OLIVER EVANS,
THE WATT OF AMERICA,




A CATECHISM
OF
HIGH PRESSURE
OR
Non-Condensing Steam  Engines.
INCLUDING THE
MODELING, CONSTRUCTING, RUNNING AND
MANAGEMENT
OF
STEAM ENGINES AND STEAM BOILERS.:ith tbliion~.
BY STEPHEN ROPER,
ENGINEER.
PHILADELPHIA:
CLAXTON, REMSEN & HAFFELFINGER,
624, 626 & 628 MARKET STREET.
1874.




Entered, according to Act of Congress, in the year 1873, by
STEPHEN ROPER,
in the Office of the Librarian of Congress, at Washington...........................................................................................................
J. FAGAN & SON,
STEREOTYPEaS, PHILAD'A.
Selheimer &  Moore, Printers,
501 Chestnut Street.




THIS VOLUME
IS
ty d$attA
TO
ARTHUR  ORR, D.M.P.,
AS A TRIBUTE OF RESPECT TO HIS EMINENT ABILITIES
AS AN ENGINEER AND MECHANIC.








INTRODUCTION.
THE writer of the following pages has made it his
study to produce a work for the use of practical engineers, by furnishing them with a simple and clear explanation of each subject treated. In its preparation a
great effort has been made to secure accuracy, and to
render every subject plain and easy of comprehension,
by treating it in a clear style, taking up each subject in
regular order and examining it by the light of daily
experience. The range of subjects comprehends everything directly connected with the steam-engine and
steam-boiler. At the end of many of the articles, tables
have been appended and examples introduced, to make
explicit and distinct the principles set forth.
Many of the books heretofore published have been
written by men Of mere theory, for the purpose of instructing practical engineers in matters which the authors
have never learned. Abstract theory can never meet the
wants of practical men, nor instruct them in the discharge
of their duties. But the writer does not wish to be considered an unbeliever in theories; because theories can
never be dispensed with by any class of men, however
unlearned, as theories aid us in the discovery of new facts
and new truths. A book, however, to be useful to all classes
vii




V111             INTRODUCTION.
of engineers, must give strong evidence of the author's
experience as a practical engineer. The writer has had
an experience of over thirty years with every description
of engines and boilers, and in the preparation of this
little book he has drawn almost entirely upon his own
experience and observation. His aim has been to convey
his meaning, to those for whom it is intended, by means
of plain language, with familiar and practical illustrations, and to instruct'those who are intrusted with the
care and imanagement of steam-engines and steam-boilers,
so that they may understand with certainty whether they
are deriving the greatest amount of practical advantage
from the power they have generated. Hints and examples have also been given, intended to show how a great
many practical improvements can be made by engineers
and owners of steam-engines.
Another feature of the work, and one which it is believed will greatly benefit engineers of limited education,
is that the use of decimals has been dispensed with, and
fractions also, except those expressed by the common
signs, i, ~,:, &c.
In order to render the book useful to those who employ
or are employed about steam-engines, the writer has endeavored to embody all the necessary information relative to improvements in the construction, use and management of steam-engines and steam-boilers that have
come into use up to the present time.
S. R.




CONTENTS.
PAGE
INTRODUCTION                                    vii
THE STEAM-ENGINE..13
WATER.                                          15
Table showing the Weight of Water in Pipes of
Various Diameters One Foot in Length. 19
AIR                                              20
Table of Expansion of Air by Heat. Showing
the Increase of Bulk in Proportion to the
Increase of Temperature.... 22
H[EAT                                            23
Table showing the Temperature required to
Ignite different Substances.... 27
THE THERMOMETER                                  27
Comparative Scale of English, French and German Thermometers.                          29
STEAM.                                          30
Table showing the Temperature of Steam at
different Pressures.                      35
THE ENGINEER                                     36
THE STEAM-BOILER.'... 41
Cylinder Boilers.44
Flue Boilers....... 46
Tubular Boilers.47
Double-Deck Boilers.                        49
Locomotive Boilers.               49
Mud-Drums....                               50
Boiler-Heads..                              51
Boiler-Shells...52
Table deduced from Experiments on Iron Plates
for Steam-Boilers, by the Franklin Institute,
Philadelphia...59
Table deduced from Experiments on Iron of different Boilers, by the Stevens Institute of
Technology....                     60
Steel Boilers..                            61
is




x                   CONTENTS.
PAGE
Internal and External Pressures...   62
Rules.                                      64
Table of Internal Pressures..   67, 68, 69, 70
Foaming in Steam-Boilers.... 71
Rust..                                    72
Patent Steam-Boilers....  72
THE SAFETY-VALVE..... 73
Rules.....                                  76
Table for Safety-Valves...         79
FEED-WATER HEATERS..... 80
FUEL.... 83
Table showing the Total Heat of Combustion of
Various Fuels.....85
CHIMNEYS..                                     85
SMOKE.. 87
GRATE-BARS                                       89
DUTIES OF AN ENGINEER IN THE CARE AND MANAGEMENT OF THE STEAM-BOILER.        93
STEAM-ENGINES.               106
Table showing the Average Pressure of the
Steam. upon the Piston throughout the Stroke 116
Lap on the Slide-Valve..118
Table showing the Amount of "Lap" required
for Slide-Valves when the Steam is to be
worked expansively.....               120
Lead on the Slide-Valve                     121
"Cushion "......123
Setting Valves..... 124
Size of Steam-Port.....     126
Size of Steam-Pipe.                        127
Size of Exhaust-Pipe... 127
Size of Piston-Rod.                        127
Material for Different Parts of Engines. 128
Spring-Packing.129
Proportions of Engines..129
Reversing an Engine.130
Putting an Engine in Line. 130
Setting up Engines..                  132
Table containing the Circumferences and Areas
of Circles from 4 to 26 inches in Diameter 134-137




CONTENTS.                 xi
PAGE
RULES FOR THE CARE AND MANAGEMENT OF
THE STEAM-ENGINE.. 138
DIFFERENT KINDS OF ENGINES...  142
KNOCKING IN ENGINES.. 149
VACUUM.....    151
THE INDICATOR.....                          154
Explanation...                         164
Remarks.                               165
Rule for Computing the Power of a Diagram   165
THE GOVERNOR. 166
Short Rules for Calculating the Size of Pulleys
for Governors.. 170
THE INJECTOR..  170
Table of Capacities of Injectors. 174
STEAM-PUMPS....    176
CENTRIFUGAL PUMPS....    178
NOISELESS BOILER FEED-PUMP.         180
Directions for Setting Up Steam-Pumps. 180
Table containing the Diameters, Circumferences,
and Areas of Circles, and the Cubical Contents of Cyvlinders, in Gallons..  182
PISTON-ROD PACKING....  184
INCRUSTATION.. 185
BOILER EXPLOSIONS...          193
STEAM- AND FIRE-REGULATOR..     198
CENTRAL AND MECHANICAL FORCES..  200
MENSURATION.. 201
Circle, Cylinder, Sphere, etc.          201
BELTINGC.. 205
Leather Belts.                          206
Lacing Belts.             207
Horizontal Belts.207
Perpendicular Belts.. 207
Greasing Belts                           208
Rules for Finding the Proper Width of Belts. 208
RULES TO BE OBSERVED IN CASE OF ACCIDENTS   209
A BRIEF HISTORY OF THE STEAM-ENGINE.. 210
History of the Different Parts of the SteamEngine in Detail.212
VOCABULARY...213




I
THE ENGINEER'S CHART.
xii




A CATECHISM
OF
HIGH PRESSURE,
OR
NON CONDENSING STEAM.ENGINES.
THE STEAM-ENGINE.
IN the early records of the human race, whenever
power was required in order to provide for human wants, it was supplied by the muscles of human
beings, or by those of horses, oxen, or other animals.
But men soon learned to supplement muscular
power with that created by the descent of water, and
by the winds of heaven. In modern times even
these sources of power have been to a great extent
superseded by steam, and at the present day there
is hardly any purpose for which power is required,
that is not furnished by the steam-engine.
Of all the efforts of human ingenuity known, perhaps none has monopolized so large a share of inventive genius as the steam-engine. No other object in
the entire range of human devices has so irresistibly
arrogated to itself the devotion of scientific men, as
2                               13




14      CATECHISM OF HIGH PRESSURE, OR
the production of an artificial movement from the
vapor of boiling water.
The progressive history of the invention commences with the days of Hero of Alexandria, two
thousand years ago, and advances down through the
labors of the Marquis of Worcester, of Savery and
Papin, to the days of Watt, whose splendid improvements of the working principle of the steam-engine
are well known.
In late years the improvement of the steam-engine
has been steady, rather than remarkable in any one
particular. It has advanced by improvement in
construction, rather than by the development of any
new principle. The facilities for the manufacture of
steam-engines, and the amount of capital invested in
that branch of mechanics, has increased very rapidly
within the last few years.
Thousands of skilled workmen are continually inventing ingenious devices to replace the different
parts of the engine now in use, and modifications are
constantly resorted to to secure good construction
and general improvement.
As might be expected, we find an infinite variety
of constructions, some of inferior design, inferior
workmanship, and inferior finish, whilst others have
splendid symmetrical proportions, elaborate finish,
and beautiful and simple mechanism.
But still there appears to be a wide field open for
experiment and improvement in the steam-engine,




NON-CONDENSING STEAM-ENGINES.       15
since it is asserted by persons competent to judge,
that first-class engines yield less than ten per cent. of
the work stored up in good fuel, and the average engines probably utilize less than four per cent. of the
fuel.
The best steam-engine, apart from its boiler, has
about ive-sixths of the efficiency of a perfect engine.
The remaining sixth is lost through waste of heat by
radiation and conduction externally, and by condensation and friction externally.  It is to improvements in these points that inventors must turn their
attention.
WATER.
Q. What are the constituent parts of fresh-water?
A. Oxygen and hydrogen.
Q. In what proportion?
A. Oxygen, 89 parts by weight, and by measure I
part; hydrogen, by weight 11 parts, and by measure
2 parts.
Q. How many cubic feet of fresh-water make 1
ton?
A. 36 cubic feet.
Q. How many cubic feet of sea-water make 1 ton?
A. 35 cubic feet.
Q. How do you account for the difference in
weight between sea- and fresh-water?
A. Sea-water is more dense.




16     CATECHISM OF HIGH PRESSURE, OR
Q. How much does a cubic foot of water weigh?
A. 62~ pounds.
Q. How many gallons in a cubic foot of water?
A. 61 gallons.
Q. How much does a cubic inch of water weigh?
A. About I an ounce.
Q. How much does a cylindrical foot of water
weigh?
A. 49 pounds.
Q. What is the weight of a cylindrical inch of
water?
A. Nearly i an ounce.
Q. How much does a cubic foot of ice weigh?
A. 681 pounds.
Q. What is the boiling-point for water?
A. 2120 Fah.
Q. What is the freezing-point of water?
A. 32~ Fahrenheit.
Q. What is the difference between water, ice, and
steam?
A. Water is a fluid, ice is a solid, steam is a vapor.
Q. What is the difference in volume between
water and steam at the pressure of the atmosphere?
A. 1700; that is to say, that any given quantity
of water will make 1700 times that amount of steam
at a pressure of 15 pounds to the square inch, or atmospheric pressure.
Q. At what temperature does water attain its
greatest density?




N01-CONDENSING STEAM-ENGINES.        17
A. 390 Fah.
Q. Is water compressible?
A. No: it-presses in every direction and finds its
level.
Q. What is the centre of pressure of a column of
water?
A. 3 of its depth from the surface.
Q. At what degree of temperature does the water
boil in a vacuum?
A. 980 Fah.
Q. At what degree of temperature does water become solid?
A. 32~ in the open air.
Q. Does water expand in freezing?
A. Yes.
Q. Do all fluids expand with heat?
A. Yes; all fluids expand with heat, and contract
with cold down to 400 Fah.
Q. Are all waters equal for the production of
steam?
A. No; sea-water, or other waters holding salt in
solution, require a higher temperature to produce
steam of the same elastic force.
Q. How is the gravity of water ascertained?
A. By means of a hydrometer.
Q. If water be boiled in an open vessel, can the
temperature of the water be raised above 212~ Fah.?
A. No; as all the surplus heat which may be applied passes off with the steam.
2*                B




18      CATECHISM OF HIGH PRESSURE, OR
Q. How do you explain the theory of ebullition,
or boiling water?
A. In this way; that in metals heat is communicated by the conducting properties they possess, but
in liquids heat is communicated by a separation of
particles.
Q. If heat be applied to the top of a vessel containing water, will ebullition take place?
A. No; as very little heat will be communicated to
other parts of the vessel, and the water will never boil.
Q. Is it a common thing in steam-boilers to indicate a larger supply of water than that which really
exists in the boiler?
A. Yes; as the steam is forming in the water it
rises in bubbles to the surface, which by their bulk
displace a great amount of water, indicating a great
rise at the gauge-cocks.
Q. What is the vaporization of water?
A. It is the conversion of water, as a liquid, into
vapor as steam.
Q. What is solidification?
A. It is a change which water undergoes from a
liquid to ice as a solid.
Q. Does the density of water increase with its
depth?
A. Yes; there is a theoretical depth at which water
would become as dense as iron.




'ON-CONDENSING STEAM-ENGINES.              19
TABLE
SHOWING THE WEIGHT OF WATER IN PIPES OF VARIOUS
DIAMETERS ONE FOOT IN LENGTH.
Diameter  Weight   Diameter  Weight  Diameter  Weight
in Inches. in Pounds. in Inches. in Pounds. in Inches. in Pounds.
3        3        121      51        23      1801
31       31       12~      531       231    188s
3~       41       121      55I    24         1961
31       43       13       57j       24~    2041
4        5~       131      591       25      213
41       61       13~      621       25I     221~
4~       7        131      64~       26      230~
43       7        14       661       26~    239~
5        8~       141      694       27      248~
51       91       14~      71~       27~    2571
5~      101       141      741       28      2671
50      11i       15       764       28~    2761
6       121       151      791       29      286~
61      131       15~      82        29~     296~
6~      14~       151      84~       30      3061
61      15  16             871       30i    3171
7       161       16i      90        31      327~
71      18        16~      921       31~    3381
7~      191       16t      95~       32      349
71      20~       17       98~       32~    360
8       21:       171    101~        33      3711
81      231       17~    104~        33~    382~
8~      24~       171    1071        34      394
81      26        18      110       34~    4051
9       27~       181    113~        35      417~
91      291       18~     116~       35~    429~
9~      301       181    1194        36      4411
9       32~       19      123        36~    454
10       34        191    1264        37      466~
10       35~       19/     129~       371    4791
10~      37~       191    132         38      4921
10      391       20      1361       38~    5051
11      411        20~     1431       39      518~
11     431        21      1501       391    5311
11+      45        21~    157~        40      5451
11t      47        22      165
12    I 49         22~    172~




20      CATECHISM OF HIGH PRESSURE, OR
AIR.
Q. What are the constituent parts of air, or what
does air consist of?
A. It consists, by volume, of oxygen 21 parts, of
nitrogen 79 parts, and by weight, of oxygen 77 parts,
and of nitrogen 23 parts.
Q. Does any other gas enter into the constituent
parts of air?
A. Yes; in 1,000,000 parts of air there are 4 parts
of carbonic acid.
Q. How many cubic feet in 1 pound of air?
A. 13,817 cubic feet.
Q. What is the weight of 1 cubic foot of air at
the surface of the earth, temperature 34  Fah.?
A. 527 grains, or i ounce avoirdupois.
Q. What is the difference in weight between air
and water?
A. Air is 829 times lighter than water.
Q. What is the mean weight of a column of air 1
inch square and 45 miles high?
A. 15 pounds
Q. Is the pressure of the air the same at all altitudes?
A. No; at 7 miles above the surface of the earth
the air is 4 times lighter than at the earth's surface;
at 14 miles, 16 times; at 21 miles, 64 times.
Q. How much air does it require to consume 1
pound of coal?




NON-CONDENSING STEAM-ENGINES.       21
A. 18 pounds, or 240 cubic feet.
Q. Is it possible to construct an air-engine of any
great power?
A. No; as -air, like all other gases, expands but
one volume for each 4930 of temperature through
which it is raised; and in order to double its volume,
we must raise it 4930 more, which will bring it to a
temperature of 9860 Fah., which is entirely too
high for practical purposes. Even if air could be
worked at this temperature, it would be necessary to
have a feed-pump of nearly the capacity of the engine, which would be very cumbrous, and the engine
itself would have to be more than twice the size of a
steam-engine of the same power.
Q. Is it possible to obtain much power from air at
a lower temperature?
A. Yes; but as we lower the temperature, we must
increase the capacity of the engine and pump, which
will become very bulky and expensive.
Q. Is the expansion of air, like all other elastic
fluids, uniform at all temperatures?
A. Yes; the following table will show the rate of
expansion of and according to temperature:




22          CATECHISM OF HIGH PRESSURE, OR
TABLE.
EXPANSION OF AIR BY HEAT. SHOWING THE INCREASE OF
BULK IN PROPORTION TO THE INCREASE OF TEMPERATURE.
Fahrenheit.                   Bulk.  Fahrenheit.                     Bllk.
Temp. 32 Freezing-point. 1000   Temp. 75............ 1099
c   33..................... 1002      "   76 Summer heat... 1101
"   34..................... 1004     I"   77............ 1104
"   35..................... 1007     c"   78................. 1106
"   36..................... 1009     i"   79.................... 1108
"   37..................... 1012     I"   80................. 1110
"   38.................... 1015     i"   81................. 1112
"   39..................... 1018     9"   82................. 1114
40..................... 1021         i" 83................. 1116
41..................... 1023         "   84................. 1118
"   42..............  1025            "   85..................... 1121
"   43..................... 1027      "   86................. 1123
44..................... 1030           " 87................. 1125
"   45..................... 1032     "   88................. 1128
"   46.................... 1034       "   89................. 1130
"   47................... 1036      "   90................. 1132
48..........1........... 038    i"   91.................. 1134
if   49.................... 1040     i"   92................. 1136
"   50..................... 1043    ("   93................. 1138
"   51..................... 1045."   94.................. 1140
"   52..................... 1047    i"   95................. 1142
i"   53..................... 1050    "   96 Blood heat...... 1144
"   54................    1052          " 97................. 1146
"   55..................... 1055     ".  98................. 1148
"   56 Temperate....... 1057          "   99................. 1150
"   57..................... 1059      "  100..................... 1152
"   58..................... 1062     "  110 Fever heat 112 1173
"   59................... 1064       "  120.................. 1194
"   60..................... 1066     "  130................. 1215
"   61..................... 1069     "140..................... 1235
2..................... 1071         "  150................... 1255
"   63................... 1073       "  160................. 1275
"   64..................... 1075     "  170 Spirits boil 176 1295
"   65..................... 1077      "180 180................. 1315
"   66.................... 1080       "  190................ 1334
"   67.................... 1082      "  200................. 1364
"   68.................... 1084       "  210................. 1372
"    69..................... 1087     "  212 Water boils..... 1375
" 70..................... 1089        "  302..................... 1558
"   71..................... 1091      "  392..................... 1739
"   72.................... 1093      "  482................. 1919
"   73.................... 1095       "  572................. 2098
"   74..................... 1097      "  680..................... 2312




NON-CONDENSING STEAM-ENGINES.       23
HEAT.
Q. What is heat?
A. It is a species of motion, or one form of mechanical power.
Q. Is heat capable of producing power?
A. Yes; and power is capable of producing heat.
Q. With any given degrees of temperature, and
any given expenditure of heat, will the amount of
power generated be the same?
A. Yes.
Q. What is specific heat?
A. Specific heat of a substance is an expression for
the quantity of heat in any given weight of it at certain temperatures.
Q. What is sensible heat?
A. That which is sensible to the touch.
Q. What is latent heat?
A. It is that which a body absorbs in changing
from a solid to a fluid state.
Q. What is meant by the radiation of heat?
A. It is the effect produced by the direct rays of a
hot body through space.
Q. Is the latent heat in steam uniform at all temperatures?
A. No; neither is the total amount of heat the
same at all temperatures.
Q. Does the total and latent heat in steam increase
with the pressure?




24     CATECHISM OF HIGH PRESSURE, OR
A. No; as the sensible heat increases the latent
heat diminishes.
Q. Can the absolute heat of any body be determined?
A. Only by the relative heat of other bodies at the
same temperature.
Q. What is combustion?
A. It is an energetic combination of gases, or a
mutual neutralization of opposing electricities.
Q. Does the quantity of heat in any body vary
with the temperature?
A. Yes; the temperature of steam rises with the
pressure.
Q. What method is adopted to determine temperatures so high that no thermometer can give a reliable result?
A. We take a body, such as platinum, and place
a mass of this metal in a blast furnace, and when the
mass has acquired the temperature of the furnace we
transfer it to a vessel containing a known weight of
water. We can then observe the rise of temperature
by means of an ordinary thermometer.
Q. How do you determine the specific heat of different bodies?
A. By mixing different substances together at different temperatures, and noting the temperature of
the mixture. For instance, when water is at 1000 and
mercury at 400, the mixture will be at 80~; the 20~
lost by the water causes a rise of 40~ in the mercury.




NON-CONDENSING STEAM-ENGINES.        25
Q. What is a unit of heat?
A. The unit of heat is the amount of heat required
to raise the temperature of 1 pound of water 1~, or
from 320 to 330 Fah.
Q. What is the mechanical equivalent of heat?
A. The power necessary to raise 1 pound 772 feet
high.
Q. What is the capacity of any body for heat?
A. It is the relative power of a body in receiving
and retaining heat at any given temperature.
Q. What is the reflection of heat?
A. It is the passage of heat from one surface to:
another, or into space.
Q. What is the communication of heat?
A. It is the passage of heat to different bodies with
different degrees of velocity.
Q. What is the transmission of heat?
A. It is the passage of heat through different
degrees of intensity.
Q. How much heat does a pound of water receive
in passing from a liquid at 2120 Fah. to a vapor at
2120?
A. It receives as much heat as would raise it 9660
if the heat was sensible as well as latent.
Q. What is conversion of heat?
A. It is the transfer or diffusion of heat in a fluid
mass by means of its particles.
Q. Will water boil in a vacuum with less heat
than under the pressure of the atmosphere?
3




CATECHISM OF HIGH PRESSURE, OR
A. Yes; in a vacuum water boils at 980 to 100~,
according as the vacuum is perfect.
Q. Does water give out heat in freezing?
A. Yes; water in freezing gives 1400 of heat.
Q. At what degree of temperature do fluids evaporate in a vacuum?
A. From 100~ to 1200 below the boiling-point.
Q. What is a thermal unit?
A. It is the quantity of heat required to raise 1
pound of water 10, the water being at its maximum
density (- 390 Fah.).
Q. How can the amount of heat stored up in any
fluid, that might be utilized by perfect mechanism,
be shown?
A. It must be represented by a fraction, the numerator of which is the temperature of the fluid
while doing its work, and the denominator the temperature of the fluid when entering a vessel, to be
measured from absolute zero.
Q. Does the nature of the medium upon which
heat acts in the production of power make any
difference?
A. No; whether water, air, metal, or any other
substance is the medium, it is immaterial, except so
far as the agent is convenient and manageable; and
just in the proportion in which power is generated,
so will heat disappear.




WNON-CONDENSING STEAM-ENGINES.              27
TABLE.
The following Table will show the Temperature required
to Ignite different Substances.
Name of Substance.                        Temp. of Ignition.
Phosphorus........................................ 1400 Fah.
Bisulphide of Carbon.......................... 3000  "
Fulminating Powder........................... 374~ "
Fulminate of Mercury........................ 3920  "
Gun-Cotton...................................... 428~ "
Nitro-Glycerine..................................    494~ "
Rifle-Powder...................................... 550~ "
Forced Gunpowder.............................. 563   "
Picrate Powder for Torpedoes................ 5700 "
Charcoal from Willow Wood................ 6600 "~
Picrate Powder for Cannon................... 715~  "
Very Dry Pine Wood......................... 8000  "
Dry Oak Wood................................ 900~
Steam, 100 lbs. per square inch pressure.. 332~
Steam, 200 "   "    "                     387~  "
Steam, 240 "   "'4    "       "       403~ "
THE THERMOMETER.
Q. What is an absolute zero?
A. It is the point at which heat-motion is supposed
to cease entirely, estimated to be 461~ Fah. below
the zero of the common scale.
Q. How is the zero of the common scale fixed?
A. It is fixed by mixing salt with snow until the
mercury in the tube falls 32~ below  the freezingpoint for water.
Q. What do you mean by Fahrenheit?
A. I mean Fahrenheit's scale or thermometer, the
one generally used in this country.
Q. What do you mean by Centigrade?




28      (~CATECHISM OF HIGH PRESSURE, OR
A. I mean the Centigrade scale or thermometer,
by which they measure temperatures in France.
Q. What do you mean by Reaumur?
A. I mean Reaumur's rule or thermometer that is
commonly used in Germany.
Q. What is the difference between Fahrenheit's,
Centigrade, and Reaumur's rules?
A. Fahrenheit's zero is 320 below freezing, boilingpoint of water 2120; Centigrade, zero 320 or freezing,
boiling-point 1000; Reaumur's, zero 320 or freezing,
boiling-point 800. Hence Fahrenheit 180~, Centigrade 1000, Reaumur 80~.
Q. What are fixed temperatures?
A. One the melting-point of ice, and the other
the boiling-point of pure water.
Q. Why do you call these fixed temperatures?
A. Because it is impossible to raise the temperature of ice above 32~ Fah., and no amount of heat
will raise boiling water above a temperature of 2120
Fah., if contained in an open vessel.
Q. Does the thermometer indicate the amount of
heat in any body?
A. No; only the changes in temperature.
Q. What is a differential thermometer?
A. An instrument that measures minute differences of temperature.




NON-CONDENSING STEAM-ENGINES.          29
COMPARATIVE SCALE OF ENGLISH, FRENCH
AND GERMAN THERMOMETERS.
Boiling-point 100 --  212-  80 Boiling-point
of water.          200         of water.
90 —  190 — 70
80-  1800 —        60
-   — 60
60 -   140  — 50
50 — 10    _ 40
-110
4O —  _ - -— 30
30 ---  90
20-  70_- 20.20 — 70 — 20
Mercuryfre    -   0       1- 20
Freezing-point.. 0 -    0
= 40
84




30      CATECHISM OF HIGH PRESSURE, OR
STEAM.
Q. What is steam?
A. Steam is vapor arising from water at a temperature of 2120 Fah.
Q. What are the most prominent properties possessed by steam?
A. First, its high expansive force; second, its property of condensation; third, its concealed or undeveloped heat.
Q. By whom were the expansive properties of
steam discovered?
A. By Hornblower, who obtained a patent for his
invention in 1781.
Q. From what cause does the expansive force of
steam arise?
A. From the absence of cohesion between the particles of water.
Q. How is the condensation of steam effected?
A. By the abstraction of its temperature.
Q. What is the difference in volume between
water and steam at a temperature of 2120 Fah.?
A. 1700; that is to say, any given quantity of
water converted into steam at the pressure of the atmosphere or 2120 Fah., will present a volume 1700
times greater than its original bulk.
Q. Can steam mix with air?
A. Not while its pressure exceeds that of the atmosphere.




WON-CONDENSING STEAM-ENGINES.      31
Q. If a cylinder be filled with steam at a pressure
of 15 pounds to the square inch, will the air be
expelled from the cylinder?
A. Yes.
Q. Now as the existence of the steam depends upon
its temperature, by abstracting that temperature will
the steam assume the state due to its reduced temperature?
A. Yes; by immersing the cylinder in cold water
the steam contained therein is condensed into water.
Q. Now, as the water cannot occupy the volume
which it did under its former temperature, what is
the result?
A. As the steam in the cylinder is condensed by
the abstraction of its heat, the result will be a vaCuuln.
Q. What is the amount of latent or concealed
heat that exists in steam?
A. The latent heat of steam, though showing no
effect on the thermometer, may be easily shown by
placing 5~ pounds of water in a vessel at 32~ Fah.,
and admitting steam through a pipe from another
vessel until the temperature of the water in the first
vessel is raised to the boiling-point. It will then be
discovered that the weight of the water in the vessel
is 6~ pounds.
Q. How do you account for this additional pound
of water?
A. It is the result of the admission of one pound




32     CATECHISM OF HIGH PRESSURE, OR
of steam to the vessel; and this pound of steam, while
retaining its own temperature of 212~, has raised 5]
pounds of water 180~, or an equivalent to 9900, and
including its own temperature we have 1202~, which
the pound of steam must have possessed at first.
Q. Is the sum of latent and sensible heat of steam
nearly constant?
A. Yes; and does not vary much from 1200~.
Q. If a known volume of steam of a certain pressure be made to occupy ~ that volume, is its elastic
force doubled?
A. Yes; the same pressure is exerted within I of
its original capacity.
Q. What do you mean by steam pressure?
A. I mean the initial elastic force of the steam,
which is always the same in equal weights of steam.
Q. Does the elasticity of steam increase with an
increase of temperature?
A. Yes, but not in the same ratio; because if
steam is generated from water at a temperature which
gives it the pressure of the atmosphere, an additional
temperature of 380 will give it a temperature of two
atmospheres, and a still further addition of 420 will
give it a pressure of 4 atmospheres.
Q. Why is it that every additional degree of temperature between 40 and 50 doubles the pressure?
A. The heat in generating the steam has to overcome the attraction among the particles of water, and
likewise of the gravity of the water itself; and as the




NON-CONDENSING STEAM-ENGINES.       33
water becomes rarefied by heat, the attraction and
gravity become diminished, and an additional tem-n
perature does not have to contend with the same resistance as the one that preceded it.
Q. Is steam in itself invisible?
A. Yes; and it only becomes visible by loss of
temperature, as when a jet is discharged into the
open air, and is then seen in the form of vapor.
Q. In treating of steam, why are the terms heat
and caloric used?
A. The term heat is understood as expressing sensible heat, while the term caloric expresses every
conceivable existence of temperature.
Q. Is steam produced from impure water equal in
density to steam from pure water?
A. No; steam from pure water, at a temperature
of 2120 Fah., supports a column of. mercury of 30
inches, while steam from sea or impure water, at the
same temperature, supports only 22 inches.
Q. Can the heat of steam be raised to a very high
temperature?
A. Yes; steam can be heated to nearly a red heat,
but not while it is held in contact with water.
Q. Does the temperature of steam at ordinary
pressure contain heat enough to ignite wood?
A. Not without the intervention of some other
substance, such as linseed oil, greasy rags, or iron
turnings.
Q. How do you explain that?
C




34     CATECHISM OF HIGH PRESSURE, OR
A. Because we know that the temperature of
superheated steam is only about 400~ Fah., and it
requires more than double that intensity of heat to
ignite wood. See Table under the head of Heat.
Q. What is liquefaction?
A. It is the condensing of steam through the
abstraction of heat.
Q. Do you know of any reliable rule for connecting the temperature and elastic force of saturated
steam?
A. No; various formulas have been at different
times introduced for the purpose of deducing the
elastic force of saturated steam, but without any very
reliable or satisfactory results.
Q. Can you tell the number of superficial feet of
steam-pipe necessary to warm any room or number
of rooms?
A. One superficial foot of steam-pipe to 6 superficial feet of glass in the windows, or 1 superficial foot
of steam-pipe for every 100 square feet of wall, roof
or ceiling, or 1 square foot of steam-pipe to 80 cubic
feet of space; 1 cubic foot of boiler is required for
every 1500 cubic feet of space to be warmed. One
horse-power boiler is sufficient for 40,000 cubic feet
of space.




