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Cornel) University Library 
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 Lectures on geography delivered before t 
 
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LECTURES ON GEOGRAPHY 
 
LECTURES 
 
 ON 
 
 GEOGRAPHY 
 
 DELIVERED 
 
 BEFORE THE UNIVERSITY OF CAMBRIDGE 
 
 DURING THE LENT TERM 1888 
 
 LIEUT.-GEN. R.^STRACHEY, R.E., C.S.I. 
 
 PRESIDENT OF THE ROYAL GEOGRAPHICAL SOCIETY 
 
 Ronton 
 
 MACMILLAN AND CO. 
 
 AND NEW YORK 
 1888 
 
 All rights reserved 
 
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 LIBRARY /> 
 
CONTENTS 
 
 LECTURE I 
 
 Introduction — Proper scope of geographical teaching — Proposed 
 treatment of the subject — Sketch of the growth of knowledge 
 of the form, movements, and magnitude of the earth — Of the 
 construction of maps and the art of navigation Pages 1-49 
 
 LECTURE II 
 
 Progress of geographical discovery — Operation of physical forces on , 
 terrestrial phenomena — Influences of the form and movements 
 of the earth — Terrestrial magnetism — Relation of geology to 
 geography — The terrestrial sphere and its interior 50-101 
 
 LECTURE III 
 
 The external features of the earth — The land, its distribution and 
 elevation — The ocean, its depth, currents, and tides — The 
 atmosphere — Phenomena of climate and their dependence on 
 the conditions of the earth's surface — Winds — Rain — Ice 
 
 102-150 
 
 LECTURE IV 
 
 Phenomena of Life — Doctrine of evolution under varying terrestrial 
 conditions — Distribution of vegetable and animal life — The 
 place of man — His dependence, physical and intellectual, on 
 Geographical influences — Geography in relation to the practical 
 affairs of life and the prosecution of other studies— Conclusion 
 
 . IS'- 211 
 
LECTURES ON GEOGRAPHY 
 LECTURE I 
 
 Introduction — Proper scope of geographical teaching — Proposed 
 treatment of the subject — Sketch of the growth of knowledge 
 of the form, movements, and magnitude of the earth — Of the 
 construction of maps and the art of navigation. 
 
 When the University of Cambridge resolved 
 in June last to accept the proposal of the 
 Royal Geographical Society to provide a 
 lecturer on geography with the aid of funds 
 to be supplied by that Society, a wish was 
 expressed that the appointment should be 
 postponed until the next year ; and that the 
 Council of the Society should endeavour to 
 arrange in the interval for the delivery of 
 
 B 
 
LECTURES ON GEOGRAPHY 
 
 introductory lectures, illustrative of the 
 general character and scope of the instruc- 
 tion in geography suitable for a University 
 course, which it would in future be the duty 
 of the lecturer to impart. 
 
 It is by desire of the Council of the 
 Royal Geographical Society that I have 
 undertaken to give effect to this wish of 
 the University authorities. 
 
 After careful consideration, I have come 
 to the conclusion that I should direct atten- 
 tion to the subjects with which instruction in 
 geography should deal, rather than to the 
 form in which it should be imparted. I can 
 profess no personal experience qualifying me 
 as a teacher, nor do I think that any useful 
 end would be gained by my offering sugges- 
 tions as to the method of teaching geo- 
 graphy most suitable for students at the 
 University. I cannot doubt that it should 
 be left to the lecturer to select the particular 
 
TEACHING AT UNIVERSITIES 
 
 methods which best satisfy himself, and 
 appear to him most appropriate in relation 
 to the general course of instruction pursued 
 at the University. 
 
 That the study of geography should have 
 been recognised by our two great Uni- 
 versities, for the first time in the past year, 
 as deserving a place among the subjects 
 which they undertake to teach, no less than 
 my own presence here for. the purpose 
 already stated, are sufficient indications that 
 there have hitherto been no very precise 
 notions of the position of geography as a 
 branch of knowledge susceptible of scientific 
 treatment, nor indeed as to its deserving any 
 special attention apart from its utility in 
 supplying various branches of study with 
 topographical facts. Hence the view of the 
 matter which I shall place before you must 
 be understood as representing only my own 
 personal opinions, though I have every 
 
LECTURES ON GEOGRAPHY 
 
 reason to think that, in substance, the same 
 opinions are held by all those, both in this 
 country and elsewhere, best qualified to be 
 your guides. 
 
 Geography has till a comparatively short 
 time ago been commonly viewed rather in 
 the light of its practical value in supplying 
 maps of the world, and of the interest that 
 attaches to the exploration of unknown 
 countries, than in relation to other branches 
 of knowledge, or to the general body of 
 physical science. The more obvious facts 
 for geographical observation are such as 
 strike the least instructed, and the first 
 steps were taken by those who had neces- 
 sarily little appreciation of the true signi- 
 ficance of much that they saw, and were 
 incapable of doing more than collect, and 
 that very imperfectly, the materials which 
 their successors are bringing into a scientific 
 
RECENT VIEWS OF GEOGRAPHY 
 
 form. The present generation has almost 
 lost remembrance of the thrilling interest 
 created by the accounts of those geograph- 
 ical discoveries which were among the 
 glories of the past two or three centuries, 
 and the standard volumes of voyages and 
 travels, which delighted the boyhood of their 
 elders, lie forgotten or neglected by the 
 youth of to-day. A new phase of thought 
 has become operative. The connection 
 between geography and physical science is 
 more distinctly recognised, and attention has 
 been especially drawn to the value of geo- 
 graphical knowledge in relation to the or- 
 dinary affairs of man, and to the importance 
 of extending such knowledge. There is a 
 clearer appreciation of the influence which 
 geographical features and conditions have 
 exerted on the past history and present state 
 of the several sections of the human race, on 
 the foundation and growth of kingdoms, the 
 
LECTURES ON GEOGRAPHY 
 
 development of industry and commerce, and 
 the spread of civilisation. 
 
 The growing sense of the importance of 
 geography in all these aspects has led the 
 Royal Geographical Society for many years 
 past to make continuous efforts to secure for 
 the study of geography a more prominent 
 place in general education ; and in order to 
 bring about a more satisfactory system of 
 instruction in our schools, it has sought and 
 obtained from the Universities of Oxford 
 and Cambridge the recognition of this study 
 as a subject that should fall within the range 
 of their teaching, and for which suitable 
 provision will accordingly be made. 
 
 In its earliest shape, geography, as I have 
 already observed, concerned itself chiefly 
 with the mere topographical features of the 
 surface, and viewed the earth almost ex- 
 clusively as the habitation of man. The 
 inquiries it made were ' directed to the dis- 
 
I PROGRESS OF GEOGRAPHICAL IDEAS 7 
 
 tribution of the land and water, the positions 
 of the continents, islands, and seas, and of 
 the plains, mountains, and rivers ; to the 
 manner in which the land was divided into 
 various countries, and occupied by various 
 nations ; to the divisions of countries into 
 provinces, and the situation of the chief 
 cities. The geographer further took note 
 of matters concerning the language, customs, 
 and modes of government of the inhabitants, 
 as well as of the climate and products of the 
 various parts of the earth. 
 
 By the gradual extension of observation, 
 and the ultimate adoption of true notions as 
 to the form and magnitude of the earth, the 
 more serious errors of the earlier approxi- 
 mate ideas were corrected, and at length a 
 solid foundation was laid for precise deter- 
 minations of position, and accurate repre- 
 sentation of terrestrial features in detailed 
 maps. And as knowledge thus advanced, 
 
LECTURES ON GEOGRAPHY 
 
 the earlier impressions of travellers, based 
 on the striking differences between distant 
 countries, were supplemented by the percep- 
 tion of coexisting similarities no less re- 
 markable and real. Attention was soon 
 drawn to the peculiarities which persistently 
 characterise the great regions of polar cold 
 and equatorial heat ; to the main features of 
 the mountain ranges, the plains, the coasts, 
 and interior of the continents, and of the 
 oceans ; to the local and periodical variations 
 of temperature and climate ; and to seasons 
 of wind and rain over certain areas of land 
 and sea. 
 
 At a later period, the grouping of plants 
 and animals of peculiar structure or of 
 peculiar families in certain terrestrial or 
 marine areas attracted attention, and fresh 
 occasion for observation and thought was 
 found in the circumstances under which such 
 groups varied from place to place, or re- 
 
RELATION TO OTHER SCIENCES 
 
 appeared, more or less completely, under 
 identical or similar forms in widely separated 
 regions, or were more or less strictly limited 
 in number or in respect to the areas over 
 which they were found. Combined with 
 these facts, and studied with them, were 
 the analogous physical peculiarities of the 
 races of man, their languages, customs, and 
 history, varying from one region of the earth 
 to another, yet often having certain common 
 features over large areas. 
 
 But before these observations could be 
 viewed as parts of a connected whole, or 
 the true significance of their mutual relations 
 could be properly appreciated, it was neces- 
 sary that considerable progress should have 
 been made in many special branches of 
 physical knowledge. The ancient sciences 
 of mathematics and astronomy had first to 
 receive the additions which followed the 
 revival of learning in the sixteenth century ; 
 
LECTURES ON GEOGRAPHY 
 
 the modern sciences of chemistry and 
 physics, biology and geology, had to be 
 created, and the study of history to be 
 placed on a more scientific basis ; and all 
 had to throw their light on the facts brought 
 together from many lands and seas to make 
 a truly scientific conception of geography 
 possible. 
 
 Science, whether applied to geography or 
 any other subject, being, in truth, nothing 
 more than well - arranged knowledge, its 
 methods, though first developed by the 
 study of mathematics and of the physical 
 forces of nature, are applicable to all the 
 objects of our senses and the subjects of 
 our thoughts. The foundation of all know- 
 ledge is the direct observation of facts ; by 
 applying thought to the facts thus observed, 
 we seek through a process of classification 
 and comparison for the causes of which 
 observed phenomena are the results, and 
 
ITS PROPER SCOPE 
 
 the conclusions thus obtained constitute 
 science. 
 
 The aim of geographical science, there- 
 fore, is to investigate and delineate the 
 various features of the earth ; to study the 
 distribution of land and sea, the configuration 
 and relief of the surface, position on the 
 globe, and so forth, facts which determine 
 the existing conditions of various parts of 
 the earth, or which indicate former condi- 
 tions ; and to ascertain the relations that 
 exist between those features and all that 
 is observed on the earth. Geography is 
 thus ancillary to many other branches of 
 science and learning, for which a know- 
 ledge of the relations of such facts or 
 features to the matters with which they 
 deal is essential. 
 
 It is evident that the investigation of the 
 causes of terrestrial phenomena, embracing 
 as these do all animate as well as inanimate 
 
LECTURES ON GEOGRAPHY 
 
 nature, requires a knowledge of physical 
 science both wide and deep. But though 
 this be true, it puts no serious difficulty in 
 the way of imparting a thoroughly sound 
 general or elementary knowledge of results 
 already attained, to those who from want of 
 leisure, or perhaps of capacity, are unable to 
 extend their knowledge farther. Nor need 
 such acquaintance with the subject be either 
 superficial or of small value. In every 
 branch of learning the student has to rely 
 on the researches and conclusions of those 
 who cultivate other branches of knowledge. 
 In this respect geography in no way differs, 
 except in degree, from other natural sciences, 
 in all of which it is found that, as knowledge 
 increases, the subject-matters proper to each 
 are necessarily involved with those constitut- 
 ing the special subjects of investigation in 
 other fields. From the great extent of 
 human knowledge, the special branches into 
 
I SUPPLIES CONNECTED VIEW OF NATURE 13 
 
 which it is divided have become very numer- 
 ous ; and from the rapid progress in recent 
 times, the difficulty of prosecuting original 
 research in more than a single branch is so 
 much increased, that it becomes continually 
 more important to obtain in a connected 
 form the best possible view of the aggregate 
 result obtained. It should be the aim of 
 scientific geography to supply this, as re- 
 gards all the phenomena observed upon the 
 earth, so far as they depend upon the 
 material globe and the features of its surface ; 
 and to this end I think the teaching of 
 the University should be directed. 
 
 It will of course be understood that it 
 is to persons who have acquired a sound 
 elementary knowledge of the subject, such 
 as is demanded by the University in all 
 other branches of study, that the teaching 
 now contemplated will be offered. Objec- 
 tions to including scientific geography in the 
 
14 LECTURES ON GEOGRAPHY i 
 
 course of an ordinary school education, 
 founded on the variety and complexity of 
 the subjects it involves, may without hesi- 
 tation be discarded. These objections have, 
 in truth, had their origin in the too general 
 absence of scientific knowledge which char- 
 acterised a generation that had not itself 
 received even an elementary education in 
 physical science, and which stood much in the 
 same position in regard to these matters as 
 that in which men who can neither read nor 
 write stand in regard to the world of letters ; 
 such views will no doubt be abandoned as 
 more rational methods of education are 
 adopted. 
 
 But it cannot be too emphatically stated 
 that this preliminary training in scientific 
 geography, to be effectual, must be founded 
 on, and combined with, thorough instruction 
 in the general topography of the globe. It 
 appears to me that there is some risk at the 
 
i ELEMENTARY TEACHING 15 
 
 present time of this important consideration 
 being lost sight of, in the reaction that has 
 set in against the merely formal system of 
 teaching geography in our schools, through 
 lists of names, involving little more than ill- 
 directed efforts of memory. I desire, there- 
 fore, to express a very decided opinion that 
 no greater mistake can be made in the in- 
 terests of education than to treat the teaching 
 of elementary geography as supplying the 
 occasion for giving indiscriminate instruction 
 on the various phenomena of which it affords 
 illustrations, and to which it is thus virtually 
 made to appear subordinate. It should be 
 so conducted as primarily to impart an accu- 
 rate knowledge of the main topographical 
 features of the entire earth, though with a 
 judicious addition of suitable instruction in 
 the physical, economical, and historical char- 
 acteristics of the various places, whose posi- 
 tions it is important to impress on the 
 
16 LECTURES ON GEOGRAPHY i 
 
 memory of the pupil. The acquisition of 
 really useful knowledge in the necessarily 
 limited time that can be devoted to ele- 
 mentary teaching in geography will assuredly 
 be much facilitated by avoiding trivial details 
 which have neither educational nor other 
 value, but which I fear constitute too large 
 a part of the so-called geography found in 
 our schoolbooks and taught in our schools ; 
 and it should never be lost sight of that 
 correct ideas cannot be conveyed to the 
 learner without constant reference to maps, 
 illustrated by frequent use of a globe. 
 
 The extended scope of geography, as I 
 have defined it, seems to me to afford no 
 sufficient reason for abandoning that well- 
 known name, and applying to the enlarged 
 field of study that I would throw open any 
 other designation than the old honoured one 
 of geography. I am not to be understood 
 as implying that the study of geography 
 
I LIMITS TO RANGE OF STUDY 17 
 
 requires the simultaneous or complete 
 mastery of all the branches of knowledge, 
 physical, biological, historical, or economical, 
 with which it has relation, or that the 
 teacher of geography should attempt to in- 
 clude them in his course of instruction. It 
 is obvious that it is only within certain re- 
 stricted limits that these subjects come into 
 contact with geography. My contention 
 simply is, that so far as the results obtained 
 through the study of such special subjects 
 indicate an interdependence between the 
 physical features of the earth and what 
 occurs upon it, that relation should be con- 
 stantly recognised as falling within the 
 province of geography. For reasons which 
 I shall endeavour to develop more fully 
 as I proceed, I am unable to draw any 
 hard and fast line between the material 
 earth and its manifold attributes ; and 
 much that is found upon the earth cannot 
 
LECTURES ON GEOGRAPHY 
 
 be properly understood otherwise than in 
 relation to its geographical and topographi- 
 cal features. 
 
 I therefore claim for geography, in the 
 sense that I have spoken of it, a place 
 among the natural sciences, as supplying 
 the needful medium through which to obtain 
 a connected and consistent conception of 
 the earth and what is on it, on the import- 
 ance of which I have already insisted. In 
 this respect the position of geography may 
 be looked on as analogous to that of mathe- 
 matics, a term to the use of which I never 
 heard an objection, though it is hardly pos- 
 sible to limit the extent of its range ; and, 
 following this analogy, it might be convenient 
 to give some such designation as Applied 
 Geography to the outlying portions of the 
 subject which connect it with other inde- 
 pendent branches of knowledge. 
 
i PROPOSED TREATMENT OF SUBJECT 19 
 
 In proceeding now to place before you 
 in a succinct form a connected view of the 
 matters lying within the range of scientific 
 geography, and which would supply the 
 subjects for University teaching, I shall first 
 direct your attention to the manner in which 
 our knowledge of the form and magnitude 
 of the earth has been acquired, and the 
 gradual extension of geographical explora- 
 tion has taken place. I shall then pass to 
 that part of the subject which treats of the 
 manifold phenomena exhibited by our planet 
 and its aerial envelopment, all of which are 
 determined, first, by the action of the great 
 physical forces, attraction and heat, con- 
 trolled by the earth's figure and its move- 
 ments on its axis and round the sun ; and 
 secondly, by the distribution of the sea and 
 land, and the configuration of the surface 
 of the latter above and below the sea- 
 level. Finally, I shall consider the rela- 
 
Lectures on geography 
 
 tions of vegetable and animal life with 
 past and present terrestrial features, and 
 the influence of geographical conditions on 
 
 man. 
 
 The intimate relation between geography 
 and astronomy is at once indicated by the 
 dependence of the geographer on the latter 
 science for a knowledge of the methods of 
 determining the magnitude and true form 
 of the earth, and of ascertaining position on 
 its surface. It is of the highest interest to 
 contemplate how man, many centuries ago, 
 with instrumental appliances of the rudest 
 description, and with no other aid than his 
 wonderful reasoning faculty, discovered by 
 observations of the apparent motions of those 
 heavenly bodies from which an impassable 
 gulf divides him, the figure and dimensions 
 of the globe on which he stands, of which he 
 had as yet seen but a very small part ; and 
 
RELATION TO ASTRONOMY 
 
 how he thence extended this knowledge to 
 the magnitude, the distances, and the laws 
 that regulate the movements of all parts of 
 the planetary system to which the earth 
 belongs. 
 
 Leaving the obscure origin of astronomical 
 conceptions to be sought for in Babylonia or 
 Egypt, it is to Greece that we turn to find 
 the first definite scientific opinions on these 
 subjects. Thales of Miletus, 640 years 
 before the Christian era, already taught that 
 the earth was a sphere. To his successor, 
 Anaximander, is attributed the invention of 
 maps ; and Pythagoras, the disciple of 
 Anaximander, is believed to have sug- 
 gested the true doctrine of the revolution 
 of the earth on its axis and round the 
 sun, though this conception, which is de- 
 scribed by Cicero in very clear language 
 as having been adopted by the school 
 of Pythagoras established in the Greek 
 
LECTURES ON GEOGRAPHY 
 
 colonies in Italy, dropped out of sight for 
 centuries. 
 
 Eratosthenes, of the Greek school of 
 Alexandria, in the third century before Christ, 
 executed what was probably the first mea- 
 surement of the magnitude of the earth, 
 adopting for the purpose, in principle, the 
 method still in use. He observed the sun's 
 meridional altitude at the time of the solstice 
 both at Syene and Alexandria, which are 
 nearly on the same meridian, and thence 
 deduced the angular distance of the zeniths 
 of those two places, which represented the arc 
 of the terrestrial meridian between them ; 
 from which, knowing their distance from one 
 another measured in stadia, the standard in 
 use in his day, he calculated the length of 
 the entire terrestrial meridian, and the earth's 
 radius, in terms of his standard, our ignor- 
 ance of the exact value of which, how- 
 ever, prevents our knowing what degree of 
 
I GREEK SCHOOL OF ASTRONOMY 23 
 
 accuracy he attained. This astronomer also 
 first determined the obliquity of the ecliptic, 
 or the angle made by the plane of the earth's 
 equator with that of its orbit, thus supplying 
 the key to the cause of the succession of the 
 seasons of the year. 
 
 Hipparchos, of the same school, who lived 
 a century later, was the greatest of the Greek 
 astronomers, and his additions to the science 
 were truly remarkable. He discovered the 
 precession of the equinoxes, or the periodical 
 change of direction of the earth's axis from 
 east to west, in the opposite direction to its 
 motion in its orbit ; also the eccentricity of 
 the sun's apparent orbit, and the inequality 
 of its apparent motion, and he calculated 
 its distance from the earth. To him are 
 due the methods of calculating triangles, 
 spherical as well as rectilinear, the system 
 of fixing geographical position by means 
 of latitude and longitude, and the method of 
 
24 LECTURES ON GEOGRAPHY 
 
 calculating longitudes from eclipses of the 
 moon. 
 
 An interval of 300 years followed 
 which records little progress calling for 
 notice. It is, however, marked by the 
 rectification of the Roman calendar, by the 
 introduction of the leap year, carried out by 
 Julius Caesar, with the aid of an astronomer 
 of the school of Alexandria ; and the recog- 
 nition of the dependence of the tides of the 
 ocean on the apparent movements of the 
 moon and the sun, attributed to Posidonios. 
 
 Ptolemy, about 150 A.D., was the last 
 eminent man of this school. He adopted 
 the sound principle of constructing geogra- 
 phical maps or charts from latitudes and 
 longitudes, determinations of which for all 
 known places he tabulated with this object. 
 But these data were to a great extent vague 
 and inaccurate ; and his results, though given 
 a scientific form, did not rest on any scientific 
 
I ENDING WITH PTOLEMY 25 
 
 basis of fact. He is better known, however, 
 by his treatise on Astronomy, the MeyakT) 
 %wTdf;i<}, which long continued to be the great 
 authority on such subjects, and which caused 
 his name to be given to the conceptions of 
 the solar system it contained, though these 
 were really due to his predecessors. He 
 taught that the sun, moon, and planets 
 moved round the earth in what is known as 
 a system of epicycles, the several bodies 
 revolving in circular orbits round centres, 
 which in turn revolved in circles round the 
 earth — a view which was accepted till the 
 time of Copernicus. 
 
 From the time of Ptolemy until the six- 
 teenth century, a space of 1400 years, no 
 progress of any importance was made towards 
 the formation of more correct ideas of the 
 relation of the earth to the celestial system to 
 which it belongs. The study of astronomy 
 was revived, however, in the ninth century 
 
26 LECTURES ON GEOGRAPHY i 
 
 after Christ, among the Arabs. Al-Mamun, 
 the son of the famous Khalif, Harun-al- 
 Rashid, caused the treatise of Ptolemy to be 
 translated into Arabic, in which shape it 
 became known as the Almagest; he also 
 undertook the measurement of a degree of 
 the meridian on the plains of Mesopotamia ; 
 and it was mainly through the teaching of 
 the schools established by the Mahommedans 
 in Spain, and thence transmitted to Italy and 
 diffused in Europe, that the knowledge 
 already acquired was retained and eventually 
 so vastly extended. 
 
