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THE 

STEAM  ENGINEER'S 
HANDBOOK^ 

A  CONVENIENT  REFERENCE  BOOK 
For  All  Persons  Interested  In 

Steam  Boilers,  Steam  Engines,  Steam  Turbines, 

and  the  Auxiliary  Appliances  and 

Machinery  of  Power 

Plants 


BY 

International  Correspondence  Schools 

SCRANTON,  PA. 


1st  Edition,  18th  Thousand,  3d  Impression 


\\    SCRANTON,  PA. 
INTERNATIONAL  TEXTBOOK  COMPANY 


COPYRIGHT,  1913,  RY 

INTERNATIONAL  TEXTBOOK  COMPANY 

COPYRIGHT  IN  GREAT  BRITAIN 

ALL  RIGHTS  RESERVED 


PRESS  OF 

INTERNATIONAL  TEXTBOOK  COMPANY 
SCRANTON,  PA. 


27463 


PREFACE 

This  handbook  is  intended  as  a  reference  volume 
for  persons  engaged  in  the  actual  management  and 
care  of  steam  engines,  steam  boilers,  and  the  auxil- 
iary appliances  to  be  found  in  the  average  steam- 
power  plant.  The  aim  of  the  publishers  has  been 
to  select  data  of  general  interest  from  the  vast  store 
of  available  material,  and  to  combine  therewith 
information  relating  to  the  problems  and  difficulties 
likely  to  be  encountered  in  the  daily  work  of  the 
engineer  and  the  fireman. 

In  order  to  keep  the  book  of  such  size  as  to  be 
carried  conveniently  in  the  pocket,  the  treatment 
of  many  of  the  subjects  has  necessarily  been  brief; 
but  subjects  of  greater  importance,  as,  for  example, 
the  care  and  operation  of  boilers  and  engines,  have 
been  dealt  with  more  fully.  The  various  tables  have 
been  selected  with  great  care,  and  only  those 
have  been  included  which  are  likely  to  be  consulted 
most  frequently.  The  numerous  rules  and  form- 
ulas are  stated  as  simply  and  concisely  as  possible, 
and  their  applications  are  clearly  illustrated  by  the 
full  solution  of  many  examples. 

Another  important  feature  is  the  inclusion  of 
abstracts  from  the  license  laws  of  the  various  cities 


and  states  in  which  such  laws  have  been  adopted. 
These  abstracts  serve  to  indicate  how  and  to  whom 
applications  for  license  must  be  made  and  what 
qualifications  are  necessary  in  order  to  obtain 
licenses  of  the  various  grades.  The  United  States 
marine  license  law  is  given  in  full. 

Care  has  been  taken  to  arrange  the  several  por- 
tions in  a  convenient  and  logical  manner,  and  a 
very  full  index  increases  further  the  facility  with 
which  any  given  subject  may  be  located. 

This  handbook  was  prepared  by  Messrs.  R.  T. 
Strohm  and  C.  J.  Mason,  under  the  supervision  of 
Mr.  J.  A.  Grening,  Principal  of  the  School  of  Steam 
and  Marine  Engineering. 

INTERNATIONAL  CORRESPONDENCE  SCHOOLS 

Nov.  1,  1912 


NDEX 


Absolute  zero,  57. 
Accidental  oil  fuel  fires,  158. 
Acids,  128. 

Addition  of  decimals,  4. 
of  fractions  or  mixed  num- 
bers, 3. 

Advantages     and     disadvan- 
tages of  injectors,   127. 
of  turbines,  224. 
Air   for   atomizing   oil   fuels, 

Steam  and,  84. 
in  oil  burning,   Excess  of, 

85. 
Mixtures  of  oil  spray  and, 

84. 

pump,  Pounding  in,  214. 
required  for  combustion,  77. 
Allegheny,    Pa.,   license  law, 

252. 
Angles  or  arcs,  Measures  of, 

42. 

Anthracite  coal,  79. 
Apparent,  cut-off,  183. 

slip,  231. 
Approximate   mean   effective 

pressure,   190. 
Arcs,  Measures  of  angles  or, 

42. 

Area  of  chimney,  110. 
of  safety  valve,  115. 
Areas,  Irregular,  35. 

of  circles,  Table  of  circum- 
ferences and,  38. 
Arrangement  of  piping,  122. 
Atlanta,  Ga.,  license  law,  252. 
Atomic  weight,  55. 

weights  of  elements,  Table 

of,  55. 

Atomization  of  oil,  83. 
Attachment  of  indicator,  175. 

of  indicator  cord,  180. 
Automatic  injectors,  123 


Axially  expanded  pitch,  234. 
Axle,  Wheel  and,  66. 


i,  81. 
Baltimore,  Md.,  license  law, 

253. 

Banking  fires,  164. 
Barrel  calorimeter,  97. 
Bearing,  Refitting  cut,  216. 
Bearings,  Brass-bound,  210. 

Danger  of  increasing  heat- 
ing of,  215. 

Dangerous  heating  of,  216. 

Effects  of  external  heat  on, 
222. 

Grit  in,  220. 

Hot,  215. 

Lubrication  of  turbine,  228. 

Newly  fitted,  217. 

Oils  squeezed  out  of,  220. 

Remedies     for     increasing 
heating  of,  215. 

Running  engine  with  hot, 

216. 

Bed  plate,  Springing  of,  222. 
Belt  pulleys,  66. 
Belting,  69. 
Belts,  Horsepower  of,  70. 

Lacing  of,  72. 

Sag  of,  69. 

Speed  of,  70. 
Bends,  Expansion,  121. 
Bituminous  coal,  80. 
Blade  area,  237. 

area,  Developed,  234. 

area,  Helicoidal,  234. 
Blades,  Clearance  of  turbine, 
225. 

Erosion  of  turbine,  226. 

Stripping  of  turbine,  226. 
Blow-off,  Bottom,  119.- 

-off  cocks  and  valves,  119. 


VI 


INDEX 


Blow-off,  Inspection  of  water 

gauge  and,  170. 
-off  pipe,  Protection  of ,  119. 
Blowing  down,  165. 
Boiler  efficiency,  144. 
explosions,  170. 
feed,  Equalizing  the,  148. 
feeding,  123. 
fittings,  113. 
horsepower,    Standard    of, 

141. 

inspection,  165. 
inspection,  External,  165. 
inspection,  Internal,  167. 
management,  145. 
piping,  120. 
Preparations    for   shutting 

down  a,  163. 
test,  Hydrostatic,  169. 
trials,  140. 
tubes,  Dimensions  of  iron, 

58. 
tubes,  Dimensions  of  steel, 

52. 