NON-CONDENSING STEAM-ENGINES.                            35
TAB I E.
Showing the Temperature of Steam at different Pressures,
from 15 pounds per Square Inch to 100 pounds, and the qiuantity of Steam produced from a Cubic Inch of Water according
to Pressure.
Total                                Total
Pressure  Corresponding CubicInches of Pressure  Corresponding  Cubic Inches
of Steam  Temperature of Steam from a  of Steam  Temperature of of Steam from
in lbs.    Steam to    Cubic Inch of  in lbs.   Steam to   a Cubic Inch of
perSquare    Pressure.   Water accord- perSquare   Pressure.  Water accordInch.                ing toPressure.  Inch.                ing toPressure.
15        212 8          1669         58        292.9          484
16        216.3          1573         59        294.2          477
17        219.6          1488         60        295.6          470
18        222.7          1411         61        296.9          463
19        225.6          1343         62        298.1          456
20        228.5          1281         63        299.2          449
21       2231.2          1225         64        300.3          443
22        233.8          1174         65        301.3          437
23        236.3          1127         66        302.4          431
24        2:38.7         1084        67         303.4         425
25        241.0          1044        68         304.4         419
26        243.3          1007        69         305.4         414
27        245.5           973        70         306.4         408
28        247.6           941        71         307.4         403
29        249:6           911        72         308.4         398
30        251.6           883        73         309.3         393
31        253.6           857         74        310.3         388
32        255.5           833         75        311.2         383
33        257.3           810         76        312.2         379
34        259.1           788         77        313.1         374
35        260.9           767         78        314.0         370
36        262.6           748.79        314.9         366
37        264.3           729         80        315.8         362
38        265.9           712         81        316.7         358
39        267.5           695         82        317.6         354
40        269.1           679         83        318.4         450
41        270.6           664         84        319.3         346
42        272.1           649         85        320.1         342
43        273.6           635         86        321.0         339
44        275.0           622         87        321.8         335
45        276.4           610         88        322.6         332
46        277.8           598         89        323.5         328
47        279.2           586        90         324.3         325
48        280.5           575        91         325.1         322
49        281.9           564        92         325.9         319
50       283.2            554        93         326.7         316
51       284.4            544        94        327.5          313
52       285.7            534        95         328.2         310
53        286.9           525        96         329.0         307
54        28S.1           516        97         329.8         304
55        289.3           508        98         330.5         301
66        290.5           500        99         331.3         298
57        291.7           492       100         332.0         295




36      CATECHISM OF HIGH PRESSURE, OR
THE ENGINEER.
THE duties of an engineer intrusted with the care
and management of a steam-engine and steam-boilers,
are of more importance than would appear at first
sight, as the mechanics of any other class might be
ignorant or neglectful of duty without subjecting
themselves or their employers to any danger or much
inconvenience; but ignorance or neglect of duty on
the part of an engineer, might at any time result in
great destruction to life and property.
Steam-boilers require constant care and attention,
and when in charge of careful and intelligent engineers are perfectly safe, when well-constructed; but
when their management falls into the hands of reckless and ignorant, men, they become a source of constant danger to their owners and the public. For
the above reasons any engineer who may offer to take
charge of an engine and boiler ought to be able to
show that he fully understands the duties and responsibilities involved in their care and management. He
ought to be able to calculate safety-valve lever examples, and thoroughly understand the principles involved. He should also be able to calculate the
pressure required to burst a boiler when all the dimensions are given. He should understand the difference between longitudinal and curvilinear strains,
the difference in value between single- and doubleriveted seams, and the comparative strength of the




NON-CONDENSING STEAM-ENGINES.       37
shell, flues, and other parts of the boiler. He should
also fully understand the causes which tend to produce
explosions, and be conversant with all the details of
construction, use and management of steam-boilers.
But, above all, he should be a man of good sound
sense and intelligence.
Now, it requires time, study and experience to acquire the above fund of information; and if the engineer should qualify himself accordingly, will his intelligence be appreciated and his services be remunerated by steam users? Yes; undoubtedly they
will, as there seems to be a steady and increasing demand for skilled workmen in this country in every
branch of mechanics -and in none more so than in
steam - engineering. Perhaps there may be some
steam users who do not desire the services of a good
engineer, for the reason that they think he might interpose an intelligent remonstrance against their
recklessness in the use and management of their
steam-boilers, or he might decline to gratify their
avarice by allowing himself to be degraded to the
position of man-of-all-work. Not being familiar with
the properties of steam themselves, many owners of
steam-boilers seem to think that almost any manno matter how ignorant he may be- can in a short
time qualify himself for the position of an engineer;
it not seeming to occur to them that there is no place
where experience and intelligence are of so much imra4




38      CATECHISM OF HIGH PRESSURE, OR
portance as they are in the care and management of
steam-boilers.
It is also a frequent assertion of some steam users
that a great many engineers are incapable. They
seem to forget that the same thing might be said of the
members of any other trade or profession. But it might
be said, without fear of contradiction, that engineers in
general are as capable and intelligent as any other
class of mechanics. Even if the above assertion is
true - that a great many engineers are incapable -
it might be pertinent to the question to ask: Are
they wholly to blame? or does some of the responsibility rest with the owners of steam-engines and
steam-boilers, who have been for years encouraging
ignorance and incapacity by employing incompetent
men, from motives of false economy?
Under such circumstances, it is not to be wondered
at that a great many errors have found their way
into the business; but the remedy for nearly all of
them is within reach of the engineers themselves —
more particularly the young men. They must educate themselves, so that their opinion on all questions
connected with steam-engineering will give strong
evidence that they fully understand the principles
and practice of their profession, then their opinions
will command respect, and their services be correspondingly remunerated. They must remember that
it is not the trade that elevates the man, but it is
rather the man that dignifies the pursuit or calling;




NON-CONDENSING STEAM-ENGINES.       39
and that muscular power, though very good in its
place, is not the most essential requisite of an engineer, but that the cultivation of the mind is the first
step towards eminence in any trade or profession.
It is true that in steam-engineering, as in all other
trades, there are a great many men who are totally
unfit for the business - men that, perhaps, would
succeed, to a certain extent, in some other pursuit,
but who become a failure, and often a reproach to
the profession they have adopted, simply for the reason that they have made a mistake in the selection
of a suitable trade.
Although no modern writer on steam or the steamengine has made any allusion to engineers, or called
public attention to the importance of their education
to steam users and the public, still it cannot be
denied that engineers have made very creditable
progress in the acquirement of knowledge connected
with their business within the past ten years. But
yet there seems to be ample room for improvement
on the part of both engineers and their employers,
and that such change will soon come there is no
reason to doubt. For improvement in steam-engines
and steam-boilers will also require more able management; and intelligent steam users will begin to see
that the most important essentials to the economical
working of the steam-boiler and steam-engine are
care, skill and intelligence, and these'qualifications
will liberally repay all the money expended in securing them.




40     CATECHISM OF HIGH PRESSURE, OR
PLAIN CYLINDER BOILER.
FLUE BOILER.
TUBULAR BOILER.




NON-CONDENSING STEAM-ENGINES.        41
THE STEAM-BOILER.
IN the choice of steam-boilers, the three most important objects to be attained are safety, durability,
and economy.
To secure safety, it is necessary that the boiler
should be made of good material, with good workmanship.
To secure durability, the boiler ought to be constructed so as to give the greatest facilities and
easiest access for cleaning, repairing, and renewal of
any of its parts. The boiler should also be so designed as to avoid unequal strains by expansion and
contraction as far as possible.
In attempting to secure economy in the generation
of steam, it is necessary, first, to secure perfect combustion of the fuel, so as to produce the greatest
amount of heat; second, to apply the heat in the
very best manner to the boiler, so as to heat the
water in the most rapid manner possible; third, great
care must also be taken to prevent the heat escaping
by radiation, or with the products of combustion. If
these three conditions be complied with, our arrangements will be of the most economical character. The
evaporative efficiency of any boiler and furnace is to
be measured by the amount of water evaporated by
any given weight of fuel in a given time. Mere
waste of fuel, however, is not the only defect attendant upon an inferior construction of boiler and fur4*




42      CATECHISM OF HIGH PRESSURE, OR
nace. Where these are not of the best kind, they
must be of larger size in order to do the required
amount of work; the grate-surface must be larger, and
more air must be needlessly raised to a higher temperature, thus carrying off a large amount of heat in
the waste products of combustion; all of which involves increased outlay of capital and larger running
expenses.
Many of the defects of modern boilers might be
attributed, first, to the fact that some of the inventors
or designers seem to be partly, if not totally, ignorant of the first principles of mechanical science;
second, to competition between boiler-makers themselves, in their efforts to undersell each other, consequently they have to deceive purchasers and steam
users by magnifying small boilers into large ones.
Therefore, when the boiler comes to be tested, its
evaporative powers are found to be lacking, the fuel
has to be burned under a sharp draught, and instead
of the best results, the worst are obtained.
In regard to the metal of the boiler itself, it is a
well known fact that the thicker the iron is, and the
poorer its conducting qualities, the greater will be
the amount of heat that will be lost or wasted; when
by using a superior quality of iron, one whose tensile
strength and conducting powers are both very great,
we lessen the resistance to the passage of the heat
from the furnace to the water and greatly increase
the economy of the boiler. It is well known to en



NON-CONDENSING STEAM-ENGINES.       43
gineers that some qualities of iron are two and a half
times stronger than others; consequently, if we make
a boiler of poorer iron than would be as strong as I
inch of the best iron, we should have to use plates 5
of an inch thick. Even then a heavy boiler would
be weaker than the light one, from the fact that the
heavy plates would sustain great injury in the
making. In point of economy and durability, the
ligbt boiler would be far superior to the heavy one.
Every attempt to lessen the first cost of a boiler
by diminishing the heating- and grate-surface is, to a
certain extent, carrying out the principle of "penny
wise and pound foolish."
An engine extra large for the work to be done
causes a loss of fuel, whilst a boiler extra large for
the work to be done makes a great saving.
A boiler taxed to its full evaporative capacity will
evaporate from 5 to 6 pounds of water to 1 pound of
coal. Double the size of the boiler, and you will get
the same amount of steam with 35 to 40 per cent.
less fuel.
The quantity of water evaporated depends not only
on the heating-surface, grate-surface, and draught,
but also on the quantity of air which passes through
the furnace in a given time.
For instance: a locomotive boiler burning 10
pounds of coal on each square foot of grate-surface in
an hour, will evaporate about 8 pounds of water for
each pound of coal. The same boiler, running at a




44      CATECHISM OF HIGH PRESSURE, OR
high speed, and burning 75 pounds of coal on each
square foot of grate-surface, will evaporate 7 pounds
of water for each pound of coal burned. Here is a
vast difference in the total amount of evaporation,each pound of coal produces less steam in the proportion of 9 to 7 pounds.
So that it will be seen that the economy of fuel
in one case is very evident; in the other, it will be
seen that the waste of fuel under a forced draught is
very great.
A boiler may generate steam with great economy,
but, owing to the steam being wasted by improper
application to the engine, the result is unsatisfactory,
and the boiler unjustly blamed. A boiler that carries out water with its steam may show a large evaporation, but the steam being wet, is almost useless in
the engine.
The maximum evaporative capacity of any boiler
is the amount of water it would evaporate in 10 hours
from a temperature of 60~ Fah., with good fuel, good
draught, and the steam allowed to escape as fast as
generated.
Steam-boilers are of almost every kind and description: cylinder, tubular, and flue; upright, horizontal, inclined, and patent.
CYLINDER BOILERS.
Q. What advantage do cylinder boilers possess
over other boilers?




NON-CONDENSING STEAM-ENGINES.         45
A. First, the old plain cylinder boiler is light, is
easy to clean and repair;. second, it is less dangerous,
and requires less attention than any other kind of
boilers now in use.
Q. What are the disadvantages of the cylinder
boiler, or why is it so fast passing out of use, more
particularly in cities?
A. First, the cylinder boiler, on account of its extreme length, is unsuited to cities, where space is so
limited and of great value; second, because it requires a greater amount of fuel to evaporate a certain
amount of water than any other boiler now in use;
third, because it takes so long to raise steam from
cold water.
Q. What do you believe to be the most economical
length for a cylinder boiler?
A. It is found by experience that the length of a
cylinder boiler should never exceed 7 times its diameter.
Q. What might be considered a horse-power in a
cylinder boiler?
A. The term horse-power, as applied to the steamboiler, has no definite application. It has been customary to fix on some unit of heating- and grate-surface as the unit of horse-power for a boiler; and that
unit is about 15 square feet of heating-surface, and
4 of a square foot of grate-surface to the horse-power
in cylinder boilers.
Q. What would you call a fair evaporation of
water in a cylinder boiler?




46     CATECHISM OF HIGH PRESSURE, OR
A. 6 pounds of water to one pound of coal.
Q. How should cylinder boilers be set?
A. Cylinder boilers, or any other boiler, should
have an incline of 1 inch to every 20 feet towards
the end where the blow-off is situated. In case cylinder boilers are extremely long, they ought to be supported in the centre with a midfeather.
FLUE BOILERS.
Q. What are the advantages and disadvantages
of flue boilers?
A. The advantage is that they occupy less room
than the cylinder, from the fact that they present a
greater amount of heating-surface. The disadvantages are, first, they are heavier than the cylinder;
second, they cost more; third, they are difficult to
repair or clean; fourth, they are very dangerous on
account of the liability of the flues to collapse.
Q. In making flue boilers, what proportion should
be carried out in regard to the flues?
A. They should always be made of small diameter, not more in any case than 12 or 14 inches, for
the reason that small diameters give them greater
strength.
Q. In case it should be necessary to make flues of
large diameter, say 18 or 20 inches, what is the best
plan of constructing them?
A. The flues should be made with butt-joints, and
of heavier iron than the shell of the boiler.




NON-CONDENSING STEAM-ENGINES.        47
Q. What is a butt-joint?
A. It is a joint formed by bringing the ends of two
sections of the flue together and overlapping them on
the outside and inside with separate pieces of iron.
This plan of construction gives them additional
strength, and makes them less liable to collapse.
Q. What is a collapse?
A. It is a crushing in of a flue or tube by external
pressure.
Q. What would be considered a fair allowance of
grate- and heating-surface to the horse-power in flue
boilers?
A. From 14 to 15 square feet of heating-surface,
and I square foot of grate-surface.
Q. What might be called fair evaporation in a
flue boiler?
A. 7 pounds of water to 1 pound of coal.
Q. What length do you consider most economical
for flue boilers?
A. The length of flue boilers should be about 5
times their diameter.
TUBULAR BOILERS.
Q. What advantage does a tubular boiler possess
over the cylinder and flue boilers?
A. The tubular takes up less room, generates
steam more rapidly, and requires less fuel; and the
tubes are less dangerous than flues on account of
their small diameter and great strength.




48      CATECHISM OF HIGH PRESSURE, OR
Q. What are the disadvantages of tubular boilers?
A. First, the tubular boiler is heavy, the first cost
of them is more than either the flue or the cylinder;
second, they are difficult to repair, and almost impossible to clean; third, they require great care and attention to prevent the water from becoming low and
exposing the tubes to the action of the fire.
Q. What would you consider the proper length
for a tubular boiler?
A. The length of a tubular boiler should be about
4 times its diameter.
Q. What would you consider fair evaporation in
a tubular boiler?
A. The evaporation of 9 pounds of water to 1
pound of coal.
Q. What might be called a fair allowance of heating- and grate-surface to the horse-power in a tubular
boiler?
A. 14 square feet of heating-surface, ~ square foot
of grate-surface. But in the tubular, as in all other
boilers, the horse-power of the boiler depends upon
the following conditions: first, the grate-surface;
second, the heating-surface; third, draught; fourth,
the qualities of the fuel used; fifth, the conducting
powers of the iron; and sixth, the proper application
of the steam after it leaves the boiler.




NON-CONDENSING STEAM-ENGINES.      49
DOUBLE-DECK BOILERS.
Q. What do you mean by a double-deck boiler?
A. I mean a tubular and cylinder connected together by what are called water-necks - the cylinder
being uppermost and used as a steam-dome.
Q. What are the advantages of the double-deck
boiler?
A. A double-deck boiler occupies less space than
any of the three former kinds of boilers; it steams
very economically, and is also more safe than the
single tubular, because the lower or tubular cylinder
is entirely free from water.  There is very little
danger of the water becoming low in this kind of a
boiler. The ends of the tubes are not exposed to the
action of the fire, as in the single tubular, as the
draught passes under the boiler and returns through
the tubes, and re-returns between the tubular and
cylinder. This boiler seems to have no objectionable
features, with the exception that the lower or tubular
section is impossible to clean. It might be said also
that the boiler is heavy and expensive; but it presents an immense amount of heating-surface.
LOCOMOTIVE BOILERS.
Q. What are the advantages and disadvantages of
the locomotive boiler?
A. The advantages are: the locomotive form of
the boiler is compact and powerful, and, when well
proportioned to its work, is very economical for fac6                D




50      CATECHISM OF HIGH PRESSURE, OR
tory use; it occupies small space and generates steam
very rapidly. Its disadvantages are: first, it is expensive; second, impossible to clean; third, it requires
great care in keeping the water above the tubes and
crown-sheet. It is also very difficult to repair, and
where the water is impure soon burns out.
Q. Are all steam-boilers fired alike?
A. No; some boilers, such as the locomotive, Dimfield, and Cornish boilers, are fired internally; while
the cylinder, flue, and tubular boilers are fired externally; though in the last two the heat is applied
both internally and externally.
MUD-DRUMS.
Q. What is a mud-drum?
A. A mud-drum is a small cylinder boiler, generally
24 inches in diameter, connected with the main boiler
at the bottom, for the purpose of receiving the feedwater before it enters the boiler.
Q. What are the advantages and disadvantages of
the mud-drum?
A. Mud-drums at one time were considered a benefit, as imparting extra heat, and also retaining the
sediment carried in by the feed-water. But after
years of experience in the use of the mud-drum, it
was found that the drum imparted very little heat to
the feed-water, and retained nothing but the earthy
matter that is not injurious to a boiler. But all the
destructive carbonates that form the hard glassy scale




NON-CONDENSINTG STEAM-ENGINES.     51
were carried into the boiler. Experience showed us
that the mud-drum was positively dangerous, on account of not receiving sufficient heat to keep the iron
dry. The corrosion of the mud-drum was very rapid,
and became dangerous, in many cases before parties
using them were actually aware of it. Some very
serious accidents happened through the bursting of
mud-drums. The mud-drum was generally worn
out in 5 or 6 years, and the expense of removing the
old drum and replacing it with a new one was more
than the benefit derived from its use. The muddrum is fast going out of use.
BOILER-HEADS.
Q. What kinds of material are most commonly
used for boiler-heads?
A. Wrought and cast iron.
Q. Which kind of material do you consider most
safe?
A. Wrought iron; as it is lighter, possesses greater
strength, and presents better advantages for bracing
in boilers of large diameter than cast iron.
Q. What are the most common shapes for castiron heads of boilers?
A. Flat, concave, and convex.
Q. What are the advantages and disadvantages of
the above-named heads?
A. First, the flat head should be avoided, like all
flat surfaces in steam-boilers, because when subjected




52      CATECHISM OF HIGH PRESSURE, OR
to a great strain they are positively dangerous. Second, the concave presents greater strength with less
metal than the flat head. The only disadvantage we
know of in the concave is in cases where the flange
of the head is too deep on the inside, preventing the
water from coming in contact with the rivets, and
the boiler is liable to be burned through at that
point. Third, the convex is not so strong as the concave, but is very much safer, with the same amount
of metal, than the flat head.
BOILER-SHELLS.
Q. What thickness of boiler-iron do you consider
the safest, most durable, and economical for boilers?
A. First, to insure safety in shells and flues of
boilers, the thickness proper to use depends very
much on the quality of the iron, diameter of boiler,
and pressure to be carried. Second, as to durability,
the thickest iron is not always the best, as the outside
of the sheet becomes burned and crystallized, and in
most cases gives less wear and satisfaction than a
thinner gauge. Third, as to economy, thin boilers
are more economical with fuel, and wear longer,
provided in all cases that the diameter and the pressure are in proportion.
Q. What would you consider the proper thickness
for all boilers?
A. The thickness of boiler-iron for all boilers must
range between -7 and -3 of an inch, for the reason




NON-CONDENSING STEAM-ENGINES.       53
that I inch iron is almost too thick to be riveted and
T,3 is too thin to be caulked. Of course, it will be
understood that the choice of thickness between these
two limits will depend on the quality of the iron, diameter of the boiler, and pressure to be carried, as
before stated.
Q. What would you consider the proper thickness
of iron for a boiler 48 inches in diameter, carrying a
pressure of 90 pounds to the square inch?
A. 8 of an inch for ordinary brands of iron, but
i inch of superior iron would be just as strong.
Q. What do you consider the proper thickness for
the wrought-iron heads of a boiler 48 inches in diameter, carrying a pressure of 90 pounds?
A. as or 4; either thickness would be perfectly
safe.
Q. What would you consider the proper thickness
for the tube-sheets and crown-sheets of boilers?
A. The thickness of the iron will depend on the
diameter of the boiler and the quality of the iron,
but the range for all boilers will be perhaps from -
to i of an inch thick.
Q. Is the temperature of thick boiler-plates often
much higher than that of the steam?
A. Yes; thick boiler-plates or tube-sheets are in
many instances several hundred degrees above the
temperature of the steam in the boiler, and as a consequence are extremely dangerous.
6*




54      CATECHISM OF HIGH PRESSURE, OR
Q. Is the pressure the same on all riveted seams
in boiler-shells?
A. No; the pressure on the longitudinal rivets is
nearly double that on the curvilinear rivets.
Q. What do you mean by longitudinal and curvilinear rivets?
A. By longitudinal rivets, I mean the rivets or
seams that run lengthwise on the boiler; the curvilinear are those that are around the circumference of
the shell.
Q. If the pressure on the longitudinal seams is
double that on the curvilinear, how can all parts of
the boiler sustain the same pressure?
A. By making the longitudinal seams double
riveted and the curvilinear single.
Q, What is the difference in strength between
single and double riveted seams?
A. Single-riveted seams are equal to 56 per cent.
of the material used, while double riveting is equal
to 70 per cent.
Q. What do you mean by "equal to 56 per cent.
of material used"?
A. I mean that the boiler-plates lose 44 per cent.
of their strength in the process of punching.
Q. What do you consider the proper diameter for
rivets of boilers?
A. That would depend very much on the diameter
of the boiler, thickness of iron, and pressure to be carried. For boilers from  36 to 42 inches diameter,




NON-CONDENSING STEAM-ENGINES.        55
and 8 iron, if single riveted, the rivets ought to be 5
of an inch for curvilinear, and I for the longitudinal;
if double riveted, 8- will answer for both longitudinal
and curvilinear seams. From -A iron down to -3X,
smaller rivets will answer.
Q. Which do you consider the best method of riveting boilers -by hand or by machine?
A. For average or thin boiler-plates, hand riveting
does very well, but for heavy iron, -7 or 2 inch thick,
machine work is far superior, the power of the machine brings the work together far better and with
less injury to the iron than can be done by hand.
Q. How should the fibre of the iron be placed to
give the greatest strength?
A. The direction in which the iron is rolled should
always be placed around the boiler, and not lengthwise, because in cylindrical boilers the strain in the
line of the axis is much less than the circumferential
bursting strain.
Q. Do you consider it an advantage to drill the
rivet-holes in boilers instead of punching?
A. Yes; for all first-class work there can be no
doubt but that all the rivet-holes ought to be drilled,
on account of the liability of the plates to become
fractured by the process of punching, causing a great
reduction in the strength of the boilers.
Q. Would the same sized rivets answer for punched
and drilled holes?




56      CATECHISM OF HIGH PRESSURE, OR
A. No; drilled holes require larger rivets than
those that are punched.
Q. How do you explain that?
A. Because the shearing strain on the drilled
holes is far greater than on the punched, as the hole
is more perfect and sharp, and there is less friction
between the sheets when drilled. A - rivet will
stand as much shearing strain in a punched hole as
a i will in a drilled hole.
Q. Do you consider the use of the drift-pin ought
to be dispensed with as much as possible in making
boilers?
A. Yes; a reckless use of the drift-pin has in
many cases resulted in great injury to the boilerplates; and there is good reason to believe that such
injuries as are caused by the drift-pin, often hasten
the destruction of the boiler.
Q. What is a drift-pin?
A. It is a tapering steel pin introduced into the
holes in the seams, to bring them into line.
Q. How do you propose to dispense with the use
of the drift-pin?
A. If the holes are laid off carefully in the sheet,
and punched with judgment, there will be very little
need for the drift-pin, as the holes can be straightened by a flat reamer. Such work will be greatly
superior to that where the drift-pin is used.
Q. Do you think it would be any benefit to




NON-CONDENSING STEAM-ENGINES.         57
slightly heat the boiler-plates before rolling them to
form the shell of the boiler?
A. Yes; I think it would add very materially to
the strength and durability of boilers if the sheets
were rolled while warm, as the fibre of the iron
would be drawn out; while, in the common practice
of cold rolling, the fibre is crushed and broken.
Q. Does hammering improve the quality of iron?
A. No; it only hardens it, but at the same time
renders it more brittle, whilst rolling imparts toughness.
Q. What fact is observable when boiler-iron is
broken suddenly, as in the case of steam-boiler explosions?
A. It generally presents a crystalline fractured
appearance; when, if broken by some slow process, it
presents a fibrous or silky appearance, - in the first
case the fibre is fractured, and in the other it is
drawn out.
Q. What does the crystalline fracture indicate?
A. It indicates hardness, while a fibrous fracture
is a mark of softness and ductility. The finer and
more uniform the crystals the higher the quality of
the iron.
Q. Is the pressure equal on all sides of the shell
of a boiler when under steam?
A. No; there is more pressure on the lower than
on the upper side of a boiler; as the steam presses
equally on the surface of the water as on the upper




58     CATECHISM OF HIGH PRESSURE, OR
side of the boiler, the weight of the water must be
added to the pressure on the lower side.
Q. How do you explain that?
A. In this way: in a boiler 36 inches in diameter,
circumference 113 inches, if full of water, the water
would weigh 441 pounds to the foot in length; now,
if the boiler was 20 feet long, the water would weigh
8820 pounds; take i of that (which would be about
the quantity of water in a boiler when under steam)
and the weight of water would be 5880 pounds,
which shows the excess of pressure on the lower side
of the boiler.
Q. Are the shells and flues of boilers sometimes
injured by the application of the cold water or
"Hydrostatic" test?
A. Yes; the shells and flues of boilers are sometimes injured by a reckless use of the test, and in
many cases explosions take place soon after the test
is applied.
Q. Would the shell and flues of a boiler be
stronger under a cold water pressure of 70 or 80
pounds to the square inch than under the same
steam pressure?
A. No; as iron increases in strength by the application of heat up to 5500 Fah., the boiler would be
stronger under the steam pressure.
Q. What is the maximum strength of wrought
iron?
A. 60,000 pounds to the square inch at a tem



NON- CONDENSING STEAM-ENGINES.           59
perature of 5500 Fah., or in other words, a bar of
iron one inch square would stand a tensile strain of
60,000 pounds.
A  Table deduced from Experiments on Iron Plates for
Steam-Boilers, by the Franklin Institute, Philadelphia.
Iron boiler-plate was found to increase in tenacity
as its temperature was raised, until it reached a temperature of 550~ above the freezing-point, at which
point its tenacity began to diminish. The following
table exhibits the cohesive strength at different temperatures: -
At 32~ to 800 tenacity is 56,000 lbs. or one - seventh below its maximum.
At   5700      "    " 66,000'"  the maximum.
At   7200      "    " 55,000 "  the same nearly as at
320.
At   10500     "    " 32,000 "  nearly one - half the
maximum.
At   12400     "    " 22,000 "  nearly one - third the
maximum.
At   13170     "    "  9,000 "  nearly one-seventh the
maximum.
At 30000 wrought iron becomes fluid.
It will be seen that by the accidental overheating
of a boiler the tenacity of the iron would soon become reduced to nearly half its strength.
The following Table is the result of experiments
made on different brands of boiler-iron at the Stevens Institute of Technology. The samples tested
were taken from lots of iron sent to market by va



60        CATECHISM  OF HIGH PRESSURE, OR
rious manufacturers of boiler-plate, and may be considered to represent in most cases an average quality
of the several grades of iron.
Thirty-three experiments were made upon iron
taken from the exploded steam-boiler of the ferryboat Westfield. The following were the results:'Lbs. per sq. inch
Average breaking weight.............................. 41,653
16 experiments made upon high grades of American boiler-plate.
Average breaking weight..............................  54,123
15 experiments made upon high grades of American flange iron.
Average breaking weight.............................. 42,144
6 experiments made upon English Bessemer steel.
Average breaking weight.............................. 82,621
5 experiments made upon best English Lowmoor boiler-plate.
Average breaking weight............................ 58,984
6 experiments made upon samples of tank iron from different
manufacturers.
Average breaking weight, No. 1..................... 43,831
t" " f        No. 2..................... 42,011
cc " " No. 3..................... 41,249
2 experiments made on iron taken from the exploded steamboiler of the Red Jacket.
Average breaking weight.............................. 49,000
It will be noticed that the above experiments reveal a great variation in the strength of boilerplate of different grades of iron, and furnish conclusive evidence that the tensile strength of boiler-iron
ought to be taken at 50,000 pounds to the square
inch, instead of 60,000.
Q. What reduction in length does wrought iron
undergo when subjected to compression?
A. It is reduced.0001 of its length by every ton




NON-CONDENSING STEAM-ENGINES.          61
per square inch up to 13 tons, beyond which the
amount of compression increases more rapidly.
STEEL BOILERS.
In stiffness or rigidity, as well as high ultimate re.
sistance and good conducting powers, steel presents
many advantages, as a substitute for iron, in the construction of boilers. Some of the largest locomotive
establishments in this country are using steel for boilers. The substitution of steel for iron in the manufacture of boilers is rapidly spreading in all the
countries of Europe.
Q. What advantages do steel boilers possess over
iron?
A. The advantages of steel boilers are: first, they
are lighter; second, they are stronger; third, their
conducting powers are higher. For instance, a steel
boiler 48 inches in diameter and i inch thickness
of sheets is as strong as an iron boiler of the same
diameter and' inch thickness of iron, and will evaporate 25 per cent. more water with the same amount
of fuel in a given time. Steel boilers are more free
from incrustation and corrosion than iron, on account
of the density and compactness of the material. But
in the manufacture of steel boilers great care should
be taken that the plates are not fractured in punching.
6




62      CATECHISM OF HIGH PRESSURE, OR
INTERNAL AND EXTERNAL PRESSURES.
An important difference of condition, never to be
lost sight of in boiler-work, is that all internal pressure tends to preserve the symmetry of form of the
boiler, while all external pressure tends to destroy
that symmetry, which, if altered at all, places the
boiler in new conditions, likely to end in sudden
destruction.
Q. If pressure is exerted on the internal or external surface of the cylinder, is the effect the same in
both cases?
A. No; when pressure is exerted within a tube or
cylinder, the tendency of the strain is to cause the
tube to assume the true cylindrical form; but when
pressure is exerted on the outside of the tube, the
tendency of that pressure is to crush the tube or
flatten it; as it is a well-known fact that iron of
any strength when formed into a tube will require a
much greater strain to tear it asunder than it would
take to crush it.
Q. How do you explain that?
A. In this way: a thin hodp of iron will resist a
very great amount of tearing force, but if that same
hoop or circle be placed as a prop under half the
weight that was exerted to tear it apart, it would be
crushed flat.
Q. What is the difference between external and
internal strain?