 The revival of learning, and the material 
 progress of the States of Europe during the 
 thirteenth and subsequent centuries, gave a 
 fresh and powerful impetus to the spirit of 
 investigation and exploration that had so 
 long remained in abeyance, and were followed 
 by a remarkable series of scientific and geo- 
 graphical discoveries. 
 
i COPERNICUS TO NEWTON 27 
 
 A little after 1500 a.d. Copernicus put 
 forth the view — this time to be finally 
 accepted — that the earth and planets move 
 round the sun. The discoveries made 
 almost simultaneously by Galileo and Kepler 
 at the commencement of the seventeenth 
 century completed and corroborated this 
 theory, and so opened the way for that 
 explanation of the whole series of astrono- 
 mical phenomena by the operation of the law 
 of universal attraction, which is due to the 
 genius of Newton, and which was published 
 in the Principia in 1687. 
 
 A great impulse was given to precise 
 geographical knowledge by Galileo's inven- 
 tion of the telescope, and by the application 
 of the pendulum to clocks by Huyghens 
 and of spiral springs to watches by Hooke. 
 The employment of these instruments sup- 
 plied the means for obtaining greatly increased 
 accuracy in astronomical and geodetic observa- 
 
28 LECTURES ON GEOGRAPHY I 
 
 tions ; while the invention of logarithms by- 
 Napier, 1 6 14, was a most important aid to 
 progress by facilitating all computations. 
 More exact determinations of the dimensions 
 and figure of the earth soon followed. 
 
 The measurement of an arc of the 
 meridian near Paris by Picard, 1669, with 
 the help of improved instruments furnished 
 for the first time with telescopes, led to 
 attempts to verify by actual measurements 
 Newton's theory of gravitation, as applied to 
 the form of the earth and its attractive force. 
 For this purpose the French Academy, 
 in 1735, sent out expeditions to Quito on 
 the Equator, under Bouguer and De la 
 Condamine, and to Lapland within the 
 Arctic circle, under Maupertuis. The 
 measurements thus obtained were supple- 
 mented by Lacaille at the Cape of Good 
 Hope in 1752, and those originally made by 
 Picard were repeated and extended. The 
 
I FRENCH GEODETIC OPERATIONS 29 
 
 operations thus carried out finally established 
 the fact of the earth's ellipticity, by means of 
 combined geodetic and pendulum observa- 
 tions ; the former showed the smaller length 
 of a degree of the terrestrial meridian at the 
 Equator and its gradual increase in advanc- 
 ing towards the poles ; and the latter proved 
 the increase of the force of gravity at the 
 surface with increase of latitude, as indicated 
 by the time of vibration of the pendulum, 
 which was found to increase or diminish as 
 the distance from the earth's centre is greater 
 or less. Nothing then remained to be done 
 in this direction but to attain results of 
 greater precision, by the employment of 
 better methods in detail, and of improved 
 instrumental appliances. 
 
 The geodetic operations commenced by 
 the French Academicians were extended to 
 England in 1783 : since which time many 
 other arcs of the meridian and of circles of 
 
30 LECTURES ON GEOGRAPHY I 
 
 latitude have been measured in Europe, Asia, 
 and America ; and geodetic surveys of great 
 accuracy have been extensively carried out, 
 forming the basis of most modern maps. 
 
 The dimensions of the earth, adopted by 
 our latest, and I believe our best authority, 
 General Clarke, are as follows : — Polar radius, 
 3949.79 statute miles; equatorial radius, 
 3963.30 statute miles; ellipticity, 13.51 
 statute miles, or ^^. The radius of the 
 mean sphere approximating most closely to 
 the ellipsoid is 3959 miles, its diameter is 
 very nearly 7920 miles, and the length of a 
 degree on such a sphere is 69.09 miles. 
 
 The exact determination of the figure of 
 the earth, and of the relative positions of 
 places on its surface, on which the accuracy 
 of all delineations of its features in maps 
 depends, is a task involving many difficulties 
 and calling for rare abilities in the geodetic 
 
i DIMENSIONS AND FIGURE OF EARTH 31 
 
 surveyor. It is not likely that the results 
 obtained from the measurements already 
 made will be found to require any but very 
 slight correction hereafter, and future varia- 
 tions will probably represent little more than 
 discrepancies due to actual irregularities in 
 the figure of the globe, which often bear a 
 by no means unimportant ratio to the devia- 
 tion of the elliptical from a spherical form, the 
 difference between the equatorial and polar 
 radii of the terrestrial ellipsoid being only 
 about 13^ miles. 
 
 Among the causes of the uncertainty that 
 attends such measurements, other than those 
 just referred to, one specially calling for 
 notice is the variation of the direction and 
 force of gravity, due to local attraction by 
 mountains, or to variations in the density of 
 the interior of the earth. As variations in 
 the force of gravity depend not only on 
 distance from the centre of the earth, but also 
 
32 LECTURES ON GEOGRAPHY I 
 
 on the greater or less density of the interior, 
 difficulties arise in distinguishing to which of 
 these two causes the effects are due. The 
 observed facts have led to the conclusion that 
 gravity is invariably greater at coast than at 
 inland stations, and greater on islands than on 
 the coasts of continents. Moreover, while 
 this indicates greater density below the ocean- 
 bed, there is reason to think that the density 
 is reduced among mountains, for the deviations 
 of the plumb-line from the vertical caused 
 by them are found to be considerably less 
 than would be due to local attraction, unless 
 the mountain density be less than that of the 
 earth's crust below. It has been argued, 
 with apparent reason, that this varying 
 density may be due to an actual contraction 
 and condensation of the ocean-beds, in some 
 degree corresponding to their depth ; and to 
 an expansion and attenuation of the land- 
 masses corresponding to their elevation. 
 
I IRREGULARITIES OF FORM 33 
 
 The want of regularity in the earth's figure 
 is not confined to the solid surface, but 
 necessarily extends to the ocean surface, 
 which must be affected by the local variations 
 of attraction, though the exact amount of the 
 disturbances will apparently remain unknown, 
 at least to a great degree. It has been 
 calculated that, under certain assumed condi- 
 tions as to the relative density of the sea and 
 land, the effect of the absence of land between 
 the Indian Peninsula and the South Pole, 
 combined with the attraction of the Himalaya 
 Mountains and the high land of the Peninsula, 
 would be to raise the level of the sea surface 
 at Karachi as much as 500 feet above that at 
 Cape Comorin. But it is possible that the 
 smaller density of the land above the sea- 
 level, and the greater density below the 
 ocean bottom, may wholly or partially 
 compensate for the irregular distribution of 
 the land and sea, so that the ocean-level may 
 
 D 
 
34 LECTURES ON GEOGRAPHY i 
 
 not in fact be thus disturbed. The conclusion 
 however, cannot be avoided, that measure- 
 ments of heights above the sea -level as 
 commonly stated, though fairly comparable 
 one with another over a limited area, are 
 subject to no little uncertainty if regarded as 
 absolute quantities referred to the ideal sea- 
 level of the mean terrestrial ellipsoid. 
 
 The conceptions of the Greeks as to the 
 form of the earth, and the manner of deter- 
 mining position on its surface, were for 
 many centuries very imperfectly applied to 
 the preparation of maps. Methods of 
 calculating latitude, and instruments suitable 
 for applying these methods, were compara- 
 tively soon devised. The difficulty of 
 obtaining differences of longitude was far 
 greater, and could not be completely over- 
 come until correct clocks were constructed. 
 The determinations of latitudes were slowly 
 
EARLY MAPS 35 
 
 accumulated, while those of longitude long 
 remained extremely imperfect. So far as is 
 known, there would appear to be only one 
 map now existing attributable to the period 
 of Imperial Rome, referred to the third 
 century, though itineraries in a graphic form 
 were in common use. The Arabs added 
 something to the art of map-making between 
 800 and 900 a.d. The use of the magnetic 
 needle for navigation is believed to have been 
 first generally adopted in Europe about 1 200 
 a.d., and it was about the middle of the 
 thirteenth century that " compass " maps were 
 devised, the earliest representing the Medi- 
 terranean, showing the bearings between 
 various maritime stations, and indicating the 
 courses to be followed in sailing from one 
 port to another. The idea current in the 
 Middle Ages, that the inhabited earth was 
 circular, much impeded progress in the 
 preparation of correct maps. This has 
 
36 LECTURES ON GEOGRAPHY i 
 
 destroyed much of the value of the great 
 map of Fra Mauro, 1459, now in the Ducal 
 Palace at Venice. The most remarkable and 
 almost unique attempt to represent the then 
 known facts of geography, without such 
 theoretical distortion, is the Catalan Map in 
 the French National Library, dating from 
 1375. Lines of latitude and longitude are 
 believed to have been first introduced upon 
 maps by the Portuguese, when voyages in 
 the Atlantic began to be frequent, probably 
 between 1400 and 1 500. The earliest printed 
 map appeared in 1460, following the invention 
 of printing, and by 1500 maps had become 
 common. The first maps seem to have been 
 brought to England in 1489, and almanacks 
 were first printed in 1470. 
 
 The construction of charts on Mercator's 
 projection, invented by Gerhard Kramer in 
 1537, and improved by Wright, who sub- 
 stituted for the original approximate method 
 
1 ART OF NAVIGATION 37 
 
 a strictly correct graduation of the arcs of 
 latitude along the lines representing meridians, 
 may be regarded as the commencement of 
 scientific map-making, and it rendered possible 
 a very great advance in navigation. The 
 charts thus drawn were adopted by navigators 
 generally by 1600, and have continued in use 
 without modification to the present time, nor 
 does this system of projection seem to be 
 susceptible of improvement for the purposes 
 of the seaman. 
 
 Treatises on navigation first appeared 
 about 1537 in Portugal, and 1580 in Hun- 
 gary, and were introduced in England by 
 Wright in 1600, in which year also the 
 use of the log for measuring the speed of 
 ships was invented, and a knowledge of the 
 variation of the compass was acquired soon 
 after. Up to this time the only instruments 
 used at sea for astronomical observations had 
 been the cross-staff and astrolabe ; with the 
 
38 LECTURES ON GEOGRAPHY i 
 
 former, angular distances from the horizon 
 could be obtained only by looking in two 
 directions, and with the latter by help of a 
 plummet. The invention of the reflecting 
 quadrant by Hadley in 1730, when perfected 
 by the application to it of the telescope, the 
 vernier, and the accurately divided circles which 
 the progress of mechanical art provided, and 
 when further supplemented by improved time- 
 pieces, placed at the disposal of the navigator 
 all that he needed to enable him, in fixing 
 his position at sea, to apply the exact methods 
 of computation with which the astronomers 
 supplied him. Maskelyne in 1 763 perfected 
 the method of obtaining the longitude by 
 measuring distances of the moon from stars, 
 and the publication of the Nautical Almanac, 
 also due to him, commenced in the year 
 1 767. It was in 1 760 that Harrison received 
 the sum of ^20,000, for the successful con- 
 struction of a chronometer suitable for use at 
 
ITS PROGRESS 39 
 
 sea, and capable of supplying a reliable 
 measure of changes of longitude by means 
 of a comparison between its indications and 
 local time. For this, great accuracy was 
 essential, a difference of 3^ seconds of time 
 corresponding to a distance in longitude of 
 about one statute mile at the Equator, and 
 half that distance in latitude 6o°. In this 
 manner was attained the long-sought solution 
 of the most difficult problem of navigation, to 
 obtain which large rewards were for many 
 years publicly offered. 
 
 The science of navigation was thus created 
 and matured, by the help of the discovery of 
 the telescope, and the progress of mechanical 
 art, which produced instruments capable of 
 measuring angular distances and time with 
 great precision. 1 1 has supplied the means by 
 which in our time the skilful mariner passes 
 to the most distant parts of the globe in com- 
 plete security, at a speed which now makes 
 
40 LECTURES ON GEOGRAPHY 1 
 
 every part of the habitable seaboard, however 
 remote, more accessible than were many places 
 in our own islands hardly a century back. 
 
 But to admit of such triumphs, the accurate 
 representation of the features of the earth's 
 surface by charts or maps was essential ; and 
 the representation in a rigorously accurate 
 manner on a plane, such as a sheet of paper, 
 of a figure drawn on a spherical surface, being 
 necessarily impossible, much ingenuity has 
 been applied in devising the best methods 
 for approximating to the truth. 
 
 Reference has already been made to 
 M creator's projection of the sphere. On this 
 system the meridians are all drawn parallel 
 to one another, the pole being conceived to 
 be infinitely distant from the Equator, and 
 the circles of latitude being represented by 
 straight lines parallel to the Equator and at 
 right angles to the meridians. The gradu- 
 
i MERCATOR'S PROJECTION 41 
 
 ation of the meridians is so arranged that 
 everywhere on the chart the proportion 
 between the length of a degree of latitude 
 measured on the meridian, and of longitude 
 measured on the lines representing circles of 
 latitude, is the true proportion as it actually 
 subsists on the globe. It follows from this 
 construction (and this constitutes its special 
 utility to the seaman), that a straight line 
 drawn in any direction on the map represents 
 a course on the globe which everywhere cuts 
 the meridians at the same angle ; so that the 
 course of a ship may at once be laid down 
 upon the chart on any given bearing, and 
 will be correctly represented by a straight line 
 drawn with the required inclination to the mer- 
 idian through the place from which the ship 
 starts. Upon any known course and for a run 
 of any given length, the difference of latitude 
 between the point where the run began and 
 that where it ended, may be obtained by the 
 
42 LECTURES ON GEOGRAPHY I 
 
 help of tables prepared for the purpose, and 
 thus the ship's place at the end of the run 
 may readily be marked on the chart. 
 
 For other purposes than those of navi- 
 gation this projection is likely to be extremely 
 misleading. The degrees of the meridian, 
 instead of being uniform in length, as they 
 would be on any scale to which maps can be 
 drawn, appear to increase with the latitude, 
 till at the pole they become infinite; while 
 degrees of longitude measured on the small 
 circles of latitude, instead of diminishing in 
 the higher latitudes, and vanishing at the 
 pole, are made to appear constant, and every- 
 where equal to degrees of the Equator. Hence 
 the magnitudes of all parts of the map in the 
 higher latitudes are very greatly exaggerated 
 in relation to the equatorial regions, which 
 alone are in proper proportion, and the non- 
 convergence of the meridians leads to great 
 misrepresentations of true relative position. 
 
1 OTHER PROJECTIONS OF SPHERE 43 
 
 This projection must indeed be looked 
 on rather as a diagram prepared for a special 
 purpose than as giving even an approximately 
 true representation of the earth's surface. 
 In this respect, however, it differs only in 
 degree or manner from other projections in 
 use, by aid of which attempts are made to 
 represent large areas, such, for instance, as 
 that employed to exhibit the earth in two 
 hemispheres. Some projections are in the 
 nature of perspective drawings, and are 
 therefore necessarily faulty in the sense of 
 their topographical accuracy. 
 
 On the whole, the method of projection 
 or development known as the conical is 
 the easiest to follow, and usually open to 
 fewest objections. In this the surface of 
 the part of the sphere to be represented 
 is supposed to be covered by a conical 
 surface, which cuts the spherical surface 
 along two small circles of latitude inter- 
 
44 LECTURES ON GEOGRAPHY I 
 
 mediate between the upper and lower margin 
 of the area to be dealt with. Places on the 
 sphere are then represented on the conical 
 surface by the intersection of that surface 
 with lines drawn from the earth's centre 
 through those places. The meridians 
 appear as straight lines converging to a 
 point, and the circles of latitude as arcs 
 of concentric circles everywhere intersecting 
 the meridians at right angles. The sup- 
 posed conical surface being then conceived 
 to be unrolled, supplies a map on a plane 
 in the usual form ; while if bent into its 
 proper conical shape it will represent, within 
 the limits that are possible for a flat surface, 
 the true relative positions of places on the 
 spherical surface. 
 
 Many more or less complicated methods 
 have been devised for adjusting the sup- 
 posed conical surface to the portion of the 
 sphere to be represented, in the manner 
 
I CONICAL DEVELOPMENT 45 
 
 which shall lead to the least possible distor- 
 tion or local exaggeration. But there is not 
 much, if any, reason to prefer any of these 
 to an arrangement which assumes the cone 
 to cut the sphere in two places, respectively 
 half-way between the extreme north and 
 south ends of the central meridian and the 
 centre point of that meridian. 
 
 A convenient modification of this develop- 
 ment is the following : — The degrees of 
 latitude are to be set off along the central 
 meridian upon any desired scale, and of 
 uniform length, and the meridian -lines are 
 then to be drawn so that arcs of longi- 
 tude measured along the circles of latitude 
 described through the points where the 
 cone cuts the sphere shall have their true 
 length in relation to the arcs of latitude. 
 If L and / represent respectively the lati- 
 tudes, expressed in degrees, at which the 
 conical surface is supposed to intersect 
 
46 LECTURES ON GEOGRAPHY I 
 
 the sphere, then the distance of the centre 
 of the concentric circles of latitude to be 
 drawn on the map, measured from latitude 
 L along any meridian, and expressed in 
 degrees, will be 
 
 ( L -/)«f c ; sL A 
 
 v^cos / - cos Ly 
 
 On such a projection the aggregate error is 
 a minimum ; distances measured from north 
 to south would everywhere be correct, while 
 the errors in measurements from east to west 
 on a map embracing the whole of England 
 would not exceed 14 feet in a mile in 
 latitude 50°, or 17 feet in latitude 60°, 
 both being in excess of the truth. In a map 
 of Europe, extending from latitude 70° to 
 35°, the error in measurements from east 
 to west would be about five per cent at the 
 top of the map, and three per cent at the 
 bottom, both in excess, and on the middle 
 latitude about one per cent in defect. 
 
I REPRESENTATION OF MOUNTAINS 47 
 
 For maps of the Polar regions another pro- 
 jection is most convenient. The meridians 
 converge to the pole, and the circles of 
 latitude are drawn concentrically around the 
 pole. Degrees of latitude are measured 
 uniformly along the meridians. The errors 
 of distances measured on the circles of 
 latitude are about three per cent in excess 
 at latitude 6o°, and about ten per cent at 45". 
 
 Much still remains to be done in perfecting 
 the method of representing mountain features 
 on maps. The conception of indicating the 
 relief of the surface by contours drawn along 
 lines of equal altitude above the sea-level is 
 understood to be due to Laplace, and is 
 admirably well suited for many purposes. 
 The ordinary system of shading with short 
 transverse lines is difficult of execution, and 
 fails properly to distinguish such features 
 as elevated plateaus. A method, recently 
 adopted, of indicating altitude by a grada- 
 
48 LECTURES ON GEOGRAPHY i 
 
 tion of shades of colour, the borders of the 
 shades following suitable contour-lines of 
 level, appears to furnish the best solution 
 of the difficulty yet proposed, for maps to 
 which it is possible to apply it. 
 
 And here let me dwell for a moment 
 upon the very great practical value of those 
 compendious contrivances for conveying 
 information to the mind, diagrams and 
 drawings, which are little, if at all, less 
 valuable than written language. Their 
 special power consists in bringing clearly 
 within the reach of apprehension, at the 
 same moment and in suitable juxtaposition, 
 numerous objects interdependent but differ- 
 ent, and so producing an intelligent con- 
 nected conception of the whole, often without 
 effort, and always with a clearness that no 
 verbal description could secure. I desire to 
 invite particular attention to this subject, 
 feeling assured of the high utility of the 
 
i VALUE OF DIAGRAMS 49 
 
 graphical representation of facts in dealing 
 with the many complicated phenomena that 
 present themselves to the scientific student 
 of geography. To comprehend maps or 
 diagrams is within the reach of all, and a 
 certain fair facility for making them may be 
 acquired as readily as the art of writing. 4 
 Man is distinguished from all other animals 
 by the faculty of speech ; he is also the 
 only drawing animal. These faculties cor- 
 respond with the two ultimate modes by 
 which it is possible for ideas to be com- 
 municated apart from actual experience, and 
 he who possesses and exercises both, vastly 
 increases his power both of acquiring and 
 imparting knowledge. 
 
LECTURE II 
 
 Progress of geographical discovery — Operation of physical forces on 
 terrestrial phenomena — Influences of the form and movements 
 of the earth — Terrestrial magnetism — Relation of geology to 
 geography — The terrestrial sphere and its interior. 
 
 Having thus followed the growth of our 
 knowledge of the earth's figure, of the art of 
 navigation and the preparation of maps, I 
 pass on to notice the parallel onward course 
 of geographical discovery. 
 
 In many other branches of science the 
 successive steps by which knowledge has 
 been advanced bear little on the ultimate 
 results arrived at, which are complete in 
 themselves, and constitute a body of fact 
 having no necessary relation to the persons 
 
GEOGRAPHICAL DISCOVERY 51 
 
 by whom, or to the manner in which it was 
 collected. But geography presents itself in 
 a different light. Geographical discovery, 
 followed as it immediately was by political 
 movements affecting great masses of man- 
 kind, assumes an extremely important part in 
 the history of man, there being, indeed, 
 no country which has not been influenced 
 by the course of discovery during the last 
 400 years ; and it can hardly be doubted 
 that had Columbus, for instance, made his 
 famous voyages under the flag of England 
 instead of Spain, which seems to have been 
 at one time possible, the history of modern 
 Europe would have been very different. 
 
 The study of geography, like that of 
 astronomy, first took a definite shape in 
 Greece. The earliest geographical concep- 
 tions, upon which the gradually increasing 
 knowledge of the civilised world was en- 
 grafted, were necessarily based on ideas 
 
52 LECTURES ON GEOGRAPHY n 
 
 of position in relation to the locality where 
 the ancient geographers lived and wrote, 
 namely, the eastern end of the Mediterranean 
 Sea ; here the Phenicians, the earliest 
 of European navigators, had established 
 the centre of their commerce, extending 
 their voyages to the Red Sea and Persian 
 Gulf on the east, and the coasts of 
 Britain on the west. Herodotus, writing 
 450 years before the Christian era, may be 
 taken as the exponent of the earlier forms of 
 Greek geography. The junction of the 
 Mediterranean with the Atlantic was then 
 known ; ideas of the North and West of 
 Europe were vague; the form and position 
 of the Caspian were fairly ascertained ; the 
 descriptions of India did not extend beyond 
 the Upper Indus; and the coasts of Asia 
 seem to have been unknown beyond the 
 Persian Gulf. Herodotus speaks of the cir- 
 cumnavigation of Africa, but it may be 
 
II TO TIME OF ALEXANDER 53 
 
 doubted whether this was more than 
 mythical. It is a curious illustration of the 
 result of absence of effective publication, that 
 though Herodotus had a just general notion 
 of the form of the Caspian, Ptolemy entirely 
 misconceived it, and it was not recovered 
 till within the last 200 years. 
 
 Alexander's expedition, 330 B.C., passing 
 through Asia Minor, Persia, and Bactria, 
 reached the Indus, where his traces and those 
 of his successors are still to be found, and 
 the Greek names given to some of the great 
 geographical features of the country he passed 
 through are still in use on our maps. Of the 
 Greeks who accompanied him some went 
 into India Proper; while Nearchus on his 
 return followed the coast from the Indus to 
 the Persian Gulf, and ascended the Tigris 
 beyond Baghdad. The successors of Alex- 
 ander's captains in the Bactrian kingdom, 
 which they founded, extended their knowledge 
 
54 LECTURES ON GEOGRAPHY n 
 
 to Eastern India, and one of their envoys 
 visited Palibothra, believed to be Patna, on 
 the Lower Ganges. About the same time 
 Carthage, originally a Phenician colony, 
 which had become the most important 
 maritime power in the Mediterranean, 
 appears to have sent expeditions along the 
 western coast of Africa, reaching perhaps to 
 the Equator, while its ships also visited 
 France and are said to have sailed round 
 Britain. The trade between Egypt and the 
 east was maintained from Berenice in the 
 Red Sea, and other ports at the mouth of 
 the Persian Gulf, of which Hormuz was the 
 mediaeval representative, and through them 
 the commerce with Europe was carried on. 
 