Boilers,  Connecting,  147. 
Filling,  145. 
,  103. 

Use  of  zinc  in,  134. 
Bottom  blow-off,  119. 
Brake  horsepower,  191. 

horsepower,  Calculation  of, 

200. 

horsepower,  Data  for,  199. 
Prony,  l«Mi. 
I.ulU-ys,  Cooling  of,  198. 

,  198. 

Brass  and  copper  tubes,  Table 
of  weight,  of,  49. 

md  bearings,  210. 
Brasses    and    journals,    Cut, 

218. 

Imperfectly  fitted,  218. 
Loose,  210. 
pinching  journal,  Edges  of, 

218. 

Reversal  of  pressure  on, 213. 
too  long.  222. 
too  loose,  217. 
too  tight,  217. 

•  pt-d  and  crocked,  218. 
chimneys,   KM). 
Bridge  wall, 


British  thermal  unit,  58. 
Broken  piston  packing,  2J2. 
Brumbo  pulley,  ITS. 
Buffalo,   N.    Y.,   license  law, 

254. 
Burner,    Shutting   down    oil 

fuel,   l.is. 
Burners,  Location  of  oil,  151. 


Calculating   indicated   horse- 
power,  192. 

Calculation   of   brake   horse- 
power, 200. 

Calculations,  Signs  used  in,  1. 
Calorific  value  of  fuels,  78. 

value  of  oil  fuels,  ^.i. 
Calorimeter,  Barrel,  97. 
Causes     and     remedies     for 
pounding  of  engines,  210. 
Carbonate  of  lime,  127. 
Centrifugal  force,  63. 
Chemical  compounds,  Table 
of  common  names  of,  .56. 
formulas,  55. 
symbi  > 

Chemistry.  f>  \. 

Chicago,  111.,  license  law,  255. 
Chimney,  Area  of,  110. 
Form  of,  109. 
foundations,  109. 
Height  of,  110. 
Chimneys,  108. 
Bricki  109. 
Iron  and  steel,  109. 
Table  of  sizes  of,  1 12. 
Chloride  of  magnesium,  128. 

of  sodium.  !2s. 
Circle,  W. 

Circles,   Table  of  circumfer- 
ences and  areas  of,  3S. 
Circular  ring,  ^7. 
Circulating  pump,  Pounding 

in,  214. 
Circumferences  and  areas  of 

circles,  Table  of,  :is. 
Cities    having    license    laws, 

States  and,  2M. 
Classes  of  coal,  79. 
Classification      of     injectors, 

123. 
Cleaning  fires,  149. 


INDEX 


Clearance,  182. 
Effects  of,  182. 
of  turbine  blades,  225. 
Coal,  Anthracite,  79. 
Bituminous,  80. 
Classes  of,  79. 
consumption  to  speed,  Re- 
lation of,  212. 
Maximum  combustion  rate 

of,  111. 

Semianthracite,  80. 
Semibituminous,  80. 
Cocks  and  valves,  Blow-off, 

119. 

Coefficients  of  linear  expan- 
sion, 57. 
Coke,  81. 

Combination  of  pulleys,  Go. 
Combustion,  76. 

Air  required  for,  77. 
Incomplete,  78. 
rate  of  coal,  Maximum,  111. 
Common  fractions,  2. 
Comparison  of  turbines  and 

engines,  225. 

Composition  of  crude  oil,  82. 
Compound     engine,    Starting 
and     stopping     Corliss, 
210. 

engines,  Horsepower  of,  194. 
slide-valve  engine,  Starting, 

207. 

slide-valve     engine,    Stop- 
ping, 209. 
Compounds,  54. 
Table  of  common  names  of 

chemical,  56. 
Condenser,    Injection    water 

for  jet,  203. 
Condensers,     Cooling     water 

for  surface,  202. 
Surface,  200. 
Types  of,  200. 

Condensing     slide-valve     en- 
gine, Starting,  206. 
slide-valve     engine,     Stop- 
ping, 206. 

Connecting  boilers,  147. 
Connection   of  steam  gauge, 

118. 

Construction     of    oil    tanks, 
153. 


Conversion  of  temperatures, 

57. 
Cooling     of    brake    pulleys, 

198. 

water  for  surface  condens- 
ers, 202. 

Copper      tubes,      Table      of 

weight  of  brass  and,  49. 

Corliss  engine,   Starting  and 

stopping  compound,  210. 

engine,      Starting     simple, 

207. 
engine,     Stopping     simple, 

207. 
Corrosion    and    incrustation, 

127. 

External,  131. 
Internal,  130. 
Prevention  of  incrustation 

and,  133. 
Uniform,  130. 
Coverings,  Pipe,  121. 
Cracked  brasses,  Warped  and, 

218. 

Crosshead,  Pounding  at,  213. 
Crude  oil,  Composition  of,  82. 
Cube  roots,  6. 
Cubes,  9. 

Cubic  measures,  42. 
Cut  brasses  and  journals,  218. 
-off,  Apparent,  183. 
-off,  Real,  183. 
Cylinder,  36. 

heads,  Piston  striking,  212. 
Frustum  of,  37. 
ratios,  194. 
Cylinders,  Water  in,  211. 


Danger  of  increasing  heating 

of  bearings,  215. 
of  water  hammer,  204. 

Dangerous   heating   of   bear- 
ings, 216. 

Data   for  brake  horsepower, 
199. 

De    Laval   turbine,    Care   of 


gears  in,  230. 
id  plate.  104. 


Dead  plate, 

Decimal  equivalents  of  parts 
of  1  inch,  Table  of,  45. 
fractions,  4. 


INDEX 


Decimal,  Reducing  a  common 
fraction  to  a,  5. 

to     a     common     fraction, 

Reducing  a,  5. 
Decimals,  Addition  of,  4 

Division  of,  5. 

Multiplication  of,  4. 

Subtraction  of,  4. 
Delivered  horsepower,  191. 
Denver.Colo., license  law,  256. 
Detroit,    Mich.,    license   law, 

257. 

Developed  blade  area,  234. 
Diagrams,   Taking  indicator, 

181. 

