been ranged
in opposition to this host of great names; and while
it is admitted that even they had thrown off the yoke
of the schools, and had succeeded in experimental research, their credulity and their pretensions have
been adduced as a proof, that, to the greater number
of philosophers, the method of induction was unknown. The fault of this argument consists in the
conclusion being infinitely more general than the fat.
The errors of the men were not founded on their ignorance, but on their presumption. They wanted the
patience of philosophy, and not her methods. An
excess of vanity, a waywardness of fancy, and an




2B8S


I THE LIFE OF


insatiable appetite for that species of passing fame
which is derived from eccentricity of opinion, moulded
the reasonings and disfigured the writings of these ingenious men; and it can scarcely admit of a doubt, that,
had they lived in the present age, their philosophical
character would have reeived the same impress from
the peculiarity of their tempers and dispositions. —
This is an experiment, however, which it is impossible
now to make; but the history of modern science
supplies the defect, and the experience of every man
furnishes a proof that in the present age there are
many philosophers of elevated talents and inventive
genius, who are as impatient of experimental research
as Paracelsus, as fanciful as Cardan, and as presumptuous as Van Helmont.
Having thus shown that the distinguished philosophers, who flourished previous to the time of Bacon,
were perfect masters both of the principles and practice of inductive research, it becomes interesting to
inquire whither or not the philosophers who succeeded him acknowledged any obligation to his system, or derived the slightest advantage from his precepts. If Bacon constructed a method to which
modern science owes its existence, we shall find its
cultivators grateful for the gift, and offering the richest
incense at the shrine of a benefactor whose labours
conducted them to immortality. No such testimonies,
however, are to be found. Nearly two centuries
have passed away, teeming with the richest fruits of
human ingenuity, and no grateful disciple has made
his appearance to vindicate the rights of the alleged
legislator of science. Even Newton, who was born
and educated after the publication of the "Novum
Organon," never mentions the name of Bacon or his
system in any of his works; and the amiable and
indefatigable Boyle treated him with the same disrespectful silence. When we are told, therefore, that
Newton owed all his discoveries to the method of




SIR ISAAC NEWTON.


269


Bacon, nothing more can be meant than that he proceeded in that path of observation and experiment
which had been so warmly recommended in the
" Novum Organon;" but it ought to have been added,
that the same method had been used by his predecessors,-that Newton possessed no secret that had not
been used by Galileo and Copernicus-and that he
would have enriched science with the'same splendid
discoveries if the name and the writings of Bacon had
never been heard of.
From this view of the subject we shall now proceed to examine the Baconian process itself, and consider if it possesses any merit as an artificial method
of discovery, or if it is at all capable of being employed
for this purpose even in the humblest walks of scientific inquiry.
The process of Lord Bacon was, we believe, never
tried by any philosopher but himself. As the subject
of its application he selected that of heat. With his
usual erudition, he collected all the facts that science
could supply,-he arranged them in tables-he crossquestioned them with all the sagacity of a special
pleader,'-he combined them with all the sagacity of a
judge-and he conjured with them by all the magic
of his exclusive processes. But, after all this display
of physical logic, Nature thus interrogated was still
silent. The oracle, which he had himself established,
refused to give his responses, and the ministering
spirit was driven with discomfiture from his own
shrine.  This example, in short, of the application
of his system, will remain to future ages as a memorable instance of the absurdity of attempting to fetter
discovery by any artificial rules.
Nothing, even in mathematical science, can be
more certain than that a collection of scientific facts
are of themselves incapable of leading to discovery,
or to the determination of general laws, unless they
contain the predominating fact or the relation in




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which the discovery mainly resides.    A  vertical
column4of arch-stones possesses more strength than
the same materials arranged as an arch without the
key-stone. However nicely they are arranged, and
however nobly the arch may spring, it never can pbssess either equilibrium or stability.  In this comparison all the facts are supposed to be necessary to the
final result; but, in the inductive method, it is impossible to ascertain the relative importance of any
facts, or even to determine if the facts have any value
at all, till the master fact which constitutes the discovery has crowned the zealous efforts of the aspiring
philosopher. The mind then returns to the dark and
barren waste over which it has been hovering; and
by the guidance of this single torch it embraces under
the comprehensive grasp of general principles, the
multifarious and insulated phenomena which had formerly neither value nor connection. Hence, it must
be obvious to the most superficial thinker, that discovery consists, either in the detection of some concealed
relation-some deep-seated affinity which baffles ordinary research, or in the discovery of some simple
fact which is connected by slender ramifications with
the subject to be investigated; but which, when once
detected, carries us back by its divergence to all the
phenomena which it embraces and explains.
In order to give additional support to these views,
it would be interesting to ascertain the general character of the process by which a mind of acknowledged
power actually proceeds in the path of successful inquiry. The history of science does not furnish us
with much information on this head, and if it is to be
found at all it must be gleaned from the biographies
of eminent men. Whatever this process may be in
its details, if it has any, there cannot be the slightest
doubt that in its generalities at least it is the very revese of the method of induction.  The impatience of
genius spurns the restraints of mechanical rules, and




SIR ISAAC NEWTON.


271


never will submit to the plodding drudgery of inductive
discipline. The discovery of a new fact unfits even a
patient mind for deliberate inquiry.  Conscious of
having added to science what had escaped the sagacity
of former ages, the ambitious spirit invests its new
acquisition with an importance which by no means
belongs to it. He imagines innumerable benefits to
follow from  his discovery. He forms a thousand
theories to. explain it, and he exhausts his fancy in
trying all its possible relations to recognized difficulties
and unexplained facts. The reins, however, thus freely
given to his imagination, are speedily drawn up. His
wildest conceptions are all subjected to the rigid test
of experiment, and he has thus been hurried by the
excursions of his own fancy into new and fertile paths,
far removed from ordinary observation. Here the
peculiar character of his own genius displays itself by
the invention of methods of trying his own speculations, and he is thus often led to new discoveries far
more important and general than that by which he
began his inquiry.  For a confirmation of these opinions, we may refer to the history of Kepler's Discoveries; and if we do not recognize them to the same
extent in the labours of Newton, it is because he kept
back his discoveries till they were nearly perfected,
and therefore withheld from our knowledge the successive steps of his inquiries.
The social character of Newton was such as might
have been expected from   his intellectual attainments. He paid and received frequent visits, he assumed no superiority in conversation; he was candid,
cheerful, and affable; his society was therefore much
Sought, and he submitted to intrusions on his valuable
time without a murmur; but by early rising, and by
a methodical distribution of his hours, he found leisure
to study and compose, and every moment which he
could command he passed with a pen in his hand and
book before him. He had none of the ecntricitie




272


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of genius, but suited himself to every company, and
always spoke of himself and others in such a manner
that he was never suspected of vanity. Dr. Pemberton remarks, " But this I immediately discovered in
him, which at once both surprised and charmed me.
Neither his extreme great age, nor his universal reputation, had rendered him stiff in opinion, or in any
degree elated. Of this I had occasion to have almost
daily experience. The remarks I continually sent
him by letters on the Principia were received with
the utmost goodness.  These were so far from being
any way displeasing to hih, that on the contrary it
occasioned him to speak many kind things of me to
my friends, and to honour me with a public testimony
of his good opinion."
The modesty of Sir Isaac Newton, in reference to
his great discoveries, was not founded on any indifference to the fame which they conferred, or upon any
erroneous judgment of their importance to. science.
The whole of his life proves that he knew his place as
a philosopher, and was ready to assert and vindicate
his rights. His modesty arose from the depth and extent of his knowledge, which showed him what a,
small portion of nature he had been able to examine,
and how much remained to be explored in the same
field in which he had himself laboured. In the mag-:: nitude of the comparison he recognised his own littleness; and a short time before his death he uttered
this memorable sentiment: -' I do not know what I
may appear to the world; but to myself I seem
like a boy playing on the sea shore and diverting myself in now and then finding a smoother pebble or a
prettier  shell than  ordinary, whilst the  great
ocean of truth lay undiscovered before me."  What a
lesson to the vanity and presumption of philosophers
-to those especially who have never once found the
smoother pebble or the prettier shell!  What a preparation for the latest inquiries And the last views of