 Up to the Augustan age the only addi- 
 tions to geography were obtained through 
 the Roman conquests in Western and 
 Northern Europe. In the time of Pliny the 
 coasts of Asia had hardly been described 
 
II TO END OF TWELFTH CENTURY 55 
 
 with certainty beyond the mouths of the 
 Ganges, and only vague conceptions of 
 China had been formed. These ideas had 
 become more defined, and extended to the 
 Malay Peninsula, Sumatra, and Java, by the 
 time of Ptolemy, 150 a.d. 
 
 Till the end of the twelfth century the 
 further progress of geographical, like that of 
 all other branches of knowledge, was very 
 inconsiderable. Something was done by the 
 Arab geographers in the early period of the 
 growth of Mahommedan power, and some- 
 thing by Norwegian Vikings whose voyages 
 extended to Iceland, Greenland, and event- 
 ually to the coasts of North America. But 
 in the thirteenth and following centuries, 
 when the civilisation of Europe was becoming 
 consolidated, a more active spirit of enter- 
 prise was gradually awakened. 
 
 The formation of the powerful republics 
 of Venice and Genoa, and the spread of their 
 
56 LECTURES ON GEOGRAPHY n 
 
 commerce under the stimulus of many 
 causes, of which the Crusades may be 
 reckoned as one of the most prominent, was 
 followed by a development of maritime 
 habits, knowledge, and enterprise among the 
 nations bordering the Mediterranean, which 
 was destined to produce great results. 
 
 The institution of the orders of friars, the 
 desire to spread Christianity, and the terror 
 produced by the incursions of Jenghiz Khan 
 into Eastern Europe, were followed by 
 journeys, of which one of the most remark- 
 able was that of the monk Rubruquis, 1253 
 a.d., into Central Asia. The growth of 
 commercial activity sent forth the Polos, 
 1265, on similar expeditions, which extended 
 to Mongolia and China. The friar Odoric, 
 1320, visited Persia, Western India, Sumatra, 
 and Java, as well as China, returning by 
 Tibet, and was the first European to reach 
 Lhassa. Thence he travelled by Cabul and 
 
ii EARLY TRAVELS IN ASIA 57 
 
 Tabriz to Venice. His accounts are unques- 
 tionably the basis of much that is found in 
 Sir J. Mandeville's travels, which there is 
 great reason to think are mainly, if not 
 wholly, fictitious. 
 
 Among the travellers of this period should 
 also be specially mentioned Ibn Batuta, an 
 Arab of Tangier, 1325-55, who, after visiting 
 Egypt and Arabia, went through Persia, 
 Afghanistan, and India, whence he was sent 
 by Muhammad Toghlak, then king of Delhi, 
 on an embassy to China. He travelled 
 thither by sea down the west coast of India 
 to the Maldives and Ceylon, and on through 
 the Eastern Archipelago to China. His 
 journeys are reckoned to have extended over 
 75,000 English miles. 
 
 Thus we are brought to the eve of that 
 great series of voyages which are the glory 
 of the fifteenth and sixteenth centuries, and 
 among the most remarkable events recorded 
 
58 LECTURES ON GEOGRAPHY n 
 
 in history ; they opened out the way to 
 Eastern Asia round the Cape of Good Hope, 
 and added in the west a new continent to 
 the known world. 
 
 The honour of taking the initiative rests 
 with the Portuguese. Soon after 141 5 a 
 course of maritime exploration was entered 
 on, and continued for many years under 
 Prince Henry, which led to the successive 
 discoveries of Madeira, the Azores, the Cape 
 de Verd Isles, and by 1484 extended 
 along the west coast of Africa beyond the 
 Equator. In i486 King John sent out 
 Diaz to endeavour to reach India by sea, the 
 belief having become established that this 
 could be done by passing round the continent 
 of Africa ; but this expedition advanced little 
 beyond the Cape of Good Hope. 
 
 Eleven years later, and two years after 
 Columbus had returned from his first voyage, 
 Vasco da Gama, the largest of whose ships 
 
II PORTUGUESE DISCOVERY 59 
 
 did not exceed 120 tons burden, doubled the 
 Cape of Good Hope, and passing along the 
 east coast of Africa to Mozambique and 
 Mombasa, crossed the Arabian Sea and 
 arrived on the western coast of India, near 
 Calicut, in 1498 a.d. Cabral in 1500, on his 
 way to India by the same route, discovered 
 the coast of Brazil. Many similar voyages 
 followed, and in the course of the next few 
 years the western and eastern coasts of Africa, 
 and the shores of the Arabian Sea, were 
 explored ; the islands of St. Helena, Tristan 
 da Cunha, Madagascar, Socotra, Bourbon, 
 and Mauritius were made known ; and the 
 Portuguese under Albuquerque had estab- 
 lished themselves at numerous places along 
 the coast of Arabia and India, making Goa 
 the seat of their government. Their advance 
 to Malacca immediately followed, and they 
 explored Sumatra, Java, and the much 
 coveted Spice Islands or Moluccas, their 
 
6o LECTURES ON GEOGRAPHY n 
 
 ships reaching China for the first time in 
 1 5 14. Their settlements at Macao, near 
 Canton, date from 1537. Thus in less than 
 fifty years from the discovery of the Cape of 
 Good Hope the Portuguese had opened out 
 the whole of the coasts of Africa and Southern 
 Asia as far as China, as well as a large part 
 of the Eastern Archipelago. 
 
 Almost simultaneously, Spain, adventurers 
 from which had already reached and occupied 
 some of the Canary Isles, entered on a course 
 of discovery and conquest still more remark- 
 able. After the final triumph of Ferdinand 
 over the Moors, the perseverance of Columbus 
 was rewarded by the acceptance of his pro- 
 posals to attempt to reach the Indies by 
 sailing across the Atlantic, in the hope of 
 thus finding a shorter route than that which 
 the Portuguese were seeking round the 
 continent of Africa. 
 
 It was in 1492 a.d. that Columbus, guided 
 
n SPANISH DISCOVERY 61 
 
 by a truly scientific course of induction, for 
 the first time so applied by any navigator, 
 embarked on the first of the celebrated 
 voyages which resulted in the discovery of 
 the land which was at the outset supposed 
 to be the eastern shore of Asia ; an error 
 largely due to mistaken reliance on Ptolemy's 
 vastly exaggerated estimate of the longitude 
 of those shores, and on distances deduced 
 from the itineraries of Marco Polo and other 
 travellers. From the first newly-discovered 
 islands, ever since known as the West Indies, 
 advances were soon made to the neighbouring 
 coasts of the continent along the narrow 
 isthmus between the gulfs of Darien and 
 Panama, and the discovery of the Pacific 
 Ocean by Nunez de Balboa followed in 
 15 13. The accounts of this were received 
 with an interest little less keen than that which 
 had followed the discoveries of Columbus, 
 indicating as it did the existence of another 
 
62 LECTURES ON GEOGRAPHY n 
 
 great ocean still intervening between the new 
 continent found by Columbus and Eastern 
 Asia. The exploration of the Gulf of 
 Mexico, and the entry of Cortez into that 
 country in 1520, and its final conquest, 
 followed in rapid succession. In 152 1 the 
 first advances were made along the shores of 
 the Pacific; Peru was first seen in 1526, 
 Pizarro landed there in 153 1, and the whole 
 of that country and Chili were shortly added 
 to the Spanish kingdom. 
 
 Meanwhile the discovery of Nunez had 
 led to the despatch of an expedition under 
 Magellan, a Portuguese who had sailed under 
 Albuquerque, but had entered the service 
 of Spain in order to undertake the enter- 
 prise of reaching the shores of Asia by 
 passing round the extremity of the new 
 continent, and crossing the lately-discovered 
 Pacific Ocean. This object he successfully 
 carried out. The Straits now called after 
 
THE PACIFIC 63 
 
 Magellan were passed in 1520, and first the 
 Ladrone Islands and then the Philippines 
 were discovered, where Magellan was killed 
 in a conflict with the natives. His com- 
 panions, however, continued their voyage, 
 and passing through the Indian Archipelago, 
 where the Portuguese had already established 
 themselves, one of the ships, which alone sur- 
 vived, reached Spain again in 1522, having 
 for the first time in the history of man ac- 
 complished the circumnavigation of the globe. 
 
 The enterprise of Spain thus completed 
 that great work of maritime discovery in 
 which Portugal took so honourable a share, 
 and which in a period of less than fifty years 
 had led to the acquisition of a fairly accurate 
 knowledge of the distribution, on the surface 
 of the earth of the principal areas of land and 
 sea in their main features. 
 
 It was soon after the commencement of 
 this course of discovery, 1494, that an agree- 
 
64 LECTURES ON GEOGRAPHY n 
 
 ment was come to by Spain and Portugal, for 
 the division between the two nations of the 
 newly-discovered parts of the world. This 
 was submitted to the Pope for his sanction, 
 and a Bull was accordingly issued by Alex- 
 ander VI, which declared that a line should 
 be drawn from pole to pole, across the globe, 
 ioo leagues, (afterwards removed to 370 
 leagues,) west of the Azores and Cape de 
 Verd Islands, and that all newly-discovered 
 territories to the east of this line should fall 
 to the share of Portugal, all those to the west, 
 to Spain. This arrangement determined the 
 direction given to the voyages undertaken 
 by the two countries. The line proposed is 
 nearly on the 50th meridian west of Green- 
 wich, and the corresponding line in the other 
 hemisphere is on the 1 30th meridian east. Its 
 adoption as a boundary served to confirm 
 Portugal in its occupation of Brazil ; but 
 subsequently led to a conflict as to the right 
 
n COAST OF NORTH AMERICA 65 
 
 of Spain to the Philippines and Moluccas 
 which lie along the 120th meridian. It is a 
 singular circumstance that the Pope was once 
 more referred to, only a year or two ago, to 
 arbitrate on the occasion of a dispute with 
 Germany as to the territorial rights of Spain 
 over the Caroline Islands ; and, if I mistake 
 not, the Bull of Alexander was adduced as 
 evidence in the discussion. 
 
 Before the end of the sixteenth century 
 the exploration of the western shores of the 
 North Atlantic as far as the polar seas had 
 been completed by English and French 
 sailors. The earliest English voyages of 
 discovery are those of Cabot, believed to 
 have been a Venetian, who had settled at 
 Bristol in the reign of Henry VII. In 1494, 
 when in search of a north-west passage to the 
 Indies, he reached Newfoundland, and his 
 sons sailed along the American coast as far 
 south as Florida, already known through the 
 
66 LECTURES ON GEOGRAPHY n 
 
 Spaniards. Frobisher and Davis, 1576-85, 
 explored Labrador and the west coast 
 of Greenland, and entered the bay now 
 called after Baffin, who in 161 6 penetrated 
 still farther, and reached lat. 78° N., but only 
 to find the way onward blocked with ice, and 
 impracticable. 
 
 In the latter part of the same century the 
 Spaniards sent several expeditions from Peru 
 across the Pacific, still seeking the Philip- 
 pines and far-famed Spice Islands, and for 
 the first time visited various groups of islands 
 in that ocean, the Marquesas, the Society 
 Islands, and the New Hebrides. Drake, 
 1577, passing through Magellan Straits, ex- 
 tended his explorations up the western coast 
 of America as far as California, and for the 
 second time accomplished the circumnaviga- 
 tion of the earth. 
 
 So far as the great geographical features 
 of the globe are concerned, all that 
 
AUSTRALIA 67 
 
 remained to be done was to define the 
 position and extent of the continent of 
 Australia, and this was virtually accomplished 
 by the Dutch in the next half century. The 
 voyages of the Dutch into the Eastern Seas 
 began about the year 1600, and this enter- 
 prising nation by degrees displaced the 
 Portuguese from their possessions in the 
 Eastern Archipelago, establishing themselves 
 in their place, and in this position they still 
 remain. A Dutch expedition bound for the 
 Eastern Islands first determined, 16 16, the 
 true extremity of the South American con- 
 tinent by rounding Cape Horn. The northern 
 and parts of the western coasts of Australia 
 were explored by the Dutch in 1627. In 
 1642 Tasman sailed round Australia ; he first 
 discovered what he named Van Diemen's 
 Land, but which is now called Tasmania 
 after him, believing it to be a portion of the 
 mainland, and subsequently New Zealand, 
 
68 LECTURES ON GEOGRAPHY n 
 
 whence he passed on through the Fiji and 
 Solomon groups, by New Britain and round 
 New Guinea. In 1606 Torres, a Spanish com- 
 mander, in a voyage from Peru, had already 
 reached the north-east angle of Australia, 
 and, passing through the straits which now 
 bear his name, had sailed up the south-west 
 coast of New Guinea, thus showing that the 
 extreme north-eastern limit of Australia had 
 here been reached. 
 
 It is worthy of notice that all the voyages 
 across the Pacific were directed almost along 
 the same line, from the extremity of South 
 America towards New Guinea, doubtless 
 with the object of reaching the Moluccas or 
 Philippines, which, from a belief in the wealth 
 there to be acquired by commerce and plunder, 
 had become the centre of attraction to all 
 classes of adventurers, whatever flag they 
 flew ; and to this cause may be attributed 
 the circumstance that the geography of Aus- 
 
II SEPARATION OF ASIA FROM AMERICA 69 
 
 tralia and the Northern Pacific was not made 
 known until a comparatively late period. 
 
 With the latter part of the seventeenth 
 century we reach the period when a spirit of 
 commercial enterprise in a great degree 
 replaced the old spirit of adventure and love 
 of conquest, which had stimulated the earlier 
 voyages of discovery. Concurrently with 
 this change a great development of scientific 
 knowledge had taken place, and expeditions, 
 mainly for purposes of scientific discovery 
 and investigation, began to be despatched to 
 many distant or little known parts of the 
 earth. Of the results of these it is only 
 necessary to refer specifically, first, to the 
 discovery by Behring, in 1728, of the straits 
 separating Asia from America, through which 
 Cook also, fifty years later, after traversing 
 the Pacific from south to north, penetrated 
 as far as lat. 70° 40' N., when he was stopped 
 by ice ; and, second, to the fact established 
 
70 LECTURES ON GEOGRAPHY n 
 
 by the last-named great navigator, that, what- 
 ever land there may be around the South Pole 
 does not extend beyond the Antarctic circle. 
 
 A position had by this time been, reached 
 in which the further progress of geography 
 chiefly required a more exact delineation of 
 details, and the extension into the interior of 
 the great continents of the explorations 
 which at first had to so considerable an 
 extent been confined to the sea-coasts. In 
 this labour the services of France and 
 England were most conspicuous until the 
 commencement of the present century. As 
 we approach the present time, there has been 
 a general co-operation among all civilised 
 nations in the advancement of geographical 
 knowledge, and the scientific value of the 
 work done by explorers both by land and 
 sea became greater, as the full extent of 
 the requirements of scientific investigation 
 were more completely realised. 
 
n REGIONS STILL UNEXPLORED 71 
 
 So thorough is the success with which 
 these labours have been prosecuted that 
 it would be impossible for me here to 
 describe what is known of the earth, other- 
 wise than by pointing to what is still un- 
 known, and this may be summarised in a 
 very few words. 
 
 Besides the interior of Borneo and New 
 Guinea, and the portion of Central Africa 
 where Stanley is for the present moment lost 
 to view, no considerable part of the earth's 
 surface is unexplored, with the exception of 
 the polar regions, which have till now proved 
 inaccessible. The maps of the interior of 
 Africa now supply trustworthy representations 
 of a vast system of rivers, lakes, and mount- 
 ains, till recently wholly unknown to the 
 civilised world, and what remains to be 
 done is little more than to fill in the de- 
 tails of well -ascertained outlines. Australia 
 has been crossed and recrossed in many 
 
72 LECTURES ON GEOGRAPHY II 
 
 directions. The darkness which so long 
 enveloped Central Asia has been entirely 
 cleared away, and though parts of Tibet are 
 yet to be visited, the true nature of that 
 remarkable country, and of the central plain 
 lying between it and Siberia is completely 
 known. The geographical features of North 
 America are little less perfectly mapped than 
 those of Europe; but large parts of the 
 interior of South America, much of which is 
 covered by forest, are still unsurveyed. The 
 southern border of the North Polar Sea and 
 the very complicated system of islands and 
 channels along the northern margin of the 
 American continent, between Behring Strait 
 and Greenland, have been precisely delineated, 
 and the boundary of the same sea along 
 Northern Asia has also been determined. 
 The highest northern latitude" reached is 
 about 83^° N., which is within 500 miles of 
 the Pole. The nearest approach to the 
 
ii OPERATION OF PHYSICAL FORCES 73 
 
 South Pole has been in 78 n' S., but the 
 difficulties arising from climate have till now 
 stood in the way of any satisfactory or 
 comprehensive survey of the land seen at 
 some few points in the Antarctic area. 
 
 I have thus far traced in broad outlines 
 the manner in which our present knowledge 
 of the form and magnitude of the earth, and 
 of the features of its surface, has been 
 acquired in the course of many centuries by 
 the mental and physical efforts of a long 
 succession of remarkable men, to a few only 
 of whom was it possible that I should make 
 special reference. The part of my subject 
 to which I shall next ask your attention will 
 principally regard the operation on the in- 
 organic constituents of the globe of the great 
 physical forces, gravity, heat, and chemical 
 affinity, which control and determine its 
 movements, form, and constituents, and 
 
74 LECTURES ON GEOGRAPHY u 
 
 underlie the distribution of land and sea 
 and all the conditions of its surface. 
 
 The figure of the earth, and its existing 
 features, have had their origin in a former 
 state of the planet, during which it has been 
 subject to the gradual changes that accom- 
 panied its cooling from a previously much 
 higher temperature. The forces of nature 
 which are still at work, including the most 
 wonderful of all, life, have operated upon the 
 globe while it thus passed through the stages 
 which have led to what it now is ; producing 
 varied conditions of surface, from which have 
 arisen as direct consequences, differences of 
 climate, and corresponding variations in the 
 forms and distribution of living creatures, 
 vegetable and animal. Thus it is that while 
 every part of the earth has its own character- 
 istics, the general system of nature is one and 
 the same everywhere ; the special characters 
 of the several regions being due to the action 
 
ii EFFECTS OF EARTH'S MOTION AND FORM 75 
 
 of local features or conditions, which are no 
 sooner called into existence than they in turn 
 become secondary efficient causes of the 
 infinitely varied phenomena that our globe 
 presents to us. In this manner has been 
 evolved the face of nature as we now see it — 
 nature which, working with never-varying 
 forces, appears to man in the present as his 
 type of stability, whilst it is constantly lead- 
 ing, through ever-varying forms, from the 
 hidden shapes of an impenetrable past to 
 those of an unknown future. 
 
 The dominant influence of the movements 
 and figure of the earth, which may every- 
 where be traced among the phenomena 
 brought to our knowledge by the more and 
 more complete exploration of its surface, first 
 calls for special notice. 
 
 The diurnal and annual motions of the 
 globe, subject to the effects of the spherical 
 form of the earth and the direction of its axis 
 
76 LECTURES ON GEOGRAPHY it 
 
 of rotation, determine at all parts of its 
 surface the amount of heat and light received 
 from the sun, and thus regulate all the 
 conditions of existence upon it ; they give 
 rise to the varying length of days and of 
 seasons at different places, and to a multitude 
 of recurring phenomena which characterise 
 or influence the animate and inanimate world. 
 In whatever direction we turn are to be 
 found alternations of what may be termed 
 terrestrial work and rest ; day and night, 
 summer and winter, periodical winds extend- 
 ing over longer or shorter periods, seasons 
 of rain and dry weather. The tides of the 
 ocean, and the less apparent, though not less 
 regular, periodical oscillations of the atmo- 
 sphere, as well as the little understood 
 variations in terrestrial magnetism, are con- 
 sequences of the same general causes. All 
 nature, indeed, is subject to them. Under 
 their control the ocean currents flow, the 
 
ii DIRECT EVIDENCE OF ROTATION 77 
 
 rivers rise and fall, the fields yield their 
 harvests, the mountains are covered with 
 snow, the florets of the daisy close and 
 open, and the lark and nightingale pour forth 
 their song ; they regulate the migrations and 
 hibernations of animals, the daily labours of 
 man and beast, the hours of active life and 
 sleep, the increase and decrease of births, 
 disease and death. 
 
 Though many of the diurnal changes thus 
 observed would equally follow as conse- 
 quences of the sun moving round a stationary 
 earth, yet it is not difficult to find direct 
 evidence, which immediately appeals to the 
 senses, of the rotation of the earth on its 
 own axis. This is very completely supplied 
 by what is known as Foucault's experiment, 
 which is performed by means of a pendulum 
 consisting of a somewhat heavy plummet 
 attached to a long and slender string, which 
 therefore has a long period of oscillation, 
 
78 LECTURES ON GEOGRAPHY n 
 
 while the direction of its motion, when 
 swung, is not liable to disturbance by torsion 
 of the suspending string. If such a pendulum 
 be set in motion, with suitable precautions, 
 over a line drawn on the earth's surface, it 
 will be found that the direction of oscillation 
 gradually departs from that of the line over 
 which it commenced, the divergence being 
 caused by the gradual change of the absolute 
 direction of the line, consequent on the 
 revolution of the earth on its axis ; a change 
 not communicated to the pendulum, which, 
 being only connected with the earth by 
 means of the flexible string, continues to 
 swing in the same absolute direction as that 
 given to it when it was first set in motion. 
 The apparent angular motion of the pendulum 
 will be equal, but opposite in direction, to 
 the angular motion of the earth on its axis 
 multiplied by the sine of the latitude of the 
 place where the pendulum is swung ; which 
 
n EVIDENCE FROM WIND AND CURRENTS 79 
 
 at London would give an angular velocity 
 of i° in about five minutes. This, with a 
 pendulum that swung through an arc of 10 
 feet, would produce an apparent displacement 
 of about 2 inches in ten minutes, taking 
 place from south, round by west, north, and 
 east. 
 
 The movements of the atmosphere and 
 of the currents of the ocean supply evidence 
 of the same truth, though in a less obvious 
 manner. The air and water at the earth's 
 surface, when undisturbed, everywhere acquire 
 the velocity of rotation of the globe, which 
 is dependent on the latitude, being greatest 
 at the equator and diminishing gradually 
 towards the poles. The velocity thus ac- 
 quired gives an apparent eastward impulse 
 to all air or ocean currents moving from the 
 equator towards the poles, and an apparent 
 westward impulse to air and water moving 
 the other way. This had long been re- 
 
80 LECTURES ON GEOGRAPHY n 
 
 cognised as the true cause of the directions 
 of the trade winds and monsoons. More 
 recently the same cause has been seen to be 
 universally operative, the direction of the 
 south-west and north-east gales that charac- 
 terise our own coasts, for instance, being due 
 to the passage over our islands of areas of 
 low or high pressure, which, according as 
 they give rise to currents of air from the 
 south towards the north, or vice versa, 
 produce winds with westerly or easterly 
 tendencies. The revolving winds or cyclones, 
 which are developed within the tropics in so 
 intense a form, also carry with them a terrible 
 testimony to the true direction of the earth's 
 rotation on its axis from west to east. 
 