NON-CONDENSING STEAM-ENGINES.         63
A. Internal is a tearing strain, whilst external is
a crushing strain; and flues and tubes of boilers
are nothing but a series of props, and a constant tendency of the pressure is to flatten the tube or flue,
and cause it to collapse.
Q. What is a collapse?
A. It is the crushing or flattening of a flue by overpressure, and is often attended ~vith terrible results.
Q. What is an explosion?
A. It is an accident that takes place in most cases
from  the water becoming low, when, through ignorance or recklessness, cold water is admitted to the
boiler, and explosion takes place.
Q. What is a burst?
A. It is an accident that occurs from over-pressure,
and is generally more terrible in effect than either an
explosion or a collapse.
Q. Why should the burst be more destructive than
the explosion?
A. Because, in the case of the explosion, the tenacity of the iron is partly destroyed by being overheated; while, in the case of the burst, the iron is torn
apart at its maximum strength.
Q.'What is the best preventive against explosions, bursts and collapses?
A. Never tax the boiler above a safe working
pressure; keep it clean and in good repair, the
safety-valve in good order, and the water at all times
at the proper level.




64      CATECHISM OF HIGH PRESSURE, OR
Q. What part gives way first when a boiler bursts?
A. A boiler gives way in the weakest place.
Q. What should be considered the strength of a
boiler?
A. The weakest part of the boiler.
Q. How do you explain that?
A. In this way: if some parts of a boiler are I
of an inch thick, whilst other parts are not more
than 3, the pressure carried on the boiler should
be that which would be safe for -36 of an inch.
RULES.
Rule for finding the quantity of water in a boiler
in cubic inches.
Multiply the internal area of the head of the boiler,
in inches, by the length of the boiler in inches, the
product will be the number of cubic inches of water
in the boiler. Divide this product by 1728, and the
quotient will be the number of cubic feet of water in
the boiler.
Q. In what way do riveted joints give way?
A. Either by shearing off the rivets in the middle
of their length, or by tearing through one of the plates
in the line of the rivet-holes. In a perfect joint, the
rivets should be on the point of shearing just as the
plates were about to tear; hence, in good practice, it
is an established rule to employ a certain number of
rivets to the linear foot. If these are placed in a
single row, the rivet-holes so nearly approach each




NON-CONDENSING STEAM-ENIGINES.        65
other that the strength of the plates is much reduced;
but if they are arranged in two lines, a greater number may be used, and yet more space left between
the holes, and greater strength and stiffness imparted
to the plates at the joint.
It is perfectly obvious that in perforating a line
of holes along the edge of a plate, we must greatly
reduce its strength.
When this great deterioration of strength at the
joint is taken into account, it cannot but be of the
greatest importance that in structures subjected
to such violent strains as steam-boilers are, the
strongest method of riveting should be adopted.
Rule for finding safe external pressure on boilerflues.
Multiply the square of the thickness of the iron
by the constant whole number 806,300; divide this
product by the diameter of the flue in inches; multiply the quotient by the length of the flue in feet;
multiply this product by 3.
Rule for finding safe working pressure of any boiler.
Multiply the thickness of the iron by.56 (or.70,
according as the boiler is single or double riveted);
multiply this product by 10,000 (safe load); then
divide this last product by the internal radius: the
quotient will be the safe working pressure in pounds
per square inch.
Five times the safe working pressure is the bursting pressure.
6*               E




66       CATrECHISM  OF HIGH PRESSURE, OR
The experiments of Mr. Fairbairn and others have
established the following relative strengths as the
value of plates with either single or double riveted
joint.
Taking the strength of the plate at.......... 100
The strength of the double-riveted joint would then be... 70
And the strength of the single-riveted joint....... 56
The following Table will show the safe working
pressure for boilers of different diameters and different thicknesses of iron, according to Fairbairn's
experiments.
For internal pressure, - of the value of ordinary
boiler-iron, or 50,000 pounds for the inch of section,
is taken to be safe, while in external pressures I is
taken.




NON-CONDENSING STEAM-ENGINES.          67
TAB L E.
INTERNAL PRESSURES.
GAUGE.             00      0     1      2
Thickness of Iron..375.358.340.300.284
External     24 180.65 172.20 163.29 143.59 135.75
Diameter.  26 166.34 158.58 150.39 132.28 125.08
28 154.13 146.96 139.38 122.63 115.95
30 143.59 136.92 129.88 114.29 108.07
32 134.40 128.17 121.58 107.01 101.20
34 126.31 120.47 114.29 100.60  95.14
36 119.15 113.64 107.81  94.92  89.77
Longitudinal 38 112.75 107.54 102.04  89.84  84.98
Seams, 40 107.01 102.07  96.85  85.28  80.67
Single       42 101.81  97.12  92.11  81.16  76.77
Riveted. 44  97.11  92.63  87.90  77.42  73.24
46  92.82  88.54  84.02  74.01  70.01
48  88.89  84.80  80.47  70.89  67.06
50  85.28  81.36  77.21  68.02  64.35
52  81.95  78.18  74.20  65.37  61.84
54  78.87  75.25  71.42  62.92  59.53
56  76.02  72.53  68.84  60.65  57.38
58  73.36  70.00  66.43  58.54  55.38
60  70.89  67.63  64.19  56.57  53.52
62  68.57  65.43  62.10  54.72  51.78
64  66.40  63.36  60.14  53.00  50.15
66  64.37  61.42  58.30  51.38  48.61
68  62.45  59.59  56.57  49.85  47.17
70  60.65  57.87  54.93  48.41  45.81
72  58.95  56.25  53.39  47.06  44.53
74  57.34- 54.71  51.94  45.78  43.32
76  55.81  53.26  50.56  44.56  42.17
78  54.37  51.88  49.25  43.41  41.08
80  53.00  50.57  48.01  42.32  40.04




68      CATECHISM OF HIGH PRESSURE, OR
TABLE.
INTERNAL PRESSURES. - (Continued.)
BIRMINGHAM   3      4     5    6    7       8
WIRE GAUGE.                     6
Thickness of.259.238.220.203.180.165
Iron.    X Full.   - Scant.  ~ 2 6Ful. -6 -Sc't. 35 Full.
In.
External 24 123.53 113.31 104.58 96.36 85.28 78.07
Diameter 26 113.84 104.44  96.40 88.83 78.63 71.99
28 105.55  96.85  89.40 82.39 72.94 66.79
30  98.39  90.29  83.36 76.83 68.02 62.29
32  92.14  84.56  78.07 71.96 63.72 58.35
34  86.64  79.51  73.42 67.68 59.93 54.89
36  81.75  75.04  69.29 63.88 56.57 51.81
Long.   38  77.39  71.04  65.60 60.48 53.56 49.06
Seams. 40  73.47  67.44  62.29 57.42 50.86 46.58
Single   42  69.93  64.19  59.29 54.66 48.41 44.35
Riveted. 44  66.71  61.24  56.57 52.15 46.20 42.32
46  63.78  58.55  54.08 49.87 44.17 40.46
48  61.09  56.09  51.81 47.77 42.32 38.77
50  58.62  53.82  49.72 45.84 40.61 37.21
52  56.35  51.74  47.79 44.07 39.04 35.77
54  54.24  49.80  46.00 42.42 37.58 34.43
56  52.28 48.01  44.35 40.90 36.23 33.20
58  50.46  46.34  42.81 39.48 34.98 32.04
60  48.77  44.78  41.37 38.15 33.80 30.97
62  47.18  43.33  40.03 36.91 32.71 29.97
64  45.69  41.96  38.77 35.75 31.68 29.02
66  44:30  40.68  37.58 34.66 30.71 28.14
68  42.99  39.48  36.47 33.64 29.80 27.31
70  41.75  38.34  35.42 32.67 28.95 26.53
72  40.58  37.27  34.43 31.76 28.14 25.78
74  39.48  36.25  33.50 30.89 27.38 25.08
76  38.43  35.29  32.61 30.08 26.65 24.42
78  37.44  34.38  31.77 29.30 25.96 23.79
80  36.49  33.52  30.97 28.56 25.31 23.20




NON-CONDENSING STEAM-ENGINES.         69
TAB IL E.
INTERNAL PRESSURES. — (Continued.)
BIRMINGHAM WIRE   3    00      0      1     2
GAUGE.             00      0      1
Thcns.375.358.340.300.284
Thickness of Iron.   3   3      119
x.  Scant.   6; 
In.
External    24 225.81 215.26 204.12 179.49 169.67
Diameter.  26 207.93 198.23 187.91 165.35 156.34
28 192.66 183.70 174.23 153.28 144.94
30 179.4-9 171.15 162.35 142.86 135.09
32 168.00 160.21 151.98 133.76 126.49
Longitudinal 34 157.89 150.58 142.86 125.75 118.93
Seams, 36 148.94 142.05 134.77 118.64 112.21
Double       38 140.94 134.43 127.55 112.30 106.22
Riveted. 40 133.76 127.58 121.06 106.60 100.83
Curvilinear  42 127.27 121.40 115.20 101.45  95.96
Seams, 44 121.39 115.79 109.88  96.77  91.55
Single       46 116.02 110.68 105.03  92.51  87.52
Riveted. 48 111.11 106.00 100.59  88.61  83.83
50 106.19 101.70  96.51  85.02  80.43
52 102.44 97.73  92.75  81.71  77.31
54  98.59 94.10  89.27  78.69  74.41
56  95.02 90.66  86.04  75.81  71.73
58  91.70 87.49  83.04  73.17  69.23
60  88.61  84.54  80.24  70.71  66.90
62  85.71  81.78  77.63  68.40  64.72
64  83.00 79.17  75.17  66.25  62.68
66  80.46 76.78  72.87  64.22  60.77
68  78.07 74.49  70.71  62.31  58.96
70  75.81 72.34  68.67  60.52  57.26
72  73.68 70.31  66.74  58.82  55.66
74  71.67  68.39  64.92  57.22  54.15
76  69.77 66.60  63.19  55.70  52.71
78  67.96 64.85  61.56  54.26  51.35
80  66.25 63.22  60.01  52.90  50.06




70      CATECHISM OF HIGH PRESSURE) OR
TABLE.
INTERNAL PRESSURES. — (Continued.)
BIRMINGHAM    3   4      5      6     7 
Thickness.259.238.220.203.180.165
of Iron.    Full.   Scant.  F3  ull. i-Scant. -5Full.
In.
Ext'l  24 154.42 141.64 130.73 120.45 106.60 97.59
Diam. 26 142.30 130.54 120.50 111.04  98.21 89.99
28 131.94 121.06 111.76 102.99  91.17 83.48
S30 122.99 112.86 104.19  96.03  85.02 77.86
32 116.32 105.70  97.59  89.95  79.65 72.94
Long. 34 108.30  99.39  91.78  84.60  74.91 68.61
Seams, 36 102.19  93.80  86.61  79.84  70.71 64.76
Doub'e 38  96.74  88.80  82.00  75.60  66.95 61.32
Riv't'd 40  91.84  84.30  77.86  71.78  63.57 58.23
Curvil. 42  87.41  80.24  74.11  68.33  60.52 55.44
Seams, 44  83.39  76.56  70.71  65.19  57.75 52.90
Single  46  79.72  73.19  67.60  62.33  55.22 50.58
Riv't'd 48  76.37  70.11  64.76  59.71  52.90 48.46
50  73.28  67.28  62.11  57.31  50.77 46.51
52  70.43  64.67  59.74  55.08  48.80 44.71
54  67.80  62.25  57.51  53.40  46.98 43.04
56  65.35  60.01  55.44  51.12  45.29 41.50
58  63.07  57.92  53.51  49.35  43.72 40.06
60  60.96  55.98  51.71  47.69  42.25 38.71
62  58.98  54.16  50.03  46.14  40.88 37.46
64  57.12  52.45  48.46  44.69  39.60 36.28
66  55.37  50.85  46.98  43.33  38.39 35.18
68  53.73  49.35  45.59  42.05  37.26 34.14
70  52.19  47.93  44.28  40.84  36.19 33.16
72  50.73  46.59  43.04  39.70  35.18 32.23
74  49.35  45.32  41.87  38.62  34.22 31.36
76  48.04  44.11  40.76  37.60  33.32 30.53
78  46.80  42.98  39.71  36.63  32.46 29.74
80  45.62  41.90  38.71  35.71  31.64 28.99




NON-CONDENSING STEAM-ENGINES.       71
FOAMING IN STEAM-BOILERS.
Q. What is the cause of foaming in steam-boilers?
A. Foaming in steam-boilers might be attributed
to different causes. First, to the boiler not having
a sufficient amount of steam-room, so that whenever
the valve opens to admit steam to the cylinder, the
pressure on the surface of the water is lessened,
allowing the water to rise up from the bottom of the
boiler. Second, foaming is sometimes caused by the
foul condition of the boiler; but in such cases it will
be easy to discover the cause, as the water in the glass
gauge will appear quite muddy. Third, foaming is
caused by the presence of any substance of a soapy
or greasy nature in the water. But whatever may
be the cause of foaming, it is always attended with
great danger to the boiler and a certain amount of
injury to the engine.
In all cases where a boiler foams badly, the water
is lifted from the fire-surface of the boiler, and allows
the iron to burn; also, the mud and water from the
boiler are carried over with the steam to the cylinder,
occupying the clearance between the piston and the
head of the cylinder; not only destroying the surface
of the cylinder by the grit and dirt, but in many
cases causing the fracture of the cylinder-head.
Q. What is the best preventive against foaming?
A. The best preventive against foaming is:
First, a clean boiler. Second, pure water. Third, a




72     CATECHISM OF HIGH PRESSURE, OR
sufficient amount of steam-room. Fourth, a steampipe well proportioned to the size of the cylinder.
RUST.
Q. From what cause does the decay of iron arise?
A. From the joint action of air and water, the
oxygen from which combines with the iron and forms
a hydrate called rust.
Q. What parts of steam-boilers are most liable to
corrode or burn out?
A. The parts directly over the fire when coated
with scale, and those exposed to dampness.
PATENT STEAM-BOILERS.
There is hardly anything connected with steamengineering that is so uncertain as the records of the
results of experiments made with patent boilers. A
great many new designs have been brought forward
and tested, but the results have been either imperfectly recorded or kept secret by men who did not
care to announce that they had been unsuccessful.
It is to be regretted that steam users and the public
know so little of the evaporative capacity of patent
boilers; even such information as we do have is very
imperfect, as those who supply it are almost invariably inaccurate. First, because they do not know
how to secure accuracy; second, because they deceive themselves and, third, because they deceive
the public.




NON-CONDENSING STEAM-ENGINES.        73
There are three great objects to be attained in designing a steam-boiler; in the first place it should be
safe; in the second, it should be economical with
fuel; in the third, it should steam well. Now, as
regards patent boilers, there is information wanted
concerning them on the three above points.
THE SAFETY-VALVE.
THE form and construction of this indispensable
adjunct to the steam-boiler are of the highest importance,, not only for the preservation of life and
property, which would in the absence of this means
of safety be constantly jeopardized, but also to secure
the durability of the steam-boiler itself.
Increasing the pressure to a dangerous degree
would be impossible in any boiler, if the safety-valve
were what it is supposed to be,-a perfect means for
liberating all the steam which a boiler may produce
with the fires in full blast, and all other means for
the escape of steam closed. Until such a safetyvalve shall be devised and adopted into general use,
safety from gradually increasing pressure must depend on the attention and watchfulness of the engineer.
We have decidedly too much theory on the safetyvalve, and most of this theory is the merest vagary,
which it is impossible to harmonize with experience
and sound practice. All that the safety-valve needs
7




74      CATECHISM OF HIGH PRESSURE, OR
to make it what it was intended to be, is, first, an
orifice proportioned to the grate-surface; second,
simplicity of construction; third, directness of action.
Q. What is the object or use of the safety-valve?
A. It is a valve intended to relieve the boiler from
extra pressure, and prevent bursting, collapse or
explosion.
Q. What do you consider a proper proportion for
the safety-valve of a boiler?
A. The area of the safety-valve should be ~ square
inch to each square foot of grate-surface.
Q. Will this amount of opening of safety-valve be
safe for any ordinary pressure?
A. Yes; it will be safe for any pressure from 10
pounds to the square inch up to 100 pounds.
Q. Is an enlargement of the safety-valve greatly
beyond what is customary in common practice, dangerous?
A. Yes; if such a safety-valve by any accident
should be knocked or lifted suddenly from its seat, it
would probably cause the destruction of the boiler.
Q. Should every steam-boiler have two safetyvalves?
A. No; one safety-valve of suitable proportions,
and in good order, is sufficient.
Q. How should the safety-valve be kept or cared
for?
A. It should always be kept as free as possible from
dust and ashes, and all its working parts in good order.




NON-CONDENSING STEAM-ENGINES.       75
Q. How often should the safety-valve be moved?
A. At least once a day, more particularly in the
morning.
Q. Why should the safety-valve be moved in the
morning?
A. So as to be sure that it is in good working order
before starting the fire.
Q. What are the most important principles to
be adhered to in the construction of the safetyvalve?
A. Simplicity of construction, directness and freedom of action.
Q. Does the safety-valve become worn and leaky
by the continual action of the steam?
A. Yes; all safety-valves become leaky, and ought
to be ground carefully on their seats.
Q. What is the best material to use for grinding
safety-valves?
A. Pulverized glass, grit of grinding-stones, or
fine emery.
Q. Should safety-valves be constructed with loose
or vibratory stems?
A. Yes; as the rigid or solid stem is apt to become jammed by the canting of the lever and weight,
and in such cases the higher the pressure the more
difficult is the action of the valve.
Q. Is the marking on safety-valves sometimes
incorrect?
A. Yes; decidedly so.




76      CATECHISM OF HIGH PRESSURE, OR
Q. How can you tell whether the safety-valve lever
is marked correctly or not?
A. By calculation.
B, lever. A, short arm of lever. S 5, stem. V, valve. G, guide. W.
weight.
RULES.
Rule for finding the weight necessary to put on a
lever, when the area of valve, pressure, etc., are known.
Multiply the area of valve by the pressure in
pounds per square inch; multiply this product by
the distance of the valve from the fulcrum; multiply the weight of lever by one-half its length (or its
centre of gravity); then multiply the weight of valve
and stem by their distance from the fulcrum; add
these last two products together, and subtract their
sum from the first product, and divide the remainder
by the length of lever; the quotient will be the weight
of the ball.




NON-CONDENSING STEAM-ENGINES.           77
EXAMPLE.
Area of valve,    7 sq. in.   60 lbs.  9 lbs.  6 lbs.
7 in.  12 in.   3 in.
Pressure,       60 lbs.
420 lbs. 108 lbs. 18 lbs.
3 in. 18 lbs.
Fulcrum,         3 in.. 1  lbs.
1260 lbs. 126 lbs.
126 lbs.
Length of lever, 24 in. 24)1134 lbs.
24)1134 lbs.
Weight of lever, 9 lbs.      47.25 lbs. weight of ball.
Weight of valve and stem, 6 lbs.
Rule for finding the Pressure per Square Inch when the
Area of Value, Weight of Ball, etc., are known.
Multiply the weight of ball by length of lever, and
multiply the weight of lever by one-half its length,
(or its centre  of gravity;)  then  multiply  the
weight of valve and stem  by its fulcrum.  Add
these three products together. This sum, divided by
the product of the area of valve, and its distance
from the fulcrum, will give pressure in pounds per
square inch.
EXAMPLE.
Area of valve,    9 sq. in.   60 lbs.  20 lbs.  5 lbs.
Fulcrum,          4 in.      36 in.   18 in.   4 in.
Length of lever,  36 in.    2160 lbs. 360 lbs. 20 lbs.
Weight of lever,  20 lbs.    360 lbs.
Weight of ball,   60 lbs.    20 lbs.    9 in.
Weight of valvee  t 5 lbs. 36)2580 lbs.  4 in.
~and stem,  ~       70.55 lbs. 36 in.
Pressure per sq. in.
7*




78      CATECHISM OF HIGH PRESStRE, OR
Rule for finding the Area of a Circle when the Diameter
is given.
Multiply the square of the diameter by the decimal.7854.
EXAMPLE. Diameter, 3 inches, 3.7854
3         9
9 sq. in. 70.686 sq. in. -- area.
Q. How do you square a diameter?
A. Any diameter multiplied by itself is squared;
as, for instance, 10 squared equals 100.
Q. Why do you multiply the square by.7854?
A. By squaring the diameter we get square inches,
and if we multiply by.7854, we get circular inches.
Q. What is the difference between circular and
square inches?
A. A circular inch is.7854 part of the square
inch.
Q. What do you mean by the word "area "?
A. By area we mean the amount of surface exposed to the action of the steam.




NON-CONDENSING STEAM-ENGINES.            79
A TABLE FOR SAFETY-VALVES.
Containing the Circumferences and Areas of Circles from
AV of an inch to 4 inches.
Diameter. Circumfe Area.  Diameter. cumfer-    Area.
ence.    Ae.D        r    ence.
TV.1963.0030    2 in.    6.2832    3.1416
~w    [.3927.0122 [[         6.4795     3.3411
i3    [.5890.0276    8        6.6759    3.5465.7854.0490            6.8722    3.7582
w.9817.0767    i        7.0686    3.9760
3     1.1781.1104  A[         7.2649    4.2001
7     1.3744.1503    3        7.4613    4.4302
2      1.5708.1963   A        7.6576    4.6664
16    1.7671.2485 ~            7.8540    4.9087
A     1.9635.3068   9         8.0503    5.1573
[Q 2.1598.3712 [         8.2467    5.4119
~:   [2.3562.4417   44        8.4430     5.6727
[4     2.5525.5185 [          8.6394     5.9395
-7-   2.7489.6013   1[    8.8357         6.2126'15    2.9452.6903            9.0321     6.4918
fw      9.2284     6.7772
1 in.  3.1416.7854
1 3.3379.8861    3 in.    9.4248   7.0686
1      3.5343.9940      9.6211           7.3662
3     3                  1
-    3.7306   1.1075 [          9.8175    7.6699
1     3.9270   1.2271   3w,    10.0138      7.9798
1WS    4.1233   1.3529   i       10.2102    8.2957.~   /4.3197   1.4848 IH        10.4065    8.6179
1W  4.5160   1.6229 I      10.6029    8.9462
2     4.7124   1.7671   A       10.7992    9.2806
9W    4.9087   1.9175  I        10.9956    9.6211
x     5.1051   2.0739    9      11.1919     9.9678
1W     5.3015   2.2365 ]         11.3883   10.3206
[ 5.4978   2.4052 [[            11.5846    10.6796
1W     5.6941   2.5801    3     11.7810    11.0446
5.8905   2.7611   44     11.9773    11.4159
44     6.0868   2.9483    I     12.1737    11.7932
44     12.3700    12.1768
4 in.   12.5664    12.5664
For larger Areas, see Table for Cylinders, page 183.




80      CATECHISM OF HIGH PRESSURE, OR
FEED-WATER HEATERS.
THE waste of fuel and danger arising from the
rapid incrustation of steam-boilers from the deposit
of mineral substances of impure water are well
known; and the damage done to sheets and rivets by
overheating, in consequence of heavy deposits of
mineral substances, is one of the causes which produce explosions in steam-boilers, causing, as they do,
terrible destruction and loss of life. He whose inventive genius and mechanical skill contribute to
avert such disasters by purifying the feed-water for
steam-boilers, will, in point of safety and economy,
confer a boon on mankind.
The'saving in fuel that might be effected by
thoroughly heating the feed-water- by means of the
exhaust-steam in a properly constructed heater —
would be immense, which will be seen from the following facts:A pound of feed-water entering a steam-boiler at
a temperature of 50~ Fah., and evaporating into
steam of 60 pounds pressure, requires as much heat
as would raise 1157 pounds of water 1 degree. A
pound of feed-water raised from 50~ Fah. to 220
Fah., requires 987 thermal units of heat; which, if
absorbed from exhaust-steam passing through a heater,
would be a saving of 15 per cent. in fuel. Feedwater, at a temperature of 200~ Fah., entering a
boiler, as compared in point of economy with feed



NON-CONDENSING STEAM-ENGINES.     81
water at 50~ Fah., would effect a saving of over 13
per cent. in fuel; and with a well-constructed heater
there ought to be no trouble in raising the feed-water
to a temperature of 2120 Fah.
F
So                  1~~~~a
L c|  




82     CATECHISM OF HIGH PRESSURE, OR
STILWELL'S PATENT  IMPROVED  LIME-EXTRACTING HEATER AND FILTER
COMBINED.
Has obtained a world-wide reputation as the only
lime-extracting heater extant that will positively and
entirely prevent incrustation in steam-boilers. It is
indispensable to an economical use of steam, apd does
its work in the only safe and rational manner, by
removing all impurities from the feed-water before it
enters the boilers.
EXPLANATION OF CUT.
A. - Steam enters the heater, and is divided into
two currents. B. — Steam escapes from the heater.
J. - Hot water leaves heater. a. - Overflow - cup
suspended on end of cold-water pipe. bbbb. - Removable shelves or depositing surfaces. c. - Filtering chamber, to be filled with any suitable filtering
material. The feathered arrows indicate the course
of the steam, and the plain arrows the course of the
water.
The device is claimed to be an established success,
over 3000 being now at work. We are informed
that it has been fully tested over a period of 9 years,
and that it is guaranteed by its makers to completely
prevent incrustation.
They are manufactured by the Stilwell & Bierce
Manufacturing Company, Dayton, Ohio.




NON-CONDENSING STEAM-ENGINES.     83
FUEL.
Q. What are the constituents of coal?
A. The chief constituent is carbon.
Q. How much carbon does good coal contain?
A. About 90 per cent., and 10 per cent. of earthy
matter.
Q. Are there any other gases in coal except
carbon?
A. Yes; hydrogen, nitrogen, and sulphur in small
quantities.
Q. How much heat does 1 pound of pure carbon
yield in burning?
A. 14,000 units.
Q. How much heat does 1 pound of good coal,
containing 90 per cent. of carbon, produce?
A. It produces in burning about 13,000 units of
heat.
Q. What is the mechanical equivalent of 13,000
units?
A. 10,036,000 pounds; that is to say, 10,036,000
pounds raised 1 foot high.
Q. How much air does it require to burn 1 pound
of coal?
A. 240 cubic feet.
Q. How much air does it require to burn 100
pounds of coal?
A. 15,524 cubic feet of air.
Q. What is the difference between anthracite and
bituminous coal?




84      CATECHISM OF HIGH PRESSURE, OR
A. Anthracite coal consists of about 90 per cent.
of carbon, and bituminous about 80 per cent.
Q. What is the difference between anthracite coal
and good pine wood?
A. 1 pound of good anthracite coal will evaporate
as much water as 21 pounds of wood.
Q. What is the difference between anthracite coal
and coke?
A. Good coke will evaporate more water than the
best anthracite coal.
FIRE.
Q. What is fire?
A. It is the rapid combustion of the constituent
elements of organic matter.
Q. What are the causes which originate this rapid
decomposition of organic matter?
A. Fire sometimes occurs without any visible
cause when materials are in a favorable position, and
under such circumstances is called spontaneous combustion.
Q. Is there any other cause from which fire originates?
A. Yes; fire is sometimes induced by friction,
sometimes kindled by electricity; but the mode in
which it is most commonly propagated is from the
combustion of other matter that has been already
ignited.