SIR ISAAC NEWTON.             273
the decaying spirit,-for those inspired doctrines
which alone can throw a light over the dark ocean of
undiscovered truth!
The native simplicity of Sir Isaac Newton's mind
is beautifully pourtrayed in the affecting letter to Mr.
Locke, in which he acknowledges that he had thought
and spoken of him uncharitably; and the humility
and candour in which he asks the forgiveness of his
friend, could only have emanated from a mind as
noble as it was pure.
In his religious and moral character there is much
to admire and to imitate. While he exhibited in his
life and writings an ardent regard for the general interests of religion, he was at the same time a conscientious believer in Revelation. He was too deeply
versed in the sacred writings, and too much imbued
with their spirit, to judge rashly of other men who
took different views of them  from  himself.  He
cherished the great principles of religious toleration,
and never hesitated to express his detestation of persecution, even in its mildest form. Immorality and
impiety he never permitted to pass without censure;
and whenever Dr. Halley, who was not over scrupulous, ventured to say anything disrespectful of
religion in his presence, he invariably checked him,
and said, 11I have studied these things-you have
not."
After Sir Isaac Newton took up his residence in
the metropolis; he lived in a very handsome style,
and kept his carriage, with an establishment of three
males and three female servants.  In his own house
he gave splendid entertainments, though without
ostentation or vanity. His own diet was frugal, and
his dress was always plain, if we except one occasion,
when he opposed Mr. Annesley in 1705, as a candidate
for the university of Cambridge, when he dressed
himself in a suit of laced clothes.
s




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He was generous and charitable, one of his maxims
being, "that those who gave nothing before death,
never, in fact gave at all"-a sentiment which ought
to fall as a solemn admonition on the ear of those
miserable-minded men who bequeath their property
for such a purpose as may purchase a posthumous
character for philanthropy. Though his wealth had
become considerable by prudent economy, yet he had
always a contempt for money, and he spent a considerable part of his income in relieving the poor-in
assisting his relations-and in encouraging ingenuity
and learning. The sums which he gave to his relations, at different times, were enormous. James
Hutton, Esq., of Pimlico, a gentleman of his mother's
family, informs us that " he was very kind to all the
Ayscoughs. To one he gave ~800, to another ~200,
and to a third ~100, and many other sums; and other
engagements did he enter into also for them. He was
the ready assistant of all who were any way related to
him-to their children and grandchildren." But his
generosity was not confined to his own relations. In
1724, he wrote a letter to the Lord Provost of Edinburgh, offering to contribute ~20 per annum, to a
provision for Mr. Maclaurin, provided he acccepted
the situation of assistant to Mr. James Gregory, who
was professor of mathematics in the university.
The habits of deep meditation which Newton had
acquired, though they did not show themselves in his
ordinary intercourse with society, exercised their full
influence over his mind when in the midst of his own
family. Absorbed in thought he would often sit down
on his bedside after he rose, and remain there for
hours without dressing himself, occupied with some
interesting investigation. Owing to the same absence
of mind, he neglectec to take the requisite quantity of
nourishment, and it was therefore often necessary to
remind him of his meals. The following anecdote is a
proof of this. Dr. Stukely, his intimate friend, who............,. - ~....,..... ~... ~.. ~..  ~..~....  e....... ^,-. -..




SIR ISAAC N]WTON.


275


had been deputy to Dr. Halley, as secretary to the
Royal Society, on visiting Sir Isaac one day, was
shown into the dining-roo  where his dinner had been
for some time served up. The Doctor waited for a
considerable time, and getting impatient, he removed
the cover from a chicken, which he ate, replacing the
bones under the cover. In a short time after Sir
Isaac entered the room, and after the usual compliments sat down to his dinner; but on taking off the
cover, and seeing nothing but bones, he remarked,
" How absent we philosophers are. I really thought
that I had not dined."
Sir Isaac Newton is supposed to have had but little
knowledge of the world, and to have been very ignorant of the usages of society. This opinion has, we
think, been rashly deduced from a letter which he
wrote in the twenty-seventh year of his age to his
young friend, Francis Aston, Esq., who was about to
set out on his travels. This letter is a highly interesting production; and while it shows much knowledge
of the human heart, it throws a strong light upon the
character and opinions of its author.
Trinity College, Cambridge,
May 18th, 1669.
"Sir,
"Since in your letter you give me so much liberty
of spending my judgment about what may be to your
advantage in travelling, I shall do it more freely than
perhaps otherwise have been decent. First, then, I
will lay down some general rules, most of which, I
believe, you have considered already; but, if any of
them be new to you they may excuse the rest; if noe
at all, yet is my punishment more in writing than yours
1i reading.
"When you come into any fresh country, 1. Obre their humours.     2. Suit your own carriage
thereto, by which insinuation you will make their con-,"""'"~~ '- -- -             C;. *




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verse more free and open. 3. Let your discourse be
more in queries and doubtings than peremptory assertions or disputings, it bein#the design of travellers to
learn, not to teach. Besides it will persuade your acquaintance that you have the greater esteem of them,
and so make them more ready to communicate what
they know to you; whereas nothing sooner occasions
disrespect and quarrels than peremptoriness.  You
will find little or no advantage in seeming wiser, or
much more ignorant than your company. 4. Seldom
discommend any thing though never so bad, or do it
but moderately lest you be unexpectedly forced to an
unhandsome retraction. It is safer to commend any
thing more than it deserves, than to discommend a
thing so mrach as it deserves; for commendations meet
not so often with oppositions, or, at least, are not
usually so ill resented by men that think otherwise as
discommendations; and you will insinuate into men's
favour by nothing sooner than seeming to approve and
commend what they like; but beware of doing it by
a comparison. 5. If you be affronted, it is better, in
a foreign country, to pass it by in silence, and with a
jest, though with somq dishonour, than to endeavour
to revenge; for in the first case your credit is ne'er the
worse when you return into England, or come into
other company that have not heard of the quarrel.
But, in the second case, you may bear the marks of
the quarrel while you live, if you outlive it at all.
But if you find yourself unavoidably-engaged, 'tis best,
I think, if you can command your passion adid language, to keep them pretty evenly at some certain
moderate pitch, not much heightening them to exasperate your adversary, or provoke his friends, nor letting them grow over much dejected to make him insult. In a word, if you can keep reason above passion, that and watchfulness will be your best defendants.
To which purpose you may consider, that, though such
excuses as this, —He provoked me so much I could




SIR ISAAC NEWTON.             277
not forbear,-may pass amongst friends, yet amongst
strangers they are insigniicant, and only argue a traveller's weakness.
" To these I may add some general heads for inquiries or observations, such as at present I can think
on. As, 1. To observe the policies, wealth, and state
affairs of nations, so far as a solitary traveller may
conveniently do. 2. Their impositions upon all sorts
of people, trades, or commodities that are remarkable.
3. Their laws and customs, how far they differ from
ours. 4. Their trades and arts, wherein they excel or
come short of us in England.  5. Such fortifications
as you shall meet with, their fashion, strength, and
advantages for defence, and other such military affairs
as are considerable. 6. The power and respect belonging to their degrees of nobility or magistracy.
7. It will not be time mis-spent to make a catalogue
of the names and excellencies of those men that are
most wise, learned, or esteemed in any nation. 8. Observe the merchandise and manner of guiding ships.
9. Observe the products of nature in several places,
especially in mines, with the circumstances of mining,
and of extracting metals or minerals out of their ore,
and of refining them; and if you meet with any transmutations out of their own species into another, (as
out of iron into copper, out of any metal into quicksilver, out of one salt into another, or into an iisipid
body, &c.) those, above all, will be worth your noting,
being the most luciferous, and many times luciferous
experiments, too, in philosophy. 10. The prices of
diet and other things. 11. And the staple commodities of places.
"These generals, (such as at present I could think
of) if they will serve for nothing else, yet they may
assist you in drawing up a model to regulate your
travels by. As for particulars, these that follow are
all that I can now think of, viz., Whether at Schemnitium, in Hungary,' (where there are mines of gold,




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copper, iron, vitriol, antimony, &c.) they change iron
into copper by dissolving it in a vitriolate water, which
they find in cavities of ro&ks in the mines, and then
melting the slimy solution in a strong fire, which in
the cooling proves copper. The like is said to be done
in otherplaces, which I cannot now remember. Perhaps, too, it may be done in Italy. For about twenty
or thirty years ago there was a certain vitriol came
from thence, (called Roman vitriol) but of a nobler
virtue than that which is now called by that name;
which vitriol is not now to be gotten, because, perhaps, they make a better gain by some such trick as
turning iron into copper with it than by selling it.
2. Whether in Hungary, Sclavonia, Bohemia, near
the town Eila, or at the mountains of Bohemia near
Silesia, there be rivers whose waters are impregnated
with gold; perhaps the gold being dissolved by some
corrosive waters like aqua regis, and the solution carried along with the stream that runs through the
mines. And whether the practice of laying mercury
in the rivers till it be tinged with gold, and then
straining the mercury through leather, that the gold
may stay behind, be a secret yet, or openly practised.
3. There is newly contrived, in Holland, a mill to
grind glasses plane withal, and I think polishing them
too. Perhaps it will be worth the while to see it.
4. There is in Holland one --    Borry, who some
years since was imprisoned by the Pope, to have
extorted from him secrets (as I am told) of great
worth,,both as to medicine and profit, but he escaped
into Hollandj where they have granted him a guard.
I think he usually goes clothed in green. Pray inquire what you can of him, and whether his ingenuity
be any profit to the Dutch. You may inform yoniself whether the Dutch have any tricks to keep their
ships from being all worm-eaten in their voyages to
the Indies. Whether pendulum clocks do any servie
in finding out the longitude, &c.