Diameter    of    propeller,    Re- 
quired, 237. 
Differential  pulley,  Go. 
Dimensions    of    iron    boiler 
tubes,  53. 

of  pipe  flanges,  51. 

of  steel  boiler  tubes,  52. 
Dirty  and  gritty  oils,  219. 
Disadvantages  of  oil  fuel,  1GO. 
Disk  area,  234. 
Division  of  decimals,  5. 

of  fractions,  3. 

of  matter,  54. 
Double-tube  injectors,  123. 
Draft,  Measurement  of,  108. 

Production  of,  108. 

required  for  oil  fuel  burn- 
ing, 157. 

Driven  pulleys,  67. 
Driving  pulleys,  67. 
Dynamometers,  195. 

E 

Economy    of    heating    feed- 
water,  138. 
Edges    of    brasses    pinching 

journal,  218. 
Effect  of  sulphur  in  oil,  80. 

of  vacuum  in  turbines,  223. 
Effects  of  clearance,  182. 
Efficiency,  Boiler,  141. 

of  engine,  Mechanical,  191. 
Elements,  54. 
Machine,  63. 
Table  of  atomic  weight  of, 

55. 
Elgin,  111.,  license  law.  258. 


Ellipse,  36. 

Engine  management,  203. 
Mechanical    efficiency    of, 

191. 

out  of  line,  221. 
Overloading  of,  221. 
speed  and  ship  speed,  Rela- 
tion between,  243. 
Starting  and  stopping  com- 
pound Corliss,  210. 
Starting    compound    slide- 
valve,  207. 

Starting  condensing  slide- 
valve,  206. 
Starting     non  -  condensing 

slide-valve,  205. 
Starting  simple  Corliss,  207. 
Stopping  compound   slide- 
valve,  209. 

Stopping  condensing  slide- 
valve,  206. 
Stopping      non-condensing 

slide-valve,  205. 
Stopping     simple     Corliss, 

207. 
with  hot  bearings,  Running, 

216. 

Engineers'  license  laws,  244. 
Engines,  Causes  and  remedies 

for  pounding  of,  210. 
Comparison     of     turbines 

and,  225. 
Horsepower  of  compound, 

194. 

Indicating  of,  172. 
Stating  size  of,  193. 
Steam,  172. 
Steam  pipes  for,  102. 
Warming  up,  203. 
Equalizing    the    boiler    feed, 

148. 

Equivalent  evaporation,  141. 
Erosion   of  turbine  blades, 

226. 
Errors    of    reducing    motion, 

ISO. 

Evaporation,  Equivalent,  141. 
Factor  of,  142. 
Table  of  factors  of,  143. 
Evaporative  power  of  oil  fuel, 

86. 
Evolution,  6. 


INDEX 


Excess  of  air  in  oil  burning, 

85. 
Exhaust  -  steam       feedwater 

heaters,  Types  of,  139. 
-steam  turbine,  229. 
Expanded  pitch,  Axially,  234. 

pitch,  Radially,  234. 
Expansion  bands,  121. 
joints,  120. 
Ratio  of,  183. 
Explosions,  Boiler,  170. 
External     boiler     inspection, 

165. 

corrosion,  131. 
heat  on  bearings,  Effects  of, 
222. 


Factor  of  evaporation,  142. 
Factors  of  evaporation,  Table 

9f,  143. 

Feeding,  Boiler,  123. 
Feedwater  by  chemicals,  Pur- 
ification of,  136. 
by    filtration,    Purification 

of,  135. 
by    heat.    Purification    of, 

138. 
by  settlement,  Purification 

of,  135. 

Economy  of  heating,  138. 
heaters,  Types  of  exhaust- 
steam,  139. 
Impurities  in,  127. 
Purification  of,  135. 
Testing,  134. 
Figures,  Significant,  6. 
Filling  boilers,  145. 
Finding   horsepower    of   tur- 
bines, 225. 
the  mean  effective  pressure, 

184. 

Fire,  Starting  an  oil  fuel,  155. 
Firebrick  lining  of  furnaces, 

88. 

Fires,  Accidental  oil  fuel,  158. 
Banking,  164. 
Cleaning,  149. 
in  starting,  Management  of, 

146. 

Precautions    in    relighting 
oil  fuel,  158. 


Fires,  Starting,  164. 
Firing  point  of  fuel  oil,  87. 

with  liquid  fuels,  150. 

with  solid  fuels,  148. 
Fittings,  Boiler,  113. 

for  oil  tanks,  153. 

Furnace,  103. 

Fixed  and  movable  pulleys, 
64. 

grates,  103. 
Flanges,  Dimensions  of  pipe, 

51. 

Flash  point  of  fuel  oil,  87. 
Flow  of  steam,  99. 

of  water  in  pipes,  72. 

Vetocity  of,  72. 
Foaming,  163. 
Follower  plate.  Loose,  212. 
Foot-pound,  62. 
Force,  Centrifugal,  63. 
Form  of  chimney,  109. 
Formation  of  scale,  128. 

of  soot  with  oil  fuel,  157. 
Formulas,  29., 

Chemical,  55. 

for  slip,  232. 

Foundations,  Chimney,  109. 
Fraction,  Reducing  .a  decimal 
to  a  common,  5. 

to  a  decimal,  Reducing  a 

common,  5. 
Fractions,  2. 

Common,  2. 

Decimal,  4. 

Division  of,  3. 

Multiplication  of,  3. 

or  mixed  numbers,   Addi- 
tion of,  3. 

or    mixed    numbers,    Sub- 
traction of,  3. 
Friction  horsepower,  191. 

Mixtures  for  reducing,  215. 
Frustum  of  cylinder,  37. 

of  prism,  37. 

Fuel  burner,   Shutting  down 
oil,  158. 

burning,  Draft  required  for 
oil,  157. 

Disadvantages  of  oil,  160. 

Evaporative  power  of  oil, 
86. 

fire,  Starting  an  oil,  155. 


7:VDEX 


Fuel  fires,  Accidental  oil,  138. 

fires,  Precautions  in  relight- 
ing oil,  158. 

Firing  with  solid,  148. 

Formation  of  soot  with  oil, 
157. 

Furnace,    Proportions     for 
oil.  88, 

Liqir 

Objections  to  gravity  feed- 
ing of  oil,  152. 

oil,  Pairing  point  of,  S7. 

oil,  Flash  point  of,  87. 

oil,  Properties  of,  83. 

Pressure  on  oil,  152. 

Separation  of  water  from 
oil,  151. 

Specifications  for  oil,  87. 

Straining  oil,  151. 