NON-CONDENSING  STEAM-ENGINES.                  85
TABLE.
Showing the Total Heat of Combustion of Various Fuels.
Evapora- Total heat of
Equiva- tive power combustion
SORT OF FUEL.      lent in inlbs.water in lbs. water
pure  from 2120  heated 10
carbon.   Fah.       Fah.
Charcoal......................  0.93    14.00  13,500
Charred peat.............................  0.80    12.00  11,600
Coke - good........................    0.94    14.00  13,620
mean...........................  0.88    13.20  12,760
"    bad..............................  0.82    12.30  11,890
COAL:
Anthracite..............................  1.05    15.75  15,225
IEard bituminous - hardest........  1.06    15.90    15,370
CC"    "          softest.........  0.95    15.25  13,775
Coking coal...............................  1.07    16.00  15,837
Cannel coal..............................  1.04    15.60  15,080
Long flaming splint coal........... 0.91    13.65    13,195
Lignite....................................  0.81    12.15  11,745
PEAT:
Perfectly air-dry.......................  0.66    10.00  9,660
Containing 25 per cent. water.....           7.75      7,000
WOOD:
Perfectly air-dry........................50  7.50    7,245
Containing 25 per cent. water...........    5.80      5,600
REMARK. - In a boiler of fair construction, a pound of coal
will convert 9 pounds of water into steam. Each pound of this
steam will represent an amount of energy, or capacity for performing work, equivalent to 746,666 footpounds, or for the
whole 9 pounds, 6,720,000 footpounds. In other words, 1 pound
of coal has done as much work in evaporating 9 pounds of water
into 9 pounds of steam as would lift 2,232 tons 10 feet high.
CHIMNEYS.
PROBABLY there is nothing connected with the generation of steam and utilization of heat so imperfectly
8




86     CATECHISM OF HIGH PRESSURE, OR
understood, at present, as the quantity of air that
passes through the furnaces of boilers under varying
conditions of draught; it has been generally assumed,
from experiment in common practice, that double the
amount of air necessary for complete combustion of
the fuel passes through the furnace.
Experiments are greatly needed to determine the
state of combustion in varying dimensions of chimneys, as well as the quantity of air drawn through
the furnaces under these varying rates of combustion.
Q. What is a chimney?
A. It is the machine or opening through which
the air and smoke from the furnace pass.
Q. Is there any certain rule laid down for the
height of chimneys?
A. No, as much depends on the position; if a
stack or chimney is surrounded by hills or high
buildings, it ought to be higher than those in more
exposed places.
Q. Is it necessary to have higher chimneys for
long boilers than for short ones?
A. Yes; chimneys should be higher for long boilers than for short ones, but it often happens that
short chimneys draw better than long ones.
Q. Does it make any difference whether the inside
of the chimney is round or square?
A. Yes; as round chimneys have invariably more
draft than square ones.
Q. Does it make any difference whether the open



NON-CONDENSING STEAM-ENGINES.       87
ing in a chimney is more or less than the area of the
flues or tubes?
A. Yes; the opening in the chimney ought to be
in all cases one-fifth greater than the combined areas
of the flues or tubes; if it is less, it will destroy the
draught.
Q. Should the opening in the chimney be wider
at the bottom than at the top?
A. No; it should be just the reverse: it should be
wider at the top than at the bottom; if it is not, it
will retard the draught.
SMOKE.
WHEN coal is burned in an open furnace the principal products of combustion are carbonic acid and
water; certain portions of carbon escape combustion
and constitute what is commonly called smoke, which
is about 25 per cent. of the fuel in the shape of
unconsumed gases and vapors.
Various methods have been resorted to in this
country and England for the purpose of burning
smoke, but with only partial success.
Q. Will you explain some of the different arrangements brought forward at different times for the purpose of burning smoke?
A. James Watt used a hopper to feed the coal into
the furnace, supposing that the small quantity of gas
or smoke evolved by that process would be readily
consumed, but the plan soon fell into disuse.




88     CATECHISM OF HIGH PRESSURE, OR
Another device was to place a small furnace behind the bridge wall of the boiler, so that the smoke
and gases passing over it might be ignited and consumed, but this was soon abandoned. Another
method was to supply coal to one side of the furnace
at a time, in the hope that the gas and smoke from
the fresh coal would pass over the clean fire on the
other side and be consumed; but the carrying out of
this plan involved great difficulties, and had to be
abandoned. Another attempt to burn smoke was by
introducing air into the furnace above the fire, through
small holes in the door; but the attempt was attended
with no better success than the former, as the quantity
of air admitted was in most cases greater than the
quantity required, and had a tendency to chill the
gases, and the result was the air and smoke passed
into the chimney without becoming ignited.
Another, and one ofthe latest attempts to burn smoke,
is to introduce a portable or movable tube into every
tube of the steam-boiler, for the purpose of separating
the gas and smoke into thin sheets, in hopes the gas
or smoke would become ignited. But the plan was impracticable, as it involved great trouble and expense.
Q. Do you believe that smoke can be successfully
burned in common furnaces?
A. Not until the conditions under which it might
be burned are more practically defined. First, the
quantity of air that passes through the furnace more
fully understood; second, the temperature of the




NON-CONDENSING STEAM-ENdINES.      89
furnace itself better known; third, the quantity of
air required to burn different kinds of fuel, -three
conditions that are very imperfectly understood by
theorists, experts, and engineers at the present day.
GRATE-BARS.
PERFECT combustion is the starting-point in the
generation of steam; the conversion of coal and air
into heat must be the first process, and the second is
to apply that heat with full effect to the boiler. The
oxygen of the air is the only supporter of combustion, and the rate of combustion produced and the
amount of heat generated in the furnace depend on
the quantity of air supplied, and the quantity of air
admitted depends on the size of the opening through
which it passes. Then, as a matter of course, the
grate-bars that offer the least obstruction to the air
passing through them, and afford the largest area
for the air combined with an equal distribution of
the same, must be the most perfect for the purposes
of combustion.
Grate-bars to be efficient must have a narrow surface exposed to the fire, and the spaces for admitting
air must be numerous and well distributed to produce perfect combustion of the fuel.
IMPROVED GRATE-BARS AND BEARER.
The accompanying cut represents KEARNEY'S
GRATE-BARS AND BEARER, which, it is claimed, are
8*




90   CATECHISM OF HIGH PRESSURE, OR
L'l't!  dit             S
1        L    E 1, la d-.4
I S              -414g~~C1
X~~~~~~~~~~~ 3 | i  10M




NON-CONDENSING STEAM-ENGINES.        91
not only of unusual durability, but also offer the
advantage of a considerable saving in fuel. Fig. 1
shows a perspective view of the bars, of which a
suitable number are joined together to form convenient-sized sections.
A is a longitudinal brace, to which are attached
the transverse bridges, B B, of one of which an end
view is shown in Fig. 2. The same illustration represents an end section of the bars, and the manner in
which the latter are connected by the transverse
blocks, C. It also will be noticed that the interstices
or slots between the bars are widest at the bottom.
The upper surface of the grate is corrugated, the object being to give an equal amount of metal at every
point, and thus obviate the warping due to unequal
contraction and expansion. There is also another
and important advantage gained by this mode of
construction. On the perfectly flat surface which
would be afforded were the bars even on top, a
thick layer of coal would easily pack, and, forming
clinker, would make an air-tight covering, and thus
effectually hinder the draught. This difficulty is
entirely avoided by the corrugations, which admit of
a free circulation of air under the fuel, from the fact
that there will always be portions of the bars - generally the lowest points of the curves - on which the
coal will not directly rest, so that open spaces will be
formed, through which air can pass. Moreover, the
irregular surface serves as a guide to the fireman to
inform him, in cleaning the fire, when his slice-bar




92      CATECHISM OF HIGH PRESSURE, OR
has reached the grate. The shape of the interstices
between the bars, to which attention was directed
above, is favorable to the ready passage of the ashes,
while it aids in preventing clogging by clinker or
otherwise.
The ends of the bars are open and bevelled as
shown, the points of the extremities of two contiguous
sections meeting on the upper surface of the bearer.
This construction, as will be more clearly apprehended when considered in connection with the form
of the bearer, by affording open ends, admits of a free
circulation, and also prevents the bars from warping,
and thus becoming useless before they are half worn
out.
Fig. 3 represents a side view of a bearer on which
the sections of grate rest. Figs. 4 and 5 are respectively longitudinal and vertical sections of the same.
The bearer consists of two parallel bars pierced with
a number of circular openings and connected together
by transverse pieces, D D. The appliance is, therefore, in fact, a frame which, from the small amount
of metal it contains, opposes but slight resistance to
the passage of the draught. It is evident that a prominent merit of this invention is the ingenious combination of the hollow bearer and open ends of the sections
of bars, so that the part of the grate which, in ordinary use, is the most liable to become packed and
difficult to keep clean, is here as free and as clear as
any other portion. A uniform circulation of air is
consequently afforded through the entire length of




NON-CONDENSING STEAM-ENGINES.      93
the grate, and also a transverse current through the
open supports on the under side.':
This device has been thoroughly tested for some
time, during which a continuous fire has been maintained. The result of two years' experiment at the
Jersey City water-works, at Belleville, N. J., showed
a direct saving of ten to fifteen per cent. in cost of
both fuel and grates.
Any information concerning these bars can be
had from WILLIAM KEARNEY, Belleville, N. J., or
MCFARLAND & MCILRAVY, Newark, N. J.
DUTIES OF AN ENGINEER IN THE CARE AND
MANAGEMENT OF THE STEAM-BOILER.
Q. What is the first duty of an engineer when he
takes charge of an engine and boiler?
A. It is his duty to examine his boiler and see that
the water is at the proper level.
Q. How much water should the boiler contain
when in use?
A. The water should be kept up to the second
gauge whilst working, and up to the third at night.
Q. Why should the level of the water be raised at
night?
A. As a precaution against the water becoming too
low from leakage or evaporation.
Q. In case thewater should become dangerously
low, what would be the duty of the engineer?




94     CATECHISM OF HIGH PRESSURE, OR
A. He should immediately draw the fire and allow
the boiler to cool, and not admit any cold water to
the boiler or attempt to raise the safety-valve, as it
would be positively dangerous.
Q. Why would it be dangerous to raise the safetyvalve?.. Because it would lessen the pressure in allowing the steam to escape from the boiler, thus permitting the water to rise up and come in contact
with the overheated iron, and probably cause an
explosion.
Q. In case the water supply should be cut off
from the boiler for a short time, what would be the
duty of the engineer?
A. He should cover his fire with fresh fuel, stop
his engine, and keep the regular quantity of water
in the boiler until the accident is repaired and the
water supply renewed.
Q. How should an engineer proceed to get up
steam?
A. He should first see that the water is at the
proper level; he should then remove all ashes and
cinders from the furnace, and cover the grate with
a thin layer of coal; and after placing his wood and
shavings on the coal, he will be ready to start his fire.
Q. What advantage is it to place a covering of
coal on the grate before the wood or shavings?
A. It is a saving of fuel, as the heat that would
be transmitted to the bars is absorbed by the coal,




NON-C'ONDENSING STEAM-ENGINES.      95
and the bars are also protected from the extreme
heat of the fresh fire.
Q. Should an engineer allow his fire to burn gradually when he commences to get up steam from cold
water?
A. Yes; as by allowing the fuel to burn very
rapidly, some parts of the boiler become expanded
to their utmost limits, whilst other parts are nearly
cold. Of course, a great deal depends upon the time
in which he has to raise his steam.
Q. How should an engineer regulate his fire?
A. He should always keep the fire at a uniform
thickness, and not allow any bare places or accumulations of ashes or dead coals in the corners of the
furnace, as these places admit great quantities of cold
air into the furnace and render the combustion very
imperfect.
Q. Should an engineer avoid excessive firing as
much as possible?
A. Yes; as excessive firing is always attended
with more or less danger, because the intense heat
repels the water from the surface of the iron and
allows the boiler to be burned.
Q. How thick should an engineer keep his fires?
A. About 3 inches for anthracite coal and about
5 inches for soft coal; but he should regulate the
thickness of the fire according to the capacity of
the boiler; if the boiler is too small for the engine,
the fire should be kept thin, the coal supplied in




96     CATECHISM OF HIGH PRESSURE, OR
small quantities and distributed evenly over the
grate, and the grate kept as free as possible from
ashes and cinders; but if the boiler is extra large
for the engine, the thickness of the fire makes but
little difference.
Q. What should an engineer do in case, from
neglect or any other cause, his fire should become
very low?
A. He should neither poke nor disturb it, as that
would have a tendency to put it entirely out, but he
should place shavings, sawdust, wood, or greasy
waste, on the bare places, with a thin covering of
coal; then by opening the draught to its full extent,
the fire will soon come up. If it should become
necessary to burn wood on a cold fire, it is always
best to make an opening through the coal to the
grate-bars, so that the air from the bottom of the
furnace can act directly on the wood and increase
the combustion.
Q. Should an engineer give great attention to the
regulation of the draught in the furnace?
A. Yes; the regulation of draught is one of the
most important of an engineer's duties, for in fact it
is next in importance to the regulation of the water
in the boiler.
Q. How do you explain that?
A. Because it is well known that immense quantities of fuel are recklessly wasted by ignorance and
carelessness in the management of the draught.




NON-CONDENSING STEAM-ENGINES.        97
Q. How should an engineer regulate his draught
to obtain the best results from the fuel?
A. He should have no more draught at any time
than would produce a sufficient combustion of the
fuel to keep the steam at the working pressure, as
by opening the damper to its utmost limits great
quantities of heat are carried into the chimney and
lost.
Q. Can an engineer carry out this principle of
regulating the draught in all cases?
A. No; only in furnaces and boilers that are sufficiently large to furnish the necessary amount of
steam without forcing. Of course, where the boiler
is too small for the engine, or has not sufficient heating surface, it is impossible to economize fuel.
Q. Do you consider it a good practice to throw a
jet of steam under the furnace bars?
A. Only in some cases, where the draught is insufficient to produce the necessary combustion of the
fuel; but it is considered an advantage, before cleaning the fire, to throw some water under the grate
bars, as the oxygen from the steam thus generated
under the furnace will unite with the oxygen of the
atmosphere and insure a more rapid combustion of
the fuel after the fire is cleaned.
Q. Is it objectionable to throw steam or water
under the grate-bars of locomotive boilers, when
such boilers are used for stationary engines?
A. Yes; as steam or water in the ash-pit forms a
9                 G




98     CATECHISM OF HIGH PRESSURE, OR
lye with the ashes and corrodes the iron and destroys
the water-legs of the boiler.
Q. Should an engineer in all cases keep his ashpit clean?
A. Yes; by allowing the ash-pit to become filled
with ashes and cinders the air becomes heated to.a
high temperature before entering the fire, which materially interferes with the combustion of the fuel;
the grate-bars also become overheated, and in many
cases either badly warped or melted down.
Q. How should an engineer keep his safety-valve?
A. He should keep it at all times in good working
order, and move it at least once a day, particularly
in the morning.
Q. Why should he move the safety-valve every
morning?
A. To see that all its parts are in good working
order before getting up steam.
Q. Would you consider it reprehensible conduct
on the part of an engineer who would weight his
safety-valve in order to carry a pressure greater than
that he knew to be safe?
A. Yes; such conduct, if proved, ought to be sufficient to disqualify any engineer from ever taking
charge of an engine and boiler again.
Q. What is the duty of an engineer in regard to
blowing out his boilers?
A. He should carefully remove all the fire from
the furnace, and see that the steam is at the proper




NON-CONDENSING STEAM-ENGINES.      99
pressure, say from 45 to 50 pounds. He should also
close his damper.
Q. Should any time intervene between the drawing of the fire and the blowing out of the boiler?
A. Yes; at least one hour.
Q. Why should the blowing out of the boiler be
deferred for an hour after the fire is drawn?
A. To allow the furnace to cool, and prevent the
boiler from being injured with the heat after the
water is all blown out.
Q. Why not blow out the boiler under a high
pressure of steam, say 70, 80, or even 90 pounds to
the square inch?
A. Because the higher the steam-pressure the
higher the temperature of the iron, so that by blowing out the boiler under a high steam-pressure, the
change is so sudden that it has a tendency to contract
the iron and cause the boiler to leak.
Q. Should the engineer fill his boiler with cold
water immediately after blowing out?
A. No; as the introduction of cold water into the
boiler before the temperature of the iron becomes
lower would in all probability cause the boiler to
leak.
Q. How often should an engineer blow out his
boiler?
A. Whenever he discovers any appearance of
mud in the water.
Q. Is it not customary with some engineers and




100     CATECHISM OF HIGH PRESSURE, OR
owners of steam-boilers to blow out their boilers once
a week?
A. Yes; but the wisdom of this practice is extremely doubtful, for, when fresh water is boiled, it is
supposed to deposit its minerals, and after that it is
not advisable to blow out the pure water and fill the
boiler with water holding matter in solution and suspension; once in two or three weeks is as often as
boilers ought to be blown out.
Q. Should an engineer, when filling his boilers,
open some cock or valve in the steam-room of the
boiler and allow the air to escape?
A. Yes; otherwise the air would retard the ingress
of the water, and also collect in the steam-room of the
boiler and prevent the regular expansion of the iron
when the fire is started.
Q. What do you mean by the steam-room of a
boiler?
A. I mean that portion of the boiler occupied by
steam above the water.
Q. What is meant by the water-room in a steamboiler?
A. That portion of the boiler occupied by water.
Q. What do you call the fire-line of the boiler?
A. The fire-line of the boiler is a longitudinal
line above which the fire cannot rise on account of
the masonry by which the boiler is surrounded.
Q. How often should an engineer clean the tubes
9r.flues of his boiler?




NON-CONDENSING STEAM-ENGINES.      101
A. At least once a week; he should also remove
all ashes and soot that become attached to the out,
side of the boiler.
Q. What advantage is gained by cleaning the
flues and tubes regularly, and also removing the soot
and ashes that become attached to the boiler?
A. It makes a great saving in fuel, as it allows
the fire to act directly upon the iron.
Q. How often should an engineer clean his boilers?
A. Every three months, if possible.
Q. Should an engineer, when cleaning his boilers,
examine all stays, braces, seams, and angles of the
boiler or boilers?
A. Yes; he should make a thorough examination
of all parts of the boiler, seams, rivets, crown-sheet,
crown-bars, crow-feet, cotters and braces; he should
also sound the shell of the boiler with a very light
steel hammer.
Q. Why should the engineer sound the boiler?
A. Because it is the only way in which he can
determine the condition of the iron.
Q. How often should an engineer test his steam- or
pressure-gauge?
A. At least once a year.
Q. Can an engineer test a steam-gauge himself?
A. No; unless he has a test-gauge, which is not
very often the case. The gauge ought to be tested
by another gauge built or made expressly for that
purpose.
9*




102    CATECHISM OF HIGH PRESSURE, OR
Q. How should an engineer keep his glass watergauges?
A. He should keep them perfectly clean inside
and out.
Q. How can an engineer clean his glass watergauges inside?
A. By opening the drip-cock and closing the watervalve, and allowing the steam to rush down the glass
and carry out the mud or sediment: They should also
be swabbed out with a piece of cloth or waste on a
small stick, when the boiler is cold; but care should
be taken not to touch the inside of the glass with wire
or iron, as an abrasion will immediately take place.
Q. In case an engineer has a glass water-gauge,
should he neglect his gauge-cocks?
A. No; he should examine them several times in
the day, see that they are in good working order, and
grind or repair them if necessary. He should always
be sure to shut them tight, as by leaving them loose
the steam and water destroy the seat of the valve and
render them useless.
Q. What evidence do dirty or broken glass gauges,
filthy boiler-heads, leaking and muddy gauge-cocks
give of a man's ability as an engineer?
A. They furnish strong evidence of his ignorance
or neglect of duty.
Q. What should an engineer do in cold weather,
when his pumps, boiler connections, steam-gauges, or
water-pipes are liable to be frozen?




NON-CONDENSING STEAM-ENGINES.    103
A. He should open all drip- or discharge-cocks and
allow the water to run out when he stops work at
night, and in the morning make a thorough examination of all steam and water connections before he
starts his fires.
Q. In case it becomes necessary to stop the engine,
and the steam commences to blow off at the safetyvalve, what is the duty of the engineer?
A. He should immediately start his pump or injector, and also cover his fire with fresh coal, so that
the circulation might be kept up by the feed-water,
and the extreme heat of the fire absorbed by the
fresh coal, instead of being communicated to the iron
of the boiler; and he should not attempt, under any
circumstances, to interfere with the free escape of the
steam through the safety-valve.
Q. Whenever the fire-door of the furnace is open,
should the damper be closed, if possible?
A. Yes; the door and the damper should never be
open at the same time, unless it is absolutely necessary, as the cold air, that would otherwise have to
pass through the fire and become rarefied, rushes in
through the open door above the fire and impinges
on the tube and crown-sheets, and has a tendency to
contract the seams and cause them to leak.
Q. In case it should become necessary to examine
the check-valve while steam is on the boiler, how
should it be done?.A. The stop-cock between the check-valve and




104    CATECHISM OF HIGH PRESSURE, OR
boiler should be first closed before any attempt is made
to unscrew or remove the check. Any neglect to close
the stop-cock might result in a serious accident.
Q. How should an engineer proceed to make a
joint on the man-hole or hand-holes of his boiler?
A. He should first carefully remove all gum or
other material from the seat or flange where the joint
is to be made, so that the gasket may have a smooth
and solid bearing before he commences to tighten
the nut.
Q. Do you know any other important duty an engineer should consider himself bound to perform?
A. Yes; he should daily make a thorough examination of all safety-val'es, pumps, injectors, and all
steam and water connections.
Q. What should be said of an engineer that would
allow his boiler and engine to run on from bad to
worse, expecting some day to have a general overhauling, instead of making repairs as they were needed?
A. He should be considered totally unfit for the
position of an engineer.
Q. When can it be said that an engineer has done
his duty?
A. When he shows by his work that he has cared
for everything connected with his engine and boiler
in the best possible manner.




NiON-CONDENSING  STEAM-ENGINES.                   105
i             i
100 HORSE-POWER VERTICLE STEAM-ENGINE.
Kelly, Howell & Ludwig, Philadelphia, Pa.




106    CATECHISM OF HIGH PRESSURE, OR
HIGH-PRESSURE STEAM-ENGINES.
BEFORE the introduction of the steam-engine,
horses were used to furnish power for various kinds
of work, such as pumping water out of mines, raising
coal, etc. When it was proposed to substitute the
power of steam for that of horses, the proposal naturally took the form of furnishing a steam-engine capable of doing the work of a number of horses.
Hence followed the usage of stating the number of
horses which any particular engine was equal to.
Q. How is the power of a steam-engine generally
expressed?
A. In horse-power.
Q. What is a nominal horse-power?
A. 33,000 pounds raised 1 foot high in 1 minute.
Q. Why is it that 33,000 pounds raised 1 foot
high in 1 minute is adopted as a standard for a steamengine?
A. Because, before the introduction of the steamengine, it was found by experiment that with the
average of horses the best speed for work was at the
rate of 2  miles per hour; and at that rate of speed a
horse could raise perpendicularly a weight of 150




NON-CONDENSING STEAM-ENGINES.      107
pounds 220 feet high in 1 minute, which is equivalent to 33,000 pounds raised 1 foot high in 1 minute,
and was taken by Watt as a standard for horsepower, and is universally received as such. For instance; an engine of 60 horse-power can raise
33,000 pounds 1 foot high in a second, or an engine
of 420 horse-power would raise 33,000 pounds 1 foot
high in - of a second.
Q. What is the indicated horse-power of an engine?
A. It is the power of an engine as shown by an
instrument called an indicator.
Q. What is the actual horse-power of an engine?
A. It is the actual performance of the engine or
the amount of power given out.
Q. What is the net horse-power of an engine?
A. It is the available power of an engine as determined by the indicator after deducting from it the
power required to overcome the friction of the engine
itself.
Q. What should be considered the unit of commercial horse-power in high-pressure steam-engines?
A. 4 circular inches area of piston, with an average pressure of 40 pounds to the square inch and a
piston velocity of 400 feet per minute.
Q. What is the most convenient rule for finding
the horse-power of an engine?
A. Multiply the area of the piston by the average
pressure in pounds, less 5 pounds per square inch for




108      CATECHISM OF HIGH PRESSURE, OR
friction; then multiply that product by the number
of feet the piston travels per minute; then divide by
33,000 pounds. That will give the horse-power of
the engine.
For example:
Diameter of cylinder in inches...........  10
10
Square of diameter of cylinder............  100.7854
Area of piston...............................   78.54
Pressure 60 lbs., cut-off i stroke.........  45
Average press. 50 lbs., 5 off for friction 5
39270
31416
3534.30
250
33000)883575.00
26. horse-power.
Another Rule for finding the Horse-power of an
Engine.
Multiply area of piston by boiler pressure, and this
product by travel of piston in feet per minute; divide this last product by 33,000; then deduct 13 per
cent. for loss by friction and condensation.




NON-CONDENSING STEAM-ENGINES.             109
For example:
Diameter of cylinder in inches....................  12
12
Square of diameter of cylinder....................  144.7854
Area of piston...................................... 113.0976
Pressure...................................................  60
6785.856
Travel of piston.................................   300
33000)2035756.800
61.689
Percentage off for friction, etc........................13
8.01957
Horse-power of engine.......................... 53.669
Q. What do you mean by "average pressure "?
A. I mean, if the pressure is 60 pounds per square
inch, and cut off in the cylinder at I stroke, the average pressure for the whole length of the stroke would
be 50 pounds; if cut off at i stroke, it would be 57
pounds.*
Q. How do you find the area of the piston?
A. Square the diameter of the cylinder, and multiply the product by the decimal.7854.
Q. Why do you square the diameter of the cylinder and multiply by.7854?
A. Because, when we square the diameter of the
* See Table of Averages, page 116.
10




110    CATECHISM OF HIGH PRESSURE, OR
cylinder, we get square inches, and when we multiply
by.7854, we get the circular inches.
Q. What is the meaning of the word "area "?
A. It is the amount of surface exposed to the action
of the steam.
Q. How do you find the travel of the piston in feet
per minute?
A. We first find the length of the stroke of the engine, and the travel of the piston is double the stroke.
Q. What is the stroke of an engine?
A. Double the distance between the centre of the
crank-pin and the centre of the crank-shaft. For instance, if it is 12 inches between the centre of the
crank-pin and the centre of the crank-shaft, the engine is 2 feet stroke.
Q. Is the stroke and a revolution of an engine just
the same?
A. Yes; whether we call it a stroke or a revolution, the travel of the piston is the same.
Q. What do you mean by the effective pressure pn
the piston?
A. I mean that the piston is under the action of
the pressure of the steam from the boiler on one side,
and the back-action caused by the pressure of the atmosphere on the other side. The difference between
the two pressures is the effective pressure on the piston, and the power developed will depend upon the
number of square inches acted upon, and the speed
of the piston in feet per minute.




NON-CONDENSING STEAM-ENGINES.       111
Q. What ought to be the minimum  speed of the
piston of any engine?
A. 240 feet a minute.
Q. Is the pressure in the boiler and the pressure
in the cylinder nearly equal in all cases?
A. No; the pressure in the cylinder is in many
cases 3 less than the pressure in the boiler; for that
reason, in calculating the power of whole-stroke engines, or engines that do not work by expansion, not
more than 2 of the boiler pressure should be taken
as the effective pressure in the cylinder.
Q. From what cause does the difference between
the pressure in the boiler and the pressure in the
cylinder arise?
A. It arises from  different causes; first, from  a
malconstruction of the steam-pipe and steam-ports;
second, from loss by radiation and condensation;
third, by the action of the governor; and fourth, by
the bad condition of the piston.
Q. What is the most economical steam pressure to
use in the cylinder of a high-pressure engine?
A. From 80 to 90 pounds to the square inch.
Q. Why should 80 or 90 pounds to the square
inch be more economical than lower pressure, say,
40 or 45 pounds to the square inch?
A. Because the loss is greater in low pressure thant
it is in high, owing to the pressure of the atmosphere;
for instance, if we have a pressure of 45 pounds to
the square inch on the piston, the loss by atmospheric




112    CATECHISM OF HIGH PRESSURE, OR
pressure is 15 pounds to the square inch, which is
about 1 of the pressure on the piston, leaving only
30 pounds for useful effect and to overcome the friction of the engine; if we have a pressure of 90 pounds
to the square inch, the loss is only 15 pounds to the
square inch, or about 6.
Q. Has the above calculation any reference to
the pressure on the boiler as indicated by the gauge?
A. No; it refers only to the pressure on the piston.
Q. Does it take any more fuel to carry steam at a
pressure of 90 pounds to the square inch than it
does at 50 pounds to the square inch?
A. No; not quite so much.
Q. If that is the case, why not carry a pressure of
100 pounds to the square inch, or more?
A. Because, to carry such high pressures, it would
be necessary to have boilers of smaller diameters and
of better material; they should also be carefully protected from radiation by good non-conductors.
Q. Does a steam-engine that is too large for the
work to be done, and running at a high speed, waste
fuel?
A. Yes; as, for instance, an engine of 40 horsepower doing the work of a 20 horse-power engine,
and running at a high speed, the steam would have
to be throttled down, say, from 60 pounds boiler
pressure to 25 pounds on the piston, which would be
a loss of nearly 3 in fuel.
Q. Is it a common error to get an engine too large
for the power required?