4




SIR ISAAC NEWTON.


279


" I am very weary, and shall not stay to part with
a long compliment, only I wish you a good journey,
and God be with you.
" Is. NEWTON."
Sir Isaac Newton's wonderful faculties were very
little impaired, even in extreme old age; and his cheerful disposition, combined with temperance and a conttitution naturally sound, preserved him from the
usual infirmities of life. In his personal appearance
he was of middle size, with a figure inclining to plumpness. According to Mr. Conduit, "he had a very
lively and piercing eye, a comely and gracious aspect,
with a fine head of hair as white as silver, without
any baldness, and when his peruke was off was a
venerable sight." Bishop Atterbury asserts, on the
other hand, that the lively and piercing eye did not
belong to Sir Isaac during the last twenty years of
his life. He says, " Indeed in the whole air of his
Aee and make there was nothing of that penetrating
Sagacity which appears in his compositions. He had
something rather languid in his look and manner,
which did not raise any great expectation in those
who did not know him."  This opinion of the Bishop
is confirmed by Mr. Thomas Hearne, who says " that
Sir Isaac was a man of no very promising aspect.
He was a short well-set man. He was full of thought,
and spoke very little in company, so that his conversation was not agreeable. When he rode in his coach,
one arm would be out of his coach on the one side,
and the other on the other." Sir Isaac's sight was
preserved to the last, so that he never required spectacles; and he never " lost more than one tooth to the
day of his death." The severe trial of this great
man's bodily suffering was reserved for the last stage
of his existence, and he supported it with characteristic resignation.
Besides the statue of Newton executed by Roubillie,




280


THE LIFE OP


there is a bust of him by. the same artist in the
Library of Trinity College, Cambridge.   Several
good paintings of him are extant. Two of these are
in the hall of the Royal Society of London, and have
been often engraved. Another, by Vanderbank, is in
the apartment of the Master's lodge in Trinity College, and has been engraved. by Vertue. Another,
by Valentine Ritts, is in the landing-place near the
entrance to Trinity College Library; but the best
was painted by Sir Godfrey Kneller, and is in the
possession of Lord Egremont at Petworth.  In the
University Library there is preserved a cast taken
from his face after death.
Every memorial of so great a man as Sir Isaac
Newton has been preserved and cherished with peculiar veneration. Iis house at Woolsthorpe has been
religiously protected by Mr. Turner of Stoke Rocheford. The proprietor Dr. Stukely, who visited it in
Sir Isaac's lifetime on the 13th of October, 1721,
gives the following description of it in a letter to Dr.
Mead, written in 1727. "'Tis built of stone as is the
way of the country hereabouts, and a reasonable good
one. They led me up stairs and showed me Sir
Isaac's study, where I suppose he studied when in
the country in his younger days, or perhaps when he
visited his mother from the university. I observed
the shelves were of his own making, being pieces of
deal boxes which probably he sent his books and
clothes down in on these occasions. There were some
years ago two or three hundred books in it of his
father-in-law, Mr. Smith, which Sir Isaac gave to
Dr. Newton.
" When the house was repaired in 1798, a tablet of
white marble was put up in the room where Sir
Isaac was born, with the following inscription:" Sir Isaac Newton, son of John Newton, Lord of
the Manor of Woolsthorpe, was born in this room on
the 25th December, 1642."




SIR ISAAC NEWTON.


281


Nature and Nature's laws lay hid in night,
God said " Let Newton be," and all was Light.
The following lines have been written upon the
house:Here Newton dawned, here lofty wisdom woke,
And to a wondering world divinely spoke.
If Tully glowed, when Phmdrus's steps he trode,
Or fancy formed Philosophy a God;
If sages still for Homer's birth contend
The sons of science at this dome must bend.
All hail the shrine! All hail the natal day,
Cam boasts his noon-this Cot his morning ray.
The house still contains the two dials made by
Newton, but the styles of both are wanting. The
celebrated apple-tree, the fall of one of the apples of
which is said to have turned the attention of Newton
to the subject of gravity, was destroyed by wind in
the year 1827; but the proprietor has preserved it in
the form of a chair.
The chambers which Sir Isaac inhabited at Cambridge are known by tradition. They are the apartments next to the great gate of Trinity College, and it
is believed that they then communicated by a staircase
with the Observatory in the Great Tower,-an observatory which was furnished by the contributions of
Newton, Cotes, and others. His telescope is preserved
in the library of the Royal Society in London, and his
globe, his universal ring-dial, quadrant, compass, and
a reflecting telescope said to have belonged to him, in
the library of Trinity College.  There is also in the
same collection, a long and curled lock of his silverwhite hair. The door of his bookcase, is in the Museum of the Royal Society of Edinburgh.
' The manuscripts, letters, and other papers of
Newton, have been preserved in different collections;
but the great mass of his papers came into the possession of the Portsmouth family, through his niece,
Lady Lymington, and have been safely preserved by
that noble family.




APPENDIX.
As every circumstance connected with Sir Isaac
Newton must be interesting, we are enabled, through
the industrious research of Dr. Brewster, to insert the
following " Observations on the family of Sir Isaac
Newton," which we trust will be gratifying to our
readers:" In the year 1705, Sir Isaac gave into the Herald's
Office an elaborate pedigree, stating, upon oath, that
jh kad reason to believe that John Newton of Westby,
in the County of Lincoln, was his great grandfathers
father, and that this was the sameJohn Newton who
was buried in Basingthorpe church, on the 22d December, 1563. This John Newton had four sons,
John, Thomas, Richard, and William Newton of-Guunerly, the last of whom was grandfather to Sir John
Newton, Bart., of Hather.  Sir Isaac considered himself as descended from these, ' he having, by tradition
from his kindred, ever since he can remember, reckoied himself next of kin (among the Newtons) to Sir
John Newton's family.'"
The pedigree founded upon these and other onsiderations was accompanied by a certificate from Sir
John Newton, of Thorpe, Bart., who states that he




APPENEIX.                283
had heard his father speak of Sir Isaac Newton " as
of his relation and kinsman," anda that "he himself
believed that Sir Isaac was descended from John
Newton, son to John Newton of Westby, but knoweth
not in what particular manner."
The pedigree of Sir Isaac, as entered at the Herald's
Office, does not seem to be satisfactory either to himself or to his successors, as it could not be traced with
certainty beyond his grandfather; and it will be seen
from the following interesting correspondence, that,
upon making further researches, he had some reason
to believe that he was of Scottish extraction:EXTRACT OF A LETTER FROM THE REV. DR. REID, OF
GLASGOW, TO DR. GREGORY, OF EDINBURGH.
" Glasgow, 14th March, 1784.
" I send you on the other page an anecdote respecting Sir Isaac Newton, which I do not remember whether I ever happened to mention to you in conversation. If his descent is not clearly ascertained (as I
think it is not in the books I have seen), might it not
be worth while to inquire if evidence can be found to
confirm the account which it is said he has given of
himself. Sheriff Cross was very zealous about it when
death put a stop to his inquiries.
" When I lived in Old Aberdeen, above twenty
years ago, I happened to be conversing, over a pipe of
tobacco, with a gentleman of that country, who had
been lately at Edinburgh. He told me that he had
often been in company with Mr. Hepburn, of Keift
with whom I had the honour of some acquaintance. —
He said that, speaking of Sir Isaac Newton, Mr.
Newton mentioned an anecdote which he had from
Mr. James Gregory, professor of mathematics at
Edinburgh, which was to this purpose:Mr. Gregory being at London for some time after
heresigned the mathematical chair, was often with




284


APPENDIX.