Thermal  advantages  of  oil, 

159. 
Fuels,  7! i. 

Calorific  value  of,  78. 

Calorific  value  of  oil,  83. 

Firing  with  liquid,  150. 

for  steam  making,  79. 

Heating  of  oil,  152. 

Solid,  7'.<. 

Steam  and   air  for   atomi- 
zing oil,  si. 
Furnace  fittings,  103. 
.     Proportions  for  oil  fuel,  88. 
Furnaces,  Firebrick  lining  of, 

Fusible  plugs,  116. 
Fusing  point,  ">'.). 
Fusion      and      vaporization, 
Table     of     temperatures 
and  latent  heats  of,  60. 
Latent  heat  of,  5<t. 
Temperature  of,  5(». 


Gauge  and  blow-off.  Inspec- 
tion of  water,  170. 
Connection  of  steam,  118. 
Testing  st--:un,  170. 
Gears   in   De   Laval   turbine, 

Care  of,  _V.<>. 
Goshen,  Ind.,  license  la 

ii.-ir,  Herrins,'l><>;]<',    101. 
Grates,  Fixed,  lo.i. 


Grates,  Shaking,  105. 
Gravity   feeding   of   oil   fuel, 

Objections  to,  152. 
Specific,  45. 
Grit  in  bearings,  220. 
Gritty  oils,  Dirty  and,  219. 
Grooving,  131. 

H 

Head  of  water,  Pressure  due 

to,  72. 
Heat,  56. 

in  wet  steam,  96. 
Latent,  59. 
Measurement  of,  58. 
Mechanical  equivalent  of, 

59. 

of  fusion.  Latent,  59. 
Specific,  60. 

Heaters,    Types   of   exhaust- 
steam  feed  water,   139. 
Heating  feedwater,  Economy 

of,  138. 

of  oil  fuels,  152. 
Heats  of  fusion  and  vaporiza- 
tion,  Table  of  tempera- 
tures and  latent,  tiO. 
Table  of  specific,  ill. 
Height  of  chimney,   110. 
Helicoidal  blade  i 
Herringbone  grate  bar,  10 1. 
Hints  for  use  of  planimeter, 

186. 
Hoboken,  N.  J.,  license  law, 

260. 
Honeycombing,     Pitting    or, 

131. 
Horsepower,  62. 

and    revolutions,    Relation 

of,  240. 
and     steam     consumption, 

191. 

Brake,  11)1. 

Calculating  indicated ,  192. 
Calculation  of  brake,  2(K). 
Data  for  brake,  199. 
Delivered,  191. 
Friction,  191. 
Indicated,  191. 

I'.tl. 

of  belts.  70. 
of  compound  engines,  194. 


INDEX 


Horsepower  of  steam  turbines, 

Finding,  225. 
Standard  of  boiler,   141. 
when  towing,  Reduction  of, 

240. 

Hot  bearings,  215. 
Huntington,  W.  Va.,   license 

law,  262. 
Hydraulics,  73. 
Hydrostatic  boiler  test,  169. 


I 

fitted 


brasses, 


Imperfectly 

218. 
Improper  steam  distribution, 

213. 

Impurities  in  feedwater,  127. 
Incomplete  combustion,  78. 
Incrustation    and    corrosion, 
127. 

and   corrosion,    Prevention 

of,  133. 
Indicated  horsepower,  191. 

horsepower,       Calculating, 

192. 

Indicating  engines,  172. 
Indicator,  Attachment  of,  175. 

cord,  Attachment  of,   ISO. 

diagrams,  Taking,   181. 

Inside-spring,  172. 

Outside-spring,  174. 

springs,  174. 

Injection  water  for  jet  con- 
denser, 203. 

Injectors,     Advantages     and 
disadvantages  of,  127. 

Automatic,  123. 

Classification  of,  123. 

Double-tube,  123. 

Lifting,  123. 

Location  of,  124. 

Non-lifting,  123.    ' 

Positive,  123. 

Size  of,  123. 

Steam  supply  to,  124. 

Troubles  with,  125. 
Inside-spring  indicator,  172. 
Inspection,  Boiler,  165. 

External  boiler,  165. 

Internal  boiler,  167. 

of  safety  valve,  169. 

of  turbines,  227. 


Inspection  of  water  gauge  and 

blow-off,  170. 

Installation  of  oil  tanks,  154. 
Insufficient  lead,  213. 

oil,  219. 
Internal  boiler  inspection,  167. 

corrosion,  130. 
Involution,  6. 
Iron  and  steel  chimneys,  109. 

boiler  tubes,  Dimensions  of, 
53. 

Table  of  weight  of  round 
and  square,  50. 

Table  of  weight  of  sheet,  48. 
Irregular  areas,  35. 


Jersey  City,  X.  J.,  license  law, 

263. 
Jet  condenser,  Injection  water 

for,  203. 

Joints,  Expansion,  120. 
Journal,     Edges    of     brasses 

pinching,  218. 
Journals,    Cut    brasses    and, 

218. 


Kansas    City,     Mo.,    license 

law,  205. 
Kerosene  as  a  scale  remover, 

129. 
Kinetic  energy,  62. 


Lacing  of  belts.  72. 
Lamination,  132. 
Latent  heat,  .'!». 
heat  of  fusion,  50. 
heat  of  vaporization,  60. 
heats  of  fusion  and  vapori- 
zation, Table  of  tempera- 
tures and,  GO. 
Law,  Allegheny,  Pa.,  license, 

262. 

Atlanta,  Ga.,  license,  253. 
Baltimore,      Md.,    license, 

253. 

Buffalo,  X.  Y..  license,  254. 
Chicago,  111.,  license,  255. 
Denver,  Colo.,  license,  256. 
Detroit,  Mich.,  license,  257. 


xii 


INDEX 


Law,  Elgin,  111.,  license,  258. 
Goshen,  Ind.,  license,  260. 
Hoboken,  N.  T.,  license, 

260. 
Huntington,  W.Va.,  license, 

262. 

Jersey  City,  N.  J.,  license, 
.  263. 
Kansas  City,  Mo.,  license, 

265. 

Lincoln,  Neb.,  license,  266. 
Los  Angeles,  Cal.,  license, 

267. 

Massachusetts  license,  244. 
Memphis,  Tenn.,  license, 

268. 
Milwaukee,    Wis.,    license, 

269. 

Minnesota  license,  247. 
Mobile,  Ala.,  license,  271. 
Montana  license,  248. 
New  Haven,  Conn.,  license, 

272. 
New  York,  N.  Y.,  license, 

273. 