 The remarkable force inherent in the 
 globe, known as terrestrial magnetism, which 
 gives a determinate direction to a freely 
 suspended magnetic needle, and is of inestim- 
 
II TERRESTRIAL MAGNETISM 81 
 
 able value to man, has long been the subject 
 of observation and study. The general 
 properties of the magnetic needle were 
 known and applied to navigation by European 
 sailors early in the eleventh century, but 
 much earlier by the Chinese. The fact that 
 the direction of the needle deviates from the 
 true north, such deviation being termed its 
 variation or declination, was probably known 
 before the time of Columbus ; but to him is 
 due the first record of the gradual change 
 which takes place in passing from one place 
 to another, he having observed in his voyage 
 across the Atlantic that the variation which 
 had at first been easterly at length became 
 westerly. At an early period also, 1576, the 
 dip of a properly balanced magnetic needle, 
 or the inclination from the horizon at which 
 it comes to rest, had been observed by Nor- 
 man, an Englishman, as well as the fact that 
 this angle also varies with geographical position. 
 
 G 
 
82 LECTURES ON GEOGRAPHY n 
 
 The conception that the earth itself is a 
 magnet, and gives the needle its direction, is 
 due to Gilbert, also an Englishman, about 
 1600 a.d. Halley, who, in 1676, had visited 
 St. Helena to make astronomical observations, 
 and in 1698 undertook a special voyage to 
 study terrestrial magnetism, first put -forward 
 a consistent theory of the variation of the 
 compass. His final conclusions, based upon 
 his own observations and all available data 
 derived from other navigators, were published 
 in 1 701, when he showed that the com- 
 plicated movements of the needle might be 
 referred to the influence of four foci of 
 magnetic force — two in the vicinity of either 
 pole of the earth — a view which, with some 
 qualifications, subsequent investigation has 
 confirmed. 
 
 Halley's conclusions were derived from a 
 comparatively small number of observations 
 of the declination and dip alone, measure- 
 
n MAGNETIC POLES 83 
 
 ments of the intensity of magnetic force not 
 having at that time been made. This force, 
 too, is now known to vary from place to 
 place. The more ample collection of facts 
 relating to both intensity and direction, since 
 brought together from all parts of the earth, 
 has led to somewhat modified views as to 
 the phenomena of terrestrial magnetism. It 
 is now established that there are two mag- 
 netic poles, one in each hemisphere, at which 
 the needle would point vertically upwards 
 and downwards. Their position, which is 
 not coincident with the geographical poles, 
 is found to have varied according to some 
 yet unknown law. In the year 1878 the 
 northern pole was in lat. 70° N., long. 96° 
 W., and the southern in lat. 73^° S., long. 
 147^° E. Between these poles, a line that 
 has been termed the magnetic equator, where 
 the needle assumes a horizontal position, is 
 found to pass round the earth, following an 
 
84 LECTURES ON GEOGRAPHY n 
 
 unsymmetrical line which, in 1878, lay 
 almost wholly to the north of the terrestrial 
 equator in the hemisphere east of Green- 
 wich, and to the south of it in the western 
 hemisphere. 
 
 It further appears that the magnetic force 
 is not evenly distributed on the earth, and 
 that the points of maximum intensity do 
 not coincide with either of the magnetic 
 poles. In the northern hemisphere there 
 are two foci of maximum force of unequal 
 intensity, the more powerful lying at about 
 lat. 52° N., long. 92° W., near the great 
 American lakes, the weaker in lat. 65 N., 
 long. 115° E., in Siberia. For the southern 
 hemisphere, the available data are far , less 
 numerous, and the determination of the foci 
 of force is less complete. It is, however, 
 believed that here also there are two points 
 of maximum, of nearly equal power, and 
 not far removed from one another, one in 
 
FOCI OF FORCE 85 
 
 lat. 65 S., long. 140 E., the other in 
 lat. 50° S., long. 120° E. 
 
 The unit by which magnetic force is 
 measured has been assumed, adopting 
 English standards of weight and length, 
 to be that which would impart to a weight 
 of one grain a velocity of one foot in one 
 second of time. On this scale the magnetic 
 force, where least, is found to be 6.0 ; the 
 northern maxima are 14.2 and 13.3 re- 
 spectively, and each of the southern 15.2. 
 
 The declination or variation of the direc- 
 tion of the needle from the true meridian is a 
 consequence of these unequal forces operating 
 upon it, the westerly or easterly tendency 
 of the needle (as the case may be) following 
 the geographical position of the place of 
 observation in its relation to the several 
 foci of force, with a general result of con- 
 siderable complexity. Up to the sixtieth 
 parallel of latitude, north or south, the 
 
86 LECTURES ON GEOGRAPHY n 
 
 declination, whether easterly or westerly, 
 rarely exceeds 30° ; and, speaking generally, 
 it is easterly in the Pacific and westerly in the 
 Atlantic and Indian Oceans. Near the poles, 
 where the dip is high, the directive force 
 of the earth's magnetism is much reduced, 
 and the magnetic needle becomes compara- 
 tively untrustworthy and of little use. 
 
 As what is termed the north pole of a 
 magnetic needle or bar, attracts the south 
 pole and repels the north pole of another 
 needle, the magnetism of the earth at the 
 north pole should strictly speaking be called 
 south polar, and vice versa. To avoid 
 confusion from this cause, the north and 
 south poles of the needle are now frequently 
 termed the red and blue poles respectively. 
 It may also be mentioned that magnetic 
 declination is always measured from the 
 true north, being described as positive when 
 westerly, and negative when easterly. 
 
n NATURE OF MAGNETISM 87 
 
 The nature and mode of operation of 
 magnetism, and the allied phenomena of 
 electricity, continue to be subjects of specu- 
 lation, no explanation of them having yet 
 been proposed such as that which refers 
 heat and light to the vibrations of an elastic 
 medium. Our knowledge of the phenomena 
 of terrestrial magnetism therefore still re- 
 mains in the empirical stage ; they are, how- 
 ever, held to show that the earth's mag- 
 netism is distributed through its mass, and 
 that the magnetic force resides either wholly 
 or mainly in the interior, and cannot be 
 attributed to external influences, though it 
 may be affected by them. Local variations 
 of this force are not unfrequently found to 
 accompany the presence of certain rocks in 
 the subjacent strata, but how far geograph- 
 ical features have any influence on its general 
 distribution is doubtful. 
 
 Observation shows that all the elements 
 
LECTURES ON GEOGRAPHY 
 
 of the earth's magnetism vary not only from 
 place to place, but from time to time ; the 
 variations being in some cases periodical 
 and dependent on the time of the day or 
 the season of the year, and in others 
 extending, with no apparent tendency to 
 periodicity, over considerable lengths of 
 time. The gradual alteration of the declina- 
 tion at London was first noticed in 1622, 
 and the diurnal variations in 1722, in which 
 year also the first attempt was made to 
 measure the magnetic force. The manner 
 in which these variations occur is still a 
 matter of investigation, and their causes are 
 doubtful, but the diurnal and annual changes, 
 which are small in extent, are probably 
 connected with changes of the temperature 
 of the earth or its atmosphere, and may be 
 influenced by geographical conditions. The 
 non- periodical changes that have been re- 
 corded are very large. For instance, the 
 
ITS VARIATIONS 89 
 
 declination in England, having been n° 15' 
 E. in 1580, became 24° 34' W. in 1820, and is 
 now 18° 30' W. The dip has changed from 
 71" 50' in 1576, to 74° 42' in 1723, and again 
 to about 67§° at the present time. These 
 variations have been attributed by some to 
 changes going on in the condition of the 
 interior of the earth, and by others to external 
 influences ; but they continue to be among 
 the most obscure of physical phenomena. 
 
 Besides the variations above-mentioned 
 there also arise other irregular disturbances 
 of the magnetic needle, of short duration, 
 which are sometimes spoken of as magnetic 
 storms. They occur with a frequency which 
 shows a tendency to periodicity, diurnal or 
 annual, and often almost simultaneously at 
 distant parts of the earth, with nearly identical 
 effects, and with a marked increase in inten- 
 sity with increase of latitude. They likewise 
 exhibit a period of increase and decrease 
 
90 LECTURES ON GEOGRAPHY n 
 
 coinciding with that observed in the sun-spot 
 area, thus giving additional reason to connect 
 them with modifications of the magnetic or 
 electric condition of the earth or atmosphere 
 arising in some manner from the action of 
 the sun. The probable connection of these 
 disturbances with the. electrical condition of 
 the atmosphere is indicated by their frequent 
 occurrence simultaneously with appearances 
 of the aurora, and with electrical earth-currents. 
 The frequent, if not continuous, display of 
 the aurora in the vicinity of the magnetic 
 poles, further suggests a relation between 
 the electrical and magnetic conditions of 
 the earth. The true nature of all these 
 phenomena is, however, still very imperfectly 
 ascertained. 
 
 As the form and movements of the earth, 
 and the distribution of the land and sea upon 
 it, became more completely known, and as 
 
ii RELATION OF GEOGRAPHY TO GEOLOGY 91 
 
 the conceptions arising from their study were 
 more clearly developed, inquiry was naturally 
 extended to the nature of the terrestrial 
 sphere, and to the forces by the action of 
 which its surface has received its existing 
 outlines, elevations, and depressions. The 
 science of geology is the result ; and the 
 relation of geography to this science is what 
 we have next to consider. 
 
 A very little observation and thought 
 threw discredit on the ancient cosmogonies, 
 and showed that they failed to give any 
 satisfactory solution of the problems submitted 
 by the advance of knowledge. If the 
 extravagant myths of Asiatic origin, which 
 peopled the earth millions of years ago with 
 races of anthropomorphic demigods, and 
 heroes descended from the sun and 
 moon, could not bear the test of facts, 
 neither have those traditions fared better 
 which unveil the earth fully equipped with 
 
92 LECTURES ON GEOGRAPHY n 
 
 all the present forms of life and specially- 
 prepared to be the dwelling-place of man, 
 some few thousand years ago. Precise 
 observation has now supplied satisfactory 
 proof that the earth's surface, with all that is 
 on it, has been evolved through countless 
 ages, by a process of constant change. 
 Those features that at first sight appear most 
 permanent, yet in detail undergo perpetual 
 modification, under the operation of forces 
 which are inherent in the materials of which 
 the earth is made up, or are developed by its 
 movements, and by its loss or gain of heat. 
 Every mountain, however lofty, is being 
 thrown down ; every rock, however hard, is 
 being worn away ; and every sea, however 
 deep, is being filled up. The destructive 
 agencies of nature are in never-ceasing 
 activity : the erosive and dissolving power 
 of water in its various forms, the disintegrat- 
 ing forces of heat and cold, the chemical 
 
II EARLY CONDITION OF GLOBE 93 
 
 modification of substances, the mechanical 
 effects produced by winds and other agencies, 
 the operation of vegetable and animal organ- 
 isms, and the arts and contrivances of man, 
 combine in the warfare against what is. 
 
 But hand-in-hand with this destruction — 
 nay, as a part of it- — there is everywhere to 
 be found corresponding reconstruction, for 
 untiring nature immediately builds up again 
 that which it has just thrown down. If 
 continents are disappearing in one direction, 
 they are rising into fresh existence in 
 another. Though the ocean tears down the 
 cliffs against which it beats, the earth takes 
 its revenge by upheaving the ocean's bed. 
 
 When we look back, by the help of 
 geological science, to the more remote past, 
 through the epochs preceding our own, we 
 find complete evidence that the globe has 
 passed in succession through an infinitude 
 of anterior states, by means of small modi- 
 
94 LECTURES ON GEOGRAPHY n 
 
 fications extending over a vast period of 
 time, but not differing in essentials from 
 those which we see to be now going 
 on. There are still preserved to us the 
 remains of land and marine plants and 
 animals — which lived, produced successive 
 generations, and died — possessed of organs 
 proving that they were under the influence 
 of the heat and light of the sun ; indications 
 of seas whose waves rose before the winds, 
 breaking down cliffs, and forming beaches of 
 boulders and pebbles ; of tides and currents 
 spreading out banks of sand and mud, on 
 which are left the impress of the ripple of the 
 water, of drops of rain, and of the tracks of 
 animals ; of volcanoes pouring forth streams 
 of lava ; and all these appearances are 
 precisely similar to those we observe at the 
 present day as the result of forces which we 
 see actually in operation. Every successive 
 stage, as we recede in the past history of the 
 
ii RELATION TO OTHER HEAVENLY BODIES 95 
 
 earth, teaches the same lesson. The forces 
 which are now at work, whether in degrading 
 the surface by the action of seas, rivers, or 
 frosts, and in transporting its materials into 
 the sea, or in reconstituting the land by the 
 elevation of mountains, or by raising beds 
 laid out in the depth of the ocean, or in 
 volcanic eruptions, are traced as having 
 continued in action from the earliest times. 
 
 Pushing back our inquiries, we at last 
 reach the point where the apparent cessation, 
 or failure of evidence, of former terrestrial 
 conditions such as now exist, requires us to 
 consider the relation in which our planet 
 stands to other bodies in celestial space ; and, 
 vast though the gulf be that separates us 
 from these, science has been able to bridge it. 
 By means of spectroscopic analysis, it has 
 been established that the constituent elements 
 of the sun and other heavenly bodies are 
 substantially the same as those of the earth. 
 
96 LECTURES ON GEOGRAPHY n 
 
 The examination of the meteorites which 
 have fallen on the earth from the interplanet- 
 ary spaces, shows that they contain nothing 
 foreign to the constituents of the earth. 
 The inference seems legitimate, corroborated 
 as it is by the manifest physical connection 
 between the sun and the planetary bodies 
 circulating around it, that the whole solar 
 system is formed of the same kinds of matter, 
 and is subject to the same general physical 
 laws. These conclusions further support the 
 supposition that the earth and other planets 
 have been formed by the aggregation of 
 matter once diffused in space around the sun ; 
 that the first consequence of this aggregation 
 was to develop intense heat in the consolid- 
 ating masses ; that the heat thus generated 
 in the terrestrial sphere was subsequently 
 lost by radiation ; and that the surface at 
 length cooled and became a solid crust, enclos- 
 ing a nucleus of much higher temperature. 
 
II FORMER HIGK TEMPERATURE 97 
 
 The heat of the interior of the globe 
 increases about i° F. for every 50 or 60 feet 
 of depth below the surface. The surface 
 appears to have now reached a temperature- 
 which is virtually fixed, the loss of heat from 
 radiation into surrounding space being so 
 nearly compensated by the gain from the sun 
 as to make the present rate of cooling practi- 
 cally imperceptible. As the exterior gradually 
 cooled from its earlier condition, contractions 
 necessarily ensued, producing change of form 
 and dimensions ; and to these, acting in com- 
 bination with gravity, are, no doubt, largely due 
 the greater irregularities of the earth's surface. 
 The forces set up by these strains must have 
 continued to cause movements for a vastly pro- 
 longed period, and are doubtless still in action. 
 
 But the irregularities of the surface con- 
 stitute only a small part of the effects of 
 internal heat on the earth, and mineralogy is 
 the branch of science to which reference must 
 
 H 
 
LECTURES ON GEOGRAPHY 
 
 be made for a knowledge of the many simple 
 and compound substances that have issued, 
 under the operation of chemical forces, from 
 the vast laboratory contained within the cool- 
 ing crust of the once incandescent globe. 
 
 The solid nucleus of the earth, with the 
 ocean and the atmosphere, as we now find 
 them, may be regarded as the products 
 which have resulted after the globe, by 
 cooling, had attained a condition of practical 
 equilibrium, and after the more active process 
 of aggregation had ceased, and the combina- 
 tion of its elements, under the requirements 
 of the laws of affinity, into the various solid, 
 liquid, or gaseous matters found on or near 
 the surface, had been completed ; and it is not 
 a little remarkable that two residual collections 
 of matter, as I may term them, the air and 
 the sea, which constitute a mere film on the 
 solid earth's surface, should exercise so pre- 
 dominant an influence on terrestrial economy. 
 
u EFFECTS OF COOLING 99 
 
 During the passage of the globe to its 
 present state many wonderful changes must 
 have taken place. The ocean, after its 
 condensation from a condition of vapour into 
 that of liquid, must have long continued in 
 and bordered on a state of ebullition, sur- 
 rounded by an atmosphere densely charged 
 with watery vapour. Apart, however, from 
 the movements in the solid crust of the earth 
 caused by its gradual cooling and contraction, 
 and the character of its inorganic constituents, 
 its early higher temperature hardly enters 
 directly into any of the considerations that 
 arise in connection with its present condition ; 
 and it must probably ever remain doubtful 
 how long and to what extent former conditions 
 of climate which interest us most, as having 
 occurred during the period in which the 
 existence of life is indicated, were affected 
 by such early higher temperature. 
 
 In the absence of any direct means of 
 
LECTURES ON GEOGRAPHY 
 
 ascertaining the condition of the earth's 
 interior, aid has been sought from mathe- 
 matical science, by which it has been 
 established, that the thickness of the solid 
 outer shell of the earth must be considerable ; 
 and that if the interior is in a fluid state at all, 
 which is very doubtful, it must be covered by 
 a great thickness (probably not less than 
 several hundred miles) of solid, comparatively 
 unyielding matter ; and it is argued, with 
 apparent force, that no passage can exist by 
 which molten matter, if there be any, could 
 ascend from such depths to the surface. 
 Recent speculation has consequently sug- 
 gested that even volcanic phenomena may be 
 consequences of the heat developed by intense 
 pressures set up by the mechanical forces 
 concerned in the movements of the cooling 
 outer solid crust, and that they are not 
 immediate results of the very high tempera- 
 ture which almost certainly still subsists at 
 
VOLCANIC PHENOMENA 
 
 great depths in the earth's interior. A more 
 probable explanation would, however, seem to 
 be that by some local or partial removal of 
 pressure in the otherwise solid interior, a 
 portion of intensely-heated matter is able to 
 pass into the fluid state, and so finds a way 
 through some fissure to the surface. 
 
 It is still an open question among 
 geologists, whether the explosions accom- 
 panying volcanic eruptions, which are at 
 times of most extreme violence, are due to 
 gases generated in the formation of the 
 ejected melted matter, or to the sudden 
 conversion of water into vapour in cavities 
 containing such melted matter ; the latter 
 view being supported by the facts that great 
 volumes of steam are discharged by volcanoes 
 during eruptions, and that the majority of 
 active volcanoes are on islands, while those 
 on continents are near the sea. 
 
LECTURE III 
 
 The external features of the earth — The land, its distribution and 
 elevation — The ocean, its depth, currents, and tides — The 
 atmosphere — Phenomena of climate and their dependence on 
 the conditions of the earth's surface — Winds — Rain — Ice. 
 
 The subjects of which I last spoke related 
 to the globe viewed as a whole, and its in- 
 terior. I next pass to the consideration of 
 its exterior, with which geography is more 
 immediately concerned. 
 
 In the ocean we see the waters of the 
 earth accumulated, after their condensation 
 from a state of vapour, in pre-existing 
 depressions of the solid surface. We find 
 almost everywhere evidences of movements 
 of the earth's solid crust on a very large 
 
in EXTERNAL FEATURES OF EARTH 103 
 
 scale, and of frequent changes in the 
 distribution of land and sea. The great 
 continents include the areas that have last 
 risen above the sea, and clusters of islands in 
 many cases appear to indicate the remains of 
 former continents now disappearing. 
 
 The gradual building-up of the existing 
 face of the earth can be traced in the 
 succession of deposits, often of vast thickness, 
 collected around ancient land-surfaces ; and 
 indications are everywhere to be found of 
 subsidences and elevations, though apparently 
 without any altogether fundamental change 
 in the great features or relative positions of 
 the chief areas of land and sea, which seem 
 to have been preserved for very long periods ; 
 so that we may not improbably still see relics 
 of the earliest forms taken by the surface 
 soon after it attained a solid condition. 
 Movements such as these have continued till 
 the latest geological period, and there is 
 
104 LECTURES ON GEOGRAPHY JH 
 
 complete evidence that it was during this 
 epoch that mountains among the highest in 
 the world, the Himalaya and the Alps, 
 attained their present elevations. 
 
 Mountain ranges, which are due either to 
 pressures arising from irregular contractions of 
 the earth's crust, or to other internal forces 
 capable of producing an upward thrust, occur 
 in various forms. Frequently the areas of 
 elevation with which mountains are associated 
 cover very large tracts, and assume the 
 character of tablelands or plateaus, often 
 broken up by minor mountain ranges 
 or elevations following some determin- 
 ate direction. In the larger mountain 
 masses the valleys often appear to occupy 
 lines of rupture or fissure determined by the 
 tensions produced by the strains that gave 
 rise to the elevation ; and attempts have been 
 made to explain the characteristic directions 
 observed in the elementary portions of such 
 
LAND SURFACE 105 
 
 mountain masses, on mechanical principles. 
 In the case of areas of elevation long as 
 compared to their width, such as the 
 Himalaya and Tibet, the very constant 
 combination of long ridges and valleys with 
 shorter intervening transverse ruptures or 
 connections, may be thus accounted for ; and 
 it has been argued that radiating ridges and 
 valleys accompany a roughly circular area of 
 elevation. That valleys are very frequently 
 caused in great part, or wholly, by erosion, 
 due to the action of surface drainage or 
 ocean currents, especially in unconsolidated 
 deposits, is beyond dispute ; but even in such 
 cases their origin often appears to have been 
 in a fault or rupture of the strata through 
 which they pass. 
 
 The great masses of land which cover a 
 large part of the northern hemisphere are 
 connected around the north pole, and send 
 out diverging offshoots towards the south ; 
 
106 LECTURES ON GEOGRAPHY in 
 
 these, however, do not reach within 50 
 degrees of the south pole, with the exception 
 of a small portion of South America. 
 Generally speaking, the coasts of the con- 
 tinents rise steeply from great ocean depths, 
 and very frequently high land occurs along 
 or near their shores. In many cases the 
 mountain-chains which bound or traverse the 
 continents are of vast lineal extent, indicating 
 dislocations of the solid crust of the earth 
 which reach over very great distances and to 
 great depths, and their frequent parallel 
 direction suggests a probable association in 
 the causes and time of their production. 
 The usual distribution of volcanoes along 
 continuous lines, extending in many cases 
 over thousands of miles, can hardly be 
 explained otherwise than as being consequent 
 on the existence of ruptures in the solid crust 
 of the earth penetrating to very great depths. 
 The superficial extent of many of these 
 
in ELEVATION OF MOUNTAINS 107 
 
 dislocations of the earth's crust is not less 
 remarkable than their lineal development, 
 and leads to similar conclusions. Such were 
 the movements that raised the tablelands of 
 Asia Minor," Persia, and Afghanistan, and the 
 great desert plateau of Central Asia, and 
 above all, the huge protuberance of Tibet, 
 and its component gigantic mountain-chains, 
 including the Himalaya. The high lands in 
 both North and South America supply 
 evidence of the same nature. 
 
 There was at first no little disinclination 
 to accept theories which accounted for the 
 observed facts of geology by the continued 
 action through vast periods of time of forces 
 now in operation. But these objections have 
 at length disappeared, and with them the 
 school that explained the successive steps 
 which led to the great differences between 
 the past and the present, by a series of 
 catastrophes, or convulsions of nature, for 
 
108 LECTURES ON GEOGRAPHY in 
 
 which we have no authority in actual 
 experience. 
 