Sir Isaac Newton.  One day Sir Isaac said to him,
' Gregory, I believe you don't know that I am connected with Scotland ' ' Pray how, Sir Isaac,' said
Gregory. Sir Isaac said he was told that his grandfather was a gentleman of East Lothian; that he
came to London with King James, at his accession to
the crown of England, and then spent his fortune, as
many more did at that time, by which his son (Sir
Isaac's father) was reduced to mean circumstances.
To this Gregory bluntly replied, 'Newton a gentleman of East Lothian; I never heard of a gentleman
of East Lothian of that name.'  Upon this Sir Isaac
said, 'that being very young when his father died,
[The reader will observe from the foregoing biography, that Sir Isaac was a posthumous child, his
father having died before he was born,] he had it
only by tradition, and it might be a mistake,' andimmediately turned the conversation to another subject.
" I confess I suspected that the gentleman who was
my author had given some colouring to this story,
and therefore I never mentioned it for a good many
years.
" After I removed to Glasgow, I came to be very
intimate with Mr. Cross, then Sheriff of Lanark, and
one day at his own house mentioned this story without
naming my author, of whom I expressed some diffidence.
" The Sheriff immediately took it up as a matter
worth being inquired into. He said he was well acquainted with Mr. Hepburn of Keith, (who was then
alive) and that.he would write him to know whether
he ever heard Mr. Gregory say that he had such a
conversation with Sir Isaac Newton.  He said he
knew that Mr. Keith, the ambassador, was also intimate with Mr. Gregory, and that he would write
him to the same purpose.
" Some time after, Mr. Cross told me that he had
answers from both the gentlemen above mentioned,




APPENDIX.


285


and that both remembered to have heard Mr. Gregory
mention the conversation between him and Sir Isaac
Newton, to the purpose above narrated, and at the
same time acknowledged that they had made no further inquiry about the matter.
"Mr. Cross, however, continued the inquiry, and a
short time before his death, told me that all he had
learned was, that there is, or was lately, a baronet's
family of Newton in West Lothian, or Mid Lothian,
(I have forgot which).  That there is a tradition in
that family, that Sir Isaac Newton wrote a letter to
the old knight that then was (I think Sir John Newton, of Newton, was his name,) desiring to know
what children, and particularly what sons he had,
their age, and what professions they intended: That
the old baronet never deigned to return an answer to
this letter which his family was sorry for, as they
thought Sir Isaac might have intended to do something for them."
Several years after this letter was written, d Mr.
Barron, a relative of Sir Isaac Newton, seems to have
been making inquiries respecting the family of his ancestor, and in consequence of this the late Professor
Robison applied to Dr. Reid, to obtain from him a
particular account of the remarkable conversation between Sir Isaac and Mr. James Gregory, referred to
in the preceding letter. In answer to this request, Dr.
Reid wrote the following letter, for which I was indebted to John Robison, Esq., Sec., R. S. E. who
found it among his father's manuscripts.
LETTER FROM DR. REID TO PROFESSOR ROBISON, RESPECTING THE FAMILY OF SIR ISAAC NEWTON.
C DEAR SIR,
"I am very glad to learn by yours of April 4, that
a Mr. Barron, a near relation of Sir Isaac Newton, is
a1xious to inquire into the descent of that great man,




286


APPENDIX.


as the family cannot trace it farther, with any certainty, than his grandfather. I, therefore, as you
desire, send you a precise account of all I know; and
am glad to have this opportunity, before I die, of
putting this information in hands that will make the
proper use of it, if it shall be found of any use.
"Several years before I left Aberdeen, (which I did
in 1764) Mr. Douglas of Feckel, the father of Sylvester Douglas, now a barrister at London, told me, that
having been lately at Edinburgh, he was often in company with Mr. Hepburn of Keith, a gentleman of
whom I had some acquaintance, by his lodging a night
at my house, at New Machar, when he was in the
rebel army in 1745. That Mr. Hepburn told him,
that he had heard Mr. James Gregory, professor of
mathematics, Edinburgh, say, that being one day in
familiar conversation with Sir Isaac Newton at London, Sir Isaac said, 'Gregory, I believe you don't
know that I am a Scotchman.' ' Pray, how is that '
said Gregory. Sir Isaac said he was informed that
his grandfather (or great-grandfather) was a gentleman
of East (or West) Lothian; that he went to London
with King James I., at his accession to the crown of
England; and that he attended Court in expectation,
as many others did, until he spent his fortune, by
which means his family was reduced to low circumstances. At the time this was told me, Mr. Gregory
was dead, otherwise I should have had his own testimony, for he was my mother's brother. I likewise
thought at that time, that it had been certainly known
that Sir Isaac had been descended from an old English
family, as I think is said in his eloge before the Academy of Sciences at Paris, and therefore I never mentioned what I had heard for many years, believing
that there must be some mistake in it.
" Some years after I came to Glasgow I mentioned
(I believe for the first time) what I had heard to have
been said by Mr. Hepburn to Mr. Cross, late Sheriff


1




APPENDIX.


287


of this county, whom you will remember. Mr. Cross
was moved by this account, and immediately said:
' I know Mr. Hepburn very well, and I know he was
intimate with Mr. Gregory. I shall write him this
same night, to know whether he heard Mr. Gregory
say so or not.' After some reflection he added, I
know that Mr. Keith, the ambassador, was also an
intimate acquaintance of Mr. Gregory, and, as he is at
present in Edinburgh, I shall likewise write to him
this night.'
"The next time I waited on Mr. Cross he told me
that he had written both to Mr. Hepburn and Mr.
Keith, and had an answer from both, and that both
of them testified that they had several times heard
Mr. James Gregory say, that Sir Isaac Newton told
him what is above expressed, but that neither they
nor Mr. Gregory, as far as they knew, ever made any
farther inquiry into the matter. This appeared very
strange both to Mr. Cross and me, and he said he
would reproach them for their indifference, and would
make inquiry as soon as he was able."
"He lived but a short time after this, and in the
last conversation I had with him upon the subject, he
said, that all he had yet learned was that there was a
Sir John Newton, of Newton, in one of the counties
of Lothian, (but I have forgot which,) some of whose
children were yet alive; that they reported that their
father, Sir John, had a letter from Sir Isaac Newton,*
desiring to know the state of his family, what children
he had, particularly what sons, and in what way they
were. The old knight never returned an answer to
this letter, thinking probably that Sir Isaac was some
upstart, who wanted to claim a relation to his worshipful house. This omission the children regretted,
conceiving that Sir Isaac might have had a view of
doing something for their benefit."
"After this I mentioned occasionally in conversation what I knew, hoping that these facts might lead
*                              -




288


APPENDIX.


to some more certain discovery, but I found more
coldness about the matter than I thought it deserved.
I wrote an account of it to Dr. Gregory, your colleague, that he might impart it to any menber of the
Antiquarian Society, who he judged might have the
curiosity to trace the matter farther."
" In the year 1787, my colleague, Mr. Patrick Wilson, Professor of Astronomy, having been in London,
told me on his return that he had met accidentally
with a James Hutton, Esq., of Pimlico, Westminster,
a near relation of Sir Isaac Newton, to whom he mentioned what he had heard from me with respect to
Sir Isaac's descent, and that I wished much to know
something more decisive on that subject. Mr. Hutton
said, if I pleased to write to him he would give me all
the information he could give. I wrote him accordingly, and had a very polite answer, dated at Bath,
25th December, 1787, which is now before me. He
says, ' I shall be glad, when I return to London, if I
can find, in some old notes of my mother, anything
that may establish the certainty of Sir Isaac's descent.
If he spoke so to Mr. James Gregory, it is most certain he spoke truth. But Sir Isaac's grandfather, not
his great-grandfather, must be the person who came
from Scotland with King James I. If I find anything to the purpose, I will take care it will reach
you.
In consequence of this letter I expected another
from Mr. Hutton when he should return to London,
but never had any. Mr. Wilson told me he was a
very old man, and whether he be dead or alive I know
not."
" This is all I know of the matter, and for the facts
qbove-mentioned I pledge my veracity. I am much
obliged to you, Dear Sir, for the kind expressions of
yolir affection and esteem, which, I assure you, are
mutual on my part, and I sincerely sympathise with
you on your afflicting state of health, which makes


-"




APPENDIX.