Niagara   Falls,    N.   Y.,   li- 
cense, 275. 
Ohio  license,  249. 
Omaha,  Neb.,  license,  277. 
Pennsylvania  license,  250. 
Pe9ria,  111.,  license,  278. 
Philadelphia,    Pa.,    license, 

279. 

Pittsburg,  Pa.,  license,  280. 
Rochester,  N.  Y.,  license, 

280. 
Santa  Barbara,  Cal. .license, 

281. 

Scranton,  Pa.,  license,  285. 
Sioux  City,  la.,  license,  285. 
Spokane,  Wash.,  license, 

286. 
St.    Joseph,    Mo.,    license, 

282. 

St.  Louis,  Mo.,  license,  283. 
Tacoma,  Wash.,  license, 

287. 

Tennessee  license,  251. 
Terre  Haute,  Ind.,  license, 

288. 

United   States  marine  en- 
gineer's license,  291. 


Law,  Washington  and  District 
of  Columbia  license,  289. 

Yonkers,     N.    Y.,    license, 

289. 
Laws,  Engineers'  license,  244. 

States    and    cities    having 

license,  244. 
Lead,  Insufficient,  213. 
Levers,  63. 

License  law,  Allegheny,   Pa., 
252. 

law,  Atlanta,  Ga.,  252. 

law,  Baltimore,  Md.,  253. 

law,  Buffalo,  N.  Y.,  254. 

law,  Chicago,  111.,  255. 

law,  Denver,  Colo.,  256. 

law,  Detroit,  Mich.,  257. 

law,  Elgin,  111.,  258. 

law,  Goshen,  Ind.,  260. 

law,  Hoboken,  N.  J.,  260 

law,  Huntington,  W.  Va., 
262. 

law,  Jersey  City,  N.  J.,  263. 

law,  Kansas  City,  Mo.,  265. 

law,  Lincoln,  Neb.,  266. 

law,  Los  Angeles,  Cal.,  267. 

law,  Massachusetts,  244. 

law,  Memphis,  Tenn.,  268. 

law,  Milwaukee,  Wis.,  269. 

law,  Minnesota,  247. 

law,  Mobile,  Ala.,  271. 

law,  Montana,  248. 

law,    New   Haven,    Conn., 
272. 

law,  Niagara  Falls,  N.  Y., 
275. 

law,  New  York,  N.  Y.,  273. 

law,  Ohio,  249. 

law,  Omaha,  Neb.,  277. 

law,  Pennsylvania,  250. 

law,  Peoria,  111.,  278. 

law,  Philadelphia,  Pa.,  279. 

law,  Pittsburg,  Pa.,  280. 

law,  Rochester,  N.  Y.,  280. 

law,  Santa  Barbara,  Cal., 
281. 

law,  Scranton,  Pa.,  285. 

law,  Sioux  City,  la.,  285. 

law,  Spokane,  Wash.,  286. 

law,  St.  Joseph,  Mo.,  282. 

law,  St.  Louis,  Mo.,  283. 

law,  Tacoma,  Wash.,  287. 


INDEX 


License  law,  Tennessee,  251. 
law,    Terre    Haute,    Ind., 

288. 
law,  United  States  marine 

engineers',  291. 
law,  Washington  and  Dis- 
trict of  Columbia,  289. 
law,  Yonkers,  N.  Y.,  289. 
laws,  Engineers',  244. 
laws,  States  and  cities  hav- 
ing, 214. 

Lifting  injectors,  123. 
Lignite,  81. 
Lime,  Carbonate  of,  127. 

Sulphate  of,  128. 
Lincoln,    Neb.,    license    law, 

266. 
Linear  expansion,  Coefficients 

of,  57. 

measures,  42. 
Liners,  210. 
Lining  for  furnaces,  Firebrick, 

88. 
Liquid  fuel,  82. 

fuels,  Firing  with,  150. 
measures,  44. 

Location  of  oil  burners,  151. 
of  injectors,  124. 
of  safety  valve,  116. 
Loose  brasses,  210. 
piston,  211. 
thrust  block,  211. 
Los  Angeles,  Cal.,  license  law, 

267. 

Lubrication  of  turbine  bear- 
ings, 228. 


Machine  elements,  63. 
Magnesium,  Chloride  of,  128. 
Maintenance    of    a    uniform 

steam  pressure,   160. 
of  vacuum  in  turbines,  230. 
Management,  Boiler,  145. 
Engine,  203. 
of  fires  in  starting,  146. 
Marine  engineer's  license  law, 

United  States,  291. 
Massachusetts     license     law, 

244. 

Materials,  Weights  and  sizes 
of,  45. 


Mathematics,  1. 
Matter,  Division  of,  54. 

Organic,  128. 
Maximum    combustion    rate 

of  coal,  111. 

Mean  effective  pressure,  Ap- 
proximate, 190. 
effective  pressure  by  ordi- 

nates,  187. 
effective  pressure,  Finding 

the,  184. 
effective  pressure,  Referred, 

195. 

Measurement  of  draft,  108. 
of  heat,  58. 
of  pitch,  234. 
Units  of,  42. 
Measures,  Cubic,  12. 
Linear,  42. 
Liquid,  44. 
of  angles  or  arcs,  42. 
of  time,  45. 
of   United    States    money, 

44. 

of  weight,  43. 
Square,  42. 

Mechanical  efficiency  of  en- 
gine, 191. 

equivalent  of  heat,  59. 
stokers,  105. 
Mechanics,  62. 
Memphis,  Tenn.,  license  law, 

268. 

Mensuration,  33. 
Milwaukee,  Wis.,  license  law, 

269. 

Minnesota  license  law,  247. 
Mixed  numbers,  Addition  of 

fractions  or,  3. 
numbers,     Subtraction     of 

fractions  or,  3. 
Mixtures    for    reducing    fric- 
tion, 215. 

of  oil  spray  and  air,  84. 
Mobile,  Ala.,  license  law,  271. 
Moisture  in  steam,  95. 
Molecular  weight,  55. 
Money,   Measures  of  United 

States,  44. 

Montana  license  law,  248. 
Movable  pulleys,  Fixed  and, 
64. 


INDEX 


Mud,  Removing,  130. 
Multiplication  of  decimals,  4. 
of  fractions,  3. 

N 

Nature  of  combustion,  76. 
Net  horsepower,  191. 
New   Haven,    Conn.,   license 

law,  272. 
York,  N.    Y.,  license  law, 

273. 