 Should any still hesitate to believe that 
 mountains like the Himalaya or the Andes, 
 and analogous depressions of the bed of 
 the ocean, can have been produced by a 
 mere secular change of the earth's tempera- 
 ture, I would remind them that the forces 
 called into action by the earth are propor- 
 tionate to its magnitude, and that their effects 
 must be on a corresponding scale. It has 
 been calculated on sound data that the 
 contraction of the diameter of the earth, 
 consequent on the fall of temperature from a 
 fluid state to its present condition, has been 
 about 190 miles. At this rate a subsidence 
 of 5 miles, which is the approximate 
 greatest depth of the ocean, would correspond 
 to a fall of temperature of about 200° F. 
 But the elevations and depressions of the 
 earth's surface were probably produced by a 
 
in INSIGNIFICANT RELATIVE TO GLOBE 109 
 
 comparatively much smaller loss of heat, and 
 were due rather to tangential strains than to 
 direct upthrust or subsidence. 
 
 An illustration may assist in forming a 
 proper estimate of the irregularities of the 
 earth's surface, which, though apparently 
 great, are insignificant when viewed in 
 relation to its actual dimensions. This hall 
 might contain a globe 40 feet in diameter. 
 If this globe represented the earth it would 
 be on a scale of one foot to about 200 miles ; 
 and one inch would be equivalent to a distance 
 of i6f miles, or 88,000 feet. On such a 
 globe the difference between the polar and 
 equatorial diameters would be less than one 
 inch, and the greatest elevations in Britain 
 would be about the thickness of a three- 
 penny-bit. The highest mountains and the 
 deepest seas would be shown by elevations 
 and depressions Of hardly more than one- 
 third of an inch ; and if they were distributed 
 
LECTURES ON GEOGRAPHY 
 
 as such features are on the earth, they would 
 be visible only with difficulty, and to the 
 unaided eyes of a casual observer would 
 hardly interfere with the apparent perfect 
 smoothness of the globe's surface. 
 
 The conception of the vast duration of 
 geological time is one with which -most 
 persons are now more or less familiar. It is 
 well to remember that great though the 
 changes in human affairs have been since the 
 most remote epochs of which there are 
 records in monuments or history, nothing 
 indicates that within this period there has 
 occurred any appreciable modification of the 
 main outlines of land and sea, or of the con- 
 ditions of climate, or of the general characters 
 of living creatures. The distance that separates 
 us from those days is as nothing when com- 
 pared to the remoteness of past geological ages. 
 No numerical estimate on which reliance can 
 be placed has yet been made of the duration 
 
in ESTIMATES OF GEOLOGICAL TIME in 
 
 even of that portion of geological time which 
 is nearest to us ; and we can say no more than 
 that the earth's past history, as recorded in 
 what we now find upon it, or as inferred 
 thence, probably extends over hundreds of 
 thousands or millions of years. 
 
 The duration of the successive ages of the 
 earth's past existence is measured almost 
 wholly by reference to the fossil remains of 
 animals and plants included in the rocks of 
 which the crust is composed. The likeness 
 of existing forms to those that characterise 
 each gradually receding period constantly 
 diminishes, and the more ancient shapes 
 which connect the present with the several 
 stages of the past, often, by their diffusion, 
 supply indications of the synchronism of 
 deposits at distant places. Light is thus 
 thrown, though it be an imperfect one, on 
 the former distribution of land and sea, and 
 on the existence of antecedent communica- 
 
LECTURES ON GEOGRAPHY 
 
 tions by land and sea between parts of the 
 earth now severed, or the converse. 
 
 It is through the facts of geography as 
 now acquired and interpreted, that the 
 geologist is supplied with the means of 
 arriving at the true signification of much 
 that occurred in past time, the traces of which 
 survive in physical features or organic forms. 
 He finds that the most important agencies 
 in determining and modifying the present 
 conditions of existence on the earth, whether 
 as affecting inorganic nature or organic 
 beings, are directly controlled by the actual 
 distribution of land and sea, and the con- 
 figuration of the surface ; and he learns that 
 it is by reference to these agencies that he 
 must seek to unravel the intricacies of the past. 
 
 The study of geology, in its turn, enables 
 the geographer to understand many things 
 that would otherwise be unintelligible to him. 
 He thus learns how the boundaries of sea 
 
in PAST EXPLAINED THROUGH PRESENT 113 
 
 and land have been determined ; where 
 connections formerly existing have been 
 severed ; how islands have risen from the 
 ocean and may be sinking below it ; to what 
 causes are due the rocky coasts and head- 
 lands, the indentations of the coasts, the 
 formation of bays and fiords ; at what time 
 and by what means mountains have been 
 raised up, plains laid out, valleys excavated, 
 and the courses of rivers and positions of 
 lakes fixed ; and he is taught the constituents 
 and qualities of the materials forming the 
 surface of the earth, of the soil upon it, and 
 of the minerals beneath it. 
 
 And as a better insight is obtained into 
 the natural relations of the mountains, the 
 plains, the valleys, rivers, lakes and seas, 
 the conviction arises that the ever-diversified 
 details of the face of the globe are in no 
 sense accidents or fortuitous results, little 
 worthy, as such, of admiration unless for 
 
ii4 LECTURES ON GEOGRAPHY in 
 
 their picturesque forms or wonderful proporr 
 tions ; but that they are the direct, orderly, 
 and necessary outcome of the action of forces 
 simple in themselves, and operating in ac- 
 cordance with well-known and invariable 
 physical and mechanical laws. The percep- 
 tion of general characteristics of structure 
 among the various features of the earth's 
 surface that pass under our review, is, 
 indeed, too often overshadowed and obscured 
 by their magnitude, by the multitude of their 
 details, and by the variety of their forms, 
 which at first produce impressions of hopeless 
 confusion ; but, when once the idea of sub- 
 ordination to common laws is duly conceived, 
 it receives confirmation at every fresh step 
 taken. 
 
 The area of the dry land is very greatly 
 exceeded by that which is covered with 
 water. The whole surface of the globe 
 
in AREA AND ELEVATION OF LAND 115 
 
 being 197 millions of square miles, about 55 
 millions are land, and 142 millions water. 
 The average height of the land above the 
 sea -level is also very much less than the 
 average depth of the sea-bottom below that 
 level ; so that a rearrangement of the surface 
 would be possible, by which the whole of the 
 land might be submerged with comparatively 
 little disturbance of the present level of the 
 sea, or reduction of its average depth. 
 
 The highest measured peak of the Hima- 
 laya, known as Mount Everest, which is also 
 the highest in the world accurately deter- 
 mined, just rises 29,000 feet above the sea- 
 level, but such elevations even as 15,000 
 feet, excepting on the Himalaya and in parts 
 of Tibet, are confined to isolated peaks or 
 very narrow bands along the crests of a few 
 of the highest mountain ranges. The area 
 above 12,000 feet is about two per cent of the 
 whole land, and that above 6000 feet less than 
 
ii6 LECTURES ON GEOGRAPHY m 
 
 nine per cent. From a careful computation 
 recently made, it would appear that the mean 
 height of the surface of the land above the 
 sea-level is about 2250 feet ; the continental 
 areas having the following elevations : — 
 Europe, 939 feet ; Asia, 3073 feet ; North 
 America, 1888 feet; South America, 2078 
 feet ; Australia, 805 feet. 
 
 The greatest depths measured in the 
 ocean exceed 27,000 feet, and it has been 
 estimated that the mean depth is about 
 12,500 feet. About five per cent of the ocean 
 area is less than 600 feet in depth, and a 
 somewhat smaller proportion more than 
 18,000 feet. About seventeen per cent is 
 less than 3000 feet. The ocean bed generally 
 appears to present very extensive, compara- 
 tively uniform plateaus, varied only by moder- 
 ate undulations possibly to be attributed to the 
 contractions of the earth's crust caused by its 
 original cooling ; these range in depth from 
 
in AREA AND DEPTH OF OCEAN 117 
 
 '1 
 
 12,000 to 17,000 feet, and their general 
 direction maintains a rough parallelism with 
 that of the neighbouring continents. Sub- 
 marine deposits derived from the land do not 
 extend beyond 300 or 400 miles from the 
 shores ; but at great depths deposits are 
 being formed with extreme slowness, which 
 are probably derived from decomposed 
 organisms, or from cosmic, volcanic, or other 
 matter, carried down through the water. 
 
 Accepting these estimates, it will appear 
 that the volume of land above the sea-level 
 is about x^th part only of the volume of the 
 ocean. This relatively very small volume 
 of land, and comparatively uniform great 
 depth of the sea over very large areas, when 
 considered in connection with the evidence 
 that exists of the continuity of the earth's 
 history within the range of geological time, 
 strengthens the view, based on other con- 
 siderations, that the chief masses of land as 
 
u8 LECTURES ON GEOGRAPHY m 
 
 we now find them have not greatly varied 
 from their original position. Owing to the 
 great depth of the sea, any upheaval of the 
 sea-bottom sufficient to form new land, 
 would be likely to displace a volume of water 
 greater than that of the new land, unless it 
 were accompanied by an equivalent subsid- 
 ence and increase of depth in some other 
 locality. Failing this, such an upheaval 
 would be followed by an encroachment of the 
 sea on the land, which would necessarily lose 
 an area corresponding, at all events approxi- 
 mately, with the volume of water displaced, 
 and the area thus lost might easily be greater 
 than that gained. 
 
 With the latest additions made to our 
 knowledge of the depth of the ocean there 
 has also been acquired an altogether new 
 series of facts bearing on its temperature, 
 and its capacity for supporting life. The 
 
in OCEAN TEMPERATURE 119 
 
 variations of heat and cold, due to change of 
 season or to day and night, which affect the 
 surface, descend to a comparatively small 
 depth, being greatly reduced in the first 100 
 fathoms, and below that depth for the most 
 part eliminated, so that at 300 or 400 
 fathoms an approximately uniform tempera- 
 ture is met with. With increased tempera- 
 ture at the surface there is increased 
 evaporation, followed by greater density, by 
 reason of which the surface water sinks, and 
 the higher surface temperature is partially 
 communicated to the subjacent strata. 
 Further, it appears that though the surface 
 temperature of the ocean varies generally 
 with latitude, reaching a maximum of 86°, or 
 perhaps a few degrees higher, yet at the 
 greatest depths, or say generally at 2000 
 fathoms (with an exception to be explained 
 immediately), the water has in all latitudes 
 a nearly constant temperature but little 
 
LECTURES ON GEOGRAPHY 
 
 above the freezing-point. This is mainly- 
 due to the flow of glacial water from the 
 Antarctic polar area towards the warmer 
 equatorial regions, along the sea -floor, to 
 which it sinks by reason of its greater 
 density. The exception referred to occurs 
 in the case of any area which is cut off by 
 an intervening shoal from communication 
 with the deep glacial waters. In such cases 
 the bottom temperature is determined by the 
 mean winter temperature of the surface, 
 unless the temperature of the external 
 oceanic water at the level of the shoal be the 
 lower of the two. Thus in the great basins 
 of the Pacific, Indian Ocean, and Atlantic, 
 which are of such a depth as to be in free 
 communication with the Antarctic seas, the 
 bottom temperature ranges from 32° F. to 
 36° F. In contrast with this, in the 
 Mediterranean, which is cut off from the 
 deep waters of the Atlantic by a shoal at a 
 
in MODERATES EXTREME CLIMATES 121 
 
 depth of about 200 fathoms, an effectual 
 barrier is interposed to the entrance of water 
 of a lower temperature than about 54° F. ; 
 and no lower temperature than 55 F., which 
 corresponds to the mean winter temperature 
 of the surface, is found even at 2000 
 fathoms. In the Red Sea a similar result is 
 observed, the bottom temperature not falling 
 below 71° F., at a depth of about 700 
 fathoms. 
 
 From the mobility of water, and its high 
 specific heat, which is almost four times that 
 of the materials composing the land-surface, 
 the sea-surface never acquires a very high 
 temperature. Moreover, the evaporation 
 which is constantly going on from the whole 
 surface of the ocean, leads to a large quantity 
 of the heat it receives from the sun becoming 
 latent, and powerfully aids in preventing an 
 accumulation of heat. These facts render 
 the ocean one of the most important factors 
 
LECTURES ON GEOGRAPHY 
 
 of terrestrial existence ; it furnishes to the 
 atmosphere the moisture which is one of the 
 essentials of life, and serves by the circulation 
 of its waters and the diffusion of vapour 
 derived from it, to equalise the temperature 
 of the globe by moderating the extremes 
 both of heat and cold. Hence the greater 
 or less proximity of the sea directly and 
 powerfully affects all conditions of climate. 
 
 The circulation of the waters of the ocean, 
 which is set up chiefly by the action of winds 
 on the surface, but in part by variations of 
 temperature and of density, and by the 
 effects of evaporation, is controlled in all its 
 details by geographical features. 
 
 The trade -winds, which maintain over a 
 large part of the ocean an almost constant 
 current of air in a westward direction between 
 the tropics, converging towards the equator, 
 give rise to the great equatorial oceanic 
 currents, which, impinging on the eastern 
 
in OCEAN CURRENTS 123 
 
 coasts 1 of the continents, are deflected to the 
 north and south along them, and tend to 
 establish systems of circulation in the several 
 oceanic basins, north and south of the 
 equator, and between the east and west 
 coasts of the continents between which 
 they lie. In the northern hemisphere the 
 movement is from south to north and east 
 along the eastern coasts, and from north 
 to south and west along the western coasts ; 
 while in the southern the direction is the 
 reverse, from north to south and east along 
 the eastern coasts, and from south to north 
 and west along the western coasts. These 
 currents from or to the equator conform 
 generally to the directions that would be 
 imparted to them by the rotation of the 
 earth, and no doubt acquire additional force 
 
 1 To avoid ambiguity I employ the term coast in con- 
 nection with the land, and shore in connection with the sea, 
 so that an east coast is a west shore. 
 
124 LECTURES ON GEOGRAPHY m 
 
 from this cause, particularly where the pre- 
 vailing winds blow in the same direction, as 
 they frequently do. 
 
 The most remarkable of the ocean currents 
 is, without question, that along the east coast 
 of North America, commonly spoken of as 
 the Gulf-stream. It acquires great persistency 
 from a combination of causes, which enables 
 it to carry a very high temperature into the 
 Arctic Circle to the north of Norway, and 
 most powerfully to influence the climate of 
 Western Europe, which hence offers an 
 astonishing contrast to that of the eastern 
 shores of the Atlantic in the same latitudes. 
 Thus the isotherms of sea-surface tempera- 
 ture, from 75° F. to 40° F., on the American 
 coast range in the summer months between 
 latitudes 35° and 45° N. ; that is, over about 
 10° of latitude, or 700 miles. On the coasts 
 of Europe and Africa the same isotherms 
 range between latitudes 20° and 70° N., or 
 
in THE GULF-STREAM 125 
 
 rather beyond these limits ; that is, over 
 more than 50° of latitude, or 3500 miles. In 
 the former case there is a change of tempera- 
 ture at the rate of one degree in 20 miles, in 
 the other in 100 miles. 
 
 There are many other interesting peculi- 
 arities in the distribution of ocean tempera- 
 ture, to one of which I will refer. It is 
 the occurrence of narrow tracts of relatively 
 very cold water along certain parts of the 
 west coasts of Africa and America, in close 
 contiguity to areas presenting the normal 
 temperature corresponding to the latitude. 
 This peculiarity has been referred, with 
 apparent reason, to the effect of the pre- 
 vailing winds which, blowing from the east, 
 drive the surface-water away from the coasts, 
 where it is constantly replaced by the cold 
 water which rises from below. 
 
 How greatly local conditions of surface 
 
126 LECTURES ON GEOGRAPHY m 
 
 are able to affect the operation of the most 
 far-reaching forces of nature is well illus- 
 trated by the tides of the ocean. The 
 combined attraction of the sun and of the 
 moon tends to produce a twofold tidal wave 
 in opposite hemispheres, which, if undis- 
 turbed, would travel from east to west, or in 
 the opposite direction to that of the earth's 
 rotation, the times of high water succeeding 
 one another at intervals of twelve hours 
 twenty-four minutes, half the period of the 
 moon's revolution round the earth, and 
 following the apparent place of the moon, 
 the effect of which luminary is about double 
 that of the sun. This result is actually 
 produced in the more open part of the ocean, 
 chiefly in the more southern latitudes ; but 
 the distribution of the great masses of land 
 is such that elsewhere the progress of the 
 tidal wave in the normal direction is not 
 possible. In the Indian Ocean and the 
 
THE TIDES 127 
 
 Northern Atlantic the principal tide is 
 propagated from south to north ; speaking 
 generally, in our own seas the tidal wave, 
 in approaching the west and south coasts, 
 travels from west to east, or in a dia- 
 metrically opposite direction to that of the 
 force which generated it ; while on the east 
 coast it travels from north to south, entirely 
 reversing the direction in which it passed 
 up the Atlantic. In the open sea, as ob- 
 served on small islands, the rise and fall of 
 the tide is very little, amounting to one or 
 two feet only ; but the range is in some 
 places more than 40 feet, as in the Bristol 
 Channel, at St. Malo, on the French coast, 
 and in the Bay of Fundy. These very high 
 tides, as well as the strong currents which 
 in some localities accompany the flow and 
 ebb, are secondary results due to the gradu- 
 ally contracting area or diminishing depth 
 of the portion of the ocean in which the 
 
LECTURES ON GEOGRAPHY 
 
 tidal wave is propagated, that wave origin- 
 ating in a movement of oscillation, not of 
 translation. 
 
 The motion of the tidal wave is so greatly 
 interfered with by the land, that the veloc- 
 ity of its transmission is eventually reduced 
 to that of a free oscillating wave. This 
 velocity, which depends on the depth of 
 the water in which it is propagated, possibly 
 averaging 400 or 500 miles per hour through 
 the open seas, does not differ materially from 
 that of the great seismic waves caused by 
 the explosions which accompanied the erup- 
 tion of Krakatoa in 1883, as deduced from 
 the numerous records obtained from various 
 parts of the earth, including the coasts of 
 France and England, to which the disturb- 
 ances reached. 
 
 The great importance, for purposes of 
 navigation, of a knowledge of the extent and 
 periods of the rise and fall of the tide, which 
 
in EFFECTS OF TIDAL FRICTION 129 
 
 mainly depend on the distance and apparent 
 place of the moon, has directed the attention 
 of mathematicians to the subject, and methods 
 have been devised by which the daily times 
 and heights of high and low water at any 
 port may be computed and predicted with 
 great precision, after a comparatively short 
 series of observations. 
 
 It has been calculated that the forces of 
 attraction which produce the tides of the 
 ocean are sufficient to cause some deforma- 
 tion of the solid globe. The whole of the 
 movements due to these forces being in a 
 direction opposite to the earth's rotation, 
 give rise to friction, which leads to an ex- 
 tremely slow gradual reduction of the 
 velocity of rotation. In former conditions 
 of the earth and moon, such as there is 
 reason to think have existed, the changes 
 thus produced may have been very much 
 more rapid, and their effects may have had 
 
 K 
 
130 LECTURES ON GEOGRAPHY m 
 
 extremely important consequences when the 
 globe was in a semi-fluid state. It has been 
 suggested, in connection with speculations 
 of this nature, that the corrugations of the 
 cooling globe from which the existing great 
 masses of land and the ocean beds received 
 their original forms, may have been caused 
 by the tide-producing forces of attraction. 
 
 Among the influences which give to the 
 earth the characteristics that most immedi- 
 ately affect its fitness for occupation by man 
 and the support of life generally, those due 
 to the atmosphere are, without doubt, the 
 most prominent, and, under the designation 
 of climate, are constantly affecting us. 
 But of all recognised branches of science, 
 that which treats of the atmosphere — meteor- 
 ology — is at the present time certainly the 
 most backward. The reasons are not far 
 to seek. The air is invisible, and in its 
 
in THE ATMOSPHERE 131 
 
 upper regions inaccessible. The changes 
 it undergoes are difficult to observe, and, 
 from their great complexity, difficult to 
 grasp, while what we know of them is 
 almost wholly confined to the immediate 
 proximity of the earth. It is pretty certain 
 that the most important among the causes 
 which operate on the atmosphere are changes 
 of temperature ; but the application of mathe- 
 matical reasoning to the movements of an 
 elastic fluid such as the air, charged with 
 watery vapour, when submitted to changes 
 of temperature upon a rotating sphere such 
 as the earth, presents very serious difficulties, 
 and little has been done to grapple with 
 them. What is known of these subjects 
 is as yet almost exclusively empirical. In- 
 strumental appliances are here far in advance 
 of theories, and it is not to be disguised 
 that great waste of labour too frequently 
 results from an exaggerated refinement in 
 
132 LECTURES ON GEOGRAPHY m 
 
 observation, and subsequent numerical com- 
 putation, which has no real value. 
 
 The air is a highly attenuated fluid 
 medium, beneath which the whole surface 
 of the earth is immersed, and by which all 
 that is on the earth is surrounded, supported, 
 and penetrated. It is the vehicle through 
 which warmth, moisture, and the gaseous 
 necessaries of existence are supplied to living 
 things. The variations of the temperature, 
 of the pressure, and of the motion of the air, 
 and of the quantity of vapour it contains, 
 give rise to the great series of phenomena 
 which are included under the general term 
 climate. Of these variations the primary 
 causes are the action and reaction of the 
 mechanical and chemical changes set up by 
 the sun's heat under the influence of the 
 earth's motion, terrestrial position, and con- 
 ditions of surface ; as well as fluctuations of 
 the sun's heat itself, though of these last we 
 
in CAUSES DETERMINING CLIMATE 133 
 
 know too little to do more than recognise 
 their presence. 
 
 The conditions which determine at any 
 place the greater or less degree and duration 
 of direct exposure to solar radiation, and 
 therefore the quantity of heat received there, 
 are position in relation to latitude, combined 
 with the diurnal and annual movements of 
 the earth. The nature of the surface regu- 
 lates the local accumulation of heat, by 
 reason of the varying power of absorption 
 or radiation possessed by different substances ; 
 while with elevation above the sea-level as 
 the density of the air becomes less, the 
 sensible temperature and the quantity of 
 watery vapour are subject to corresponding 
 change. The whole of the results thus 
 produced, moreover, are modified by move- 
 ments in the air consequent on atmospheric 
 changes from place to place, or from time to 
 time. 
 
134 LECTURES ON GEOGRAPHY ni 
 
 All the determining causes of variation of 
 climate just mentioned are brought into 
 prominently contrasted action over areas of 
 land and water. The equable sea climates 
 on the one hand, and on the other the 
 extreme variations of heat and cold, of 
 drought and flood, on the great continents, 
 with the multitude of local results dependent 
 on them, supply well-known illustrations of 
 this truth. 
 