NON-CONDENSING STEAM-ENGINES.      113
A. Yes; as the steam necessary to drive a 30 horsepower high-pressure engine with no load, would give
more than 10 horse-power in a small engine. The
cylinder of any engine should be of sufficient size to
give the full power required, leaving a reasonable
margin for variation in pressure, and for recuperative
power under sudden increase of load, and no larger.
Q. Are large engines doing the work easily, and
working at a low pressure, economical?
A. Only when the number of revolutions is reduced in proportion to the work to be done.
Q. Is it difficult to fix the proper size of an engine,
unless we know the power needed?
A. Yes; it is almost impossible to fix the size of
an engine, unless we know the number of machines
to be run, and the power required to run them or
any of them: for instance, if we wish to run 3 machines, and it requires 10 horse-power for each machine, the engine ought to be 34 horse-power; if we
wish to run 10 machines, requiring 10 horse-power
each, the engine ought to be 115 horse-power.
Q. Is it necessary to know the pressure that will
be used, and also the speed at which the engine will
be run, before we can fix the power of an engine?
A. Yes; until we know the pressure to be carried,
and the velocity at which the piston will travel,
nothing very definite can be said as to the power of
the engine.
10*              H




114    CATECHISM OF HIGH PRESSURE, OR
Q. Which would be the most practicable way of
increasing the power of an engine?
A. First, by increasing the pressure in the boiler;
second, by increasing the speed of the engine; third,
by putting on a new cylinder, which should not in
any case be more than 2 inches in diameter larger
than the old one.
Q. What ought to be the maximum piston speed
of non-condensing engines?
A. Although there is a limit to the velocity of
piston speed for all engines, that speed must be determined by the size and construction of the engine,
as it would not be safe to subject any engine to a
higher pressure than that for which it was built, nor
to run it at a higher speed than its moving surfaces
would bear. The velocity of piston speed must range
between 240 and 700 feet per minute, according to
the circumstances of the case.
Q. What are the four conditions that influence the
economy of a steam-engine?
A. First, pressure; second, expansion; third,
speed; fourth, size of cylinder.
Q. What are the three practical conditions that
insure the greatest economy of steam?
A. First, the highest pressure; second, the greatest
number of revolutions; third, shortest point of cutoff. If these three conditions are favorable, the
highest point of economy is obtained.
Q. What is the common mode of applying the
power of steam to the piston of the steam-engine?




NON-CONDENSING STEAIM-ENG INES.     115
A. One is to allow the steam to flow fiom the
boiler to the cylinder during the whole length of the
stroke; the other is to cut off the steam  fiom the
boiler when the piston has travelled a certain distance.
Q., What is the object of this last arrangement,
viz., the closing of the communication between the
cylinder and the boiler?
A. The great object of this arrangement is the
saving of filel.
Q. Does this account for some engines using more
fuel and steam than others?
A. Yes,; the reason why some.engines use more
steam than others of the same capacity is because the
steam is not cut off or expanded.
Q. If the load on an engine will be such as to allow the steam to be cut off at a short point in the
cylinder, what will be the effect?
A. Tile steam will be expanded to its full available limits, and a great saving will be made.
Q. If steam. be applied,to the piston the fill length
of the stroke, what will be the average pressure in
the cylinder?
A. The average pressure will be as the pressure
per square inch upon the piston.
Q. If steam, at 65 pounds to the square inch, be
applied to the piston and cut-off at half-stroke, what
will be the average pressure the whole length of the
stroke?




116      CATECHISM  OF HIGH PRESSURE, OR
A. 55 pounds to the square inch, being only 10
pounds less than the full pressure, or 16 per cent. of
loss in power, though half the quantity of steam was
only used. This alone would effect a saving of 34
per cent. of fuel.
TABLE.
Showing the Average Pressure of the Steam upon the Piston
throughout the Stroke, when cut off in the Cylinder from
i to 3, commencing with 25 pounds and advancing in 5
pounds up to 100pounds Pressure.
Pressure in pounds at the Commencement of the Stroke.
Steam Cut-off in the 25   30   35   40   45   50  |55   60
Average Pressure in pounds upon the Piston.
i 1   1171  201  231  261  291 1321 1351
21   251  29~  331  38   421  461  503
1 24   283  33 1 38   43' 481  53   57t
Pressure in pounds at the Commencement of the Sroke.
SteamCut-offinthe 65   70 6 75 180   85  190   95   100
Cylinder.        70   7          85   90   9    100
Average Pressure in pounds upon the Piston.
i  381  411  441 1471  50f 53a  56 i591
55   591  631 671  72   768   80s  84a
4  62   671~ 2  72 771  82   87   O 914 a  96
Q. Which do you consider the most economical
and available points at which to cut off steam in the
cylinder?




NON-CONDENSING STEAM-ENGINES.     117
A. i, ~, and 4 of the stroke or travel of the piston.
Beyond 4, the saving is so small as to be hardly perceptible.
Q. What are the conditions under which steam
can be worked expansively with the best results?
A. Every part of the steam-pipe, cylinder, and
connections through which the steam flows from the
boiler to the cylinder, must be carefully covered with
some good non-conducting protectors; for, unless the
temperature of the steam and the temperature of the
cylinder are kept nearly uniform, most of the benefits to be gained by expansion will be lost by radiation through the steam-pipe and the cylinder on the
outside, and by condensation on the inside.
Q. Are the advantages arising from the working
of steam expansively increased as we raise the pressure?
A. Yes; steam at a pressure of 70 pounds to the
square inch, worked expansively, will perform more
than 7 times the duty of steam at 25 pounds per
square inch.
Q. Is it necessary to make the cylinders larger in
cases where steam is to be worked expansively?
A. No; with high pressures, by which expansion
is most available, the cylinders of steam-engines can
be smaller than they are usually made.
Q. When steam is worked expansively, which is
the most effectual method of cutting off?
A. By the main valve.




118     CATECHISM OF HIGH PRESSURE, OR
LAP ON THE SLIDE-VALVE.
AEI  i'  J              Eil
C
C        C'
A A, Valve-seat. E E, Valve-face. F F, Steam-ports. G G, Bars. C, Exhaust-port. Dotted lines, H H, indicate outside lap. Dotted lines, I I, inside lap. J, Exhaust-cavity in valve.
Q. What is " Lap" on the slide-valve?
A. It is the lengthening of the valve to cut off the
steam at 2 stroke, or any other point desired; for instance, when the valve is placed at ~ stroke over the
port, the amount by which it overlaps each steamport, either internally or externally, is known as lap.
On the steam side it is named outside lap, on the exhaust side, inside lap; when the term lap and lead
is used, it designates outside lap and lead.
Q. What is meant by inside clearance?
A. When the valve is so formed that at ~ stroke
the faces of the valve do not close the steam-ports
internally, the amount by which each face comes
short of the inner edges of the ports is known as
inside clearance.
Q. In what way is the distribution of the steam
passing to and from the cylinder controlled?
A. By the outer and inner edges of the steamports and of the valve.




NON-CONDENSING STEAM-ENGINES.        119
Q. Does the width of the exhaust-port, or the thickness of the bridges (or bats), make any difference?
A. No, if the valve is rightly proportioned; as
the extreme edges of the steam-ports and those of
the valve regulate the admission, and the inner edges
of the ports and the valve control the exhaust, as
before stated.
Q. How many distinct changes occur in the cylinder for every stroke of the piston?
A. Four: first, admission; second, suppression;
third, release; and, fourth, compression.
Q. When does expansion of steam take place in
the cylinder?
A. It takes place during the interval between the
closing of the steam-port and the release of the
exhaust.
Rule by which to ascertain the amount of lap necessary, on the steam side of a slide-valve, to cut the steam
off at various fractional parts of the stroke.
To cut the steam off after the piston has passed
through
I       7      2       3       5       7      1I
la      3      4                       T N
of its stroke.  Multiply the given stroke of the
valve by.354.323.289.250.204.177.144,
and the product is the lap of the valve in terms of
the stroke.




120      CATECHISM OF HIGH PRESSURE, OR
A TABLE
Showing the amount of "Lap " required for Slide-valves
when the Steam is to be worked expansively.
The traverse of the valves being ascertained, and also the
amount of cut-off desired, the following Table shows the
amount of "lap" required:
Traverse   1The traverse of the piston where the steam is cut off.
Valve in        3              i      3
inohes.
Th e required "lap."'
Q2      7    3    1{-1    5    9I     1    7    3
2    4    T1  a           a'    Ta   -a
2    3      21  17    13  121    99    1    7
82i    1       6   13'    3-6     2  Ta  T3F  T1
3 I     t  1 1'
1' 1   3 6 3                    1 3 2
5    3 11   1.1               7    3
4   1"       T   1a     5  11 14         1'3
3           9   1       1    1 
4     2a            9 2    l/ 141    1 4   1/ 1 
6     2    2 7a 2 3  2' 1 3  1 5  1             3
6  h   2Y1a 6         T ig 29    -a   - 19
6     2 3   2 9  219- 2    2    123 1          1
74 ~ 3a  321   2 9  2 3  2                3 1   7
81    33 3    2t' 2A   23  2 3  12    1 
8     3 5        33    3 a   24j 2 1  29    2    1 5
91    3}3  35   33  213  211  2 1  2$ 13
9     31  33 5  3          3    213  21 2A  2
91    4    313  35 34    a  3 a   3   2 3  2
10     4Y'  4    341 3 3    3  33    2     2 
12      5  ~11  4i9a  4           4     A   3    2




NON-CONDENSING STEAM-ENGINES.     121
"LEAD" ON THE SLIDE-VALVE.
Q. What is "Lead" on the slide-valve?
A. It is the amount of opening the port has on the
steam end when the engine is on the "dead centre."
Q. What do you consider the proper amount of
"lead"?
A. The amount of "lead" on the valve must be
determined by the circumstances of the case, as it is
impossible to fix the exact amount for all engines;
in most cases from -A to I of an inch is sufficient,
but in some engines it is necessary to give i of an
inch or even I lead. The amount of lead for any
engine will depend on the speed, the work to be done,
the points of cut-off, etc.
11




122     CATECHISM OF HIGH PRESSURE, OR
Q.> What is lead on the exhaust?
A. It is the amount of opening the exhaust-port
has when the piston is at the end of the stroke, or, in
other words, when the crank is on the dead centre.
Q. What do you consider the proper amount of
lead on the exhaust?
A. In good practice, the amount of lead on the exhaust should be double the amount of lead on the
steam-port. The exhaust in all cases ought to be
liberated soon enough to preclude the possibility of
back pressure, but exhaust-lead may be carried to
excess. The proportioning of slide-valves presents
so many complicated considerations, that it is impossible to give any definite instructions in any particular case without a full knowledge of the circumstances.
Q. What would be the effect on the engine if the
exhaust is liberated too soon?
A. It would materially diminish the power of the
engine; and if the engine was running at a slow speed
under a heavy load, it might be difficult for the engine to complete the stroke, or, in other words, to
pass its centres. The lead on the exhaust must be
determined by the speed, the degree of expansion,
and the amount of work to be done by the engine.
For some classes of engines, such as pumping, propelling, or engines drawing heavy freight-trains up steep
grades, steam must be forced into the cylinder to the
last possible point of the stroke. Every engine should




NON-CONDENSING STEAM-ENGINES.      123
be specially arranged both for induction and eduction of steam, if the object is to get the full amount
of power out of the engine.
Q. How can you determine accurately whether the
exhaust opens at the right time or not?
A. Take off the " cap " or cover of the steam-chest,
then disconnect the valve from the valve-rod; now
take a short straight-edge and place it lengthwise on
the edge of the exhaust-port; then with a sharp scribe
lay off lines on the valve-seat, each side of the exhaust-port, that will appear above the valve; now lay
the straight-edge on the valve-face and lay off similar lines on the exhaust-chamber that will appear on
the edges of the valve; now place the valve on its
seat, and give about - of an inch lead; if the lines
described on the valve-face are passed the corresponding lines on the valve-seat i, of an inch, the exhaust
opens at the right time, if not, the exhaust-chamber
in the valve ought to be cut away to give the necessary opening.
"CUSHION."
Q. What is "cushion "?
A. "Cushion" is steam admitted to or retained in
the cylinder in front of the piston to overcome the
inertia caused by the reciprocating parts of the engine. When the piston is cushioned with live steam
it is done by giving an extra amount of lead. In
most engines the exhaust steam remaining in the




124    CATECHISM OF HIGH PRESSURE, OR
cylinder is sufficient to cushion the piston; but when it
becomes necessary to cushion the piston with live steam,
it should be done with caution, as any amount of
cushion that retards the movement of the crank before it reaches the centre is a loss of power. Extreme cushion can always be discovered by a dull
pounding noise in the engine; in such cases it is impossible to keep the packing tight around the pistonrod.
SETTING VALVES.
The proper and accurate setting of the valves of
steam-engines is among the most important duties
the engineer has to perform, as it involves a nicety
of calculation and mechanical accuracy; no uniform
rule can be adopted, as circumstances of construction, pressure, speed, points of cut-off, and work to
be done, vary so much.
Q. How would you proceed to set the slide-valve
of an engine?
A. Place the crank on the dead centre and give the
valve the necessary amount of lead, then turn the engine on the other centre, and if the valve has the same
amount of lead it is properly set. But if the lead
on one end is more or less than on the other, the
difference must be divided. When the valve is attached to the rod by means of jam-nuts great care
must be taken not to jam the nuts against the valve,
as that would prevent the valve from seating.




NON-CONDENSING STEAM-ENGINES.      125
Q. In setting the slide-valve to cut off at any
point of the stroke, is it necessary to move the
eccentric?
A. Yes; the eccentric must be moved forward in
proportion to the amount of lap added to the valve;
whether steam is to be worked expansively or not,
the valve must open at the same point of the stroke.
Q. What is the percentage of friction of the slidevalve as compared with the percentage of the cylinder's power?
A. It ranges from 10 to 30 per cent., according to
the circumstances of the case; for while the cylinder's power decreases as the crank advances to the
end of the stroke, the friction on the valve and the
eccentrics increase until they absorb in some cases
more than 25 per cent. of the power of the cylinder.
The great aim of engineers for a long time has been
to remove the weight caused by the pressure of steam
from the back of the slide-valve, but it has been
found almost impossible to produce a frictionless
slide-valve.
Q. Is the slide-valve very imperfect and wasteful?
A. Yes; theoretically, I believe it only utilizes
about 10 per cent. of the steam-power which ought
to be produced from the combustion of good fuel;
yet, imperfect as it is, on account of its simplicity
of construction, durability and positive movement,
it is the only valve now in use by all the railways in
the world.
11*




126    CATECHISM OF HIGH PRESSURE, OR
Q. What is the stroke of the slide-valve?
A. It is the distance that the valve moves on its
seat.
Q.  How do you find the stroke of the valve?
A. Move the valve in one direction to the extent
of its stroke, and make a mark on the valve-rod;
then reverse the movement to the opposite extremity
and also make a mark; the distance between the two
marks is the stroke or travel of the valve.
Q. Can the travel of the valve be increased or
lessened by means of an intermediate bearing or slot
in the arm of the rocker.
A. Yes; as the bearing in the rocker-arm that
carries the eccentric hook is lengthened, we increase
the stroke of the valve; if the same bearing is shortened, we lessen the stroke of the valve.
Q. How do you find the throw of the eccentric?
A. Measure the eccentric at the point which is
called the throw or the heaviest side; now measure
directly on the opposite or light side; the difference
between the two measures will be the throw of the
eccentric.
SIZE OF STEAM-PORT.
Q. What proportion should there be between the
area of the steam-ports of a steam-engine and the
area of the piston?
A. Steam-ports are made, in good practice, from




NON-CONDENSING STEAM-ENGINES.    127
- to -Lo the area of the piston; but they vary according to speed, etc.
SIZE OF STEAM-PIPE.
Q. What should be the diameter of the steam-pipe
as compared with the diameter of the cylinder?
A. The diameter of the steam-pipe ought to be i
the diameter of the cylinder, but it varies on large
engines. If the area of the steam-pipe, as compared with the area of the cylinder, is too small, it
will cause wire-drawing of the steam and " priming "
in the cylinder; for when the valve opens to admit
steam to the cylinder, the rush of steam is so great
that the water is carried over from the boiler to the
cylinder, which is not only a great loss of power,
but positively dangerous, as it occupies the clearance between the piston and the cylinder-head at
the end of the stroke, and has a tendency to fracture
the cylinder-heads.
SIZE OF EXHAUST-PIPE.
Q. What ought to be the diameter of the exhaustpipe as compared with the diameter of the cylinder?
A. The diameter of the exhaust-pipe ought to be
~ the diameter of the cylinder.
SIZE OF PISTON-ROD.
Q. What ought to be the diameter of the pistonrod as compared with the diameter of the cylinder?




128     CATECHISM OF HIGH PRESSURE, OR
A. The diameter of the piston-rod ought to be about
1 the diameter of the cylinder, but when steel is used
the diameter might be less.
MATERIAL FOR PARTS OF ENGINES.
Q. What kind of material do you consider the
most suitable and durable to use in the manufacture
of steam-engines?
A. For engines running at high speed, the pistonrod and crank-pin should invariably be made of
steel; the boxes should be of brass in the proportion
of 7 of copper to 1 of tin, and 1 of " spelter " to every
40 pounds of the mixture; the iron for cylinders and
guides, if made from pig-iron, should be melted about
9 times, as that is the point at which cast-iron attains
the most suitable density.
Q. What do you consider the most suitable material for the gibbs or shoes on the cross-head?
A. Wood; as hard brass or Babbitt metal has a
tendency to wear the guides out of true, which incurs
the expense of having them replaned on the face.
Wood is free from the above objections, as it never
wears or disfigures the guides; also it requires but
little oil, and the cost is very trifling. Lignum vitce
and apple-wood answer a very good purpose for gibbs,
the latter is preferable, as it is so much easier to work.
Glass is sometimes used, and is said to answer very
well for that purpose.




NON-CONDENSING STEAM-ENGINES.      129
SPRING-PACKING.
Q. Does the setting out of the packing-rings in
cylinders require great care and judgment?
A. Yes; for, like the setting of valves of steamengines, no uniform rule can be laid down for that
kind of work. If the packing is set out too tight, it
diminishes the power of the engine, and by the increased friction has a tendency to flute or destroy
both the surface of the packing and the inside of the
cylinder. If the packing is too slack, and leaks, the
steam occupies the cylinder in front of the piston,
producing excessive cushioning, and materially diminishing the power of the engine.
PROPORTIONS OF ENGINES.
Q. What would you consider good proportions for
steam-engines?
A. The diameter of cylinders of well-proportioned
steam-engines ought to be about equal to the length
of the crank between the centres; a 6-inch cylinder
12-inch stroke, 12-inch cylinder 24-inch stroke, 5-inch
cylinder 10-inch stroke, 10-inch cylinder 20-inch
stroke, as there is more vibration to long-stroke than
to short-stroke engines. But the amount of work to
be done and the speed of the piston must, to a certain
extent, determine the diameter of the cylinder and
the length of the stroke; engines intended to be run
at high speed must of necessity be of short stroke.
I




130     CATECHISM OF HIGH PRESSURE, OR
Q. Are short-stroke engines more economical than
long-stroke?
A. Yes; in all cases where steam pressure points
of cut-off and travel of piston are the same.
REVERSING AN ENGINE.
Q. How would you proceed to reverse an engine?
A. First, make a mark on the side of the eccentric near the shaft, with a scribe or small chisel;
make a corresponding mark on the shaft at the same
point; then place one point of a pair of callipers on
the mark on the shaft, and with the other point find
the centre of the shaft on the opposite side; then with
a scribe mark this point also; now unscrew the eccentric, and move it around in the direction in which the
engine is intended to run until the mark on the eccentric comes into line with the second mark on the shaft;
then make the eccentric fast, and the engine will run
in the opposite direction.
Q. Does it make any difference in what position
the crank is when the eccentric is moved?
A. No.
PUTTING AN ENGINE IN LINE.
Q. How would you proceed to put an engine in
line?
A. First, remove the cylinder-heads, piston, crosshead and connecting-rod; now attach a small piece
of iron or wood to the back flange of the cylinder;




NON-CONDENSING STEAM-ENGINES.      131
fasten a small line to that finger and connect this line
with a piece of iron or wood fastened in the floor at the
back end of the bed-plate; now take a pair of inside
callipers and find the distance between the line and
the inside of the cylinder at four different points in
the back and front ends of the cylinder; move the
line attached to the stake at the back end of the bedplate until all the points at the front and back ends
of the cylinder are equally distant from the line;
now move the crank up and see if the centre of the
crank-pin feels the line; if so, move the crank on the
other centre, and if the point at which the crank-pin
strikes the line corresponds with the point on the other
centre the engine is in line; if not, either the cylinder
or the pillow-blocks will have to be moved, as the
case may be.
Q. After the engine is "lined," how would you
proceed to adjust the different parts?
A. First, insert the piston in the cylinder and slip
on the packing-box and cross-head; now bring the
centre of the piston-head to the centre of the
cylinder by means of the set-screws or wedges, or
whatever mechanical device may be used for that
purpose; then screw up the follower-bolts; now lay
a spirit-level on the piston-rod between the packingbox and cross-head. If the end of the rod next the
cross-head is high, it can be lowered by slacking up
the set-screws in the jaws of the cross-head. If the
end next the cylinder is high, it can be levelled




132    CATECHISM OF HIGH PRESSURE, OR
by screwing down the set-screws in the jaws; the
piston-rod and crost-head should be levelled at both
ends of the guides. Next place tlhe box and strap
on the wrist of the cross-head and put the connectingrod in position and insert the key and gibb. Now
move the crank to a convenient position and slip on
the box and strap on the crank-pin and insert the
key and gibb. It often happens in driving the keys
on engines that they are adjusted too tightly, causing
them to heat and destroy the bearings. The driving
of keys on engines, like the adjusting of packingrings in cylinders and the setting of valves, requires
the exercise of great care.
SETTING UP ENGINES.
Q. How would you proceed to set up an engine?
A. Before commencing to set up an engine, it will
be necessary to determine
First. The position or location the engine is to
occupy in the shop or factory.
Second. The line of the main shafting in the building, if there be any; if not, the line of the building
itself, at at least three different points in the direction in which the main shafting is to run; now line
down from the centre of the main shaft, or from the
line of the building, at two different points, to the
floor on which the engine is' to stand, and from these
points line to the engine-shaft.
Third. Determine the height the bed-plate is to




NON-CONDENSING STEAM-ENGINES.     133
stand above the floor; also the depth of the foundation, which in most cases would be about 3 feet below
the level of the floor and 18 inches above.
Fourth. Make a tamplet the exact counterpart of
the bed-plate, in which to hang the foundation-bolts;
now set this upon four props at right angles to the
main shaft in the building.
Fifth. Lay up the brick foundation to the level at
which the engine is intended to stand; then remove
the tamplet, and lower the bed-plate on to the foundation.
Sixth. Great care should be taken, when screwing
down the foundation-bolts, to have the bed-plate perfectly level in every direction.
Seventh. A line should now be drawn exactly
through the cefitre of the cylinder, and another line
through the centre of the pillow-blocks; and if these
two lines strike each otlier at right angles, the engine
is properly set up.
Eighth. A straight-edge should now be placed
across the bottom of the main bearings, in order
to determine, by means of a spirit-level, whether
the pillow-block boxes are perfectly level.
Ninth. The crank-shaft should now be placed in
position and turned around several times, for the
purpose of determining whether it bears equally in
the boxes; if it does, the fly-wheel and driving-pulley
can then be placed in position on their shafts, and all
the other parts of the engine adjusted.
12




134    CATECHISM OF HIGH PRESSURE, OR
TAB LE,
Containing the Circumferences and Areas of Circles from 4
to 26 inches in Diameter
Diam. Circumfer.  Area.   Diam. Circumfer.  Area.
4 in. 12.5664  12.5664  13  18 2605  26.5348
1   12.7627  12.9622       18.4569  27.1085
1   12.9591  13.3640  l 5   18.6532  27.6884
3   13.1554  13.7721  6in. 18.8496  28.2744
4 13.3518  14.1862         19.0459  28.8665
65  13.5481  14.6066       19.2423  29.4647
3   13.7445  15.0331  -3-  19.4386  30.0798
17  13.9408  15.4657  4   19.6350  30.-6796
a   14.1372  15.9043 -    19.8313  31.2964
9   14.3335  16.3492  3   20.0277  31.9192
~    14.5299  16.8001      20.2240  32.5481
14.7262  17.2573  a   20.4204  33.1831
3   14.9226  17.7205 1    20.6167  33.8244
13  15.1189  18.1900  5   20.8131  34.4717
8   15.3153  18.6655  1    21.0094  35.1252
_   15.5716  19.1472  -   21.2058  35.7847
5 in. 15.7080  19.6350  1 3  21.4021  36.4505
1   15.9043  20.1290  7   21.5985  37.1224
1   16.1007  20.6290  156  21.7948  37.8005
-3.  16.2970  21.1252  7 in. 21.9912  38.4846
1   16.4934  21.6475  -    22.1875  39.1749
5   16.6897  22.1661      22.3839  39.8713
3   16.8861  22.6907  3   22.5802  40.5469
17   17.0824  23.2215  4   22.7766  41.2825
17.2788  23.7583  5   22.9729  41.9974
a9  17.4751  24.3014  9   23.1693  42.7184
5   17.6715  24.8505  7   23.3656  43.4455
17.8678  25.4058  a   23.5620  44.1787
3   18.0642  25.9672  T9   23.7583  44.9181




NON-CONDENSINGI STEAM-ENGINES.    135
T A B L E. - (CONTINUED.)
Containing the Circumferences and Areas of Circles from 4
to 26 inches in Diameter.
Diam. CircuMlfer.  Area.   Diam. Circumfer.  Area.
8   23.9547  45.6636'7   29.6488  69.9528
~g   24.1510  46.4153  a   29.8452  70.8823
4   24.3474  47.1730   9   30.0415  71.8181
1   24.5437  47.9370  g   30.2379  72.7599
24.7401  48.7070  1   30.4342  73.7079
~1s  24.9354  49.4833  3   30.6306  74.6620
8 in. 25.1328  50.2656  1 3  30.8269  75.6223
-~   25.3291  51.0541  7   31.0233  76.5887
1   25.5255  51.8486    5-  31.2196  77.5613
3   25.7218  52.8994 10 in. 31.4160  78.5400
25.9182  53.4562  1   31.8087  80.5157
5T  26.1145  54.2748  1   32.2014  82.5160
8 26.3109  55.0885         32.5941  84.5409
17  26.5072'55.9138      32.9868  86.5903
a   26.7036  56.7451  5   33.3795  88.6643
-96  26.8999  57.5887  3   33.7722  90.7627
5   27.0963  58.4264  1   34.1649  92.8858
11  27.2926  59.7762 11 in. 34.5576  95.0334
3   27.4890  60.1321       34.9503  97.2053
13  27.6853  60.9943  1   35.3430  99.4121
27.8817  61.8625  3   35.7357 101.6234
5  28.0780  62.7369  a   36.1284 103.8691
9 in. 28.2744  63.6174  5   36.5211 106.1394
J,   28.4707  64.5041  3   36.9138 108.4342
1   28.6671  65.3968  7   37.3065 110.7536
-    28.8634  66.2957 12 in. 37.6992 113.0976
1 i
4   29.0598  67.2007   1   38.0919 115.4660
-5  29.2561  68.1120  4   38.4846 117.8590
3   29.4525  69.0293  3   38.8773 120.2766
_'9             -8              I~




136    CATECHISM OF HIGH PRESSURE, OR
TAB L E. -(CONTINUED.)
Containing the Circumferences and Areas of Circles from 4
to 26 inches in Diameter.
Diam. Circumfer.  Area.   Diam. Circumfer.  Area.
1  39.2700 122.7187   -   51.0510 207.3946
39.6627 125.1854   3  51.4437 210.5976
3  40.0554 127.6765   A   51.8364 213.8251
7  40.4481 130.1923   5   52.2291 217.0772
13 in. 40.8408 132.7326   3  52.6218 220.3537
1  41.2338 135.2974       53.0145 223.6549
] 41.6262 137.8867 17 in. 53.4072 226.9806
3  42.0189 140.5007   4   53.7999 230.3308
J  42.4116 143.1391!  54.1926 233.7055
8   42.8043 145.8021   3  54.5853 237.1049
4   43.1970 148.4896      54.9780 240.5287
8  43.5857 151.2017   W   55.3707 243.9771
14 in. 43.9824 153.9384     55.7634 247.4500
44.3751 156.6995   W   56.1561 250.9475
4   44.7676 159.4852 18 in. 56.5488 254.4696
3  45.1605 162.2956       56.9415 258.0161
45.5532 165.1303      57.8342 261.5872
5  45.9459 167.9896   -   57.7269 265.1829
3  46.3386 170.8735       58.1196 268.8031
g   46.7313 173.7820   5  58.5123 272.4479
15 in. 47.1240 176.7150   4   58.9056 276.1171
47.5167 179.6725   7  59.2977 279.8110
47.9094 182.6545 19 in. 59.6904 283.5294
3  48.3021 185.6612   A   60.0831 287.2723
1  48.6948 188.6923   4   60.4758 291.0397
49.0875 191.7480   3  60.8685 294.8312
49.4802 194.8282   1  61.2612 298.6483
49.8729 197.9330   5  61.6539 302.4894
16 in. 50.2656 201.0624   4   62.0466 306.3550
I  50.6583 204.2162   7  62.4393 310.2452




NON-CONDENSING STEAM-ENGINES.    137
T A B L E. - (CONTINUED.)
Containing the Circumferences and Areas of Circles from 4
to 26 inches in Diameter.
Diam. Circumfer.  Area.   Diam. Circumfer.  Area.
20 in. 62.8320 314.1600 23 in. 72.2568 415.4766
A   63.2247 318.0992  1    72.6495 420.0049
63.6174 322.0630   ~   73.0422 424.5577
3  64.0101 326.0514   3  73.4349 429.1362
A   64.4028 330.0643      73.8276 433.7371
64.7955 334.1018     1 74.2203 438.3636
3  65.1882 338.1637   3  74.6130 443.0146
65.5809 342.2503   7  75.0057 447.6992
21 in. 65.7936 346.3614 24 in. 75.3984 452.3904
1  66.3663 350.4970   A   75.7911 457.1150
66.7590 354.6571   4   76.1838 461.8642
67.1517 358.8419   9   76;5765 466.6380
8   67.5444 363.0511   4   76.9692 471.4363
5   67.9371 367.2849   -   77.3619 476.2592
3  68.3298 371.5432   3  77.7546 481.1065
7   68.7225 375.8261   7  78.1473 485.9785
22 in. 69.1152 380.1336 25 in. 78.5400 490.8750
8   69.5079 384.4655! 78.9327 495.7960
69.9006 388.8220      179.3254 500.7415
4  70.2933 393.2031   3  179.7181 505.7117
70.6860 397.6087   2  80.1108 510.7063
4   71.0787 402.0388   4   80.5035 515.7255
71.4714 406.4935   4   80.8962 520.7692
7  71.8641 410.9728   7  81.2889 525.8375
For the circumferences and areas of circles of smaller
diameters, see Table for Safety- Valves, page.
To find the circumferences of larger circles, multiply the diameter by 3.1416. For areas, multiply the
square of the diameter by.7854.
12*




138    CATECHISM OF HIGH PRESSURE) OR
RULES FOR THE CARE AND MANAGEMENT
OF THE STEAM-ENGINE.
First. When the engine is stopped at night, the
drip-cocks should always be left open in order to allow the condensed water to escape from the cylinder.
They should not be closed for some time after the
engine is started in the morning.
Second. Before starting the engine in the morning
the cylinder should be warmed by admitting some
steam, and moving the engine back and forth with
the starting-bar.
Third. The oil or tallow should never be admitted
to the cylinder until some time after the engine is
started and the drip-cocks in the cylinder closed, as
the tallow would otherwise be carried out by the
condensed water and lost.
Fourth. All parts of the steam-pipe and the cylinder should be covered with cloth, felt, or some other
good non-conductor to prevent radiation and condensation.
Fifth. Before packing the piston- and valve-rods
all the old packing should be carefully removed and
replaced with new packing, which should be cut in
suitable lengths, and the joints placed at opposite
sides of the box. The stuffing-box should then be
screwed up until the leakage around the rod is stopped,
and no further, as any unnecessary tightening of
the stuffing-box will greatly diminish the power of




NON-CONDENSING STEAM-ENGINES.       139.
the engine and soon destroy the packing by the increased friction.
Sixth. Piston-rod packing should always be kept
in a clean place, as any dust or grit that may become
attached to it has a tendency to cut or flute the rod.
Seventh. The spring-packing in the cylinder should
always be kept up to its proper place, because, if allowed to become loose, the leakage materially interferes with the power of the engine. Setting out packing-rings requires the exercise of great care, because,
if set too tightly, the friction produced will not only
have a tendency to cut the cylinder, but will also
perceptibly lessen the power of the engine.
Eighth. The piston should be removed from the
cylinder at least twice a year, and the joints formed
by the rings on the flange of the head and the follower-plate carefully ground with emery and oil. If
badly corroded, they should be faced up in a lathe
and made perfectly steam-tight.
Ninth. In driving the keys on the cross-head and
crank-pin, the face of the hammer should never be
used, unless the end of the key is protected by a piece
of sheet-brass or copper.
Tenth. Great care should be taken, when packing
the spindle of a governor, not to screw the packing
down too tightly, as that would interfere with the
free movement of the governor. All the parts of the
governor should be kept perfectly clean and free from
the gum formed by the use of inferior qualities of
lubricating oils.