Newly  fitted  bearings,  217. 
Niagara  Falls,  N.  Y.,  license 

law,  275. 
Non-condensing      slide-valve 

engine,   Starting,   205. 
-condensing  slide-valve  en- 
gine, Stopping,  205. 
-lifting  injectors,  123. 

O 

Objections  to  gravity  feeding 

of  oil  fuel,  152. 
Ohio  license  law,  249. 
Oil,  Atomization  of,  83. 
burners,  Location  of,  151. 
burning,   Excess  of  air  in, 

85. 

Composition  of  crude,  82. 
Effect  of  sulphur  in,  86. 
feed,  Stopped,  219. 
Firing  point  of  fuel,  87. 
Flash  point  of  fuel,  87. 
fuel  burner,  Shutting  down, 

158. 

fuel     burning,     Draft     re- 
quired for,   J">7. 
fuel,  Disadvantages  of,  160. 
fuel,  Evaporative  power  of, 

8G. 

fuel  fire,  Starting  a,  155. 
fuel  fires,  Accidental,  15s. 
fuel    fires.    Precautions    in 

relighting,   15s. 
fuel,     Formation     of     soot 

with,    i:.7. 
fuel,    Furnace    proportions 

for,  88. 
fuel.  Objections  to  gravity 

feeding  of.  152. 
fuel,  Pressure  on,  152. 


Oil  fuel,  Separation  of  water 
from,    151. 

fuel,  Specifications  f:.>- 

fuel,  Straining,  151. 

fuel,    Thermal   advantages 
of,  159. 

fuels,  Calorific  value  < 

fuels,  Heating  of,  152. 

fuels,    Steam    and    air   fur 
atomizing,  M. 

Insufficient,  219. 

Properties  of  fuel,  83. 

spray  and  air,  Mixtures  of, 
84. 

tanks,  Construction  of ,  153. 

tanks,  Fittings  for,  153. 

tanks,  Installation   of,  15}. 
Oils,  Dirty  and  gritty,  2i'i. 

of  poor  quality,  219. 

squeezed  out    of  bearings, 

220. 

Omaha,  Neb.,  license  law.  277. 
Operation  of  turM;ie>,  227. 
Organic  matter,  12S. 
Outside-spring  indicator,  174. 
Overfeed  stoker,  105. 
Overheating,  132. 
Overloading  of  engine,  221. 


Packing,  Broken  piston,  212. 
Pantograph  reducing  motion, 

177. 

Parallelogram,  34. 
Parallelepiped,  37. 
Peat,  81. 
Pendulum    reducing    motion, 

17(1. 

Pennsylvania  license  law,  25o. 
Peoria,  111.,  license  law,  27s. 

Philadelphia,  Pa.,  license  law, 

279. 
Pillow    block.    Springing    or 

shift  inn  of,  222. 
Pipe  coverniK :,,  121 . 

dimensions,  Table  of  extra- 
strong  wrought-iron,  49. 
dimensions,  Table  of  stand- 
ard, is. 

flanges,  Dimensions  of,  51. 
materials,  120. 


INDEX 


xv 


Pipe,  Protection  of  blow-off, 

119. 

Pipes,  Flow  of  water  in,  72. 
for  engines,  Steam,  102. 
Piping,  Arrangement  of,  122. 

Boiler,  120. 
Piston,  Loose,  211. 

packing,  Broken,  212. 
speed,  192. 

striking  cylinder  heads, 212. 

Pitch,  Axially  expanded,  234. 

Determining   the   kind   of, 

236. 

Measurement  of,  234. 
of  propeller,  Required,  236. 
Radially  expanded,  234 
Pitting  or  honeycombing,  131. 
Pittsburg,    Pa.,  license    law, 

280. 
Planimeter,  185. 

Hints  for  use  of,  186. 
Plate,  Dead,  104. 
Plugs,  Fusible,  116. 
Polygons,  34. 
Positive  injectors,  123. 
Pounding   at   crosshead,  213. 
in  air  pump,  214. 
in  circulating  pump,  214. 
of  engines,  Causes  and  rem- 
edies for,  210. 
Power,  Work  and,  62. 
Powering  of  vessels,  238. 
Powers,  roots,  and  reciprocals, 

Table  of.  11. 
Precautions  in  relighting  oil 

fuel  fires,  158. 
Preparations      for      shutting 

down  a  boiler,  163. 
Pressure,  Approximate  mean 

effective,  190. 
by  ordinates.  Mean  effect- 
ive, 187. 

due  to  head  of  water,  73. 
Finding  the  mean  effective, 

184. 

Oil,  152. 

on  brasses,  Reversal  of,  213. 
Referred     mean     effective, 

195. 
Prevention     of     incrustation 

and  corrosion,  133. 
Priming,  162. 


Prism,  37. 

Frustum  of,  37. 
Production  of  draft,  108. 
Products  of  combustion,  76. 
Projected  propeller  area,  234. 
Prony  brake,  196. 
Propeller  area,  Projected,  234. 

Required  diameter  of,  237. 

Required  pitch  of,  236. 
Propellers,  Screw,  232. 
Properties  of  fuel  oil,  83. 

of  steam,  89. 

Propulsion  of  vessels,  231. 
Protection   of   blow-off   pipe, 

119. 
Pulley,  Brumbo,  178. 

Differential,  65, 
Pulleys,  Belt,  66. 

Combination  of,  65. 

Cooling  of  brake,  198. 

Driven,  67. 

Driving,  67. 

Fixed  and  movable,  64. 

Solid,  66. 

Split,  66. 

Wooden,  67. 
Pump,  Pounding  in  air,  214. 

Pounding     in     circulating, 

214. 

Purification  of  feedwater,  135. 
of  feedwater  by  chemi- 
cals, 136. 

of  feedwater  by  filtration, 
135. 

of  feedwater  by  heat,  138. 

of  feedwater  by  settlement, 
135. 


Quality  of  steam,  95. 

R 

Radially  expanded  pitch,  234. 
Ratio  of  expansion,  183. 
Ratios,  Cylinder,  194. 
Real  cut-off,  183. 
Reciprocals,  10. 

Table  of  powers,  roots,  and, 

11. 

Rectangle,  34. 
Reducing  a  common  fraction 

to  a  decimal,  5. 