 The inequalities of the earth's surface, 
 which are insignificant when viewed in re- 
 lation to the whole globe, are of the greatest 
 importance in relation to the atmosphere. 
 For owing to the laws of elastic fluids, the 
 great mass of the air and of the watery 
 vapour it contains is concentrated very near 
 the surface. One-fourth of the air and one- 
 half of the vapour are found below 8000 feet 
 from the sea-level ; one-half of the air and 
 nine-tenths of the vapour are below 19,000 
 
in DISTRIBUTION OF AIR AND VAPOUR 135 
 
 feet, which hardly exceeds the average 
 elevation of the highest ranges of the Hima- 
 laya Mountains ; while three -fourths of the 
 air and virtually the whole effective vapour 
 lie below 30,000 feet, and therefore within 
 the influence of the highest summits of those 
 mountains. That portion of the atmosphere 
 which is nearest the surface is manifestly the 
 most likely to be acted upon by irregularities 
 of relief, and by local variations in the power 
 of absorbing or radiating heat or diffusing 
 vapour. Hence it is certain that it is the 
 movements of the lower strata of the 
 atmosphere that chiefly affect all conditions 
 of climate, though no doubt there are great 
 movements in the upper regions to bring 
 about the restoration of equilibrium, which 
 is being constantly disturbed from below. 
 
 The principal periodical winds — such as 
 the trade-winds, the monsoons, the land and 
 sea breezes — are found to be essentially de- 
 
136 LECTURES ON GEOGRAPHY HI 
 
 pendent on periodical variations of atmo- 
 spheric pressure, accompanying variations of 
 temperature arising from geographical position 
 or surface conditions. The proximate causes 
 of the more characteristic winds of the west 
 of Europe, and especially of our own islands, 
 have also been well made out. These, too, 
 are due to atmospheric disturbances produc- 
 ing areas of high or low pressure ; the 
 rapidity and intensity of the development 
 of which, with the direction of their paths 
 and their position, determine the force of the 
 wind, the direction in which it blows, and the 
 manner in which it veers or backs — that is, 
 changes its direction. But how the changes 
 of pressure originate, and what causes the 
 transfer of the disturbed area, in a definite 
 direction, usually from west to east, and 
 commonly under the form of an atmospheric 
 eddy or vortex, is still to be ascertained ; 
 though here, too, it is obvious that the distribu- 
 
HI CAUSES OF WINDS 137 
 
 tion of the land and sea areas, and of the 
 ocean currents, on which the temperature 
 of the superincumbent air so immediately de- 
 pends, combined with the rotatory motion of 
 the earth, are among the principal agencies at 
 work. The winds of our islands have com- 
 monly, more or less distinctly, the gyratory 
 character which, as before noted, is one of 
 the secondary results of the rotation of the 
 earth. The precise conditions under which 
 the great cyclones or hurricanes of the 
 tropics are generated are still uncertain, 
 but there is sufficient knowledge of the 
 manner of their occurrence to show that 
 they are disturbances set up by changes of 
 temperature, and to enable the instructed, 
 mariner in most cases to escape their worst 
 consequences. 
 
 With the ocean, the air performs the part 
 of equalising temperature, and mitigating 
 excessive local accumulations or losses of 
 
138 LECTURES ON GEOGRAPHY III 
 
 heat ; and as the ocean supplies the source of 
 moisture, so the air distributes it, first taking 
 it up as vapour, and then carrying it off and 
 delivering it up, with the heat absorbed 
 during evaporation, at distant places. 
 
 Among the most intricate problems of 
 meteorology are those relating to the eva- 
 poration of water, the formation of vapour, 
 its diffusion and suspension in the air, 
 and its condensation as cloud, rain, or snow. 
 The low specific gravity of aqueous vapour, 
 and the constant evaporation that releases it 
 at the earth's surface, tend to diffuse it in 
 accordance with the mechanical laws which 
 govern elastic fluids. But the reduction of 
 the temperature of the air in ascending above 
 the surface renders this diffusion impossible 
 beyond a certain point ; and observation 
 shows that the quantity of vapour actually 
 existing in the upper parts of the atmosphere 
 is mainly dependent on temperature, and 
 
in DIFFUSION OF VAPOUR 139 
 
 amounts to not more than one -fourth part 
 of what would be present if it were diffused 
 freely, and simply obeyed the law of hydro- 
 static pressure. It follows that a height in 
 the atmosphere is at length necessarily 
 reached where condensation must take place 
 and clouds or rain be formed ; and that, 
 speaking generally, the vapour in the upper 
 strata of the air is constantly tending to a 
 condition of unstable equilibrium, from which 
 it may readily be once more restored to the 
 earth in the shape of water. Thus, assum- 
 ing the temperature of the air at the sea- 
 level to be 80° F., and the vapour to be 
 eighty per cent of what air at that tempera- 
 ture can hold in suspension, the free diffusion 
 of the vapour would cause it to ascend in 
 such quantity that condensation would take 
 place at a height of between 3000 and 4000 
 feet, that being the elevation at which, the 
 temperature of the air being about 70 F., 
 
Ho LECTURES ON GEOGRAPHY Hi 
 
 the ascending vapour could no longer remain 
 in suspension. Consequently clouds or rain 
 would be formed at this elevation, and any 
 further movement of the vapour upward 
 would be arrested. This sufficiently accounts 
 for the rarity of a perfectly cloudless sky, 
 which indeed can hardly exist, excepting 
 where such a movement of the air is going 
 on as will carry off the aqueous vapour, as 
 fast as it is formed by evaporation, to a 
 region where the temperature is high enough 
 to prevent its condensation. 
 
 The great activity of the air in discharging 
 the function of equalising temperature and 
 distributing moisture over the earth is 
 remarkable. Reckoning the mean tempera- 
 ture of the air at the earth's surface at 58° 
 F., the mean maximum tension of vapour 
 possible at the surface would be less 
 than half an inch of mercury, which would 
 not represent a true hydrostatic pressure of 
 
in FORMATION OF CLOUDS AND RAIN 141 
 
 water vapour of more than one-fourth part of 
 that amount, or little over one-tenth of an 
 inch of mercury. If, therefore, the whole 
 quantity of moisture in the air at any moment 
 were condensed so as to leave it absolutely 
 dry, the resulting stratum of water, if dis- 
 tributed evenly over the whole earth, could 
 hardly be more than one inch in depth. 
 Yet it is estimated (though perhaps on 
 insufficient data) that the mean rainfall over 
 the whole globe is not less than 60 inches in 
 the year, and falls of ten times this amount 
 are known to occur in some localities. 
 Observations of the velocity of the wind at 
 marine stations show that these results are 
 due to the almost unceasing passage of air 
 highly charged with vapour over the regions 
 where, and during the time in which, rain 
 thus falls, and to the unceasing renewal of 
 the supply of moisture brought from a 
 distance ; and thus the relatively very large 
 
142 LECTURES ON GEOGRAPHY in 
 
 sea-area has an important effect in maintaining 
 the supply of the rain that falls on the land. 
 
 The immediate dependence of rainfall on 
 local geographical features is well known. The 
 presence of mountains forming a barrier in 
 the path of the vapour-bearing winds may- 
 determine on the one side a climate of 
 perpetual cloud and rain, and on the other 
 vast tracts of desert. Where no mountains 
 exist to cause condensation, such winds may- 
 pass on, leaving deserts behind them, and 
 carry their waters to fertilise more fortunate 
 lands beyond. 
 
 Instances of the fall of rain in excessive 
 quantities on the windward faces of mountains 
 exposed to winds blowing from over the sea, 
 with relative drought to leeward, may be 
 found in every part of the globe. In the 
 British Isles may be mentioned the excess- 
 ive rain on the hills of Cumberland exposed 
 to the south-west winds that blow directly up 
 
in DISTRIBUTION OF RAIN 143 
 
 the Irish Sea and St. George's Channel. In 
 Ireland the same facts are to be observed on 
 every one of the clusters of hills that stand 
 up above the otherwise low flat surface. 
 The contrast between the fall of 73 inches 
 at Bergen, on the coast of Norway, directly 
 exposed to the south-west, and its reduction 
 to one-third of that quantity at Christiania, 
 and to one-fifth at Upsala on the continental 
 side of the Scandinavian Peninsula, is most 
 striking. The rainy and well-wooded eastern 
 slopes of the Andes may be contrasted with 
 the barren western flanks of the same chain, 
 where it hardly ever rains ; and the rainless 
 district of Chili on a west coast, south of the 
 equator, coinciding with the region of the 
 south-east trades, where there is a constant 
 current of air from the coast seaward, displays 
 almost the exact reverse of what is observed 
 north of the equator on parts of the west 
 coasts of Europe and Asia, where the rain 
 
144 LECTURES ON GEOGRAPHY in 
 
 falls in torrents during the seasons when the 
 south-west winds blow inland from over the 
 ocean. 
 
 The action of the periodical winds or 
 monsoons in bringing with them the seasons 
 of rain in the tropical and semi-tropical 
 regions of the earth, is of the greatest 
 practical moment. The water-supply and 
 the production of the ordinary food-crops are 
 often wholly dependent on such rains ; and 
 the light thrown by science on the controlling 
 causes of their failure or abundance may 
 enable us to foresee the possible occurrence 
 of drought, so as to guard against its worst 
 consequences. 
 
 A few words will indicate approximately 
 the magnitude of the forces which are called 
 into silent and comparatively unobserved 
 operation in the atmosphere, in the production, 
 dissemination, and recondensation of aqueous 
 vapour. It has, as I noticed, been estimated 
 
in FORCES EXERTED IN ITS PRODUCTION 145 
 
 that on the average 5 feet of water falls 
 annually as rain over the whole earth. 
 Supposing that condensation takes place at 
 an average height of 3000 feet above the 
 surface, the forces of evaporation and diffu- 
 sion must exert a power capable of lifting 5 
 feet of water over the whole surface of the 
 globe, 3000 feet during the year. This, not 
 reckoning the force required for the transport 
 of the vapour in a horizontal direction, would 
 be equivalent to lifting 3,250,000 millions of 
 pounds of water 3000 feet in every minute, 
 which would require nearly 300,000 million 
 horse-power constantly in operation. It may 
 assist in the apprehension of these numbers 
 to mention that the engines of the largest 
 ironclad do not exceed 1 2,000 horse-power. 
 Even if the quantity of rain were, in" fact, not 
 more than one -tenth part of that above 
 supposed, which is not at all probable, the 
 forces thus exerted would still be on a scale 
 
 L 
 
146 LECTURES ON GEOGRAPHY m 
 
 of magnitude which can hardly be brought 
 within the reach of ordinary conceptions. Of 
 these huge energies a very small part is 
 transferred to the waters that run back 
 through rivers to the sea, and of this a still 
 smaller fraction is utilised by man in his 
 water-mills ; the remainder is dissipated in 
 celestial space. 
 
 A well-known consequence of the physical 
 properties of the air is the gradual reduction 
 of temperature in the higher parts of the 
 atmosphere, as observed in ascending mount- 
 ains. This, amounting to i° for about 300 
 feet of elevation, gradually produces a change 
 of conditions similar to that caused by passing 
 from the equator towards the poles ; and at 
 the greatest elevations an arctic climate is 
 established even under a tropical sun. 
 
 Among the sublimest sights furnished by 
 nature are the great ranges of mountains 
 which traverse or approach the tropics; 
 
in PERPETUAL SNOW— ICE 147 
 
 rising into the regions of perpetual snow, 
 they discharge important functions in the 
 economy of the globe. By the intrusion Of 
 the solid terrestrial surface into the upper 
 part of the atmosphere, the low temperature 
 there, which otherwise could have produced 
 no effect on the earth, is brought into active 
 operation ; great rivers spring from the 
 melting fields of snow and ice that crown 
 the mountain summits, and, swollen by the 
 copious condensation of rain on their 
 slopes, flow down to the plains below, 
 which are fertilised by their perennial 
 waters. 
 
 Ice, whether in the shape of glaciers 
 excavating their mountain beds, or as the 
 floating fragments of glaciers which, forming 
 icebergs, tear up the floor of the ocean, or 
 whether when expanding in the fissures of 
 rocks it rends them asunder, is one of the 
 most energetic of destructive agents. The 
 
148 LECTURES ON GEOGRAPHY HI 
 
 recurrence in the earth's past history of glacial 
 epochs alternating with epochs of greater heat, 
 of which geology supplies evidence, is of 
 much interest, and has given rise to much 
 speculation. Alterations of the distribution 
 of land and sea, and the elevation of mountain- 
 chains, though capable of producing great 
 changes of climate locally, seem insufficient 
 to account for the observed phenomena ex- 
 tending as they do over large portions of the 
 globe. A more probable cause is to be found 
 in the variations which in the lapse of time 
 take place in the ellipticity of the earth's orbit, 
 combined with changes of the position of the 
 axis due to precession. At a period of 
 maximum ellipticity, the quantities of heat 
 received by the earth, at its least and greatest 
 distances from the sun respectively, must be 
 increased and diminished accordingly ; and 
 should it happen that at such a time the 
 change in the direction of the earth's axis 
 
in GLACIAL EPOCHS 149 
 
 caused by precession, brought either hemi- 
 sphere to face the sun fully when nearest to 
 the earth, very considerable effects, on the 
 summer and winter temperatures of the two 
 hemispheres must be produced, without 
 affecting the mean temperature of the globe ; 
 in the more directly exposed hemisphere the 
 summer would be shorter and hotter, and the 
 winter longer and colder, while in the other 
 hemisphere there would be a milder and 
 shorter winter, and a longer but colder 
 summer. Again, it is far from impossible 
 that actual changes in the sun's heating 
 power may have had an important influence 
 on the temperature and climate of the earth, 
 and may have contributed to the results in 
 question. But in the present state of our 
 knowledge any opinion on this subject must 
 be regarded as little more than specu- 
 lative. Displacements of the earth's axis of 
 rotation have also been suggested as a means 
 
ISO LECTURES ON GEOGRAPHY m 
 
 of accounting for some of the great local 
 changes of temperature indicated by geology ; 
 but the evidences of such displacements 
 hardly amount to more than arguments 
 based on mathematical reasoning, which 
 show that they are not incompatible with 
 established facts. 
 
LECTURE IV 
 
 Phenomena of Life — Doctrine of evolution under varying terrestrial 
 conditions — Distribution of vegetable and animal life — The 
 place of man — His dependence, physical and intellectual, on 
 Geographical influences — Geography in relation to the practical 
 affairs of life, and the prosecution of other studies — Conclusion. 
 
 In my previous lectures I have endeavoured 
 to show how, under the action of inherent or 
 external forces, the globe has been moulded 
 to its present form, and has received the 
 existing configuration of its surface ; and 
 how, from the action of similar forces on the 
 atmosphere, have resulted all those local 
 conditions and characteristics of climate which 
 have fitted it for the support of life. We 
 thus find ourselves at the mysterious line 
 
152 LECTURES ON GEOGRAPHY iv 
 
 which separates inorganic from organic 
 matter. 
 
 Of the origin of life, either when or how 
 it began, we know nothing ; all that can be 
 said is that the earlier conditions of the earth 
 were altogether incompatible with life as we 
 know it. For thousands of years as the 
 globe cooled down, its surface must have 
 been deluged with boiling water ; and until a 
 temperature had been established not very 
 greatly exceeding the present, none of the 
 forms of life found in the oldest fossiliferous 
 rocks could have come into existence. 
 
 The sharp distinction between animal and 
 vegetable formerly made is quite broken 
 down ; the bond that subsists between things 
 with and things without life is testified by the 
 identity of the elements of which they are all 
 composed ; and the only possible conclusion 
 is that life is in its nature analogous to other 
 properties of matter, and that it is in fact in 
 
iv PHENOMENA OF LIFE 153 
 
 some unknown way a necessary attribute or 
 consequence of matter in certain conditions, 
 though we are wholly ignorant what the con- 
 nection is and how it is maintained. 
 
 Life is restricted to a very thin stratum on 
 the surface, quite insignificant in comparison 
 to the total magnitude of the earth. The 
 possibilities of life, its preservation, and the 
 propagation of living things, are further seen 
 to be everywhere directly influenced by ex- 
 ternal conditions such as the presence of a 
 medium necessary to existence, be it air or 
 water ; heat, moisture, and light ; the peri- 
 odical recurrence of the seasons and of days 
 and nights ; depth in the ocean ; the character 
 of the surface of the land, whether it be 
 covered by vegetation or otherwise ; the 
 nature of the soil ; the presence of other living 
 creatures ; and many others. 
 
 Discarding speculation as to its origin, of 
 which we have hitherto been unable to obtain 
 
154 LECTURES ON GEOGRAPHY iv 
 
 evidence, our scientific theories of life are 
 based on the study of the structure and dis- 
 tribution of existing plants and animals, and 
 of the corresponding facts established in re- 
 lation to past time by the aid of geology. 
 We thence learn that all forms of life may be 
 arranged in groups, which by their structural 
 affinities are suggestive of natural relation- 
 ships, and exhibit gradations of successively 
 closer degrees of proximity. Thus we find 
 at the outset the great primary divisions or 
 Kingdoms, of Animals and Vegetables, having 
 respectively certain common characteristics 
 of organisation. Subordinate to these, vari- 
 ous minor divisions or Sub-kingdoms have 
 been established in like manner, such as 
 Vertebrata or Mollusca among animals, and 
 Monocotyledons or Dicotyledons among 
 plants ; and further, in succession, Classes 
 such as Mammals or Birds, then Families, 
 and Genera, until we at length reach associa- 
 
IV AFFINITIES OF VARIOUS GROUPS 155 
 
 tions of individuals known to be related by 
 descent from a common ancestor, to which 
 the collective name of Species is applied. 
 Viewing these in a reverse order, a series of 
 allied Species will constitute a Genus, of allied 
 Genera a Family, and so forth. We also see 
 that the assemblages of living creatures found 
 in countries adjoining and easily accessible to 
 one another, and alike in climate, are similar ; 
 that as distances increase, and communication 
 becomes less easy, and climates differ, a 
 corresponding dissimilarity appears ; and that 
 great distance and complete separation are 
 generally accompanied by great changes of 
 forms. Distance in geological time has the 
 same effect as distance in space ; the farther 
 we go back into the past, the more different 
 were the forms of life from what they now 
 are. The abundance of forms of life (dis- 
 tinguished from number of individuals) is also 
 found to vary greatly in different areas, and 
 
156 LECTURES ON GEOGRAPHY iv 
 
 to be related to the existence, within or near 
 the areas, of localities offering considerable 
 variations of the conditions that chiefly affect 
 life ; to the accessibility of these areas to 
 immigration from without ; and to the com- 
 patibility of the local climate and conditions 
 with such immigration. 
 
 Thus is presented the great problem of 
 Life in its infinite variety of forms, past 
 and present ; consisting of groups of animals 
 and vegetables, manifestly connected among 
 themselves by certain common features of 
 organisation, and distributed over the globe 
 in a manner no less plainly indicating 
 a common origin. The question arises 
 whether or not these phenomena can be 
 accounted for without having recourse to 
 any other means than that which . direct 
 observation shows to be alone capable of 
 producing living creatures, namely, propaga- 
 tion by generation through descent from 
 
iv EXPLAINED BY DOCTRINE OF EVOLUTION 157 
 
 parent to offspring. The answer has been 
 given in the affirmative by Darwin, to whom 
 we are indebted for a theory of life ana- 
 logous in its breadth and the genius it dis- 
 plays to the great conceptions of Newton. 
 Darwin has shown how propagation by 
 descent, which maintains the essential char- 
 acters of hereditary likeness, accompanied by 
 certain small variations in the offspring, would 
 be followed, through the influence of external 
 conditions, by the necessary preservation of 
 some of the varieties to the exclusion of 
 others, and how this would account for many 
 of the facts observed, while inconsistent with 
 none. In the preservation or destruction of 
 forms by reason of favourable or unfavourable 
 external conditions (to which he applies the 
 term Natural Selection), he has obtained a 
 solution of the mystery of the structural 
 affinities of the various forms of vegetable 
 and animal life. He has thus also explained 
 
158 LECTURES ON GEOGRAPHY iv 
 
 how it is that uniformity of conditions and 
 facilities for diffusion over any area are found 
 in connection with similarity of forms of life 
 'throughout the area, and how any break of 
 continuity .of conditions, or surface, or time, 
 involves differences in forms of life. Great 
 tracts like Northern Europe and Asia, extend- 
 ing along the same parallels of latitude, not 
 broken up by high mountains, are biologically 
 one. Great mountain ranges like the Hima- 
 laya, great deserts and wide oceans, constitute 
 impassable barriers. Isolated lands, like 
 Madagascar, Australia, and oceanic islands, 
 are dissociated in their life -forms from the 
 great continents, in different degrees which 
 seem to connote the geological date at which 
 they were severed from the large land areas ; 
 and it is significant that this dissociation in 
 island forms is always accompanied by corre- 
 sponding depth in the intervening ocean. 
 Analogous results are found in the seas. 
 
iv FORMS VARY WITH LOCAL CONDITIONS 159 
 
 Again, accompanying the gradations of climate 
 that occur on lofty mountains rising from tropi- 
 cal plains, corresponding changes in the forms 
 of life are found at different elevations ; on 
 chains ranging through many degrees. of lati- 
 tude, like the Andes, there is greater variety 
 of life, corresponding to greater variety of 
 climate, than on those nearly following the 
 same parallel of latitude, like the Himalaya. 
 Extensive land areas appear requisite for the 
 evolution and support of the larger forms of 
 terrestrial life, while restricted areas are 
 characterised by smaller forms and fewer of 
 them. 
 
 The laws that govern the diffusion and 
 limitation of vegetable and animal life are 
 similar ; but though some of the great 
 natural provinces marked out on the earth's 
 surface by characteristic assemblages of 
 .plants and animals are respectively more or 
 less conterminous, no exact correlation has 
 
160 LECTURES ON GEOGRAPHY iv 
 
 been established between them, the cause of 
 which may no doubt be found in want of 
 complete conformity in the operation of the 
 laws of distribution on the two great divisions 
 of living creatures. 
 
 Many apparent difficulties in accounting 
 for the existing facts of distribution are 
 solved by a consideration of the great 
 changes that have taken place in the outlines 
 of land and sea in past time. The data 
 necessary for any complete solution of all the 
 questions that arise are wanting, in conse- 
 quence of our still very limited knowledge of 
 the geology of many parts of the earth, and 
 ignorance of what extinct forms of life may 
 be lost or concealed beneath its surface. But 
 every fresh fact discovered seems to strengthen 
 the evidence of the truth of Darwin's theory 
 of evolution as to its essential factors. 
 
 The phenomena of which I have been 
 speaking indicate, moreover, much more than 
 
iv PRESERVATION AND SURVIVAL OF FORMS 161 
 
 a simple conformity of life to the conditions 
 under which it subsists ; for the conditions, in 
 fact, have positively determined the forms 
 that have been preserved, so that the direct- 
 ing forces which have been efficient in 
 developing life as it exists from what went 
 before, are those same successive external 
 conditions, including the forms of both land 
 and sea and the character of the climate, 
 which have already been shown to arise from 
 the gradual modification of the material fabric 
 of the globe as it slowly attained to its present 
 state. These conditions, through the pre- 
 servation of those forms best suited to 
 survive and flourish under them, have con- 
 trolled the course of the production of living 
 creatures by propagation through successive 
 generations, leading from the past to the pre- 
 sent. In each succeeding epoch, and in each 
 separate locality, the forms thus preserved and 
 transmitted to the future were determined by 
 
 M 
 
i62 LECTURES ON GEOGRAPHY iv 
 
 the general conditions of surface at such time 
 and place ; and the aggregate of successive 
 sets of conditions over the whole earth's sur- 
 face has determined the entire series of forms 
 which have existed in the past, and have 
 survived till now. 
 