140     CATECHISM OF HIGH PRESSURE, OR
Eleventh. No more oil should be used on an engine
than is absolutely necessary, as it is not only a loss,
but often detracts from the appearance of the engine,
and greatly interferes with its free and easy movement, from the accumulation of gum and dirt on its
working parts.
Twelfth. In case the crank-pin should heat —
which is a common occurrence with engines having
a narrow bearing on the pin, but more particularly
with engines that are slightly out of line - remove
the key and slacken the strap and box; then pour in
some flour of sulphur with a liberal supply of oil;
then adjust the key, and the trouble will generally
disappear.
Thirteenth. If the pillow-blocks of an engine
should heat badly, remove the cap and pour in a good
supply of pulverized bath-brick and water while the
engine is in motion; after doing this for some time,
wash out with oil, and wipe the bearing clean with
waste, and it will be found to give permanent relief.
Fourteenth. In case any of the bearings of an
engine should heat through the accumulation of
matter deposited from the oil used, or sand, grit, or
whitewash being dropped into the bearings, use a
strong solution of concentrated lye with oil when
the engine is in motion.
Fifteenth. A steam-engine should show, by its
working and general appearance, that all its parts
are thoroughly cared for.




NON-CONDENSING STE AM-ENGINES.                141
WorkR, Phila., Pa.
Works, Phlila., Pa.




142     CATECHISM OF HIGH PRESSURE, OR
DIFFERENT KINDS OF ENGINES.
Q. What is meant by high-pressure or non-condensing engines?
A. High-pressure engines are a class of engines in
which steam is used at a high pressure and exhausted
into the open air. This class of engines includes
locomotives and a great variety of stationary engines.
Q. What is meant by low-pressure or condensing
engines?
A. Low-pressure engines are a class of engines in
which steam is used at a low pressure and exhausted
into a condenser, where a vacuum is produced by an
air-pump; the piston being under the pressure of
steam from the boiler on one side and the vacuum
on the other, the difference between the two is the
effective pressure on the piston. All ocean steamers,
large river-boat engines, and a great many powerful
factory engines, belong to this class.
Q. Is the vacuum perfect in low-pressure engines?
A. No; there is always more or less back pressure,
caused by wear of the working parts or imperfections
in the construction of the machinery.
Q. Are low-pressure engines more economical than
high-pressure?
A. Yes; low-pressure engines possess great advantages over high-pressure in point of economy; but
the first cost of a low-pressure is nearly double that
of a high-pressure of the same power.




NON-CONDENSING STEAM-ENGINES.     143
Q. What is meant by rotative engines?
A. Rotative engines are a class of engines in which
the energy of the steam produces a continuous rotation of a shaft through the medium of a crank and a
reciprocating piston. This class of engines includes
a great variety of designs, namely, horizontal, vertical, beam, inclined, etc.
Q. What is meant by rotary engines?
A. Rotary engines are a class of engines in which
a continuous rotation of a shaft is caused by the action
of steam on a piston rotating within a steam-tight
casing.
Q. Is the rotary engine as old as the rotative?
A. Yes; one was designed by James Watt, and
there is hardly a treatise on the steam-engine in existence which does not contain an allusion to rotary engines; but the writers all agree that nothing would
be gained by the substitution of the rotary for the
rotative engine, on account of the great difficulty in
making the parts steam-tight without producing extra
friction.
Q. What is meant by beam-engines?
A. Beam-engines are a class of engines in which
the reciprocating motion of the piston is transmitted
to the crank through the medium of a beam commonly called a walking-beam. The beam-engine
was for a long time in great favor with engineers and
steam users on account of its graceful and nicelybalanced movements. But within the past few years




144     CATECHISM OF HIGH PRESSURE, OR
beam-engines have been gradually superseded by
upright and horizontal engines.
Q. Does the beam-engine possess any advantage
over the horizontal engine?
A. Yes; there is less loss of power by friction in
large beam-engines than in large horizontal engines,
as the piston hangs plumb in the centre of the cylinder, and has a tendency to assist the downward movement of the stroke rather than to produce friction, as
in horizontal engines. The cylinders of beam-engines
are less liable to wear out of round than those of horizontal engines. But the first cost of beam-engines is
more than that of horizontal of the same power.
Q. Is the beam-engine as old as any of the former?
A. Yes; when steam-engines were first introduced,
more beam-engines were constructed than any other
kind.
Q. What is meant by inclined engines?
A. Inclined engines are engines set at an angle or
an inclined plane for convenience, or to give direct
motion to some machine or machinery without the
intervention of belts or gearing.
Q. What is meant by horizontal engines?
A. Horizontal engines are a class of engines in
which the cylinder, piston, and guides are set horizontally with the bed-plate.
Q. What is meant by oscillating engines?
A. Oscillating engines are a class of engines in
which the cylinder swings or vibrates on trunnions, by




NON-CONDENSING STEAM-ENGINES.      145
which the motion of the piston is transmitted directly
to the crank, without the intervention of connectingrod or cross-head.
Q. What advantage do oscillating engines possess
over other engines?
A. None at all, except in the economy of Spade,
The trunnions of oscillating engines soon become
leaky, and are difficult to repair, The speed of oscillating engines is very limited. As a factory engine,
oscillating engines might be said to be a failure.
Q. What is meant by poppet-valve engines?
A. Poppet-valve engines are a class of engines used
almost exclusively in this country. They have four
valves -- two steam and two exhaust - which are
moved by cams and levers. The poppet-valve engine
embodies some very good principles, and when in
good order works very economically. But a limit of
speed is soon reached in the poppet-valve engine, as
at a very high speed poppet-valves may not seat
themselves promptly. Poppet-valve engines take
their steam very rapidly, and probably have less back
pressure than slide-valve engines.
Q. What is meant by slide-valve engines?
A. Slide-valve engines are a class of engines in
which the steam is admitted to the cylinder by means
of a slide-valve worked by an eccentric or cam.
Q. Do slide-valve engines possess any advantage
over other engines in point of economy?
A. No; the slide-valve is very imperfect and
13              K




146     CATECHISM OF HIGH PRESSURE, OR
wasteful, as under ordinary circumstances it utilizes
only about 4 per cent. of the steam-power which
ought to be produced from the combustion of the
fuel used, and not more than 10 per cent. under the
most favorable circumstances. Yet, on account of its
simplicity of construction, durability, and positive
movement, and the fact that there is hardly any
limit to its speed, the slide -valve engine has been
enabled to compete with the best modern improvements in steam-engines?
Q. What is meant by Corliss engines?
A. Corliss engines are a class of high-pressure engines in very general use. Their design and construction embody the right principle for the steamengine. They have four valves — two steam and
two exhaust; they take steam very rapidly, and
probably have less back pressure on the exhaust than
any other class of engines in use. Thly work very
economically when in good order; but the great drawback to the Corliss engine is that the valve-gear is
complicated and expensive, liable to wear very rapidly, and is difficult to repair.
Q. What is meant by compound engines?
A. Compound engines are a class of engines which
embody both the high- and the low-pressure principles. Steam is admitted into one cylinder and used
at, high-pressure, and then exhausted into another of
much larger area and worked on the low-pressure
principle. Such engines are said to be very econom



NON-CONDENSING STEAM-ENGINES.      147
ical, but they are complicated, and the first cost of
them is very great.
Q. What is meant by side-lever engines?
A. Side-lever engines are a class of engines (used
principally for pumping water) in which the motion
of the piston is transmitted to the pump by side-levers
or beams.
Q. What is meant by duplex engines?
A. Duplex engines are a class of engines which,
like the compound, use steam on the high- and lowpressure principles, and allow a very great limit of
expansion. They are principally used for pumping
water. They work very economically, but, like the
compound, are complicated and expensive.
Q. What is meant by Cornish engines?
A. Cornish engines are a class of engines in which
the motion from the piston is communicated to the
pump by means of a beam. They are used exclusively for pumping water in cities and mines. Cornish engines might be said to belong to that class of
engines called single-acting engines, as the steam acts
on only one side of the piston. Steam being admitted to the cylinder, the piston is forced down to
the end of the stroke, when the steam escapes to the
condenser. The opposite movement of the piston is
accomplished by the inertia or weight on the pump.
Q. Are Cornish engines more economical than
other pumping-engines?
A. No; the only advantage they possess over




148     CATECHISM OF HIGH PRESSURE, OR
other pumping-engines is that they admit of a very
large measure of expansion in one cylinder.
Q. What is meant by Bull engines?
A. Bull engines are a class of direct-acting pumping-engines. These engines take their name from
their inventor - Bull. They do not sustain a high
reputation either for durability or economy.
Q. What is meant by trunk engines?
A. Trunk engines are a class of engines in which
the cylinder is stationary, and the reciprocating motion of the piston is communicated directly to the
crank without the intervention of connecting-rod or
cross-head, through the medium of a trunk or hollow
tube working through a stuffing-box. Trunk engines
are very wasteful of steam, as the large mass of metal
entering into the composition of the trunk, moving,
as it does, alternately into the atmosphere and steam,
must cool and condense a great part of the steam.
The radiation from the interior of the trunk is also
great.
Q. What is meant by caloric engines?
A. Caloric engines are a class of engines in which
air is used as a motive power. The air is forced into
the cylinder by means of an air-pump, and expanded
by heat, by which means the piston is forced forward
to the end of the stroke. Caloric engines are invariably single-acting engines, and their power is very
limited.




NON-CONDENSING STEAM-ENGINES.      149
1KNOCEING IN ENGINES.
Q. What are the principal causes of knocking in
engines?
A. Knocking in engines generally arises from the
following causes:
First. Lost motion in the boxes on the cross-head,
crank-pin, and pillow-blocks, and in the key of the
piston-rod in the cross-head.
Q. What is the most effectual remedy for knocking arising from the above causes?
A. Take up lost motion by means of the key, or
file off the edges of the boxes, if brass-bound.
Second. Knocking is sometimes caused by the
crank being ahead of the steam, which in most cases
can be relieved by moving the eccentric forward in
order to give more lead on the valve.
Third. Knocking is caused in many cases by too
much lead on the valve. The simplest remedy for
13*




150     CATECHISM OF HIGH PRESSURE, OR
this is to move the eccentric back so as to give less
lead.
Fourth. Knocking is sometimes caused by the exhaust closing too soon.  The best remedy for this
would be to enlarge the exhaust-chamber in the valve.
Fifth. Knocking is in some cases produced by
there not being sufficient clearance between the
piston and the cylinder-head at the end of the stroke.
The remedy for this kind of knocking would be to
turn off the heads of the cylinder on the inside, so as
to give more clearance.
Sixth. Knocking sometimes arises from the wrist
of the cross-head and the crank-pin becoming worn
out of round. The most effective remedy for this
cause is to file the crank-pin and wrist perfectly
round.
Seventh. Knocking is often induced by the cylinder
not being counter-bored the necessary depth. In such
cases the piston-rings wear a shoulder at each end of
the cylinder, and whenever the keys are driven or
the packing-rings set out, the edges strike these
shoulders and cause the engine to knock. The most
practical remedy for knocking arising from this
cause is to recounter-bore the cylinder.
Eighth. Knocking is sometimes caused by the engine being out of line. The surest remedy for this
kind of knocking would be to put the engine exactly
in line.
Ninth. Knocking often arises from shoulders be-.




NON- CONDENSING STEAM-ENGINES.    151
coming worn on the ends of the guides in cases where
the gibbs on the cross-head do not run over. The
most reliable remedy for such knocking would be
to replane the guides.
Tenth. Knocking is sometimes caused by the follower-plate being loose. The best preventive for
such knocking is to bring the bolts up tight. To do
so, it is sometimes necessary to remove the deposit of
rust or grease in the bottom of the holes.
Eleventh. Knocking is very often caused by the
packing around the piston-rod being too hard and
tight. The most effectual remedy for that is to remove all the old packing from the box and replace
it with new, and only screw the box up sufficiently
tight to prevent the escape of steam; for any extra
friction on the rod is a great loss of power, and has a
tendency to destroy the packing.
Twelfth. The knocking heard in the steam-chest is
sometimes caused by lost motion in the jam-nuts or
yoke that forms the attachment between the valve
and rod. The remedy for this would be to remove
the cover of the steam-chest and readjust the jamnuts on the valve-rod.
VACUUM.
Q. What is a vacuum?
A. The literal meaning of the term vacuum is
space unoccupied by matter.
Q. Suppose the cylinder of a steam-engine be filled




152     CATECHISM OF HIGH PRESSURE, OR
with steam that is vaporized from a few drops of
water, can it be said to be void of matter?
A. No; but condense that steam to its original
bulk into Water, and withdraw this water from the
cylinder, and the space formerly occupied by the
steam will be unoccupied; no matter remaining in
the cylinder, then there is what is termed a vacuum.
Q. Suppose this operation to have taken place under the piston of a steam-engine, would there be any
resistance to be overcome in the descent of the piston?
A. No; the pressure of the atmosphere alone,
which is 15 pounds to the square inch, would suffice
to force the piston down with a power equal to the
degree of vacuum formed.
Q. Were the first steam-engines constructed on this
principle?
A. Yes; the first steam-engines were constructed
with the upper end of the cylinder open to the atmosphere; steam was then admitted below the piston
to raise it; and this steam being condensed in the
cylinder by the application of cold water, the pressure of the atmosphere alone caused the downward
stroke of the piston.
Q. Suppose steam at 5 pounds pressure to the
square inch above the atmosphere, or, in other
words, 5 pounds pressure on the steam-gauge, (which
in reality is 20 pounds to the square inch,) be
applied to the piston of an engine under the conditions above stated, what would be the effect?




NON-CONDENSING STEAM-ENGINES.      153
A. If the pressure of the atmosphere be 15 pounds
to the square inch, there will be a pressure of 20
pounds exerted on the piston; but if the pressure
of the atmosphere is only 14 pounds to the square
inch, as is often the case, the pressure on the piston
would be only 19 pounds to the square inch.
Q. How do you explain that?
A. Because the resistance of the atmosphere on
the safety-valve would be less, and the steam in the
boiler also less in proportion to the reduced pressure of the atmosphere.
Q. Does it often happen that low-pressure engines
heavily loaded vary their speed with the varying
pressure of the atmosphere?
A. Yes.
Q. Suppose that the vacuum is not perfect, (in
practice it is never so,) and that there remains in
the cylinder some uncondensed steam, the resistance
of which is equal to 3 pounds to the square inch,
what would be the effect on the engine?
A. Then the steam on the upper side of the piston,
at 5 pounds to the square inch, above the pressure
of the atmosphere, would act with an effective force
of only 17 pounds to the square inch because the
upper side of the piston having exerted upon it a
pressure equal to a pressure of 20 pounds to the
square inch and the under side of the piston had a
resistance of 3 pounds to the square inch, the effective pressure would be only 17 pounds.




154    CATECHISM OF HIGH PRESSURE, OR
Q. Is a vacuum power?
A. No; all power in the steam-engine is derived
from the pressure of the steam on the piston; if
there is no.resistance on one side of the piston, the
whole pressure on the other side is available. Whenever there is resistance on one side of the piston,
whatever the amount may be, it must be deducted
from the pressure on the other side.
THE INDICATOR.
THE instrument known by the name of the SteamEngine Indicator was invented by the celebrated
James Watt. For a considerable period Watt kept
the knowledge of that useful instrument to himself, but
being obliged at last to send an engine abroad, and
being responsible for its erection and proper working, he furnished a mechanic, whom he sent out to
superintend the erection of the engine, with an Indicator, having previously instructed him in the use
of the instrument.
Since the days of Watt, the Indicator has received
several important improvements.
Q. What is the advantage of the Indicator?
A. The Indicator enables us to calculate with accuracy the pressure of steam exerted on the piston
through the whole length of the stroke; it also shows
at what part of the cylinder the piston is, and when
the valves open or close.




NON-CONDENSING STEAM ENGINES.    155
Q. Is it possible to tell these things without the
use of the Indicator?
A. No, not with any degree of accuracy. At a
glance the Indicator reveals the inner working of the
steam-engine, and by the use of the instrument, the
good and bad qualities of the engine are registered
on paper by the engine itself.
Q. Do you know of any other advantage to be
gained by the use of the Indicator?
A. Yes; by means of the Indicator the owner of a
factory may ascertain the whole power he is using,
also the force required to overcome the friction of
his engine and machinery, or the power required for
any single room, or any particular machine, or any
number of machines.
Q. Is there any other important knowledge we can
obtain, concerning the steam-engine, by the use of
the Indicator?
A. Yes; by means of the Indicator we are enabled
to calculate how much more power an engine will
exert by an increase of pressure, or by different degrees of expansion, according to the circumstances
of the case.
Q. Would an extended knowledge of the use of
the Indicator be of great importance to engineers
and owners of steam-engines?
A. Yes; by a skilful use of the Indicator they
could obtain a knowledge of the condition of every
description of engines; also how to increase the power




156     CATECHISM OF HIGH PRESSURE, OR
of each to its extreme limit of capability with the
least expenditure of fuel.
Q. Why is it that the Indicator is not more extensively. applied to steam-engines than it is at the
present day?
A. First, because the Indicator, to a great extent,
is in the hands of a class of men who try to deceive
owners of steam-engines and steam-boilers by showing the enormous amount of work an engine is doing,
for the purpose of magnifying the great evaporative
powers of some patent steam-boiler. Second, the Indicator is also applied by some steam-engine builders
(on engines of their own manufacture) who have an
interest in showing that the engine is performing a
far greater amount of work than that which was contracted for. Such men hardly ever work up their
own cards, and even if they do, there is such a vast
difference in the results of their trials on the same
engines, that the owners of steam-engines are no better informed as to the condition of their engines,
or the amount of work done by the engine, than they
were before the Indicator was applied.
It is to be regretted that the benefit to be derived
from the use of the Indicator is so imperfectly understood by engineers and owners of steam-boilers.
Bramwell, in his address before the British Association, claimed that one of the greatest incentives to
economical working which owners of steam-engines
could offer to engine-builders, would be the applica



NON-CONDENSING $TEAM-ENGINES.         157
P;90
I 4
_!ai
ar~ ~ c
14




158     CATECHISM OF HIGH PRESSURE, OR
tion of the Indicator; for he declared that the Indicator was to the proprietor of a steam-engine what
the mariner's compass is to the captain of a ship
navigating the sea.
Q. Will you explain how to apply the Indicator
to steam-engines?
A. Yes; but in order to do so it will be first necessary to give a description of the instrument itself.
First. The tap, H, forms a communication between
the cylinder of the Indicator and the cylinder of the
engine. There is a small hole in the side of the tap
which opens into the tap-plug, and when the tap is
open to the cylinder of the steam-engine and the Indicator, this small hole is closed by the plug being
turned with its perfect side against the hole. When
the tap is closed, the connection with the enginecylinder is cut off. The small hole in the tap is then
open through the plug to the cylinder of the Indicator, so that any steam remaining between the piston
of the Indicator and the plug of the tap may escape
into the atmosphere, and allow the pencil attached to
the piston of the Indicator to settle down to the atmospheric line.
Second. The cylinder of the Indicator is fitted with
a piston, the rod of which is shown at R. This piston
is accurately ground into the cylinder, thereby avoiding packing; and when properly oiled and cleaned,
it is steam-tight, except at very high pressures, wheie
perfect tightness is not required, as any small por



NON-CONDENSING STEAM-ENGINES.      159
tion of steam which may escape cannot affect the
bulk of the pressure in the cylinder. From this construction the piston works freely with little friction.
Third. The piston-rod, R, is attached to the spiral
spring, S, within the tube or casing, F, placed above
the steam-cylinder of the instrument. This spring is
so adjusted that when the piston-index is forced onetenth of an inch above the atmospheric line, 0,
marked on the scale, E, it represents 1 pound pressure of steam. The pointer forced upward each tenth
of an inch, up to 25 tenths, will represent as many
pounds pressure to the square inch. In the same
way, when the vacuum is formed in the engine-cylinder, the spring will be distended by the pressure of
the atmosphere upon the upper side of the Indicatorpiston, and the piston will be forced downward as many
tenths of an inch as the degree of rarity, or the quantity of steam extracted from the engine-cylinder in
pounds per square inch below the pressure of the
common atmosphere.
Fourth. Affixed to the casing there is.the scale, E,
with the atmospheric line, 0, in the centre. The
tenths below 0 to 15 indicate the vacuum, and
above 0 to 25 tenths, the steam pressure above the
atmospheric pressure.
Fifth. The pencil-holder, G, is attached to the piston-rod, R, through an aperture cut in the casing,
F, to allow the pencil-holder to move up and down
with the piston-rod of the Indicator. The pencil can




160     CATECHISM OF HIGH PRESSURE, OR
be screwed backward or forward, to obtain the exact
length required, and is adjusted by a spring to allow
it to accommodate itself to any little inequalities there
may be on the revolving cylinder or the paper. In
all cases a soft and good pencil should be used. The
less the pressure upon the paper, the less the resistance to the free action of the piston.
Sixth. I is the revolving cylinder outside the
casing, F. This cylinder revolves on its own axis.
The paper on which the diagram is to be taken is
fixed around this cylinder, and held in its place by
the clip, J. On the bottom of the cylinder there is a
cord round the pulley, K, which, after passing over
the swivel-pulley, a, is then attached to the crosshead of the engine. It will be obvious that the traverse of the cross-head will pull the cylinder as far
round as the string thus travels. On the relaxation
of the string, caused by the return movement of the
engine-piston, the pulley will again take up the cord,
because an internal spring, similar to the spring
of a self-winding measuring-tape, is enclosed in the
revolving cylinder. The traverse of the cross-head
pulls the cylinder one way round and the spring the
other. By means of the cord attached to the crosshead of the engine, there is thus produced a regular
traversing motion of the cylinder, I; and as the pencil presses at the same time against the paper affixed
to the cylinder, and also moves up and down with
the Indicator-piston - which piston is propelled by




NON-CONDENSING STEAM-ENGINES.        161
the same force as the engine-piston - the piston will
describe a diagram according to the circumstances.
Seventh. The area of the cylinder of the Indicator
is a quarter of a square inch, and each tenth of an
inch on the index represents 1 pound pressure to the
square inch of the piston of the engine. The spring,
S, compressed, shows the steam pressure. Distended,
it shows the atmospheric pressure upon the piston of
the Indicator caused by the formation of the vacuum
in the engine-cylinder, varying in accordance with
the pressure of the uncondensed steam left in the
cylinder. This spring is so adjusted as to meet the
requirements of the pressure as it increases. When
the steam exceeds 25 pounds to the square inch
above the pressure of the atmosphere, there is an additional spring enclosed in a case for higher pressures, up to 90 pounds to the square inch, or for a
still further increased pressure, if required, which
is to be screwed on to the top of the casing, F. This
additional spring is represented at 1.11 The pistonrod of the Indicator passes up the centre of the
spring, M, when it is fixed on the top of the casing,
F, and comes in contact with the top attached to the
second spring; so that instead of the resistance of
only one there is the resistance of two springs for
high-pressure steam.
Eighth. On the scale, E, for high pressure, the
distances are marked thirty to the inch for steam
above 25 pounds - one-thirtieth of an inch represent14*               L




162    CATECHISM OF HIGH PRESSURE, OR
ing 1 pound pressure to the square inch on the steam
side. The scale on the vacuum side, ten to the inch,
or one-tenth of an inch, represents I pound pressure
to the square inch whether with high- or low-pressure
steam. It should be borne in mind that whatever
may be the pressure of the steam, high or low, when
the engine is a non-condensing or high-pressure engine, the vacuum side of the Indicator is not required.
As to the Application. — The Indicator should be
connected with the cylinder of the steam-engine by
means of holes drilled and tapped into the clearance
at each end of the cylinder, on the side opposite to
the steam-ports; nipples should be screwed into these
holes and elbows attached to their outer ends, in order
to form a connection by means of a T, into which the
Indicator should be screwed as near the centre of the
cylinder as convenient, so that the pressure communicated from the steam-cylinder to the Indicator may
be as uniform as possible.
The following diagram (No. 1) is taken from one
of Wright's Cut-off High-pressure Steam-engines. It
will be seen that it is very perfect. Attention is also
called to the fulness of the expansion lines, E, above
the theoretical curves, T; this it is claimed is due to
the temperature of the steam in the cylinder being
kept up beyond the point 6f cut-off by a steam-jacket.
It is also claimed that. the steam pressure, in the
cylinder from the commencement of the stroke to the
cut-off point, L, is equal to the full boiler pressure.




NON-CONDENSING  STEAM-ENGINES.                   163
DIAGRAM. No. 1.
S L. Steam line. T C. Theoretical curve. E L. Expansion line.
DIAGRAM. No. 2.
S L. Steam line. T C. Theoretical curve. 1, 2, 3, etc. Divisions of the
Diagram.




164     CATECHISM OF HIGH PRESSURE, OR
A perfect Diagram. - According to Mariotte's law,
the expansion-curve (No. 2, p. 163) should be a
hyperbolic curve, where there are no extraneous circumstances to cause it to be otherwise; but unfortunately, in practice, this perfection is not attainable.
Were Mariotte's law literally true-owing to the time
required for the steam to enter and leave the cylinder, clearance of piston, leakage of valves and piston,
and condensation in cylinder-it would be impossible
to show a perfect diagram having all the corners
well defined and the expansion line a true hyperbolic
curve.
EXPLANATION.
A diagram with the steam-corner rounded shows
the valve to have little or no lead, the steam being
admitted upon the piston easily.
A diagram square and pointed shows the valve to
have too much lead; that it opens too quickly, admitting the steam upon the piston with too great a
force before the crank is in a position to receive it.
This will in most cases cause the engine to tremble,
and also the Indicator.
A diagram too much rounded at the commencement of the exhaust-corner shows want of lead, or a
quicker opening of the valve on the exhaust side.
In many instances the steam passages are too small;
in such cases the exhaust ought to be open sooner
than if the passages were of good proportion.




NON-CONDENSING STEAM-ENGINES.     165
REMARKS.
It must be understood that every change in the
engine which diminishes the area of the diagram by
the rounding of its corners, diminishes the power of
every stroke; for the space enclosed in the pencil-line
exactly represents the power of a stroke of the engine,
with the exception of the rounding of the lead corner.
While the expansion diminishes the power of each
stroke, the reduced power of the engine is more than
compensated for by the saving in the steam consuraed.
RULE FOR COMPUTING THE POWER OF A
DIAGRAM.
To compute the power of the diagram, set down
the length of the spaces formed by the vertical lines
from the base, in measurements of a scale accompanying the Indicator, and on which a tenth of an inch
usually represents a pound of pressure; add up the
total length of all the spaces, and divide by the number of spaces, which will give the mean length, or
the mean pressure upon the piston in pounds per
square inch; multiply the area of the piston in
square inches by the pressure in pounds per square
inch, and by the speed of the piston in feet per minute, and divide by 33,000, which gives the actual
number of horse-power.