INDEX 


Reducing    a     decimal    to    a 

common  fraction,  5. 
motion,  Errors  of,  180. 
motion,  Pantograph,  177. 
motion,  Pendulum,  176. 
motions,  Slotted-lever,  177. 
wheels.  178. 
Reduction  of  horsepower  when 

towing,  240. 

Referred  mean  effective  pres- 
sure, 195. 

Refitting  cut  bearing,  216. 
Relation      between      engine 
speed  and  ship  speed,  2 13. 
of     coal     consumption    to 

speed,  242. 

of  horsepower  and  revolu- 
tions, 240. 

Remedies  for  increasing  heat- 
ing of  bearings,  215. 
for    pounding    of    engines, 

Causes  and,  210. 
Removing  mud,  130. 

scale,  130. 
Reversal      of     pressure      on 

brasses,  213. 
Revolutions,       Relation       of 

horsepower  and,  240. 
Ring,  36. 

Circular,  37. 
Rochester,  N.  Y.,  license  law, 

280. 
Roots,  and  reciprocals,  Table 

of  powers,  11. 
Cube,  6. 
Square,  6. 
Rope  brake,  198. 
Round  and  square  iron,  Table 

of  weight  of,  50. 
Rules,  Safety-valve,  1 1  .">. 
Running     engine     with     hot 
bearings,  216. 

8 

Safety  valve,  Area  of,  1 1  .">. 
valve,  Inspection  of,  169. 
valve,  Location  of,  110. 
valve  rules,  115. 
valves,  113. 
Sag  of  belts.  69. 
Santa   Barbara,    Cal.,  license 
law,  281. 


Saturated  steam,  89. 
Scale,  127. 

Formation  of,  128. 
-forming    substances     and 
their  remedies,  Table  of, 
133. 

remover,  Kerosene  as  a,  129. 
Removing,  130. 
Scales,  Thermometric,  .06. 
Scranton,  Pa.,  license  law,  285. 
Screw  propellers,  232. 
Sector,  35. 
Segment,  36. 
Semianthracite  coal,  80. 
Semibituminous  coal,  80. 
Separation  of  water  from  oil 

fuel,  154. 

Shaking  grates,  105. 
Sheet  lead,  Table  of  weight  of, 

50. 
Shifting     of     pillow     block, 

Springing  or,  222. 
Ship  speed,  Relation  between 

engine  and,  243. 
Shutting  down  a  boiler,  Prep- 
arations for,  1«)3. 
down  an  oil  fuel  burner,  158. 
down  turbines,  230. 
Significant  figures,  <i. 
Signs  used  in  calculations,  1. 
Sioux   City,  la.,  license  law, 

285. 
Sizes  of  chimneys,  Table  of, 

112. 

of  engines,  Stating,  193. 
of  injectors,  123. 
of  materials,  Weights  and, 

45. 

Slack  follower  plate,  212. 
Slide-valve    engine,    Starting 

compound,  207. 
-valve  engine,  Starting  con- 
densing, 206. 

-valve  engine,  Starting  non- 
condensing,  205. 
-valve      engine.      Stopping 

compound,  209. 
-valve      engine,      Stopping 

condensing,  206. 
-valve     engine.     Stopping 

non-condensing,  205. 
Slip,  Apparent,  231. 


INDEX 


Slip,  Formulas  for,  232. 

True,  231. 

Slotteri-lever     reducing     mo- 
tions, 177. 

Sodium,  Chloride  of,  128. 
Solid  fuel,  Firing  with,  148. 
fuels,  79. 
pulleys,  66. 
Soot  with  oil  fuel,  Formation 

oi,  157. 

Specific  gravity,  45. 
heat,  60. 

heats,  Table  of,  61. 
Specifications  for  oil  fuel,  87. 
Speed  of  belts.  70. 
of  vessels,  238. 
Piston,  192. 
Relation    between    engine 

and  ship,  243. 
Relation  of  coal  consump- 
tion to,  242. 
Sphere,  37. 
Split  pulleys,  66. 
Spokane,  Wash.,  license  law, 

286. 

Springing  of  bed  plate,  222. 
or  shifting  of  pillow  block, 

222. 

Springs,  Indicator,  174. 
Square  iron,  Table  of  weight 

of  round  and,  50. 
measures,  42. 
roots,  6. 
Squares,  8. 

St.  Joseph,  Mo.,  license  law, 
282: 

Louis,    Mo.,  license    law, 
283. 
Standard  of  boiler  horsepower, 

141. 
pipe  dimensions,  Table  of, 

48. 

Starting  (an  oil  fuel  fire,  155. 
and     Stopping     compound 

Corliss  engine,  210. 
compound    slide-valve   en- 
gine, 207. 

condensing  slide-valve  en- 
gine, 206. 
fires,  164. 

non-condensing  slide-valve 
engine,  205. 


Starting  simple  Corliss  engine, 

turbines,  228. 
States     and     cities     having 

license  laws,  244. 
Steam  and  air  for  atomizing 

oil  fuels,  84. 
boilers,  103. 
consumption,  Horsepower 

and,  191. 
consumption    of    turbines, 

223. 

distribution,  Improper,  213. 
engines,  172. 
Flow  of,  99. 

gauge,  Connection  of,  118. 
gauge,  Testing,  170. 
Heat  in  wet,  96. 
Moisture  in,  95. 
pipes  for  engines,  102. 
pressure,  Maintenance  of  a 

uniform,  160. 
Properties  of,  89. 
Quality  of,  95. 
Saturated,  89. 
Superheated,  95. 
supply  to  injectors,  124. 
turbines,  223. 
Steel  boiler  tubes,  Dimensions 

of,  52. 

chimneys,  Iron  and,  109. 
Stripping  of  turbine  blades, 

226. 
Stoker,  Overfeed,  105. 

Underfeed,  106. 
Stokers,  Mechanical,  105. 
Stopped  oil  feed,  219. 
Stopping    compound    Corliss 
engine,  Starting  and,  210. 
compound    slide-valve  en- 
gine, 209. 

condensing  slide-valve  en- 
gine, 206. 
non-condensing  slide-valve 

engine,  205. 

simple  Corliss  engine,  207. 
Straining  oil  fuel,  151. 
Subtraction  of  decimals,  4. 
of  fractions  or  mixed  num- 
bers, 3. 

Sulphate  of  lime,  128. 
Sulphur  in  oil,  Effect  of,  86. 


INDEX 


Superheated  steam,  95. 

steam  in  turbines,  229. 
Surface  condensers,  200. 
condensers,    Cooling    water 

for,  202. 
Symbols,  Chemical,  55. 