289


you consider yourself as out of the world, and despair
of seeing me any more."
" I have been long out of the world by deafness,
and extreme old I age.  hope, however, if we should
not meet again in this world, that we shall meet and
renew our acquaintance 'in another.-In the mean
time, I am, with great esteem, Dear Sir, yours affectionately,


V"TkU. REID."


f' Glasgow College,
" 12th April, 1792.t


This curious letter Dr. Brewster published in the
Edinburgh Philosophical Journal for October, 1820.
It excited the particular attention of the late George
Chalmers, Esq., who sent the Doctor an elaborate
letter on the subject; but as he was at that time in
the expectation of obtaining some important information through other channels, this letter was not
published. This hope, however, has been disappointed. A   careful search was made through the
charter-chest of the Newtons of Newton in. East
Lothian, by Mr. Richard Hay Newton, the representative of that family, but no document whatever could
be found to throw the least light upon the matter. It
deserves to be remarked, however, that Sir Richard
Newton, the alleged correspondent of Sir Isaac, appears to have destroyed his correspondence; for
though the charter-chest contains the letters of his
predecessors for some generations yet there is not a
single epistolary document either of his own or his
lady's.
Hitherto  the evidence of Sir Isaac's   Scottish
descent has been derived chiefly from his conversation
with Mr. James Gregory; but Dr. Brewster was
enabled, by the kindness of Mr. Robison, to corroborate this evidence by the following information,
T
v:       l;:::




290


APPENDIX.


derived, as will be seen, from the family of the Newtons, of Newton. Among various memoranda in the
handwriting of Professor Robison, who at one time
proposed to write the life of Sir Isaac, are the following:"' 1st, Lord Henderland informed me in a letter
dated March, 1794, than he had heard from his infancy that Sir Isaac considered himself as descended
from the family of Newton of Newton. This he heard
from his uncle, Richard Newton, of Newton, (who
was third son of Lord William Hfay, of Newhall).
He said that Sir Isaac wrote to Scotland to learn
whether any descendants of that family remained, and
this (it was thought) with the view to leave some of
his fortune to the family possessing the estate with the
title of baronet. Mr. Newton not having this honour,
and being a shy man, did not encourage the correspondence, because he did not consider himself as of
kin to Sir Isaac Newton, &c."
"2nd, Information communicated to me by Hay
Newton, Esq., of that Ilk, 18th August, 1800.
" The late Sir Richard Newton of Newton, Bart.,
chief of that name, having no male children, settled
the estate and barony of Newton in East Lothian
county upon his relation, Richard Hay Newton Esq.,
son of Lord William Hay. (This entail was executed in 1724, a year or two before Sir Richard's death.)
It cannot be discovered how long the family of Newton have been in possession of the barony, there being
no tradition concerning that circumstance farther than
that they came originally from England at a very
distant period and settled on these lands."  "The
celebrated Sir Isaac Newton was a distant relation of
the family, and corresponded with the last baronet,
the above mentioned Sir Richard Newton."
The preceding documents furnish the most complete
evidence that the conversation respecting Sir Isaac
Newton's family took place between him and Mr.




APPENDIX.


291


Gregory; and the testimony of Lord Henderland
proves that his own uncle, Richard Newton, of Newton, the immediate successor of Sir Richard Newton,
with whom Sir Isaac corresponded, was perfectly confident that such a correspondence took place.
All these circumstances prove that Sir Isaac Newton
could not trace his pedigree with any certainty beyond
his grandfather, and that there were two different
' traditions in his family, one of which referred his
descent to John Newton, of Westby, and the other
to a gentleman of East Lothian, who accompanied
King James VI. of Scotland, to London, on his accession to the English throne.  In the first of these
traditions he seems to have placed most confidence in
the year 1705, when he drew out his traditionary
pedigree; but as the conversation with Professor
James Gregory respecting his Scotch extraction took
place twenty years afterwards, namely, between 1725
and 1727, it is probable that he had discovered the
incorrectness of his first opinions, or at least was disposed to attach more importance to the other tradition,
respecting his descent from a Scotch family.
In the letter addressed to Dr. Brewster by Mr.
Chalmers, the following observations respecting the
immediate relations of Sir Isaac are made. "The
Newtons of Woolsthorpe," he says, "who were
merely yeomen farmers, were not by any means
opulent. The son of Sir Isaac's father's brother was
a carpenter called John. He was afterwards appointed gamekeeper to Sir Isaac, as lord of the
manor, and died at the age of sixty in 1725. This
John had a son Robert (John?) who was Sir Isaac's
second cousin, and who became possessed of the whole
land estates at and near Woolsthorpe, which belonged
to the great Newton, as his heir-at-law.  Robert
(John?) became a worthless and dissolute person,
who very soon wasted this ancient patrimony, and
falling down with a tobacco pipe in his mouth when




* 292


APPENDIX.


he was drunk, it broke in his throat, and put an end
to his life at the age of thirty years, in 1737."
WVE conclude this volume with a short outline of
Natural Philosophy, which, it is hoped, will not be
considered inappropriate by the inquirer after scientific
knowledge. It is abridged from an excellent article
in the Dublin University Magazine; and is alike distinguished for the simplicity of its language and the
utility of its object:The history of philosophy is one of the most interesting studies of the man of letters. The view of the
progress of knowledge, from its earliest recorded development, to its present extended diffusion, offers to
the reflecting mind a field of contemplation worthy of
traversing. If we compare the feeble efforts of the
most ancient philosophers to penetrate the veil of ignorance which then   surrounded mankind, with the
mighty power of the promoters of knowledge of the
present day, we must be struck with the extraordinary
progress of the human mind through the different
stages of barbarism, semi-civilization, and recent advancement.  Let us consider the kind of knowledge
acquired by these philosophers on their travels.
Thales, of Miletus, visited Egypt, where he studied
geometry, astronomy, and cosmogony. He was the
founder of the Ionian sect of philosophy, upon his
return to his native place. IIe appears to have taught
the cause of the inequality of days and nights, and the
theory of eclipses. He maintained that water is the
principle of which all the bodies in the universe are
composed-that the world was the work of God, and
that God sees the most secret thoughts in the heart of
man. It is related that he measured the height of the




APPENDIX.


293


pyramids of Memphis by the extent of their shadows; and he is considered the first who employed the
circumference of a circle in the measurement of
angles.
Pythagoras studied geometry among the Egyptians.
This science he improved by his subsequent discovery
of several important propositions. He is the earliest
recorded teacher of the true systemn of astronomy, and
he made many important 'discoveries in the other
physical sciences. He observed many curious phenomena on the surface of the earth, which must have led
him to reason on the changes which this surface must
have undergone in the lapse of ages. In the 15th
book of Ovid's Metamorphoses, a number of these observations are mentioned, which are extremely curious,
and testify, in a very remarkable manner, the superior
mind of the philosopher.
Plato also travelled into the east, where he became
versed in the learning of the Persians and the
Egyptians. He wrote several works which treated
chiefly of metaphysical subjects. He mingled together
his doctrines of theogony and cosmogony, so that it is
a difficult matter to separate his peculiar notions of
the latter. The passage in his writings most interesting to the modern geologist, is that which treats of the
Atlantic; recorded by Plato as a large continent beyond the Pillars of Hercules, and which had sunk under water, thereby giving place to the present Atlantic
Ocean. He made many improvements in geometry;
to him is ascribed the discovery of the mathematical
bodies, called the regular solids. He conceived the
world to be a figure shaped like one of these solids,
called the " dodecahedron."
Of the opinions of Aristotle respecting the formation of the world, we have not any clear account. He
wrote upon a variety of subjects, among which Natural
history occupied a prominent place. " He regarded
the matter of the heavens as ingenerate and eternal




294


APPENDIX.


-that mankind and all species of animals, have
subsisted from everlasting by a perpetual course
of generation without any original beginning or
production; and that the earth has been for ever
adorned with trees, plants, flowers, minerals, and
other productions as we now see it to be."  It is possible that he may have taken the eternity of the world
from Lucans, a disciple of Pythagoras, who is the
most ancient assertor of this idea, so different from the
opinion of his master.
We thus find that the most eminent ancient philosophers indulged more or less in reveries respecting
cosmogony. In studying other branches of learning,
they must have been frequently led into considerations
of the probable origin of the world which they inhabited; and they endeavoured to frame hypotheses,
some of which were very ingenious, but more generally extremely absurd. Occasionally a master mind,
like that of Pythagoras, made an approximation to
the truth, which has astonished the learned of later
times. Sometimes facts were related in corroboration
of these hypotheses-sometimes they were distorted
to explain the dreams of philosophic fancy. But
among the ancients, the observation of natural facts
was not made in a way to benefit science.  We find
many of the arts and sciences brought by the ancients
to a considerable degree of perfection. In architecture, poetry, eloquence, and perhaps in some other
branches, they excel the moderns. The progress made
by them in geometry was admirable indeed; and
they based that science upon a foundation fitted to
bear the splendid superstructure raised by modern
ingenuity. But in those branches that required a
combination of the perceptive and reasoning powers,
their progress was very limited. Chemistry and experimental philosophy are of modern origin: at least
what was effected in them by the ancients, or rather
what is recorded as having been effected, is very tri



APPENDIX.