 Perfectly unbiassed evidence of the truth 
 of this conclusion is found in the tendency 
 shown before Darwin's great generalisations, 
 to give weight to geographical distribution in 
 systematic classification. And though it be 
 true that classification should rest wholly 
 on morphological considerations, yet the 
 structural likeness among forms geographic- 
 ally associated is often so complete, while so 
 many links in the chain of evolution have 
 been lost for ever, or still have to be found, 
 that, on the one hand, distribution may without 
 objection furnish collateral aid in the details 
 of systematic arrangement, and, on the other, 
 structural resemblances among forms now 
 
iv SIGNIFICANCE OF TYPE 163 
 
 dissociated may serve to suggest changes of 
 former geographical conditions of which no 
 other evidence remains. 
 
 These conceptions of the dependence of 
 animal and vegetable forms on the condition 
 of the earth in its successive stages lead to 
 views of the significance of type (i.e. the 
 general system of structure that characterises 
 the various groups of organised beings) very 
 different from those formerly held. In the 
 light of evolution, type indicates nothing 
 more than the direction given to the actual 
 development of forms of life by the surface 
 conditions of the earth. Beyond this there is 
 no indication of any inherent or prearranged 
 disposition towards a development of life 
 deviating in any particular direction from that 
 which follows the hereditary principle. It 
 rather appears that the existing face of nature 
 is the result of a succession of incidents, 
 unimportant in themselves, which by some 
 
1 64 LECTURES ON GEOGRAPHY lv 
 
 very slight alteration of local circumstances 
 might have been turned in a different 
 direction. For instance, a difference in the 
 constitution or sequence of the substrata at 
 some locality might have determined the 
 elevation of mountains where a hollow filled 
 by the sea was actually formed, or the con- 
 verse, whereby the whole of the climatal and 
 other conditions of a particular area would 
 have been changed, and an entirely different 
 impulse there given to the development of 
 life. 
 
 But further, all that we see or know to 
 have existed upon the earth has been con- 
 trolled to its most minute details by the 
 original constitution of the matter which was 
 drawn together to form our planet; The 
 character of all inorganic substances, as of all 
 living creatures, is only consistent with the 
 actual constitution and proportions of the 
 various substances of which the earth is com- 
 
IV INFLUENCES THAT CONTROL LIFE 165 
 
 posed. Other proportions than those present 
 in the constituents of the atmosphere would 
 have required an entirely different organisa- 
 tion in all air-breathing animals, and probably 
 in all plants. Any considerable difference in 
 the quantity of water either in the sea or 
 distributed as vapour, must have involved 
 corresponding changes in the constitution of 
 living creatures. Without oxygen, hydrOgen, 
 nitrogen, and carbon, what we term life would 
 have been impossible. But such speculations 
 need not be extended. 
 
 The doctrine of the dependence of life on 
 external conditions includes life itself as an 
 important concurrent agency in the general 
 results observed. Thus, in order to supply 
 the food and other requirements of animals, 
 the presence of vegetables or other animals is 
 necessary. To some animals, as well as to 
 some plants, the shelter of forests or particu- 
 lar forms of vegetation is essential. Parasites 
 
166 LECTURES ON GEOGRAPHY iv 
 
 need for their sustenance living plants and 
 animals. The fertilisation and hence the 
 propagation of plants is very commonly due 
 to insects ; and the infrequency of certain 
 forms of insect-life in some of the islands of 
 the Pacific, is held by Wallace to be the true 
 cause of a corresponding infrequency of 
 flowering plants. 
 
 So, too, the reaction of organic matter on 
 inorganic may be seen over the entire globe. 
 The building up of coral-reefs ; the laying out 
 of many calcareous and siliceous deposits 
 over the bed of the ocean ; the action of 
 vegetable life on the constituents of the 
 atmosphere ; the effects produced by vege- 
 tation in modifying the absorption and 
 radiation of heat by the soil, and the 
 conditions of moisture, — show how vital 
 forces actively affect the condition of the 
 earth. 
 
 As life, viewed in one aspect, performs the 
 
iv LIFE CONSTRUCTIVE AND DESTRUCTIVE 167 
 
 function of sustaining life, so in another it 
 works for its destruction. Among the latest 
 results of science may be noticed those that 
 trace, with certainty in many cases, and with 
 much probability in others, particular forms 
 of disease among insects and plants, as well 
 as among the higher animals, to parasitical 
 organisms ; and show how these withdraw 
 the necessary elements of healthy existence, 
 and may at length lead to the total dissolution 
 of the creature in which they are produced. 
 Thus, like the forces that act on inorganic 
 substances, life also follows the same incessant 
 round of construction and destruction ; it 
 elaborates from the constituents of the earth 
 and atmosphere new combinations of matter, 
 soon to be again dissolved, thus restoring the 
 elements on which its own renewal depends. 
 
 The divisions of the earth's surface now 
 generally adopted by naturalists as best repre- 
 
168 LECTURES ON GEOGRAPHY iv 
 
 senting the regions characterised by groups 
 of animals and plants with well - marked 
 common features, will be found to be arranged 
 round the globe, so as to conform roughly 
 with the zones of equal temperature. 
 
 Thus the vegetation has been divided into 
 three great provinces : — the Northern, 
 occupying the northern hemisphere, in both 
 the Old and New Worlds, as far as the 
 tropic ; the Tropical, embracing the regions 
 between the tropics, exclusive of Australia ; 
 and the Southern, including Australia and the 
 adjacent islands, and the temperate zones of 
 South Africa and South America. 
 
 Zoologists have adopted somewhat differ- 
 ent divisions, but they are, in their main 
 characteristics, analogous to those just 
 described. The groups usually accepted in 
 our own country are as follows : — The 
 Palcsarctic, including Europe, with temperate 
 Asia, and Africa north of the Sahara desert, 
 
iv BIOLOGICAL PROVINCES 169 
 
 and the Nearctic, extending over the corre- 
 sponding parts of America ; the Ethiopian, 
 including Africa south of the Sahara and 
 South Arabia, and the Indian, embracing 
 India south of the Himalaya, South China, 
 the Malay peninsula and islands ; the Neo- 
 tropical, extending from South Mexico, over 
 South America and the West Indian Islands ; 
 and the Australian, including the continent 
 of Australia and the neighbouring islands of 
 the Pacific. 
 
 The opinion that life originated in the 
 polar regions, where the gradually cooling 
 globe must first have reached a temperature 
 in which it became possible, was, I believe, 
 first expressed by Buffon. Speculations on 
 such subjects must obviously be received with 
 much reserve, but there are indications con- 
 sidered valid by competent authorities, that it 
 was around the north polar area that both 
 vegetable and animal life were first developed, 
 
l?o LECTURES ON GEOGRAPHY iv 
 
 and thence disseminated over the rest of the 
 earth ; and it seems to be an accepted opinion 
 that even if the northern hemisphere be not 
 the area in which both plants and animals 
 were originated, and from which they have 
 been diffused, it has at all events played a 
 most important part in the evolution and dis- 
 tribution of new types. 
 
 Within this area have been found re- 
 presentatives of all the principal known 
 fossiliferous systems, containing the remains 
 of plants and animals closely resembling the 
 present inhabitants of far lower latitudes, and 
 even of tropical climates. Thus in lat. 82 N. 
 are to be seen Silurian rocks containing 
 undoubted reef-building corals, such as now 
 exist under the equator in water having a 
 temperature from 70° to 85° F. In many 
 localities within the arctic circle, in some 
 cases reaching within io° of the pole, have 
 been found accumulations of the remains of de- 
 
iv EFFECTS OF PAST TERRESTRIAL CHANGE 171 
 
 ciduous trees, in all respects resembling those 
 now seen in the warmer temperate regions. 
 
 It is also inferred from the manner in 
 which existing forms are distributed that 
 there has been in past geological time a 
 general migration from north to south, 
 interrupted from time to time and in various 
 localities by secular changes of temperature 
 and climate, or by alterations in the bound- 
 aries of land and sea, or the elevation of 
 mountain ranges, and even occasionally re- 
 versed in direction. 
 
 The glacial epoch of the Tertiary period, 
 during the later portions of which great 
 movements of the earth's crust occurred 
 without material changes in the relative 
 positions of the chief masses of land, appears 
 to be the event which has mainly determined 
 the local characteristics of present forms of 
 vegetable life, the pre-existing flora of large 
 parts of the northern hemisphere having then 
 
172 LECTURES ON GEOGRAPHY iv 
 
 been either wholly or partially destroyed by 
 cold, or driven southwards into what are now 
 regions of tropical heat. Through the effects 
 of the change of climate that then occurred 
 has also been explained the presence of plants 
 of the Arctic regions on many of the highest 
 mountains in distant parts of the world and 
 even in the Antarctic area, to which their 
 migration under existing terrestrial conditions 
 would be impossible. Such plants might 
 have travelled southward, as the cold in the 
 north became more intense, along mountain 
 ranges extending for great distances from 
 north to south, such as the Rocky Mountains 
 and Andes, or possibly other chains no longer 
 existing. With the return of the warmer 
 climate the relics of the Arctic vegetation 
 might be left in isolated areas, where a 
 suitable temperature continued, as on the 
 highest mountains and in the Antarctic 
 regions. Such changes occurring at any 
 
iv ON THE DISTRIBUTION OF LIFE 173 
 
 time in the earth's history would have caused 
 the then existing flora to be broken up and 
 to be subjected to great modifications by 
 successive migrations in alternating or vary- 
 ing directions ; introducing tropical forms 
 into what had been temperate areas and 
 vice versa. 
 
 Changes of temperature such as those of 
 the glacial epoch, would appear to have had 
 hardly less influence in modifying the fauna 
 of large parts of the earth, though in 
 consequence of the relatively far greater 
 inability of plants to escape from conditions 
 of climate incompatible with their organisa- 
 tion, the present distribution of animals and 
 the special characters of a local fauna may be 
 more largely due on the one hand to former 
 connections between adjacent areas which 
 may no longer exist, and on the other to 
 prolonged isolation or separation. 
 
 But while these are the influences which 
 
174 LECTURES ON GEOGRAPHY iv 
 
 have determined the production and dis- 
 tribution of the existing types or forms of 
 life, it is the actual conditions of the regions 
 they inhabit that control their preservation, 
 and their greater or less abundance, and 
 indeed all that may be termed their relations 
 with the earth and one another. 
 
 The amount and extent of the variations 
 of the heat and moisture of the air and of 
 the rainfall, the force and direction of the 
 prevailing winds, and the nature of the 
 surface, are among the essential conditions 
 that determine the possibility of life ; and it 
 is therefore to geographical features and 
 position that we must look for the dominant 
 influences under which life in its various forms 
 exists on the earth. 
 
 Under these influences the vegetation 
 which clothes the land and fits it for the 
 support of animal life, in turn appears as the 
 almost impenetrable forest and undergrowths 
 
iv VEGETATION HOW AFFECTED BY CLIMATE 175 
 
 of the tropics ; as the more open woods and 
 glades of the temperate zone ; as the herbage 
 of the prairies, meadows, and plains that 
 invite the herdsman, the shepherd, or the 
 plough ; dwindles here to the dwarfed bushes 
 scattered over a desert ; is seen there as 
 a few alpine plants seeking shelter among 
 crevices in the rocks ; and finally, before 
 disappearing in the regions of eternal frost, 
 is reduced to some patches of lichen. 
 
 On the slopes of the great mountain 
 ranges that rise from tropical heat to the 
 regions of everlasting snow, the traveller as 
 he ascends may find within the compass of a 
 few days a compendium of the climate, and 
 consequently of the vegetation of the entire 
 globe. 
 
 Nowhere can such a display be better or 
 more easily obtained than upon the Himalaya 
 Mountains. The transition is abrupt from 
 the well-cultivated plain of Northern India, 
 
176 LECTURES ON GEOGRAPHY iv 
 
 with its fields of rice and millets, or golden- 
 flowering mustard, to the umbrageous forests 
 lying at the foot of the outer ranges, almost 
 wholly composed of trees of tropical forms, 
 but among which a few oaks and an elm are 
 found, and which, with a tangled growth of 
 undershrubs and creepers, and adorned with 
 epiphytal plants in profusion, give cover to 
 the elephant, rhinoceros, and tiger, and afford 
 shelter to the peacock and a multitude of other 
 gaily-coloured birds. The glens are choked 
 with gigantic grasses and feathering bamboos. 
 Great forests cover the outer slopes of the 
 chain, scandent palms spreading over the 
 lofty trees, whose stems are splendidly 
 furnished with the dark green foliage of 
 climbing aroids ; the ground beneath them is 
 concealed under a rich growth of tree and 
 other ferns, orchids and scitaminese, or broad- 
 leaved plantains. With gradually increasing 
 elevation and falling temperature, the char- 
 
iv ILLUSTRATED BY THE HIMALAYA 177 
 
 acter of the vegetation changes. More open 
 woods of evergreen trees, typical of warm 
 temperate climates, succeed, including rhodo- 
 dendrons, oaks, and laurels. Lofty pines 
 cover the vast mountain sides through many 
 thousand feet of altitude in unbroken uniform- 
 ity. Still ascending, forests of deciduous 
 trees of surpassing size and beauty appear, 
 crowning the hilltops and fringing the 
 courses of the rivers, intermingled with many 
 flowering shrubs and an abundant display of 
 herbaceous plants, of which at the greater 
 elevations the forms are for the most part 
 allied to or identical with those of Europe. 
 The arboreous vegetation, the last members 
 of which are commonly birches, pines, and 
 junipers, ends at about 12,000 or 13,000 
 feet above the sea-level, the shrubby growths 
 ascending a thousand feet higher. The 
 alpine region is thus attained, where, under 
 the influence of the frequent showers that 
 
 N 
 
178 LECTURES ON GEOGRAPHY iv 
 
 fall on the mountain slopes exposed to the 
 south, the open pastures are adorned, during 
 their short summer, with flowers of every 
 hue and in the greatest profusion and luxuri- 
 ance, including well-known European forms, 
 such as gentian, primula, anemone, ranunculus, 
 and many others. 
 
 With increased elevation, and as the 
 ranges are less directly exposed to rain- 
 bearing winds from the south, the climate 
 becomes colder and drier, the vegetation 
 more scanty, the forms fewer ; and on 
 reaching the border of Tibet at an elevation 
 of 14,000 or 15,000 feet, where the atmo- 
 spheric conditions are wholly changed, the 
 aspect of the country is that of a desert, 
 treeless and bare ; as a rule, and excepting in 
 the rare neighbourhood of water, not one- 
 twentieth of the surface is clothed with 
 vegetation, and such bushes as there are 
 seldom rise to a greater height than one or 
 
IV CONTRASTED WITH TIBET 179 
 
 two feet. . On the Tibetan plateau, where the 
 precipitation of moisture is confined to a few 
 showers in the summer, and scanty falls of 
 snow in the winter, the surface drainage 
 frequently collects in salt lakes ; and at these 
 great elevations many salt plants are found, 
 with species of wormwood, and assemblages 
 of truly seashore plants, precisely such as 
 may be seen together at any time on the 
 coasts of the British Isles. The general 
 character of the scanty vegetation is 
 European, but combined with many Siberian 
 forms, and several species are identical with 
 those of the Arctic regions. With the semi- 
 arctic climate of Tibet, corresponding north- 
 ern forms of animal life also appear, such as 
 the marmot, lagomys, and other burrowing 
 animals, the ounce and the lynx. The great 
 open half-desert plateaux supply a suitable 
 home for peculiar antelopes and troops of 
 wild asses, and the more inaccessible 
 
180 LECTURES ON GEOGRAPHY iv 
 
 mountain tracts afford shelter for several 
 species of wild sheep. 
 
 Analogous to the modifications in the 
 character of the vegetation observed in 
 ascending to great elevations, are those which 
 accompany changes of geographical position 
 and conditions in crossing a great continent 
 such as North America. 
 
 The portion of the North American 
 continent lying along the 40th degree of 
 latitude, and extending from the Atlantic to 
 the 95 th meridian west from Greenwich, over 
 a distance of about 1200 miles, may be 
 described as a great plain gradually rising 
 from the sea-level to an elevation of about 
 1000 feet along its western border. From it 
 rises, at about 200 or 300 miles from the 
 coast, the Apalachian range of mountains, 
 few of the summits of which exceed 5000 feet 
 in elevation, and but a small portion reaches 
 even 3000 feet. Along the eastern margin 
 
iv INFLUENCE OF GEOGRAPHICAL POSITION 181 
 
 of this region there is a considerable rainfall, 
 from 40 to 50 inches fairly distributed through 
 the year, which is gradually reduced to about 
 35 inches on reaching the 95th meridian west. 
 The Apalachian Mountains appear to have 
 no important influence on the total annual 
 rainfall, and the whole tract, before civilised 
 man began to intrude on it, was covered with 
 a vast primeval forest, probably the largest 
 and richest in the temperate zones. 
 
 To the westward of the 95th meridian the 
 rainfall rapidly diminishes, while the elevation 
 of the plain increases, and accompanying this 
 change the forest region ceases and that of 
 the prairies begins. This extends over a 
 distance of about 600 miles to the foot of the 
 Rocky Mountains, where, at an elevation of 
 between 5000 and 6000 feet, the rainfall is 
 reduced to little over 15 inches. As the 
 western margin of the great forest region is 
 approached it is invaded by open grassy belts, 
 
182 LECTURES ON GEOGRAPHY iv 
 
 which soon become dominant, and there is an 
 abrupt and surprising passage into the prairies, 
 which extend their bright green rolling 
 undulations to an apparently boundless hori- 
 zon, with nowhere a tree to be seen, excepting 
 along the rivers whose distant courses are 
 marked out by scattered lines of poplars. 
 
 The Rocky Mountains, which rise abruptly 
 from the prairie, and whose highest summits, 
 which reach about 14,400 feet above the sea- 
 level, immediately overlook the eastern plains, 
 constitute in truth the eastern escarpment of 
 a great irregular tableland extending for a 
 distance of 800 miles as far as the mountains 
 of California, which, in like manner, there 
 form its western flank. The average elevation 
 of this plateau, the surface of which is much 
 broken up, is probably not less than 6000 
 feet ; considerable areas rise to upwards of 
 8000 feet, and detached portions, chiefly 
 towards the eastern escarpment, reach from 
 
tv ILLUSTRATED FROM NORTH AMERICA 183 
 
 10,000 to 12,000 feet. The rainfall over 
 parts of this region does not amount to 5 
 inches in the year. 
 
 The eastern slopes of the Rocky Mountains 
 are covered with forest, but of a scanty 
 character, except in sheltered valleys and on 
 the higher ridges, where condensation is most 
 considerable, and the vegetation — arboreous, 
 shrubby, and herbaceous — is more vigorous. 
 The forest is mainly composed of pines, and 
 almost the only deciduous tree is a gregarious 
 aspen, which forms nearly impassable thickets. 
 
 A few miles beyond this more favoured 
 region begins the great desert basin, of which 
 the country round the Great Salt Lake City 
 is typical, and on which the scanty surface 
 drainage collects in salt lakes and pools. 
 There is an almost complete absence of 
 grassy sward, and the surface over very large 
 areas is exclusively clothed with the shrubby 
 sage-bush, artemisia, and various saline plants, 
 
184 LECTURES ON GEOGRAPHY iv 
 
 chiefly chenopods, stretching as far as the eye 
 can reach, in low detached clumps ; the 
 prevailing colour of these, a dull gray or 
 olive-green, conveys no unsuitable impression 
 of the dreary and inhospitable character of 
 the country, which in its general aspect 
 resembles in a marvellous degree those parts 
 of the Tibetan plateau which are in like 
 manner cut off from rain by the lofty ranges 
 of the Himalaya. 
 
 The western border of this desert region 
 is formed by the Sierra Nevada range of 
 mountains, rising to elevations from 11,000 
 to 14,000 feet, its slopes descending to the 
 Pacific, distant about 150 miles. On these 
 abundant rain once more prevails, and the 
 treeless waste is replaced by a forest tract of 
 incomparable grandeur. But the essential 
 characters of the vegetation differ in a most 
 conspicuous manner from those of the 
 Atlantic forests. Large numbers of the most 
 
iv THE ROCKY MOUNTAINS TO THE PACIFIC 185 
 
 abundant trees of the east are absent, and 
 the forests of the Pacific are chiefly made up 
 of conifers, among which must be specially 
 noticed the far-famed gigantic sequoia found 
 in the Yosemite Valley, known as Welling- 
 tonia in English gardens. The age of the 
 largest of these, which rise to the height of 
 over 300 feet, with a girth of more than ioo 
 feet at 6 feet above the ground, has been 
 estimated to exceed 3000 years ; their parent- 
 age probably goes back to the glacial epoch, 
 or even to a more remote date, but the race 
 is almost inevitably doomed to destruction by 
 the advent of man. North of lat. 35°, under 
 the influence of the equable coast temperature, 
 the moist climate, and the heavy rainfall 
 which rises to 80 inches in lat. 40°, similar 
 forests of great magnificence and beauty 
 clothe the mountains skirting the Pacific. 
 
 The distribution of life has been greatly 
 disturbed by the occupation of large parts of 
 
186 LECTURES ON GEOGRAPHY iv 
 
 the earth's surface by man, from which have 
 followed the destruction of much of the 
 primeval vegetation and animal life, and the 
 introduction of foreign or modified forms by- 
 means of artificial methods of propagation and 
 culture. But the various plants which man 
 has thus substituted to supply his food and 
 his clothing ; the cereals, sugar-cane, grape- 
 vine, tea, coffee, cotton, flax, hemp, and so 
 forth, have their special requirements of 
 climate and soil, and the areas within which 
 they can be profitably raised are well defined 
 geographically; and all such artificial opera- 
 tions are subject to similar limitations. 
 
 The animal kingdom is as directly under 
 the influence of the physical conditions of the 
 earth's surface as the vegetable, and is no 
 less certainly ruled by them. Every animal 
 must yield to the necessities imposed upon it, 
 through its dependence for food on the 
 vegetable products of the earth, or on other 
 
iv LIKE INFLUENCES ON ANIMAL LIFE 187 
 
 animals fed on those products, and for the 
 protection which vegetable life affords against 
 foes and the pressure of climate. The ter- 
 restrial conditions which permit the growth 
 of forest, determine the presence of those 
 animals for the requirements of whose organ- 
 isation tree vegetation is essential. Where 
 open plains cease, the wild horse or ass, the 
 camel and antelope, disappear. The most 
 inaccessible crags on lofty mountains are the 
 selected home of wild sheep and goats. 
 Certain genera of mollusca can exist only 
 within reach of the action of the waves of the 
 sea. Other creatures are found exclusively 
 in the lowest depths of the ocean. Such 
 instances might be extended indefinitely. 
 