166    CATECHISM OF HIGH PRESSURE, ETC.
THE GOVERNOR.
IN devices for regulating the speed of steam-engines we find that the principle of centrifugal force
has received the most attention, and has been practically applied oftener than any other since the days
of Watt, who first applied a Governor to the steamengine.
The -main object to be attained by the Governor is
uniform speed of the engine under severe changes of
machinery and varying steam pressure. A great
amount of mechanical skill and capital have been
expended, within the past few years, in efforts to improve the Governor, and the ingenuity of- engineers
and machinists has been taxed to make it sensitive
without impairing its steadiness; and, as a result,
there have been several Governors brought to notice,
each of which is claimed to be a decided improvement on the Governor as first applied. The Governors constructed by Corliss, Porter, Judson, Shives,
Jenkins, Conde, Pickering, and Brown are extensively
used, and their merits are doubtless familiar to most
engineers and steam users in this country.
CONDE'S AMERICAN GOVERNOR.
The cut on the opposite page represents Conde's
American- Sfety-stop Governor. The novelties of
this Governor consist in an improved double-acting
valve, by which the Safety-stop is effected, and the




167 
167




1G8     CATECHISM OF HIGH PRESSURE, OR
sensitive action given to the Governor. The compensating-wheel changes and regulates the speed of the
engine as required, and the increased motion-movement regulates the velocity of the balls as they approach an outivard plane. The valve, as shown in
Fig. No. 2, consists of a series of rings (connected by
internal ribs) forming three or more ports, through
which the steam passes from similar ports formed in
the qhamber by a second series of rings connected by
ribs within the globe. By thus constructing the valve
with three or more ports, greater sensitiveness is




NON-CONDENSING STEAM-ENGINES.       169
gained; for in the downward movement of the valve
three ports are cutting off steam instead of one, thus
requiring only one-third the variation to do the same
work, and but one-third the necessary change of engine speed to act on the Governor. The Safety-stop
takes effect by the valve moving upward; the ports
in the valve passing the ports in the chamber when
the balls drop through any accident, from the belt
breaking or otherwise, instantly closing all communication with the engine. This form of Safety-stop
cannot fail to act so long as the Governor is in working
order. This stop is simple and reliable, and in no
way interferes with the free action of the Governor.
The compensating-wheel, as seen in the large cut,
allows of a variation of speed in the engine at will.
It is connected to the main frame of the Governor by
a sleeve and screw, so that when operated either way,
the whole upper part of the Governor is raised or
lowered - changing the position of the valve in its
seat, and letting in more or less steam, as the case may
be. It is claimed that this is the only correct arrangement for changing the speed of an engine. But the
most noticeable feature of this Governor is, that there
are no levers, weights or springs to help its operation or
complicate its parts; its operation is controlled by
the simple and reliable principle of centrifugal force.
15




170    CATECHISM OF HIGH PRESSURE, ETC.
SHORT RULES FOR CALCULATING THE SIZE
OF PULLEYS FOR GOVERNORS.
To find the diameter of Governor shaft-pulleys:
Multiply number of revolutions of engine by diameter of engine shaft-pulley, and divide product by
number of revolutions of Governor.
To find diameter of engine shaft-pulley: Multiply
number of revolutions of Governor by diameter of
Governor shaft-pulley, and divide product by number of revolutions of engine.
THE INJECTOR.
OF all the inventions of the mechanic and the
scientist, nothing approximates so nearly to perpetual motion as the instrument now in general use
and known as the Injector. It is one of the most
beautiful productions of man's genius for the utilization of scientific purposes.
The Injector consists of a slender tube, through
which steam from the boiler passes to another, or inner tube, concentric with the first. The latter tube
conducts a current of water from a pipe into the
body of the Injector. Opposite the mouth of this
second tube,'and detached from it, is a third fixed
tube, open at the end facing the water supply-pipe,
and leading from theInjector to the boiler.
The steam and water supply-pipes are fitted with




-------------— 5 ---— ~ ~~~~~~~~  ---------! 0   _                                                                                                                            OCrI;:.e




172     CATECHISM OF HIGH PRESSURE, OR
stop-valves, and the feed-pipe to the boiler with a
check-valve.
When the instrument is ready for use, by simply
opening the steam-valve steam enters the small
steam-pipe and rushes out at its extremity, picking
up the whole stream of water leaps across the open
space with a loud hissing noise, and plunges with its
burden of water into the open end of the feed-pipe
at a tremendous velocity. Thus it will be seen that
the steam that was admitted to the Injector from the
boiler retnrns to the boiler, carrying with it more than
twenty times its weight of water — not a drop of
water is lost, not a particle of steam wasted.
Q. Can you explain the action of the Injector?
A. The principle on which the Injector works is
that which is understood as the "lateral action of
fluid." It was discovered by Venturi and Nicholson about 70 years ago. It is simply'this: steam
being admitted to the inner tube of the Injector, and
the central conical valve being withdrawn, the steam
escapes in a jet near the top of the inlet water-pipe.
If the level of the water be below the Injector, the
escaping jet of steam, by its superficial action (or
friction) upon the air around it, forms a partial vacuum in the inlet-pipe. The water then rises in virtue of the external pressure of the atmosphere. Once
risen to the jet, the water is acted upon by the steam
in the same manner as the air had been seized and
acted upon in first forming the partial vacuum into
which the water rose.




NON-CONDENSING STEAM-ENGINES.       173
Q. How can you account for the great surplus
energy displayed in the working of the Injector, by
which steam is taken from one boiler, at a pressure
of, say 60 pounds to the square inch, and enabled to
force water in-to another boiler under a pressure of
100 pounds to the square inch, or even more.
A. In this way: the velocity with which steam flows
into the atmosphere is about 1500 feet per second;
now let us suppose that steam is issuing with the
full velocity due to the pressure in the boiler through
a pipe an inch in area; the steam is condensed into
water at the nozzle of the Injector without suffering
any change in its velocity. From this cause its bulk
will be reduced, say 1000 times, and, therefore, its
area of cross-section -the velocity being constant -
will experience a similar reduction. It will then be
able to enter the boiler again by an orifice 1T'-th part
of that by which it escaped. Now it will be seen
that the total force expended by the steam through
the pipe, on the area of an inch, in expelling the
steam-jet was concentrated upon the area,1-'-oth of
an inch, and therefore was greatly superior to the opposing pressure exerted upon the diminished area.
15*




TABLE OF CAPACITIES O F INJECTORS.
PRESSURE OF STEAM IN POUNDS.
Size of
SIZE. Pipe for  10  20     30     40  | 50       60      70     80      90    100
tions.                                                                          0
CUBIC FEET OF WATER DISCHARGED PER HOUR.
No. 2 1 in.  8.3    9.      9.7   10.4   11.1   11.8   12.5   13.2   13.9   14.6
"3   "  19.27  21.04  22.81  24.58  26.35  28.12  29.89  31.66  33.43  35.2
"  4 1     36.66  39.6   42.74  45.88  49.02  52.16  55.3   58.44  61.58  64.72   9
"       541- ":  57.58  62.5   67.42  72.34  77.26  82.18  87.1   92.02  96.94 101.86   o
"  61  "  83.48  90.6   97.72 104.84 111.97 119.09 126.21 133.33 140.45 147.57 e
"  7 1" 114.03 123.75 133.48 143.2  152.93 162.65 172.38 182.1  191.83'201.55- 
"  8 2    149.2  162.   174.8  187.6  200.4  213.2  226.   238.8  251.6  264.4    Q
"9 2" 189.2  205.35 221.51 237.66 253.82 269.97 286.13 302.28 318.44 334.59   X
"10 2  "233.84 253.8  273.76 293.72 313.68 333.64 353.61 372.57 393.53 413.49   W
"   12   " 337.2  366.   394.8  423.6  452.4  481.2  610.   538.8  567.6  596.4 M
"14 2  " 451.49 491.45 531.41 571.36 611.32 651.27 691.23 731.18 771.14 811.09
"163  " 600.32 651.6  702.88 784.16 805.44 856.72 908.   959.28 1010.56 1061.84   N
One nominal horse-power per hour will require    TEMPERATURES OF FEED-WATER.
1 cubic foot of water per hour. When the pounds
of coal consumed per hour can be ascertained, di- I Minimum temperature of feed admissible at difvide this by 7.5, and the quotient will be the qua- I ferent pressures of steam:
tity of water in cubic feet per hour.      Pressure of steam (pounds) per square inch:
Minimum capacity of Injectors about 50 per    10    20    30    40    50    100
cent. of tabular capacity.                   1480  138~0  1300  1240  120~   1100




NON-CONDENSING STEAM-ENGINES.       175
Q. Why is it that the temperature of the feedwater decreases as the steam pressure increases?
A. As the temperature of the steam increases with
the pressure above a certain temperature of feedwater, it would be impossible to condense the steam
in the Injector, and, as a consequence, the instrument
would fail to work.
Q. Is the Injector more or less economical than
the pump?
A. In point of economy, perhaps the advantage
would be slightly in favor of the pump; but the advantages, if any, would be very trifling, which will
be evident when we remember that with the Injector,
as with the pump, waste heat may be employed to act
upon the water between the feeding apparatus and the
boiler, the difference being simply this: that with the
pump the water will pass into the heating apparatus
at its natural temperature,and will get all the heat it
acquires before entering the boiler from the waste
steam, while in the case of the Injector the water in
passing through the instrument will acquire a certain
amount of increase in temperature at the expense of
the steam from the boiler before it comes in contact
with the waste heat. This fraction, then, of the supply which might otherwise be derived from the exhaust steam, is all that is lost by the Injector. But
it might be said, in favor of the Injector, that it requires no belt, packing, nor even repairs, and it oce
cupies but very little space.




176    CATECHISM OF HIGH PRESSURE, OR
DOUBLE-ACTING BUCKET-PLUNGER STEAMPUMP.
THE opposite cut represents an extremely simple
and compact vertical steam - pump, provided with
crank and fly-wheel. The pump is of the combined
piston and plunger variety, and has but two valves;
though possessing the same advantages as respects a
steady delivery as the ordinary double-acting pump.
It is intended for pumping all kinds of fluids.
It is a double-acting piston-pumpthe piston having
a trunk on top. It has but one receiving and one
discharge valve. The water is received only on the
upward stroke, the amount being equal to the full
capacity of the cylinder. Only one-half, however, is
discharged, owing to the smaller area of the upper
side of the piston. On the downward stroke, the
water in the cylinder is forced out by the piston-onehalf being discharged, the other half flowing into
the upper end of the cylinder. These pumps are
very superior as a fire-pump, for the reason that they
will always start off at once when the steam is let on,
which is very essential in a pump for this duty; as
the time lost, in case of fire, to get an unreliable
pump at work, is many times of more loss than the
entire cost of a good pump.
They are made of any size to discharge from 5
to 5000 gallons per minute, and with either metal
or rubber valves.




z
BUCKET-PLUNGER STEAM PUMPS,
VALLEY MACHI-E COMIPANY, EASTU&XIPTON, MASS.




178    CATECHISM OF HIGH PRESSURE, OR
THE HEALD AND SISCO PATENT CENTRIFUGAL
PUMPS-VERTICAL AND HORIZONTAL.
MANY devices have been employed for raising
water and other liquids. Among the oldest and
most general are those which depend, either wholly
or in part, on atmospheric pressure. Of these are
the pumps containing valves, and a tight piston
moving in a straight cylinder. The numerous defects of this kind of pump long ago led the inventive
mind to seek a more efficient substitute -a pump
which, with a continuous flow, would raise more
rapidly with less power, and would be more durable.
The problem also required that anything capable of
flowing should be raised as though it were clear
water. Mud, sand, bark, etc., must prove no obstacle.
It was obvious, from the first, that the perfect
pump must work without valves. The objections to
valves are so manifest as to need no mention here.
But without valves the pump could not have a




NON-CONDENSING STEAM-ENGINES.      179
tight piston. In short, the ideas of direct pressure
and of atmospheric aid must be discarded, and a
radically different system discovered, if possible.
Reflections of this sort, we should say, finally led
to the building of pumps on the principle of the
"Fan Bellows."  This principle consists essentially
in the rapid revolution of fans or arms in a scroll,
sweeping or whirling the contained air to whatever
vent might be found; the centrifugal momentum acquired in the revolution reacting from the inner
walls of the scroll, and resolving itself into a force
acting in the direction of the discharge.
In making a pump on this plan, no new principle
was involved. But there was great merit in the
novel application of the old idea. A long stride was
made towards the solution of the problem when the
first Centr'fugal Pump was placed in the water.
The new pump was deservedly received with general favor. There were, however, certain defects still
to be remedied -the principal one being a manifest
waste of power and loss of efficiency, owing to the
interference of,the arms of the wheel with their own
work. Reflection on this point led to the invention
of the Hollow Arm Piston by Mr. Heald. This
beautiful device was patented in 1865, and is already
famous as one of the finest inventions of the age.
The pump, of which it is the distinguishing feature.,
has taken first premiums at New Orleans (1871),
Cincinnati and Brooklyn (1872), and also at tht




180     CATECHISM OF HIGH PRESSURE, OR
Fair of the American Institute of the same year,
after severe and protracted tests by the judges appointed for the purpose.
There are several thousands of these pumps in use
by tanners, paper-makers, contractors, and wreckers,
all over the United States, the Canadas, and Europe.
NOISELESS BOILER FEED-PUMP.. RR.,. a)A
Co  hk.3    cl 2    A
21 in. 4   12  12  20
21    4    12  15  35
3     5    7   15  50
4     6    3   18  100
5     6    2   18  150
6     8    1   24  200
DIRECTIONS FOR SETTING UP STEAM-PUMPS.
Never use smaller pipes than the connections on
the pump call for, and where long or crooked pipes
are used, they should be larger. Use check-valve
and strainer on the suction-pipe.




NON-CONDENSING STEAM-ENGINES.      181
Run discharge-pipe of full size to the boiler, with
check-valve between pump and boiler.
By reducing the diameter of a pipe 2, it diminishes
its capacity to i.
A pipe 2 inches diameter, 100 feet long, will deliver but 4 the quantity a pipe 2 inches diameter and
2 inches long, with same pressure.
Avoid angles, turns and bends in pipe where it is
possible, as they retard the flow much more than is
generally imagined. Where they must be used,
make the turn on as large a circle as convenient.
If very hot water is to be pumped, the supply must
be above the pump, so that the water will flow into it;
as it is impracticable to raise it by suction.
Water expands by heating; therefore a pump large
enough to furnish a given quantity of cold water
would not be large enough if the water is heated.
Run the exhaust-pipe downm from the pump where
it is possible, that the condensed steam may flow off
through it.
Care should be-taken to guard against leaks in the
suction-pipe, as a very small leak destroys the effectiveness of a pump.
Q. What should be the capacity of a pump or
Injectox to feed any particular steam-boiler?
A. As a cubic foot of water per hour is taken as
a stafdard for a horse-power, the pump or Injector
should be able to discharge more than a cubic foot
of water per hour for each horse-power for which the
16




182     CATECHISM OF HIGH PRESSURE, OR
boiler is rated; for instance, for a 10 horse-power
boiler, the pump or Injector ought to be able to discharge 15 cubic feet of water per hour; for a 20
horse, 25 cubic feet of water, and so on in proportion.
A TABLE,
Containing the Diameters, Circumferences, and Areas of Circles, and the contents of each in gallons, at 1 foot in depth.
UTILITY OF THE TABLE.
EXAMPLES.
1. Required the circumference of a circle, the diameter being five inches.
In the column of circumferences, opposite the given
diameter, stands 15.708 inches, the circumference
required.
2. Required the capacity, in gallons, of a cylinder,
the diameter being 4 feet and depth 10 feet.
In the fourth column from the given diameter
stands 93.9754, being the contents of a cylinder 4 feet
in diameter and I foot in depth, which being multiplied by 10 gives the required contents, 9394 gallons.
3. Any of the areas in feet multiplied by.03704,
the product equals the number of cubic yards at 1
foot in depth.
4. The area of a circle in inches multiplied by the
length or thickness in inches, and by.263, the product equals the weight in pounds of cast iron.




NON-CONDENSING STEAM-ENGINES.               18-3
Diam. Circ. In. Area. In. Gallons. Diam. Circ. In. Area. In. Gallons.
1 in. 3.1416.7854.04084  6tin. 19.635  30.679 1.59531
i    3.5343.9940.05169   f   20.027  31.919 1.65979
~t   3.9270  1.2271.06380   f  20.420  33.183 1.72552
i   4.3197  1.4848.07717   f  20.813  34.471 1.79249
~    4.7124  1.7671.09188   f  21.205  35.784 1.86077
f    5.1051  2.0739.10784   f   21.598  37.122 1.93034
5.4978  2.4052.12506  7 in. 21.991  38.484 2.00117
5;.8905  2.7611.14357   *  22.383  39.871 2.07329
2 in. 6.2832  3.1416.16333  It  22.776  41.202 2.14666
6.6759  3.5465.18439       2 03.169  42.718 2.22134
~    7.0686  3.9760.20675   f   23.562  44.178 2.29726
f    7.4613  4.430].23036   f  23.954  45.663 2.37448
f    7.8540  4.9087.25522   f  24.347  47.173 2.45299
f    8.2467  5.4119.28142        24.740  49.707 2.53276
f    8.6394  5.9395.30883  8 in. 25.132  50.265 2.61378
f    9.0321  6.4918.33753       25.515  51.848 2.69609
3 in. 9.4248  7.0686.36754   ~   25.918  53.456 2.77971
9.8175  7.6699.39879       26.310  55.088 2.86458
f   10.210   8.2957.43134   ~   26.703  56.745 2.95074
10.602   8.9462.46519      i27.096  58.426 3.03815
f   10.995   9.6211.50029-  f1 27.489  60.132 3.12686
f   11.388  10.320.53664   f   27.881  61.862 3.21682
f   11.781  11.044.57429  9 in. 28.274  63.617 3.30808
f   12.173  11.793.61324       t 28.667  65.396 3.40059
4 in. 12.566  12.566.65343   ~  29.059  67.200 3.49440
f   12.959  13.364.69493   f  29.452  69.029 3.58951
f   13.351  14.186.73767   f  29.845  70.882 3.68586
f   13.744  15.033.78172   if  30.237  72.759 3.78347
f   14.137  15.904.82701   f  30.630  74.662 3.88242
14.529  16.800.87360   f  31.023  76.588 3.98258
f   14.922  17.720.92143  0lin. 31.416  78.540 4.08408
f  15.315  18.665.97058   f  31.808  80.515 4.18678
5 in. 15.708  19.635  1.02102   f  32.201  82.516 4.29083
f   16.100  20.629  1.07271   f  32.594  84.540 4.39608
f   16.493  21.647  1.12564   f   32.986  86.590 4.50268
16.886  22.690  1.17988   f - 33.379  88.664 4.61052
f   17.278  23.758  1.23542   f  33.772  90.762 4.71962
f   17.671  24.850  1.29220   f  34.164  92.885 4.82846
18.064  25.967  1.35028  11in. 34.557  95.033 4.94172
18.457  27.108  1.40962   f  34.950  97.205 5.05466
6 in. 18.849  28.274  1.57025  i    35.343  99.402 5.16890
1 19.242  29.464  1.53213    f 135.735 101.623 5.28439




184       CATECHISM  OF HIGH  PRESSURE, OR
Diani. Circ. In. Area. In. Gallons. Diam. Circle.  Area.  Gallons.
11ini  36.128 103.869 5.40119  Ft. in. Ft. in.  Feet.  1 ft. depth.
k    36.521 106.139 5.51223  2  5  7  7   4.5869 34.3027
36.913 108.434 5.63857  2  6  7 10+  4.9087 36.7092
k    37.306 110.753 5.75916  2  7  8  1k  5.2413 39.1964
2  8  8  4~   5.5850 41.7668
Ft. in. Ft. in.  In feet. 1 ft.depth. 2  9  8  7k  5.9395 44.4179
1     3  1k.7854  5.8735  2 10  8 101  6.3049 47.1505
1  1  3  4k.9217  6.8928  2 11  9  1k  6.6813 49.9654
1  2  3  8    1.0690  7.9944
1  3  3 11    1.2271  9.1766  3         9  5   7.0686 52.8618
1  4  4  2k   1.3962 10.4413  3  1  9  81  7.4666 55.8382
1  5  4  Q5    1.5761 11.7866  3  2  9 11k  7.8757 58.8976
1  6  4  8+   1.7671 13.2150  3  3 10  2+  8.2957 62.0386
1  7  4 11k    1.9689 14.7241  3  4 10  5f  8.7265 65.2602
1  8  5  21   2.1816 16.3148  3  5 10  81  9.1683 68.5193
1  9  5  5k   2.4052 17.9870  3  6 10 11k  96211 73.1504
1 10  5  9    2.6398 19.7414  3  7 11  3  10.0846 75.4166
1 11  6  21   2.8852 21.4830  3  8 11  6k 10.5591 78.9652
39  91  9  11.0446 82.5959
2      6  34   3.1416 23.4940  3 10 12  5+ 11.5409 86.3074
2  16  6~   3.4087 25.4916  3 11 12  3i 12.0481  90.1004
2  2  6  9    3.6869 27.5720
2  3  7  01   3.9760 29.7340  4        12  61 12.5664 93.9754
2  4  7  3k   4.2760 32.6976
PISTON-ROD PACKING.
IT  is probable that on the whole, with steam-engines  of plain  construction, no  part is more  frequently out of order, and gives greater annoyance,
than piston-rod packing. Hemp, when properly
used, serves a good  purpose, but its usefulness is
limited, particularly where steam of a high pressure
is used, as it soon loses its elasticity and, in consequence, becomes worthless. A vast deal of. study
and ingenuity have been applied to the removal of




NON-CONDENSING STEAM-ENGINES.       185
this annoyance and the production of a durable piston-rod packing. Wire-gauze, gum, soap-stone, jute,
asbestos, and a great variety of other materials, have
been tried, and with only partial success.
There has always been a general want of a permanent and reliable piston-rod packing.
Rule for finding the size of packing for piston or
valve-rods:
Measure the piston or valve-rod; then measure stem
of stuffing-box; divide the difference between them
by two.
For example: rod 2 inches, box 4, packing 1 inch.
Rod 1 inch, box 2, packing I inch. Rod 4 inch, box
1~, packing 8. Rod 2 inches, box 3~, packing 4. Rod
h  inches, box 4 inches, packing 11.
INCRUSTATION.
ALL waters contain more or less mineral matter,
which is acquired by percolation through the earth's
surface, and consists principally of carbonate of lime
and magnesia, sulphate of lime and chloride of
sodium in solution, clay, sand, and vegetable matter
in suspension.
Some waters contain far less mineral ingredients
than others, such as rain-water, the water of lakes
and large rivers, whilst wells, springs, and creeks
hold large quantities in solution.
When such water is boiled, the carbonic acid is
16*




186     CATECHISM OF HIGH PRESSURE, OR
driven off, and the carbonates, deprived of their solvents, are rapidly precipitated in a finely crystallized
form, tenaciously adhering to the surface of the iron.
Chloride of sodium, and all such soluble salts, are
precipitated in the same way by supersaturation.
This combined deposit, of which carbonate of lime
forms the greater part, remains adherent to the inner
surface of the boiler, undisturbed by the force of the
most violent boiling currents. Gradually this accumulation becomes harder and thicker, until it is as
dense as porcelain, thereby preventing the proper
heating of the water by any fire that can be placed
in the furnace. The high temperature necessary to
heat water through thick scale will sometimes convert the scale into a substance resembling glass.
The evil effect of scale in steam-boilers is due to
the fact that it is a non-conductor of heat. The conducting power of scale compared with that of iron is
as 1 to 37; consequently, a greater amount of fuel is
required to heat water in an incrusted boiler than
if the same boiler were clean.
Scale -1' of an inch thick will require an expenditure of fifteen per cent. more fuel. This expenditure
increases as the scale becomes thicker; thus, when it
is a quarter of an inch thick, sixty per cent. more
fuel is needed to raise water in a boiler to any given
heat. If the boiler is badly scaled, the fire surface
of the boiler must be heated to a temperature according to the thickness of the scale.




NON-CONDENSING S'TEAM-ENGINES.      187
For example: To raise steam to a pressure of 90
pounds, the water must be heated to a temperature
of 324~ Fah. If a quarter of an inch of scale intervenes between the shell and the water, it would be
necessary to heat the fire surface of the boiler nearly
600OO, or 100~ Fah. above the maximum strength of
iron. Now, it is a well-known fact, that the higher the
temperature at which iron is kept, the more rapidly
it oxidizes, and is made liable at any time to bulge
or crack by internal pressure, and is often the cause
of explosions.
Within the past few years a great many patent
remedies for the removal and prevention of scale have
been offered to the owners of steam-boilers, but, after
a fair test of all these remedies, they have been nearly
all abandoned, as not only useless, but even in many
cases injurious, attacking and corroding the clean
and sound iron, and producing no visible effect on
the scale other than to change the color, and convey
the impression that it was removed.
At a recent meeting of the American Railway
Mechanics' Association, held at Louisville, Ky., the
committee to whom was referred the subject of boiler
incrustations, reported that they had prepared and
issued, through the secretary of the association, a circular of questions to all the master mechanics of
various railroads throughout the country, in order
to elicit such information as they might possess on
this subject. In compliance therewith, communica



188     CATECHISM OF HIGH PRESSURE, OR
tions had been received from forty master mechanics;
and although the number is small compared with the
whole number of roads, yet it is nearly double that
of any previous year, and the information so obtained
is correspondingly extensive and valuable, confirming in substance the-theory advanced in a paper read
in convention last year, to the effect that the only
effectual way to prevent incrustation is to purify the
water, if possible, before it is allowed to enter the
boiler. To this end the committee directed its efforts,
and had given special attention to the reports of those
who have experimented, with a view thereby of ascertaining the best and cheapest mode of accomplishing the same.
From all communications received, it is found that
most of the roads located in the Eastern and Southern
States are troubled but little with incrustation, while
those in the Middle States are variously affected -
some suffering greatly, others none at all. Western
roads suffer most, many of them finding it necessary,
in order to maintain average economy in fuel and reasonable safety to the boiler, to take out flues once in
six to twelve months, for the purpose of removing
scale from  both boiler and tubes. Railway engineers in Western States realize similar difficulties in.
a greater or less degree, according to location. Mr.
De Clerq, of the Toledo, Peoria, and Warsaw Railroad, reports having used batteries, and also many
different kinds of powders, for the removal of incrus



NON-CONDENSING STEAM-ENGINES.      189
tations, but all without any decided results. He
finds distilled water the best of anything he has ever
used to prevent lime incrustation. He thinks soft
water, well filtered, will keep a boiler free from mud
and scale.
Mr. Ham, of the New York Central, stated that he
can run with economy, on the Eastern Division, four
years without taking out the flues; while on the Middle Division, on account of lime and scale, he has to
take them out, on an average, every year and a half,
and on the Western Division every two years. He
finds it necessary, on the Middle Division, to put new
sheets in the bottom of the cylinder part of boiler on
an average every five years; and, with good water,
has only repaired that portion of the boiler once in
eight to ten years. He has used batteries and powders, but finally abandoned them all. He is troubled
with deposit of scale on the crown-sheet; gives crownbars one inch clearance, and considers it as good as
more space. He knows nothing equal to pure soft
water to keep boilers free from mud and scale.
The following extract was taken from a report of
a committee of the Railway Master Mechanics' Association, held in Boston in the summer of 1872.
After a series of exhaustive experiments, the committee reported that the only preventive against
incrustation was the use of pure water in steamboilers. It was also stated that the introduction into
the boilers of any of the so-called remedies now in




190     CATECHISM OF' HIGH PRESSURE, OR
use — whether they be batteries, powders, antilaminas, or filters - was comparatively useless for the removal or prevention of scale.
It was also stated that the extra expense in one
year, from impure water and incrustation, would
amount to $75,000 for every hundred locomotives.
The committee considered that to boil sufficient water
to supply a locomotive for one year, running 31,000
miles, would require an extra expenditure of $236
for fuel; but they considered that that was the only
reliable means for preventing incrustation and all
manner of ruptures and leaks in boilers.
Q. What is the most effective method for the prevention of incrustation?
A. The most effective method to prevent incrustation in boilers would be to boil the water in a tank,
and then allow it to settle before using in the boiler.
By this means the carbonates and minerals would
become separated and deposited on the bottom of the
tank, and the pure water could then be drawn off.
Another effective method would be to blow out the
boiler every evening, before the minerals that were
held in suspension, by the agitation of the water,
could settle and become attached to the sheets. A
third would be to use rain-water, if possible. Any
of the above three remedies would effectually prevent
incrustation in steam-boilers, although it might be
said that the two former are hardly practicable.
Q. What is the most effectual mechanical means
that you know of for removing scale from boilers?




NON'-CONDENSING STEAM-ENGINES.       191
A. By picks and scrapers.
Q. Are boilers sometimes injured by this mode of
cleaning?
A. Yes; the sheets of the boilers are sometimes
cut by the use of the pick in the hands of ignorant
or careless persons.
Q. Is this method practicable in all boilers?
A. No; only in cylinder boilers, as it is utterly
impossible to remove scale from flue, tubular, or locomotive boilers by any mechanical means.
Q. What is the best preventive against scale becoming hard and firmly attached to the surface of
the flues or tubes?
A. Never to let the surface of the flues or tubes
become dry after the boiler is blown out. The boiler
should always be again filled before the scale becomes dry.
Q. Mention some of the most common remedies
resorted to for the purpose of preventing scale in
boilers.
A. Indian meal, potatoes, oil-cake, molasses, gum
caoutchouc, slippery elm, white-oak blocks, refuse
logwood, and a variety of other vegetable substances,
were at times tried without much success.
Q. What is the effect of vegetable substances on
boilers?
A. They are sometimes as equally destructive to
boilers as scale or incrustation.
Q. How do you explain that?