295


fling. In botany, zoology, and mineralogy, a number
of detached observations have been recorded in the
writings of Aristotle, Theophrastes, and Pliny; but
no classification was ever attempted, nor any extended
train of reasoning from these facts adopted by the
ancient philosophers.
If we turn onr attention to the state of knowledge
among the Arabians, we shall find that the mathematical sciences were for the most part cultivated by
them. They cevoted, it is true, some attention to
astronomy and to alchemy; but the former being
studied for the purpose of contributing to their desire
to penetrate the mysteries of fate, was merely a compound of truth and falsehood that has been denominated astrology; and the latter, ministering to the
passions of most men for acquiring wealth, offered a
strong temptation to its votaries, but was of no service in furthering the march of mind, although it discovered facts that were afterwards of service to the
modern chemist. We may regard the Arabians more
as the preservers of ancient science. Many of the
inventions ascribed to them have been traced to the
Indians, and were received either directly from that
people, or through the medium of the Greek philosophers, whose works were translated into the Arabic
language.
The conclusion to which we may arrive from a con..
templation of the state of learning in the early and
middle ages is, that geometry was the only science
successfully cultivated, and handed down free of any
error or absurdity; all the other branches of learning
were more or less imbued with mistaken views, arising
generally from imperfect data. There seemed to be
little respect paid to knowledge acquired from the observations of facts of daily occurrence. Abstruse studies
were most esteemed. Mathematics requiring a deep
train of thought, and at the same time of correct reasoning, without needing the aid of experiment requi/::




296


APPENDIX.


site in physical science, enabled the cultivators to
~improve without any danger of perversion.
In the history of natural philosophy a knowledge
of mathematics is indispensable on the part of the
student; if he venture beyond the vestibule. The
votary of pure mathematics will be insensibly led to
the application of his favourite science for the explanation of some of the phenomena in Nature; and if
he be successful in solving any of their mysteries, he will
be encouraged to pursue still further the research after
physical truth. The ancients were thus led to apply
their mathematical knowledge. The name of Archimedes is handed down as one of the brightest in
ancient times. His discoveries form an important era
in the history of science; and they arose from his
extensive application of geometry to physics. Before
his time there were no correct notions of the theory
of mathematics, and he is the first who pointed out
the specific gravity of bodies. He is the only one of
the ancients who can bear comparison with the moderns as a natural philosopher.
When learning began, after the dark ages, to revive
in Europe, the mathematical lore of the ancients was
sought after with great avidity.  What had been effected by them in the physical sciences received also
its due appreciation. Both the truth and the absurdity of their astronomy, mechanics, and other branches,
were swallowed at first without' being questioned.
But as the attention of the early moderns became
more directed to scientific investigation, many of the
errors of the ancients became manifest. Some of these
were speedily corrected, while others, admitting of
more discussion, remained for a longer period under the
judgment of the new cultivators of knowledge. Every
successive age, however, dispelled more or less of these
errors. The study of the pure mathematics advanced
with rapid strides.  Their field was augmented with
numberless new  discoveries.  Their application to




APPENDIX.                 297
physics became every day more general; and the impulse which science had now received, carried forward
its votaries witha velocity never before known in its
progress.
Natural philosophy had now become a science of
great importance, from the additions made by its
early modern cultivators to what was received by
them from the ancients. Among the ancients, Archimedes was the first who applied geometry to physics,
and then gave it a double power. Among the first
revivors of learning in Europe was Descartes, who
applied algebra to geometry, and thus put an engine
of incalculable power into the hands of the cultivators
of natural philosophy. The attention of the learned
was now directed to experiment, a method, if investigatet, but little appreciated or understood by
the ancients.  Galileo, by his invention of the telescope, opened, as it were, the gates of the heavens,
into which rushed a host of ardent inquiriers after truth.
A number of other illustrious men at the same time
directed their attention to experiment in the other
branches of physical science. The discovery of printing some time before enabled the new acquisitions to
knowledge to be widely diffused, and enabled one
nation to communicate its knowledge to another with
a rapidity never before conceived.  The discovery
of America not only was a successful experiment
on a large scale, but it added another proof to
the true system of the world, and directed in a
further degree the attention of men to the examination of natural phenomena.    The Reformation
promoted the freedom of discussion, and enabled
the laity to take part in studies, almost previously
attended to by the clergy alone.  But what contributed in the greatest degree to the improvement
of physical science, was the new path pointed out to
its votaries by the illustrious Lord Bacon. His master
mind discovered the causes of error in the philosophy




298


APPENDIX.


of the ancients, and demonstrated that as long as
their mode of reasoning was pursued, it was impossible for the moderns to frame k true system of
science. He asked, " Wherein can arise such vagueness and sterility in all the physical systems which have
hitherto existed in the world?" It is not certainly
from anything in nature itself; for the steadiness and
regularity of the laws by which it is governed clearly
mark them out as objects of certain and precise
knowledge. Neither can it arise from any want of
ability in those who have pursued such inquiries, many
of whom have been men of the highest talent and
genius of the ages in which they lived; and it can
therefore arise from nothing else but the perverseness
and insufficiency of the methods that have been pursued.  Men have sought to make a world from their
own conceptions, and to draw from their own minds
all the materials which they employed; but if, instead
of doing so, they had consulted experience and observation, they would have had facts, and not opinions
to reason about, and might have ultimately arrived at
the knowledge of the laws which govern the material
world."
The opinions of Bacon became gradually appreciated.  The calm observation of facts became in
every succeeding age more attended to, and natural
philosophy based upon actual experiment, and not
upon the wild conceptions of the imagination.
The science of chemistry may be said to be one of
the offspring of the Baconian philosophy.  It is a
branch of physics-the first principles~ of which depend wholly upon experiment. Its progress testifies,
in a remarkable degree, the importance of the inductive method of reasoning. It required a calm and
patient examination of the changes produced on bodies
by expeiment, in order that a sufficient mass of facts
might be accumulated to raise it to the rank of a
science. It required its cultivators to divest them



APPENDIX.


299


selves of all prejudices-to view things as they really
are, and' not to set out with a previous leaning to a
particular set of opinions, and to torture the result of
their experiment to prop these opinions up. It is
impossible it could have become a regular science
under the influence of the Aristoteleian philosophy.
The more,nen reasoned from  facts, the more did
chemistry advance; and it now affords one of the
most brilliant examples of the happy mode pointed
out by Bacon, for the improvement of knowledge.
If we sum up the results of our observations on the
progress of knowledge, we shall arrive at the conclusion, that the observation of facts was the very last
object attended to in its march through successive
ages-at least the calm and unprejudiced examination
of facts. The learned of antiquity seemed more inclined to aberuse studies-to studies which required
a precision of reasoning, which often testified their
extreme ingenuity.  If their first principles were correct, so were their conclusions. But that their first
principles were, for the most part, erroneous, we have
obdurate proof in many instances. In geometry their
first data were correct, being self-evident truths, and
their conclusions were therefore just. For a succession
of ages, knowledge, derived from observation of the
common objects in nature, was looked down upon as
unworthy the regard of the philosopher. -Ther
was a consequent bar to the progress of physical
knowledge.
After the revival of learning in Europe, it was not
to be expected that the eyes of man could be all at
once opened to the errors of the ancients. Both the
truth and falsehood of the ancient philosophy were
studied.  The human mind was still imbued with
prejudice.  This, however, gradually wore awaymathematics became more extended-natural philosophy was extended and improved-chemistry was iavented. We may gradually trace the progress of real




00oo


APPENDIX.


knowledge from the first axioms of geometry, through
the more advanced stages of mathematics-through
the successive developments of natural philosophyto a science resting solely upon a careful examination
of facts, the science of chemistry.
Natural philosophy opened to man the field of space
-it taught him to regard the motion of objects upon
a grand scale-it enabled him to assign dimensions to
this space, and to measure the relations of motion.
Chemistry taught him to view the changes produced
on bodies, by motions of their minute component particles, the measurement of which motions eludes our
most subtle investigations. Natural philosophy instructed him in the external relations of the bodies in
nature-chemistry in the internal. It led him, as
it were, into the mind of inanimate matter.
During the last hundred years, the a|tention paid
to an unprejudiced examination of facts has been continually on the increase. Philosophers have entered
upon their investigations without bias to any particular opinions. Instead of commencing their researches
by laying down a favourite hypothesis, and then distorting facts to accord with it, they commenced with
an impartial examination of the facts themselves; and,
following the suggestions of Bacon, they framed their
theory by the inductive method of reasoning. By
not attending to the advice of Bacon, men were inclined to imagine circumstances which have no existence in reality.  They beheld nature through a
medium that rarely presented her in her true form.
So long as the field of physical science was limited,
the liability to view nature in this manner continued;
but, as discovery followed discovery, the disposition to
prejudice became more and more removed. For a
long period men adhered to certain dogmas that had
been handed down through a succession of ages, and
finding it difficult to reconcile many facts in nature
with these dogmas, they had recourse to hypothesis,




APPENDIX.