 In what I have thus far said I have not 
 distinguished man from the rest of the animate 
 world, in which he holds the most conspicuous 
 place. The progress of knowledge has re- 
 
LECTURES ON GEOGRAPHY 
 
 moved all reasonable doubt as to his relation 
 with other living creatures. It is now estab- 
 lished that man existed on the earth at a 
 period vastly anterior to any of which we 
 have records in history or tradition. He was 
 the contemporary of many extinct mammalia 
 at a time when the outlines of land and sea, 
 and the conditions of climate over large parts 
 of the earth, were wholly different from what 
 they now are ; and modern research has done 
 much to show how our race has been advanc- 
 ing towards its present condition during a 
 series of ages, for the extent of which 
 ordinary conceptions of time afford no suitable 
 measure. The ancient monuments of Egypt, 
 which take us back perhaps 7000 years from 
 the present time, indicate that when they 
 were erected the neighbouring countries were 
 in a condition of civilisation not very greatly 
 different from that which existed when they 
 fell under the dominion of the Romans or 
 
iv RELATION OF MAN TO OTHER ANIMALS 189 
 
 Mahommedans hardly 1 500 years ago ; and the 
 progress of the population towards that con- 
 dition can hardly be accounted for otherwise 
 than by prolonged gradual transformations, 
 going back to times so far distant as to re- 
 quire a geological rather than an historical 
 standard of reckoning. The facts thus 
 brought to light have, in recent years, given 
 a different direction to opinion as to the 
 manner in which the great groups of man- 
 kind have become distributed over the areas 
 where they are now found ; and difficulties 
 once considered insuperable become soluble 
 when regarded in connection with the now 
 ascertained extreme antiquity of the human 
 race, and those great alterations of the out- 
 lines of land and sea which are shown to have 
 been going on up to the very latest geological 
 periods. 
 
 The better knowledge now acquired of the 
 want of stability of forms of human speech 
 
igo ! : UECTURES ON GEOGRAPHY iv 
 
 has also had an important bearing on these 
 same subjects. For the evidence of the 
 modifications which the chief spoken 
 languages have undergone during the historic 
 period shows that there is probably no 
 country in which the tongue in use a thousand 
 years ago would be now intelligible; and in 
 still more remote ages, in the absence of 
 written language, the tendency to the pro- 
 duction of diverging forms of speech must 
 have been much greater. This leads to the 
 conclusion that even a radical diversity of 
 language need not imply, difference of race, 
 an inference fully supported by what is known 
 of the languages of existing savage tribes. 
 
 There is still considerable disagreement 
 among ethnologists as to the groups in which 
 the human race should be classed, and the ex- 
 planation of apparent affinities in various 
 parts of the earth. Everywhere, however, 
 a distribution is to be found corresponding 
 
RACES OF MEN 19I 
 
 in its chief features with that of other forms 
 of life, following mainly the geographical dis- 
 tribution of land and sea, and limited by local 
 conditions of climate. The largest area is 
 occupied by the Mongolian race, which ex- 
 tends over the greater part of Northern and 
 Eastern Asia, and is supposed to have spread 
 over the islands of the Pacific, and the entire 
 continent of America. The European races, 
 commonly called Caucasian, occupy Europe, 
 the northern parts of Africa, and South- 
 western Asia. The Negro races are peculiar 
 to Africa south of the great desert, though 
 with an apparently exceptional extension to 
 some of the islands in the Indian Archipelago. 
 The Australian continent is peopled by a 
 distinct race, of which traces are thought to 
 be found in Southern India, Arabia, and 
 possibly Egypt. In our ignorance of the 
 time and manner of the development of 
 these different races no thoroughly satisfactory 
 
192 LECTURES ON GEOGRAPHY iv 
 
 explanations have been given of their mutual 
 relations, or of the peculiarities of their dis- 
 tribution, some of which have been attributed 
 to the changes of the boundaries of land and 
 sea known to have occurred during, or sub- 
 sequent to, the geological period in which the 
 earliest traces of man are found. 
 
 What were the steps through which 
 primeval man passed in acquiring his present 
 place in the advancing front of living creatures 
 will probably never be more than matter for 
 speculation ; but there is no room to doubt 
 that for this position he is indebted not to 
 any special efforts of his own directed to such 
 an end, but to the wonderful compelling 
 forces of nature which, acting on some in- 
 herited capacity, have lifted him entirely 
 without his knowledge, and almost without 
 his participation, far above the animals of 
 whom he is still one, though the only one 
 able to see or consider what he is. 
 
iv PROGRESS FROM MAN'S PRIMITIVE STATE 193 
 
 For the social habits essential to his 
 progress, which he possessed even in his most 
 primitive state, man is without question de- 
 pendent on his quadrumanous ancestors, as he 
 is for his form and other physical peculiarities. 
 In his advance to civilisation he must have 
 been insensibly forced, by the pressure of exter- 
 nal circumstances, from his primeval condition, 
 in which he derived sustenance from fruits 
 or roots, and wild animals, to pastoral and 
 agricultural occupations. The requirements 
 of a population gradually increasing in 
 numbers could only be met by a supply of 
 food more regular and more abundant than 
 could be provided by the spontaneous pro- 
 duce of the earth or by the chase. But the 
 possibility of the change from the hunter to 
 the shepherd or herdsman rested on the 
 antecedent existence of animals suited to 
 supply man with food, having gregarious 
 habits, and fitted for domestication, such as 
 
194 LECTURES ON GEOGRAPHY iv 
 
 sheep, goats, and horned cattle ; for their 
 support the social grasses were a necessary 
 preliminary, and for the growth of these in 
 sufficient abundance land naturally suitable 
 for pasture was required. A further means 
 of escape from man's growing difficulty in 
 obtaining sufficient food was secured by aid 
 of the cereal grasses, which supplied the 
 means by which agriculture became the chief 
 occupation of more civilised generations. 
 Meanwhile, as these increased facilities for 
 providing food were in turn overtaken by the 
 growth of the population, new power to cope 
 with the recurring difficulty had been gained 
 through the invention of implements and 
 weapons first of stone, and then of metal. 
 Ultimately, the needful leisure was for the 
 first time obtained for the cultivation of 
 mechanical arts and of thought, when the 
 earliest steps of civilisation had rendered the 
 necessity for unremitting search after the 
 
iv HIS PRESENT ADVANCED POSITION 195 
 
 means of supporting existence less pressing ; 
 and thus was broken down the chief barrier 
 in the way of progress, and man was carried 
 forward to the condition in which he now is. 
 The needful protection against the foes of his 
 constantly increasing race — the legions of 
 hunger and disease,, infinite in number, ever 
 changing their mode of attack or springing up 
 in new shapes — could only be attained by 
 some fresh adaptation of his organisation to his 
 wants, and this took the form of that develop- 
 ment of intellect which has placed all other 
 creatures at his feet and all the powers of 
 nature in his hand. But the marvellous 
 growth of his knowledge, and his acquisition 
 of the power of applying to his use all that 
 lies without him, differ in nothing but form 
 or degree from the earlier steps in his 
 advance. 
 
 And man, with all his special faculties and 
 dispositions, still remains, in most respects, as 
 
196 LECTURES ON GEOGRAPHY iv 
 
 directly dependent on the physical charac- 
 teristics of the regions in which he dwells, 
 as any other of the beings that possess 
 the attribute of life. If, on one side, his 
 ingenuity has enabled him to withstand the 
 agencies which to other less sagacious animals 
 were irresistible, and taught him how to wield 
 them for his own purposes, yet on the other, 
 while acquiring this power, he became physic- 
 ally more susceptible to their influences when 
 they operate in a manner adverse to his well- 
 being, and he is forced more completely than 
 any other creature to shape his existence so 
 as to conform to their inexorable sway. 
 
 Thus the progress of the human race 
 towards civilisation has been controlled in all 
 directions by the features and conditions of 
 the earth's surface. The climate, tempera- 
 ture, and moisture, succession of the seasons, 
 length of day and night, have gone far in 
 determining the physical characteristics, the 
 
iv DEPENDENCE ON TERRESTRIAL FEATURES 197 
 
 bodily strength, and the duration of life in 
 various races ; and as less direct consequences, 
 and under the greater or less necessity for 
 the exercise of forethought in providing 
 against vicissitudes of existence, have been 
 developed their several capacities, social and 
 intellectual, their numbers, wealth, and 
 power. 
 
 The habits, modes of life, and occupations 
 of all communities are immediately dependent 
 on the features of the land where they dwell. 
 The presence of a soil suitable for cultivation 
 was one of the first necessities for progress ; 
 it has always remained one of the chief fac- 
 tors in the wealth of nations, and carries with 
 it an agricultural population with fixed 
 habitations. The pastoral and nomadic life 
 is associated with upland pastures, or plains 
 on which the soil or climate can provide only 
 scanty grazing grounds. The varying vege- 
 table, animal, and mineral products of 
 
LECTURES ON GEOGRAPHY 
 
 different lands and seas have supplied man 
 with corresponding means of satisfying his 
 wants or adding to his enjoyments, and hence, 
 in each locality, his occupations and industries 
 have had some special direction imparted to 
 them. The neighbourhood of the sea gave 
 birth to maritime pursuits, success in which 
 largely depends on the character of the coasts, 
 and the shelter afforded by their indentations. 
 The distribution of mountain chains and 
 valleys, of rivers and the basins they drain, 
 the boundaries of land and sea, have con- 
 trolled the extent of kingdoms, the intercourse, 
 friendly or hostile, between different coun- 
 tries, the routes of commerce ; they have 
 supplied or withheld facilities for migrations, 
 and protection against invasion. Within the 
 limits they prescribe, states have become con- 
 solidated. 
 
 The ingenuity of man has only partially 
 overcome the restraints thus put upon him. 
 
iv EXTENT AND LIMITS OF MAN'S POWERS 199 
 
 The arts of civilisation have led to the 
 transfer of the chief seats of his power from 
 the warmer latitudes where existence is most 
 easy, to colder climates where the conditions 
 are more favourable to the continued exertion 
 of his intelligence. To meet his demands, 
 civilised man compels the earth to increase 
 and vary its vegetable and animal produce by 
 cultivation and domestication. He breaks 
 into the store of minerals hid away below 
 the surface and converts them into power. 
 He turns night into day, and subdues the 
 forces of heat and cold. He pierces the 
 mountains; he spans the waters that stand 
 in his path across the land, and cuts through 
 the land that stands in his path across the 
 waters. He makes the ocean a highway 
 over which he rides, regardless of winds and 
 waves, to pursue his ends in all parts of the 
 earth, and to plant his colonies in distant coun- 
 tries ; and thus uses an obstacle impassable 
 
LECTURES ON GEOGRAPHY 
 
 to most living things, as the principal means 
 of his own migrations, and of supplying his 
 constantly increasing wants and desires. 
 
 But with all his arts, man remains subject 
 to the irresistible power of terrestrial con- 
 ditions. History tells how, under the 
 influence of causes that can be traced 
 back to the material earth, the destinies of 
 our race have been determined, nations have 
 been born, have grown, have flourished, and 
 have perished ; for whether we call it mother- 
 country or fatherland, the soil under our feet, 
 as in the Greek fable, is the true source from 
 which we draw our bodily, mental, and social 
 strength. 
 
 The persistent efficacy of these influences 
 is unmistakably shown by the little funda- 
 mental change that has taken place in the 
 geographical areas within or around which 
 the larger groups of human communities 
 continue to be associated, notwithstanding 
 
iv FORCE OF GEOGRAPHICAL INFLUENCES 201 
 
 the greatly varied political conditions to which 
 they have been subject. This is illustrated 
 in most of the States of Europe. The 
 Chinese empire still extends to what are 
 virtually its ancient limits, and maintains its 
 sway over a vast tract in Central Asia. The 
 local distribution of the several elements of 
 the population of India remains what it has 
 been for several thousand years. In the new 
 world fresh nationalities have replaced those 
 destroyed by the Spaniards in Mexico, Peru, 
 and Chili. The immigrant population of the 
 United States in North America appears to 
 have established itself in succession to the 
 race that formerly spread over the same area. 
 I cannot doubt that some of the political 
 problems that have arisen in our own country 
 at the present time will eventually be solved 
 under the pressure of geographical necessity. 
 Nor are geographical influences on man 
 limited to those of a material nature. The 
 
LECTURES ON GEOGRAPHY 
 
 constant succession of new objects which 
 gceets him as he changes his place on the 
 globe, excites in him an interest not awakened 
 by scenes of long-continued familiarity, and 
 is one of the most active agencies in arousing 
 his desire for knowledge. Thus too are 
 multiplied those fields of observation which 
 are the true and only sources from which he 
 draws his intelligence and originality ; for the 
 mind has no power of absolute production, 
 but only of perception and comparison. It 
 is the faculty of applying with rapidity and 
 precision the thoughts suggested by external 
 objects and their mutual relations, that 
 constitutes originality and gives the means of 
 invention. 
 
 This is as true of imagination as of reason ; 
 by the influence and study of external nature 
 are formed and developed man's emotional, 
 intellectual, and moral faculties. The emo- 
 tions created in the mind by the vast extent 
 
iv EXTENDS TO MAN'S MENTAL FACULTIES 203 
 
 of the ocean, its ever-moving surface, the 
 broken outlines of land and sea, the richness 
 and luxuriance of the vegetable clothing of 
 the earth, the astonishing variety of animal 
 forms, the many diverse races of men, the 
 never-ceasing transformations of the clouds 
 as they float overhead, the play of light and 
 colour over the whole of these objects, the 
 firmament set with stars, the unfathomable 
 depths of space, the large serenity of nature 
 at rest, her overwhelming violence in con- 
 vulsion — emotions thus created are the 
 source of all our ideas of the beautiful and 
 sublime. 
 
 A knowledge of the relations that subsist 
 among living beings, which is a direct result 
 of geographical discovery, shows us man's 
 true place in nature ; our intercourse with 
 other races of men in other countries teaches 
 those lessons needed to overthrow the narrow 
 prejudices of class, colour, and opinion, which 
 
204 LECTURES ON GEOGRAPHY iv 
 
 bred in isolated societies, and nourished with 
 the pride that springs from ignorance, have 
 too often led to crimes the more lamentable 
 because perpetrated by men capable of the 
 most exalted virtue. 
 
 In the review which I have thus attempted 
 of the matters that in my judgment would be 
 properly included in the geographical instruc- 
 tion to be undertaken by the University, it 
 has been my aim to treat the subject with 
 constant and almost exclusive reference to the 
 necessary relation of all that is upon the earth 
 with the features of the surface, which it is 
 the fundamental business of geography to 
 investigate and portray. A few words may, 
 I think, be usefully added on the correlative 
 aspect of the subject which regards geography 
 as an art that supplies man, through a 
 knowledge of the features of the surface and 
 their dependent attributes, with practical 
 
iv GEOGRAPHY AS A PRACTICAL ART 205 
 
 guidance in the affairs of life, or the advance- 
 ment of other branches of learning. 
 
 A very small amount of consideration will 
 show how intimately the geographical features 
 of a country are bound up with the interests 
 connected with it, and how important is a 
 knowledge of those features, and their accurate 
 delineation in maps. 
 
 The occupation of the earth's surface, from 
 the elementary unit of the smallest field or 
 humblest dwelling to the gradually increasing 
 area of the estate, the parish, the county, and 
 the kingdom, and thence to the largest 
 continent, can be defined with precision only 
 by the aid of maps ; and much in proportion 
 as correct maps have been applied to this end, 
 disputes and complications in relation to 
 property and jurisdictions have been avoided. 
 Most of the difficulties arising from the 
 extremely artificial system which secures titles 
 to land in this country, and from the chaotic 
 
2o6 LECTURES ON GEOGRAPHY 
 
 distribution of local authorities extending over 
 intersecting areas, would be removed, or 
 would never have been created, if the 
 commonest teachings of geography were 
 respected. Many of the gravest differences 
 that have arisen in modern times between 
 England and foreign countries have been due 
 to the neglect of the most simple and obvious 
 means of defining boundaries by aid. of proper 
 maps. I think I shall not be far wrong if I 
 attribute these results to the absence of a 
 rational system of teaching geography to those 
 who become our legislators and statesmen. 
 
 I have already said sufficient of the 
 necessity for accurate maps in navigation. 
 To the soldier, no less than to the sailor, 
 maps and the power of making them, and 
 understanding them rapidly and correctly, are 
 essentials of the highest moment. The 
 engineer is wholly dependent on exact 
 representations of both the horizontal and 
 
jv APPLIED TO COMMON AFFAIRS OF LIFE 207 
 
 vertical features of the surface in many of his 
 most important operations, and not less on a 
 proper knowledge of the climate, the rainfall 
 and the natural productions, mineral, veget- 
 able, and animal, of the countries in which he 
 is called on to carry out those operations. 
 The physician must be possessed of a 
 corresponding knowledge of the places to 
 which he sends his patients in search of 
 health, and must discriminate between the 
 characteristics of climate due to geographical 
 position and elevation above the sea-level. 
 To the trader geography supplies information 
 as to the condition of foreign countries to 
 which he sends his merchandise, or from which 
 he draws the commodities in which he deals ; 
 it will indicate the most convenient routes for 
 commerce, and open the way to new markets, 
 and to fresh fields from which to obtain 
 articles of utility or luxury. From geography 
 the emigrant seeks direction to a country 
 
208 LECTURES ON GEOGRAPHY iv 
 
 suited to his capacities and his constitu- 
 tion. 
 
 Geography furnishes the key by which 
 to interpret many events of the past, and 
 problems of the present, and supplies the 
 rough materials from which to build up the 
 great structure of natural science. Through 
 its aid, moreover, an instrument of research, 
 otherwise unattainable, may be to some extent 
 provided for the study of physical phenomena. 
 In dealing with many of these, no such control 
 of conditions is within our power as that 
 exercised in some branches of inquiry, 
 whereby it is possible to verify conclusions 
 by the aid of experiment, to vary the 
 conditions of investigation at pleasure, and to 
 draw inferences from the varying results 
 under the changed conditions. But this want 
 may be partly supplied, and a substitute 
 obtained for the power of direct experiment, 
 through observation of the effects produced 
 
iv ITS VALUE IN AIDING OTHER STUDIES 209 
 
 by the physical forces of nature, under the 
 varied conditions that follow variation of 
 geographical position on the globe. 
 
 The application of geographical consider- 
 ations to the study of meteorology, which led 
 to the use of synoptic charts exhibiting the 
 atmospheric conditions at a given moment 
 over a considerable area, was the immediate 
 cause of the great advance in the interpretation 
 of changes of weather that has taken place 
 during the last fifteen or twenty years. The 
 accumulation of knowledge from various 
 countries, of various forms of life, and of 
 the different conditions under which they are 
 found, could only have been obtained by 
 means of geographical exploration, and it was 
 this, without doubt, that rendered possible 
 the generalisations of Darwin and Wallace 
 as to the origin and distribution of species. 
 
 I have now discharged the task that I 
 
LECTURES ON GEOGRAPHY 
 
 undertook. It remains for the University to 
 carry out in a manner worthy of its reputation 
 the objects which the appointment of a 
 lecturer on geography is designed to meet. 
 The instruction given will doubtless supply 
 all needful corrections of the views I have 
 advanced (for I am conscious of very 
 insufficient knowledge of many parts of the 
 numerous subjects to which it was necessary 
 for me to refer), and fill in the outlines beyond 
 which it has been impossible for me to go ; 
 supplying illustrations of the particular re- 
 lations of the geographical conditions of the 
 various parts of the earth with the chief 
 classes of phenomena which they control or 
 influence, whether falling within the range of 
 natural science, history, or the economical 
 interests of man, and keeping constantly 
 before the student, by suitable examples, the 
 necessary interdependence of all that is seen 
 or done on the earth. 
 
CONCLUSION 
 
 I am confident that by these means the 
 University may become instrumental both in 
 providing teachers better qualified to diffuse 
 sound geographical knowledge through all 
 classes of our countrymen, and in training 
 travellers better able to extend that know- 
 ledge ; objects which are among the special 
 aims alike of the University and of the 
 Society which I have the honour to represent. 
 
 THE END 
 
 Printed by R. & R. Clark, Edinburgh. 
 
A NEW GEOGRAPHICAL SERIES. 
 
 Messrs. Macmillan and Co. are now issuing a series of geographi- 
 cal class-books under the editorship of Mr. Archibald Geikie, F.R.S., 
 Director-General of the Geological Survey of the United Kingdom, and 
 the following gentlemen have already expressed their interest in the 
 undertaking, and their willingness to assist either as writers or advisers. 
 H. W. Bates, F.R.S., Assistant- Secretary of the Royal Geographical 
 
 Society ; Author of "The Naturalist on the River Amazons." 
 A. Buchan, M.A., F.R.S.E., Meteorological Secretary of the Scottish 
 
 Meteorological Society. 
 John Scott Keltie, Librarian and Inspector of Geographical 
 Education to the Royal Geographical Society; Editor of "The 
 Statesman's Year-Book." 
 J. Norman Lockyer, F.R.S., Correspondent of the Institute of 
 France; Author of "Solar Physics," "Elementary Lessons in 
 Astronomy," etc. 
 Clements R. Markham, C.B., F.R.S., Secretary of the Royal 
 
 Geographical Society. 
 John Murray, Ph.D., F.R.S.E., Director of the Challenger Expedi- 
 tion Commission. 
 Rev. H. F. Tozer, M.A., Fellow of Exeter College, Oxford ; Author 
 
 of " The Geography of Greece," " Highlands of Turkey,'' etc. 
 E. B. Tylor, D.C.L., F.R.S., Keeper of the University Museum, 
 
 Oxford ; Author of " Primitive Culture," etc. 
 A. R. Wallace, LL.D., F.R.G.S., Author of "The Malay Archi- 
 pelago," "The Geographical Distribution of Animals," etc. etc. 
 Rev. Edmond Warre, D.D., Head Master of Eton. 
 Rev. J. E. C. Welldon, M.A., Head Master of Harrow. 
 
 The following is the List of Volumes contemplated : — 
 
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 for the use of Teachers. By Archibald Geikie, F.R.S., 
 Director-General of the Geological Survey of the United Kingdom, 
 and Director of the Museum of Practical Geology, Jermyn Street, 
 London ; formerly Murchison Professor of Geology and Mineral- 
 ogy in the University of Edinburgh. Crown 8vo. 2s. [Ready. 
 *»* The aim of this volume is to advocate the claims of geography 
 as an educational discipline of a high order, and to show how 
 these claims may be practically recognised by teachers. 
 
 The Saturday Reviewsxys :— " Mr. Geikie treats his subject in its fullest accept- 
 ation. His general principles must commend themselves to every teacher who wants 
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GEOGRAPHICAL SERIES— Continued. 
 
 An Elementary Geography of the British Isles. By 
 Archibald Geikie, F.R.S., etc. i8mo. is. [Ready. 
 
 The Educational News says : — " This is quite a charming little geographical 
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 takes up each country separately, and briefly discusses its size, population, towns, 
 products, etc. etc. It makes the subject very interesting." 
 
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 printed in Colours. By John Bartholomew, F.R.G.S. De- 
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 Geography. 4to. is. [Ready. 
 
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 treated generally, it being reserved for more advanced School Atlases in this series to 
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 political maps of the continents, the British Islands and Australasia, all brightly 
 coloured." 
 
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 10. Advanced Class-Book of the Geography of Britain. 
 
 11. Geography of Australia and New Zealand. 
 
 12. Geography of British North America. 
 
 13. Geography of India. 
 
 14. • Geography of the United States. 
 
 15. Advanced Class-Book of the Geography of Europe. 
 
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MESSRS. MACMILLAN & CO.'S PUBLICATIONS. 
 
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 *