192     CATECHISM OF HIGH PRESSURE, OR
A. All vegetable matter contains more or less
acid, and the iron is more open to attack from the
acid than the scale is; so that some boilers suffer
fearfully from the corrosion of the acid in the vegetable substances.
Q. What is the composition of most of the different patent boiler powders now presented to steam
users for the prevention of scale?
A. Refuse logwood, sal soda, and yellow ochre.
Q. What is the effect of the above-named articles?
A. They have a tendency to deposit on the parts
of the boiler most exposed to the fire; uniting the
loose scales in solid masses, and causing the boiler to
leak - very often to bulge or crack.
Q. Do you think it possible to separate the minerals from feed-water in the heater, by raising the
water to a very high temperature, and forcing it
through straw, shavings, or similar substances?
A. No; the capacity of any heater is so limited,
and the time so short, that it is unreasonable to eitpect that any quantity of matter could be deposited.
Even if a separation should take place in the heater,
the matter will be carried into the boiler and be deposited on the iron.
Q. Is there any difference in scales formed under
different pressures and different temperatures?
A. Yes; scales formed under low pressures and
low temperatures are nearly always soft and porous;
while scales formed under high pressures and high
temperatures are hard and glassy.




NON-CONDENSING STEAM-ENGINES.       193
Q. ~Would the removal of scale or incrustation be
attended with economical results?
A. Yes; it would effect a saving of thousands of
tons of coal annually, and a preservation of hundreds
of lives destroyed by explosions that might be attributed to this cause alone.
Q. Do you think that pure water is the only effective means to prevent the accumulation of scale in
steam-boilers?
A. Yes; for while several hundred patents encumber the records of the patent-offices of the United
States and England, not one of them answers the
purpose for which it was patented.
BOILER EXPLOSIONS.
THE risk of life and property involved in the use
of the steam-boiler is still, as it has always been, a
source of constant anxiety to the engineer and to the
public.
Explosions continually take place, with the most
disastrous results. Occurring without warning, and
occupying but an instant of time, it is generally difficult, if not impossible, except in rare instances, to ascertain with certainty their true cause, as there is
seldom a unanimous opinion on the part of experts
who examine into the causes after the event.
But experience in the care and management of
steam-boilers leaves no doubt in the minds of intelli17               N




194     CATECHISM OF HIGH PRESSURE, OR
gent men but that the principal causes that operate
to produce explosions are - inequality of expansion
caused by some parts of the boiler becoming heated
to a higher temperature than others; allowing the
water to become dangerously low and pumping in
cold water; sediment or incrustation being deposited
on the parts of the boiler most exposed to the action
of the fire, preventing the water from coming in contact with the iron, thereby allowing the plates to become overheated or burned; faulty construction;
leakage, causing oxidation or rusting away of the
iron; internal grooving; over-pressure; excessive
firing; ignorance, recklessness, and mismanagement.
The above causes include everything that experience
and intelligence teach us to believe would cause a
steam-boiler to explode; and it will be seen that the
remedy for every one of these is within easy reach of
the mechanic and the owner of steam-boilers. It
might be said, without fear of contradiction, that the
number of boilers that explode every year from all
other causes are very few compared with those that
occur from over-pressure and excessive firing.
It is also a well-known fact that a great many
destructive steamboat and locomotive explosions have
occurred just as the engine was starting, after standing
still for some time. These, like all others, were the
result of ignorance or carelessness. When an engine
is stopped, and the communication between the cylinder and the boilers is closed, the whole heat of the




NON-CONDENSING STEAM-ENGINES.       195
fire acts on the plates of the boiler directly over and
around the fire; the circulation ceases, and the iron
and water become surcharged with heat to such an
extent that, when the engine is started and the pressure on the surface of the water lessened, all the
water on the surface of the iron directly over the fire
immediately flashes into steam of tremendous elastic
force. Whereas, if care had been taken to cover the
fire with fresh coal, and the feed-pump or Injector
had been started to force water into the boiler, the
circulation of the water would have been kept up,
and the heat that was transmitted to the iron would
have been absorbed by the fresh coal and the feedwater.
The practical conclusion to be derived from all
known facts in connection with the generation of
steam is, that water in a boiler under some circumstances, - such as slow continued evaporation when a
boiler is at rest,-can be nearly deprived of air, and the
circulation being then feeble, portions of the water in
contact with the plates may be heated to a higher
temperature than that of the mass of water above it;
under such circumstances, the sudden starting of the
engine, or any other cause of agitation, producing an
active circulation of the water, might cause a certain
increase of the steam in such quantities, and of such
elastic force, as would in many instances result in
serious accident.
But that we shall continue to have frequent. and




196     CATECHISM OF HIGH PRESSURE, OR
terrible steam-boiler explosions, there is no reason to
doubt, so long as steam is used as a mere brute force,
and so long as coroners' juries can be found to exonerate engineers and owners of steam-boilers from any
blame, though it might be in evidence that the explosion, resulting in terrible loss of life, was brought
about by their recklessness or avarice. The Lord's
command, "Thou  shalt not kill," limiting  the
power of masters over their servants, was one of the
first steps towards the civilization of the world. But
this solemn injunction does not seem to have much
weight with some owners of steam-boilers in our days.
Perhaps this arises from the fact that it is not in evidence that Moses was the owner of a steam-boiler.
Whenever a boiler does explode, which is a frequent occurrence in different parts of the country, it
will be noticed that the self-styled experts are always
on hand to ventilate their pet theories. Many of
these theories are the merest vagaries, and only go
to show the ignorance of their authors. The public
read these speculations, and, in the absence of any
intelligent refutation, swallow them down, and conclude that the whole subject is involved in dark
mystery. Now, we claim that there is no mystery
about steam-boiler explosions; they are all cause and
effect. The City Inspection and the Hartford Inspection and Insurance Company have been demonstrating this fact for the past four or five years. Out
of 3,000 steam-boilers in this city we did not have
one explosion for over four years. Now, was it be



NON-CONDENSING STEAM-ENGINES.       197
cause engineers and owners of steam-boilers were
more careful, and carried the water higher in their
boilers than they had previously done, or was it because the City Inspector and the Insurance Company
discovered defects that would lead to explosions, and
compelled the owners of the boilers to repair them,
and use their boilers at a safe working pressure?
It would be safe to say that the Hartford SteamBoiler Inspection and Insurance Company have done
more to prevent steam-boiler explosions in the last
five years than had been done by all the laws passed
by the National and State Legislatures for the past
twenty years.
Few persons have any idea of the great internal
strain continually exerted on the shells of boilers; for
instance: in a boiler 54 inches in diameter, circumference 169 inches, pressure 85 pounds - a very common pressure to carry on steam-boilers - there would
be continually exerted upon each inch in length of
the shell a pressure of 14,365 pounds; and if the
boiler is 18 feet, or 216 inches in length, the entire
pressure on the shell of that boiler is 3,102,840
pounds or 1,556 tons.
In a boiler 36 inches diameter, circumference 113
indhes, with a pressure of 70 pounds to the square
inch, there would be a pressure of 7,910 pounds on
every inch in length; and if the boiler was 14 feet
in length, the whole pressure on the shell would be
664 tons.
17*




198     CATECHISM OF HIGH PRESSURE, OR
STEAM- AND FIRE-REGULATOR.
THE numerous devices which have been employed
by engineers for maintaining a uniform pressure of
steam in boilers, shows the importance of a contrivance for this purpose. As a consequence, many
steam- and fire-regulators have been introduced to
the public, but most of them, from complexity or
want of good workmanship, have failed to give satisfaction, and in many instances have proven themselves to be of more injury than advantage.
This Improved Regulator is self-adjusting, simple
and durable in its construction, and not liable to derangement or loss of sensitiveness from time or use;
having perfect control of the damper, it will, when
once set to any required' pressure, maintain that
pressure in the boiler, without any attention from the
engineer or fireman. In fact,
THE FOLLOWING ADVANTAGES ARE SECURED BY
THIS REGULATOR:
First. Uniformity of pressure in the boiler within
three pounds.
Second. Economy of fuel averaging ten per cent.
Third. Freedom from danger of explosion by excess of pressure.
The sizes of the Regulator are, No. 1, No. 2, No. 3,
No. 4. The No. 2, with one ball at extreme end of
lever, will close at 60 pounds per square inch; No. 3,
in same position, 40 pounds per square inch. For
higher pressures, extra balls are used.




NON-CONDENSING STEAM-ENGINES.  199
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200     CATECHISM OF HIGH PRESSURE, OR
CENTRAL AND MECHANICAL FORCES.
Q. What is centrifugal force?
A. It is the force with which a revolving body
tends to fly from the centre.
Q. What is centripetal force?
A. It is the force that draws to the centre, or
counteracts the centrifugal tendency.
Q. What is gravity?
A. Gravity is a downward pressure or weight.
Q. What is specific gravity?
A. It is the comparative density or weight that
one body has to another of equal bulk.
Q. What is the centre of gravity?
A. It is that point in a body on which, if rested or
suspended, the whole will remain in a state of equilibrium or rest.
Q. What is the force of gravity?
A. It is an accelerated velocity which heavy bodies
acquire when falling from a state of rest.
Q. What is meant by the centre of oscillation?
A. It is a point in vibrating bodies in which all
the force is collected.
Q. What is the centre of gyration?
A. It is the point in revolving bodies into which
the momentum of the mass is concentrated.
Q. What is motion?
A. It is the effect of an impulsive force acting in
such a manner as to impart linear or circular velocity by motive power.




NON-CONDENSING STEAM-ENGIN'ES.      201
Q. What is inertia?
A. It is that property of matter by which it tends
when at rest to remain so, and when in motion to
continue in motion.
Q. What is capillary attraction?
A. It is the property observable in all porous substances of raising water or other fluids above the
natural level.
Q. What is friction?
A. Friction is the resistance experienced when one
body is rubbed upon another, and is supposed to be
the result of natural attraction.
Q. What are logarithms?
A. Artificial numbers which stand for natural
numbers.
Q. How are the mechanical powers distinguished?
A. In the following order, viz.: lever, pulley, inclined plane, wheel and axle, and screw.
MENSURATION.
OF THE CIRCLE, CYLINDER, SPHERE, ETC.
1. The circle contains a greater area than any
other plane figure bounded by an equal primeter or
outline.
2. The areas of circles are to each other as the
squares of their diameters.
3. The diameter of a circle being 1, its circumference equals 3.1416.




202     CATECHISM OF HIGH PRESSURE, OR
4. The diameter of a circle is equal to.31831 of its
circumference.
5. The square of the diameter of a circle being 1,
its area equals.7854.
6. The square root of the area of a circle, multiplied by 1.12837, equals its diameter.
7. The diameter of a circle multiplied by.8862, or
the circumference multiplied by.2821, equals the
side of a square of equal area.
8. The sum of the squares of half the chord and
versed sine divided by the versed sine, the quotient
equals the diameter of corresponding circle.
9. The chord of the whole arc of a circle taken
from eight times the chord of half the arc, one-third
of the remainder equals the length of the arc; or,
10. The number of degrees contained in the are
of a circle multiplied by the diameter of the circle
and by.008727, the product equals the length of the
arc in equal terms of unity.
11. The length of the arc of a sector of a circle,
multiplied by its radius, equals twice the area of the
sector.
12. The area of the segment of a circle equals the
area.of the sector, minus the area of a triangle whose
vertex is the centre, and whose base equals the chord
of the segment; or,
13. The area of a segment may be obtained by dividing the height of the segment by the diameter of
the circle, and multiplying the corresponding tabular
area by the square of the diameter.




NON- CONDENSING STEAM-ENGINES.      203
14. The sum of the diameter of 2 concentric circles,
m:lltiplied by their difference and by.7854, equals
the area of the ring or space contained between them.
15. The sum of the thickness and internal diameter of a cylindric ring, multiplied by the square of
its thickness and by 2.4674, equals its solidity.
16. The circumference of a cylinder, multiplied
by its length or height, equals its convex surface.
17. The area of the end of a cylinder, multiplied
by its length, equals its solid contents.
18. The area of the internal diameter of a cylinaer, multiplied by its depth, equals its cubical
capacity.
19. The square of the diameter of a cylinder, multiplied by its length and divided by any other required length, the square root of the quotient equals
the diameter of the other cylinder of equal contents
or capacity.
20. The square of the diameter of a sphere, multiplied by 3.1416, equals its convex surface.
21. The cube of the diameter of a sphere, multiplied by.5236, equals its solid contents.
22. The height of any spherical segment or zone,
multiplied by the diameter of the sphere of which it
is a part, and by 3.1416, equals the area or convex
surface of the segment; or,
23. The height of the segment, multiplied by the
circumference of the sphere of which it is a part,
equals the area.




204    CATECHISM OF HIGH PRESSURE, OR
24. The solidity of any spherical segment is equal
to three times the square of the radius of its base,
plus the square of its height, and multiplied by its
height and by.5236.
25. The solidity of a spherical zone equals the
sum of the squares of the radii of its two ends, and
one-third the square of its height, multiplied by the
height and by 1.5708.
26. The capacity of a cylinder 1 foot in diameter
and 1 foot in length equals 5.875 of a United States
gallon.
27. The capacity of a cylinder 1 inch in diameter
and 1 foot in length equals.0408 of a United States
gallon.
28. The capacity of a cylinder 1 inch in diameter
and 1 inch in length equals.0034 of a United States
gallon.
29. The capacity of a sphere 1 foot in diameter
equals 3.9156 United States gallons.
30. The capacity of a sphere 1 inch in diameter
equals.002165 of a United States gallon: hence,
31. The capacity of any other cylinder in United
States gallons is obtained by multiplying the square
of its diameter by its length, or the capacity of any
other sphere by the cube of its diameter, and by the
number of United States gallons contained as above
in the unity of its measurement.'To CALCULATE THE SPEED OF PULLEYS.
Example 1. To find the size of driving -pulley:




NON-CONDENSING STEAM-ENGINES.      205
Multiply the diameter of the driven by the number
of revolutions it should make, and divide the product by the revolutions of the driver. The quotient
will be the size of the driver.
Example 2. The diameter and revolutions of
driver being given, to find the diameter of the driven
that shall make a given number of revolutions:
Multiply the diameter of the driver by its number
of revolutions, and divide the product by the number of revolutions of the driven. The quotient will
be the size of the driven.
Example 3. To find the number of revolutions
of the driven pulley: Multiply the diameter of driver
by its number of revolutions, and divide by diameter
of driven. The quotient will be the number of revolutions of the driven.
BELTING.
IT is a common error among mechanics and owners of factories to make the face of their pulleys narrow, in order to economize on the first cost of belting;
but this false economy seldom decreases the cost of
the machinery, and only saves a trifle in the first cost
of belting. The small amount saved is soon lost by
the stopping of machinery caused by the slipping of
belts, strain on the shafting, increased friction, requiring additional driving-power, and rapid destruction of the belts themselves. Were pulleys made of
a proper size and width and face, and then covered
18




206     CATECHISM OF HIGH PRESSURE, OR
with leather, and belts of proper width run with the
grain side of leather to the pulley, thousands of tons
of coal might be saved annually, and also an immense amount of trouble.
The importance of covering the face of pulleys
with leather is realized by but few persons having
charge of machinery; full 50 per cent. more work
can be done without the belts slipping, if the face of
the pulleys are covered with leather.
LEATHER BELTS.
Leather belts used with grain side to pulley will
not only do more work, but last longer than if used
with flesh side to the pulley; this is owing to the fact
that the grain side is more compact and fixed than
the flesh side, and more of its. surface is brought in
contact with the pulley. The smoother the two surfaces the less air will pass between the belt and the pulleys. The more uneven the surface of the belt and pulley the more strain necessary to prevent the belt slipping; for what is lost by want of contact must be
made up by extra strain on the belt.
Leather belts, with grain side to pulley, can drive
34 per cent. more than flesh side.
A belt 1 inch wide, travelling 800 feet per minute
over two smooth pulleys, will develop 1 horse-power.
A belt 1 foot wide, running at a speed of 70 feet
per minute over smooth pulleys, will be equal to 1
horse-power.




NON-CONDENSING STEAM-ENGINES.      207
A belt 3 incles wide, running at a speed of 280
feet per minute, will be equal to 1 horse-power.
A belt 5 inches wide, travelling 762 feet per minute over pulleys covered with leather, will develop
5 horse-power.
A belt 5 inches wide, in good condition, travelling
over pulleys covered with leather, running at a speed
of 1525 feet per minute, will transmit 10 horse-power.
LACING BELTS.
In lacing belts great care should be taken that the
ends intended to butt together should be cut/perfectly square; if not, the belt will stretch more on
one side than the other, which will greatly impair
its worth.
HORIZONTAL BELTS.
The driving half of horizontal belts should be the
lower half when practical, as, when the belt stretches,
the upper half will cover more of the pulley's surface. Long horizontal belts are better than short
ones, as their weight increases their contact with the
pulley.
PERPENDICULAR BELTS.
Belts running on pulleys perpendicular to each
other should be kept tightly strained, as their weight
tends to decrease their contact with the lower pulleys.




208    CATECHISM OF HIGH PRESSURE, OR
GREASING BELTS.
Belts, if dry or husky, should be greased with a
mixture of neat's-foot oil and tallow, and dried in by
the heat of the fire or sun.
RULES.
Rule for calculating the width of belts required
for transmitting different numbers of horse-powers:
Multiply 36,000 by the number of horse-powers;
divide the product by the number of feet the belt is
to travel per minute; now divide the quotient by the
number of feet, or parts of feet, of belt in contact
with the smaller pulley; divide this last quotient by 6,
and the result is the required width of belt in inches.
Rule for calculating the number of horse-powers
a belt will transmit; its velocity, and the number of
square inches in contact with the smaller pulley,
being given:
Divide the number of square inches in contact
with the pulley by 2; multiply this quotient by the
velocity of the belt in feet per minute, and divide by
36,000; the quotient is the number of horse-powers
the belt will transmit.




NON-CONDENSING STEAM-ENGINES.     209
ACCIDENTS.
RULES FOR THE COURSE TO BE FOLLOWED BY THE
BYSTANDERS, IN CASE OF INJURY BY MACHINERY,
WHEN SURGICAL ASSISTANCE CANNOT AT ONCE BE
OBTAINED.
If there is bleeding, do not try to stop it by binding up the wound. The current of the blood to the
part must be checked. To do this, find the artery
by its beating; lay a firm and even compress or pad
Fig. 1.         Fig. 2.         Fig. 3.
(made of cloth or rags rolled up, or a round stone or
a piece of wood well wrapped) over the artery, (see
Figure 1;) tie a handkerchief around the limb and
compress; put a bit of stick through the handkerchief
and twist the latter up till it is just tight enough to
stop the bleeding; then put one end of the stick under
the handkerchief to prevent untwisting, as in Fig. 3.
The artery in the thigh runs along the inner side
of the muscle in front, near the bone. A little above
the knee it passes to the back of the bone. In injujuries at or above the knee, apply the compress high
18*            0




.2.13 0 CATECHISM OF iHIGI PRESSURE, OR
up on the inner side of the thigh, at the point where
the two thumbs meet at C in Figure 4, with the knot
on the outer side of the thigh. When the leg is inured below the knee, apply the compress at the back
of the thigh just above the knee at C in Figure 2,
and the knot in front, as in Figures 1 and 3.
i
Fig. 4.                      Fig. 5.
The artery in the arm runs down the inner side of
the large muscle in front, quite close to the bone;
lower down it gets farther forward toward the bend of
the elbow. It is most easily found and compressed
a little above the middle, (see Figure 5.)
Care should be taken to examine the limb from
time to time, and to lessen the compression if it becomes very cold or purple; tighten up the handkerchief again if the bleeding begins afresh.
A BRIEF HISTORY OF THE STEAM-ENGINE.
HERO of Alexandria, who flourished about 200
B. C., has left us a description of a steam-engine by
which machinery could be set in motion.
In the year 450 A. D., Anthemius, an architect,




NON-CONDENSING STEAM-ENGINES.     211
tried some experiments with steam, which is the
second attempt on record to use steam as a motivepower.
In the year 1543, Blasgo de Garay, a Spaniard,
propelled a vessel of 200 tons, in the harbor of Barcelona, by the force of steam.
In the year 1615, De Caius, a Frenchman, devised
a machine by which water could be raised in tubes
through the agency of steam.
In the year 1630, Branca, an Italian physician,
ground his drugs by means of a wheel set in motion
by steam.
In 1656, the Marquis of Worcester made some
very important improvements in the steam-engine.
In the year 1685, some experiments were made
with steam by Pepin, a Frenchman, who devised the
mode of giving a piston an up and down movement
by alternately generating and condensing the steam
in a cylinder.
In the year 1698, Savery, an Englishman, constructed a steam-engine superior to any before invented.
In the year 1705, Newcomen made some very
important improvements in the steanim-engine. To
Newcomen belongs the honor of building the first
engine that bore any resemblance to modern steamengines.
In the year 1764, James Watt constructed the'first
perfect stationary steam-engine that was ever made
up to that date.




212    CATECHISM OF HIGH PRESSURE, OR
In the year 1769, Nicholas Cugnot constructed the
first self-moving locomotive-engine.
In the year 1786, the Marquis Jouffry constructed
a small steamboat on the Saone.
In the year 1789, William Symington made a
voyage in a small steamboat on the Firth of Clyde.
In the year 1782, Ramsey propelled a boat by
steam in New York harbor.
In the year 1788, John Fitch, of Philadelphia,
navigated a boat by steam on the Delaware River.
In the year 1793, Robert Fulton made some important experiments with steam.
In the year 1794, Oliver Evans, a native of Philadelphia, constructed the first locomotive or roadsteamer in America.
In the year 1803, John C. Stevens, of New York,
obtained a patent for a steamboat.
HISTORY OF THE DIFFERENT PARTS OF THE
STEAM-ENGINE IN DETAIL.
The inventor of the slide-valve is unknown: it
was spoken of by Hero 2,000 years ago.
The valve was made self-acting by a boy named
Humphrey Potter.
The eccentric was invented by Murdock, as was
also the crank.
The beam and connecting-rod were invented by
Newcomen.
The radius and parallel bars were invented by
Watt.




NON-CONDENSING STEAM-ENGINES.      213
BOILERS.
John C. Stevens invented the tubular boiler, 1804.
James Neville invented the multi-tubular, 1826.
VOCABULARY.
Anchor Brace. -A brace. for supporting brick walls
around boilers.
Ash Pit. - The opening under the grate-bars, through
which air is admitted to the furnace.
Back Rest. - A rest used for the piston, in cases
where the piston-rod passes through both cylinder-heads.
Baffle. -A screen in steam-boilers, to prevent water
from passing over into the cylinder.
Balance Wheels. -A wheel on the main shaft of the
engine to insure uniform motion.
Bed Plate. -The iron plate or base of the engine,
resting on the foundation.
Blow-off Cock. - A cock at the bottom of the boiler,
through which to empty the boiler.
Boiler. -The source of power; the vessel in which
the steam is generated.
Bonnet. - The cover of the steam-chest.
Bridge Wall.- The back wall of the furnace.
Buck Stave. - A brace to sustain the brick work
aroufid a boiler.
Cam. - See ECCENTRIC.
Check Valve. -The valve between the pump and
boiler, to prevent the back pressure of the water.
Chimney. - The flue through which the smoke
escapes from the furnace.
Connecting Rod. -A rod to communicate the pressure on the piston to the crank.




214     CATECHISM OF HIGH PRESSURE,. OR
Crank. - The part of the engine that converts rectilinear motion of the piston into rotary motion.
Crank Pin. -The bearing by which the connectingrod is attached to the crank.
Cross Head. -A block moving in guides, having the
end of piston secured within it at one end and attached
to the connecting-rod at the other.
Crow Feet. - Braces used in steam-boilers.
Crown Bars. - Bars- attached to the upper side of the
crown-sheet to prevent springing.
Crown Sheet. - The top sheet of the furnace directly
over the fire.
Cut Off. - An additional valve to cut off -steam in the
cylinder at any point of the stroke.
Cylinder. - The vessel or tube in which.-the pistonhead moves.
Cylinder Heads. - The back and front end;. of the
cylinder.
Damper. - A door to exclude the air from the furnace.
Dome. -An elevated chamber on top of the boiler,
from which the steam is taken.
Drip Cocks. - Small cocks in the cylinder- heads,
through which the condensed water escapes.
Driving Belts. - The belt that transmits the power of
the engine to the machinery.
Driving Pulley. -A pulley on the main shaft of the
engine.
Eccentric. - The cam that gives movement to the
valves.
Eccentric Straps. - The straps that surround the eccentric, and to which the rod is attached.
Eduction Port. - A passage on the side of the cylinder to lead away the exhaust steam.




NON-CONDENSING STEAM-ENGINES.       215
Exhaust Pipe.- The pipe through which the steam
escapes from the cylinder.
Expansion Valve.- A cut-off.
Feed Pipe. — A pipe through which feed-water is
fed into- the boiler.
Fire BoX. - The furnace of a locomotive boiler.
Flues. -Passages through which the heat is conducted in flue boilers.
Foaming. - An artificial excitement or boiling, caused
by the water becoming greasy or foul.
Follower Bolts. - Bolts that secure the follower-plate
to the piston-head.
Follower Plate. - The plate that covers the packing
on the piston-head.
Foundation. - The brick or stone base on which to
set the engine.
Foundation Bolts. - The bolts by which the bedplate is made fast to the foundation.
Furnace. — A chamber in which the coal is burned
under a boiler.
Gasket. - A packing for the man-hole of the boiler.
Gauge Cocks. - Cocks at different levels, to ascertain
the height of the water in the boiler.
Gibb. - The counter part of a key, used with the key
to take up lost motion in boxes.
Gland. — A bushing to secure the packing in the
stuffing-boxes.
Glass Gauge. - A glass tube on the front of a boiler,
to indicate the height of the water.
Governor. -- A machine to regulate the speed of an
engine.
Grate. - Parallel bars that support the fuel in the
furnace.




216    CATECHISM OF HIGH PRESSURE, OPI
Grommet. - A ring of hemp, a packing.
Guides.- The bars on which the cross-head moves.
Gusset Stay.- A stay used in boilers.
Hand Hole. - See MUD HOLE.
Heater. - A cylinder in which to heat the feed-water
before entering the water.
Housing.- The frame of vertical engines.
Induction Ports. - The passages through which the
steam is admitted to the cylinder.
Injector. -An instrument used for supplying feedwater to boilers.
Jacket.- A covering for steam-cylinders.
Journals. - The part of the engine-shaft resting in the
pillow-block boxes.
Key. - A wedge to take up lost motion in boxes on
crank-pin and cross-heads.
Lagging.- A wooden sheathing around the cylinder
or steanm-pipe.
Lap. —The distance which the valve overlaps the
steam-ports.
Lead. - The distance which the induction port is open
when the piston commences the stroke.
Link Motion. - An arrangement for reversing the
motion of engines.
Lubricator. -The cup or valve through which the
oil or tallow is admitted to the cylinder.
Man Hole. -A hole to admit a man within the boiler.
Man-Hole Brace. - A cross brace to secure the plate
in the man-hole.
Man-Hole Plate. - A plate to close the man-hole.
Midfeather.- A brace under a boiler.
Mud Hole. -A small opening at the bottom of the
boiler, through which to remove the mud.




NON-COlNDENSING STEAM-ENGINES.      217
Packing. - A substance used to make a steam-joint
around the piston-rod.
Packing Hook. — A steel hook, used for removing
packing from stuffing-boxes.
Packing Rings. - The rings that form a steam-tight
joint in the cylinder.
Packing Stick. - A small stick used to drive packing
into the box.
Pitman. -A connecting-rod.
Pet Cock. - A small cock, between the check valve
and pump, used to see if the pump is working.
Pipe (in Mechanics). - A metallic tube.
Piston Head. - The head on which the rings fit in
the cylinder.
Piston Rod. - A rod secured at one end to the
piston-head and at the other to the cross-head.
Plunger. -A solid piston of a pump.
Ports. - Openings or passages for the admission of
steam or water.
Priming. - The passage of water along with the steam
into the cylinder.
Pump. - A machine used for lifting or forcing water.
Rocker. -An intermediate bearing between the eccentric and valve rods.
Rocker Shaft. —The shaft on which the rocker vibrates.
Safety Valve.- A valve on the boiler, to discharge
surplus steam.
Shackle Bar.- A connecting-rod.
Shell. - Outside sheets of a boiler.
Slice Bar. -A bar used for the purpose of cleaning
fires in boiler furnaces.
Slide Valve. - The valve that admits the steam to the
cylinder of slide-valve engines.
19




218      CATECHISM OF HIGH PRESSURE.
Stack.- See CHIMNEY.
Spider. -A piston-head.
Stagger Plate. -A plate to prevent the passage of
water with the steam from the boiler to the cylinders.
Starting Bar. -A bar used to move the valve of an
engine when the valve-gear is disconnected.
Steam Chest. -A box on the top or side of the cylinder containing the valve which admits steam to the
piston.
Steam Gauge. -A gauge to show the pressure of
steam on a boiler.
Steam Pipe. —The pipe through which the steam
flows from the boiler to the steam-chest.
Stop Valve. - The valve that closes the communication between the boiler and steam-chest.
Straps.- The pieces that secure the crank-pin and
cross-head boxes to the connecting-rod.
Stroke. - The distance travelled by the piston at each
revolution of the crank.
Stub Ends. - The ends of the connecting-rod that butt
against the boxes.
Stuffing Box. -A chamber to receive the packing,
where rods or spindles having an end motion require to
be made steam-tight.
Thimble. - An iron ring or ferrule used for stopping
leaks in tubes of steam-boilers.
Tubes, — of a boiler through which the heat and
smoke escape to the chimney.
Tube Sheets. - The ends of the boiler or sheets to
which the tubes are, attached.
Union.- A steam-tight joint formed with a coupling.
Water Gauge. -See GLASS GAUGE.
Wrist.- The bearing in the cross-head on which the
connecting-rod vibrates.
TIIE END.