301


the frequent absurdity of which paved the way to the
exploding of erroneous principles, and dispelled the
illusion, although supported by the authority of antiquity. Knowledge derived from facts, spreading far
and wide, carried with it the examples of its own
importance. The arts of life received incalculable
improvements-they, in return, aided science. They
formed the passage from one branch to another-they
were the illustrators of theory, by showing its practical application. The ancient philosopher would have
disdained to lend his aid to the agriculturist, the mechanist, or the navigator. The modern man of science
regards, as his proudest boast, the improvements given
by him to the arts, thereby rendering man little inferior in power to the deities of the ancients.
It seems indeed strange that the impartial examination of fact's the result of a highly improved state
of scientific ]mowledge.  But so it is. It is only
within a comparatively recent period that the point
has been reached by the human mind. It has been
often remarked, that the farther we advance in knowledge, the more deeply are we impressed with a sense
of our own ignorance. Although this may not be
exactly true, still we may acknowledge that we are
less confident in broaching any new theory, in proportion to the advance of the march of intellect.
When our opinions can be submitted to the test of an
appeal to facts, we are more cautious in stating these
opinions. It is our province to study the facts attentively, so that we may not be found in the wrong.
Geometry teaches us the relations of dimensions as
conceived in the human mind, but which, in the
abstract, has no real existence. Natural philosophy
treats of the relations of existing bodies, viewed in a
state of motion. Chemistry informs us of the changes
produced in the bodies themselves.  Mathematics,.
natural philosophy, and chemistry, frequently view
conditions which have no existence in nature.
Sal:.




802


APPENDIX.


Let us now direct our attention-to a branch of knowledge which treats of the objects in nature as they
really appear-Natural History. The field of natural
history is wide indeed: it includes all nature. But as
we cannot penetrate beyond the confines of the earth
a which we inhabit, we must be content to become
acquainted with what it contains on its surface or in
its bosom. If we explore the animal, the vegetable,
or the mineral kingdom-if we mount into the atmosphere, or descend into the mine-we are impressed
with the imperative necessity of our acquaintance with
the different, branches of physics. This demonstrates
the mutual dependence of one branch of knowledge on
another, and in the consideration of this dependence a
field of interesting and delightful occupation is opened
to us. Let us enter this field ourselves, and let us
view these mutual relations.
It will be sufficient for our present purpose, if we
view the relations of natural history with the other
branches of knowledge. The relations of these other
branches among each other can be deduced from after
consideration. It will also simplify our subject, if we
select some individual part of natural science, and then
show its dependence upon other kinds of knowledge.
The consideration of any one point will lead to that of
others, and these to more, so that we have merely to
choose the particular place from which we are to start;
we shall have no difficulty in our way of gathering
materials for comparisons.
The part of natural history whi6h we have selected
for our purpose is geology. There is, perhaps, no
portion of physical science so well suited for exemplifying the relations of its different branches with each
other.  It treats of, says Lyell, "the successive
changes that have taken place in the organic and inorganic kingdoms of nature.  It inquires into the causes
f these changes, and the influence which they have
exerted in modifying the surface and external struc



APPENDIX.


%3


ture of our planet." It is the science of the earth
which we inhabit-it is a science that may, at all
times, be studied. If we explore the mountain or the
valley, the quarry or the mine, we may everywhere
find matter for reflection; we may read the book of
creation, written in characters not to be misunderstood. The language admits of no misinterpretation
-it is the language of facts.
The division of natural history that presses closest
Bupon the attention of the geologist, is mineralogy.
The mineral masses of the globe are what at first
arrest his attention. If he walk through a cultivated
country, he does not find geological phenomena of
mineral substances so interesting as in districts more
in a state of wild and uncultivated nature.    Still
there is much to claim his attention. The soil in the
fields will differ in many places, and furnish an index
of the substratum.    Thus he will distinguish the
ferrugenous clayey soil that indicates the underlying
of basaltic rocks-the calcareous clayey soil resting
upon   mountain limestone-the     chalky  soil-the
granitic soil, and various others. If he examine the
low grounds he will find the finer particles of clay
accumulated in the lowest situations; along the
slopes of the hills he will observe coarser parts of
mineral substances, increasing in size as he approaches
the rocky summits. If he enter into a mountain
district, he will discover large masses of rocks in
various states of disintegration, their harder parts
withstanding the assaults of ages, their softer parts
separated by various causes from the harder, and
carried from these elevated regions to the lower parts
of the country by the agency of rivers and torrents
In examining these mineral substances, he will find
his knowledge of mineralogy brought into requisition.
If his knowledge of it be extensive, he may be enabled to discover something that may not have been
known before.   If his knowledge of it beight, he




304


APPENDIX.


will find the examination of nature an excellent exert
cise and means of improvement.
An acquaintance of chemistry is also requisite in
the study of every department of natural history. In
zoology and botany we find it constantly referred to
for the explanation of the vital functions and the cornposition of animal and vegetable substances.  In mineralogy its importance is still greater, from the
circumstance that the elementary bodies found in
plants and animals, are very few in comparison with
those composing minerals.    In the view  of the
changes that have taken place in the globe, we are
struck with the important part played by chemical
agency.   We can conceive no alteration produced
either on the surface or in the interior of the globe in
which this agency was not, in a greater or less degree,
exerted. If we regard the action of existing causes,
still going on, in altering the surface of the earth, we
shall find at every step appeal made to chemical
knowledge.
A knowledge of mechanical philosophy is also required by the student of geology. The laws of
attraction and motion are always in action, and no
change can take place in the globe at variance with
these laws.  The consideration of the subject of attraction is of great importance to the geologist; it
leads him into the examination of the density of
mineral masses, and of the globe itself.  It will be
many phenomena which at first sight may seem
anomalous. The application of the laws of motion will
be also a powerful auxiliary, whether we view the
movement of great mineral masses, or of their fragments; or that of currents in the atmosphere or the
ocean.
The connection of hydrostatics with geology is of
the greatest importance. The vast ocean which covers
so much of the earth's surface is subject to hydrostatical laws; so are the lakes and rivers. Many of




APPENDIX.                 305
tie ienomena of the torrents that rush from the
mountains upon the plains, and which are so important agents in modifying this surface, will be
understood by applying the laws of hydrostatics.
Many geologists have conceived the globe itself to
have been at one time in a state of fluidity. How are
we to criticise the opinions of these philosophers, but
by assigning the truth of their conclusions to the
standard of hydrostatics.
The atmosphere surrounding the globe may be said
to fall within the province of the geologist. In any
system of cosmogony that has been, or ever can be
invented, the atmosphere will play a prominent part,
as its original formation may be accounted for. It is
the grand cause of most of the alterations that take
place on the surface of the earth.  It is the cause of
the rain that fertilizes one portion of this surface
while it gradually wears down another, and of the
snow that caps the lofty mountains, which is the
magazine for supplying rivers and lakes.  It is the
supporter of plants that cover the earth, and that
modify its superficies in an infinite variety'of ways;
in fact, to dilate upon this subject would require a
separate memoir.
The geologist must also take into consideration electrical phenomena.  By some cosmogonists electricity
is made to play a very prominent part in the formation
of the earth; we must therefore be acquainted with
it in order to combat them with their own weapons.
The knowledge of the different electric states of
bodies is also of the first importance in the explanation of many of the natural phenomena.  At times
of volcanic eruptions, or of earthquakes, these phenomena become most interesting, and will, if viewed
by a well-informed observer, be turned to good account in elucidating the history of our planet. The
dioveries made by some philosophers in galvas
'"  "  v         *r                   -1^




Qm6                 APPENDIX.
have been applied to expound geology; several av
conceived they had obtained a key for the solutin of
all difficulties in the action of oxygen upon the base
of the alkalies and earths brought to light by galvanism. The science of magnetism is still in its cradle,
but its connection with geology is most intimate. It
is now under the fostering care of some of the most
eminent philosophers, and will, I am sure, ere long,
throw much light upon geology.
With the science of astronomy, geology is linked
in the closest degree. In the early ages of knowledge,
the attention of men was turned to the contemplation
of the heavens, and many years of observation taught
them to recognize the celestial bodies. Their imaginations invented many fables with regard to the stars
and planets.  This play of fancy descended to the
earth, and from  astronomy the mind of the ancient
philosopher was led to consider the subject of cosmogony.    In the ancient systems of astronomy the
earth is regarded as a vast plain, and the ancient
notions of its formation and alteration, especially by
deluges, are all grounded upon the supposition of its
being a plane superficies, with the exception of the
doctrine of the Pythagoreans. That the earth is of a
plane figure, would strike the mind more forcibly than
its possessing a spherical shape. This latter opinion
is the result of deep and laborious reflection. The
causes of error among the early cosmogonists are in
this case extremely manifest. An advanced state of
the science of astronomy was requisite to prove.to the
satisfaction of all that the form of the earth is
globular.
It has been supposed by some philosophers of the
last century that there has been a change of climate
in the different regions of the earth's surface, as the
remains of organic beings are found in situations
where, had they lived, it would have been impossible
for them to have existed under the circumstances of




APPENDTX.                 307
thleresent temperature of those places. They have
conceived a solution of this difficulty will be, that the
poles of the globe have changed their positions, and
still continue to do so-that at one time their points
were in the present equator, and that the frigid regions
were where the torrid now art. This supposition can
only be refuted by a very refined train of astronomical
investigation, and it was left to the immortal Laplace
to demonstrate its incorrectness; and that, although
there is a trifling shifting of the extremities of the
terrestrial axis, these irregularities are confined within
certain limits, and are the consequence of the extreme
perfection of the system  of the world.  In many
other particulars, the connection of geology and
astronomy might be shown, but the investigation
would lead us into a field that would require a
separate paper to describe.
Although the connection of optics with geology may
not at first strike us as being very manifest, its indirect relations are not very important. Of late years,
very singular discoveries have been made in optics,
particularly by Dr. Brewster. These discoveries refer
to the action on the sight, of bodies having a crystalline form; a very remarkable connection has been
observed between their chemical composition, crystalline structure, and optical phenomena. These discoveries will evidently improve the science of mineralogy,
and the more it is improved, the better will geology be
elucidated. From the intimate connection of astronomy and geology, and of astronomy with optics,
especially with regard to the instruments for observing
the heavenly bodies, the improvements in these instru-.
ments, by adding to our knowledge of the heavens,
wil enable us to extend our acquaintance with the
earth. The invention of the microscope has unfolded
the secret of organization; and as geology treats of
the organic, as well as of the inorganic changes of the
kangdoms of nature, the minuteness of which eludes




^08


APPENDIX.


the observation of the naked eye, it will be appreated
in the highest degree.
In the study of natural philosophy, we cannot proceed far without the aid of mathematics. In geology
itself there are many points that require immediately
the mathematical skill Of the observwr;r so that, viewed
both directly and indirectly, mathanatics must be
understood by the geoogist.. I have shown that the
philosophers of antiquity Who proposed systems of
cosmogony, were all geometers, and among the moderns,
many illustrious names-:- need only quote that of
Playfair for example-have been distinguished alike
for mathematical and geological knowledge. An acquaintance with civil history is likewise required. As
history teaches us the progress of human society, and
informs us of the changes that have taken place in
human institutions, so geology instructs us in the mutations of organic and inorganic nature. Where there
are records of natural changes preserved in the pages
of history, its connection with geology becomes more
intimate, and is often of the greatest value.
As knowledge becomes more cultivated by different
nations, the languages spoken by those nations should
be attended to by the student. Many of the natural
appearances of a country cannot be described in a
maoeo to bring them before the eye of the reader, so
well fasi the language of that country.  Foreign
liFtt~rels now so much extended that it would be
iJ]  impossible and unprofitable to translate all the
eminent publications that are almost daily issuing
from the continental press. Periodical literature is
an invention of modern times.  Periodical publications must be read in the language in which they are
originally written, in order that their full force and
importance may be felt. It is also proper that the
opinions of the ancients should be studied in their
respective tongues. The difficulty of acquiring languages has been much decreased of late years, by the




APPENDIX.


309


improvements in the mode of learning them, and the
knowing of one or two will open to the student the
gates of as many more as he may desire to study.
With intellectual philosophy, the connection of
geology is very interesting. A true system of geology
can be the result only of a ighly refined train of
reasoning. I have shown the imperfection of the
ancient mode of reasoning, and its consequent influence
on physical science. Bacon pointed out to me the true
mode of observing the system of nature. In studying
geology, we should be aware of the proper mode of
conducting our A reasonings from facts, and be alive to
our liability to commit errors. The science of logic
here lends its aid, and matter is aided by the powers
of the mind.
We will readily arrive at the conclusion, that, if an
improvement take place in any one department of
knowledge, it cannot fail to be of use to all the others.
The connection which I have endeavoured to show
between geology and the other branches of philosophy,
will furnish us constantly with illustrations.  In fact,
we cannot study any one circumstance in science in an
isolated manner. We must viewits relation to others
in order to understand it.
Referring again to the definition of geology, that
at treats both of the organic and inorganic changes of
nature, we may recal an important observation which
we made a little way before, that it requires a
knowledge of the productions of the animal and
vegetable kingdoms. If the attention of the geologist
be confined to the consideration merely of the mineral
masses of our globe, his exertions will be placed within
narrow  limits-his science will be incomplete-he
must regard attentively the remains of organised
beings enshrined in many of these mineral masseshe must compare them with existing species-he
will discover many exuviae of beings very different
from the races that now inhabit the earth-he will




RI0


APPENDI.


bserve the bones of gigantic mammalia and repties,
the types of which are not now to be found-of fishes,
birds, and insects-an immense variety of fossil
shells, scarcely any of which agree with existing
species-he will discover the remains of plants, many
of which he will in vati endeavour to reconcile with
those that now clothe the surface of the earth. But
the knowledge of these fossil remains is still in its
infancy-he must be previously acquainted with those
natural productions, both animal and vegetable, that
are now found on the earth-he must study geology,
in order to know the external forms of animals, their
habits, and instincts, and anatomy, that he may be
able to recognise the species of fossil bones.  To
understand the connection of the external forms of
animals with their internal structure, he must be
acquainted with physiology. The connection of conchology with geology is of the closest description.
When an ignorant person observes another gathering
shells upon the beach, he is inclined to despise him,
considering the occupation as one belonging to
children.  When he sees him   searching for shells
imbedded in rocks, he thinks the sanity of the
collector to be dubious! He little thinks that these
imbedded shells are part of the language in which the
history of the globe is recorded. They have been
called the medals that illustrate its annals.  The
science of botany enables the geologist to investigate
the remains of plants found in strata.  To compare
them with existing species is a most interesting task.
The wonders of the antediluvian world are developed
by this application of zoology and botany.    This
illustrates how  intimately the different branches of
natural history are linked with each other. The
additions made to them within a very recent period
re so great as to astonish when enumerated. At the
present moment the utmost zeal is manifested to
acquire a knowlegde of natural productions, both




APPENDIX;                 3 11
recent and fossil: The geologists of the present day
vie with each other in their investigation of organic
remains. The illustrious Cuvier applied his profound
knowledge of anatomy to the examination of bones
found in strata; his steps have been followed by a
number of other ardent inquirers. The vast variety
of shells, corallines, and other remains of the lower
animals, discovered in rocks, are undergoing a strict
scrutiny by naturalists well versed in the knowledge
of recent productions. Very lately the examination
of fossil plants has excited the ardour of several of
the students of natural science, and their labours are
likely to be rewarded ere long with an abundant
harvest of facts.  Geology is thus becoming based
upon a sure foundation-it is showing itself worthy
of the attention of the philosopher. The more facts
that may be discovered, the surer will be the foundation upon which it will rest. The improvements in
the other departments of physical and intellectual
knowledge will contribute to cement the superstructure, while the study of the science itself will form
one of the greatest means of human happiness.
FINI S.


D. Sullivanu Printer, Dublin.




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