Table  of  atomic  weights  of 
elements,  55. 

of  circumferences  and  areas 
of  circles,  38. 

of  common  names  of  chem- 
ical compounds,  56. 

of  decimal  equivalents  of 
parts  of  1  inch,  45. 

of  extra-strong  wrought- 
iron  pipe  dimensions,  49. 

of  factors  of  evaporation, 
143. 

of  powers,  roots,  and  recip- 
rocals, 11. 

of  scale-forming  substances 
and  their  remedies  133. 

of  sizes  of  chimneys,  112. 

of  specific  heats,  61. 

of  standard  pipe  dimen- 
sions, 48. 

of  temperatures  and  latent 
heats  of  fusion  and  vapor- 
ization, 60. 

of  weight  of  brass  and 
copper  tubes,  49. 

of  weight  of  round  and 
square  iron,  50. 

of  weight  of  sheet  iron, 
48. 

of  weight  of  sheet  lead, 
50. 

of  weights  of  various  sub- 
stances, 46. 
Tacoma,  Wash.,  license  law, 

287. 
Taking    indicator    diagrams, 

181. 

Tanks,    Construction  of   oil, 
153. 

Fittings  for  oil,  153. 

Installation  of  oil,  154. 
Temperature,  56. 

of  fusion,  .V.). 

of  vaporization,  60. 


Temperatures  and  latent 
heats  of  fusion  and 
vaporization,  Table  of, 
60. 

Conversion  of,  57. 
Tennessee  license  law,  251. 
Terre  Haute,  Ind.,  license  law, 

288. 

Test,  Hydrostatic  boiler,  169. 
Testing  feedwater,  134. 

steam  gauge,  170. 
Thermal    advantages    of    oil 

fuel.  159. 
unit,  British,  58. 
Thermometric  scales,  56. 
Thrust  block,  Loose,  211. 
Time,  Measures  of,  45. 
Towing,  Reduction  of  horse- 
power when,  240. 
Trapezium,  34. 
Trapezoid,  34. 
Triangles,  33. 

Troubles  with  injectors,  125. 
True  slip,  231. 
Tubes,    Dimensions    of    iron 

boiler,  53. 
Dimensions  of  steel  boiler, 

52. 

Turbine  bearings,  Lubrica- 
tion of,  228. 

blades,  Clearance  of,  225. 
blades,  Erosion  of,  226. 
blades,  Stripping  of,  220. 
Care  of  gears  in  De  Laval, 

230. 

Exhaust-steam,  229. 
troubles,  225. 

Turbines,  Advantages  of,  224. 
and    engines,    Comparison 

of,  22.-,. 

Effect  of  vacuum  in,  223. 
Finding  horsepower  of,  225. 
Inspection  of,  227. 
Maintenance  of  vacuum  in, 

Operation  of,  227. 

Shutting  down,  230. 

Starting,  228. 

Steam,  223. 

Steam  consumption  of,  223. 

Superheated  steam  in,  229. 

Vibration  of,  227. 


INDEX 


Turbines,  Water  in,  227. 
Types  of  condensers,  200. 
of  exhaust-steam  feedwater 
heaters,  139. 

U 

Underfeed  stoker,  106. 

Uniform  corrosion,  130. 

Unit,  British  thermal,  58. 

United    States    marine    engi- 
neer's license  law,  291. 
States  money,  Measures  of, 
44. 

Units  of  measurement,  42. 

Use  of  zinc  in  boilers,  134. 


Vacuum  in  turbines,  Effect  of, 

223. 
in    turbines,    Maintenance 

of,  230. 

Valve,  Area  of  safety,  115. 
Inspection  of  boiler  safety, 

169. 

Location  of  safety,  116. 
rules,  Safety,  113. 
Valves,   Blow-off   cocks   and, 

119. 

Safety,  113. 
Vaporization,  Latent  heat  of, 

60. 

Table  of  temperatures  and 
latent  heats  of  fusion 
and,  60. 

Temperature  of,  60. 
Velocity  of  flow,  74. 
Vessels,  Powering  of,  238. 
Propulsion  of,  231. 
Speed  of,  238. 

Vibration  of  steam   turbines, 
227. 


W 

Wall,  Bridge,  103. 
Warming  up  engines,  203. 
Warped  and  cracked  brasses, 

218. 

Washington  and  District  of 
Columbia  license  law, 
289. 

Water  from  oil  fuel,  Separa- 
tion of,  154. 

gauge  and  blow-off,  Inspec- 
tion of,  170. 

hammer,  Danger  of,  204. 
in  cylinders,  211. 
in  pipes,  Flow  of,  72. 
in  turbines,  227. 
Pressure  due  to  head  of,  72. 
Wedge,  37. 
Weight,  Atomic,  55. 
Measures  of,  43. 
Molecular,  55. 
of  sheet  iron,  Table  of,  48. 
of  sheet  lead.  Table  of,  50. 
Weights  and  sizes  of  materials, 

45. 

of  elements,  Table  of  atom- 
ic, 55. 
of    various    substances. 

Table  of,  46. 
Wet  steam,  Heat  in,  96. 
Wheel  and  axle,  66. 
Wheels,  Reducing,  178. 
Wood,  81. 

Wooden  pulleys,  67. 
Work  and  power,  62. 

Y 

Yonkers,  X.  Y.,  license  law, 
289. 

Z 

Zero,  Absolute,  57. 
Zinc  in  boilers.  Use  of,  134. 


The  Steam  Engineer's 
Handbook 


MATHEMATICS 


SIGNS  USED  IN  CALCULATIONS 

+  Plus,  indicates  addition;  thus,  10+5  is  15. 

—  Minus,  indicates  subtraction;  thus,  10  —  5  is  5. 

X  Multiplied  by,  indicates  multiplication;  thus,  10X5  is  50. 

•4-  Divided  by,  indicates  division;  thus,  10  -f-  5  is  2. 

=  Equal  to,  indicates  equality;  thus,  12  in.  =  1  ft. 

Parentheses,  (  ),  brackets,  [  ],  and  braces,  {  },have  the  same 
meanings,  and  signify  that  the  operation  indicated  within 
them  is  to  be  performed  first;  or,  if  more  than  one  pair  is  used, 
that  indicated  within  the  inner  one  is  to  be  effected  first. 
Thus,  in  the  expression  5(7  —  2),  the  subtraction  is  to  be  made 
first  and  the  difference  then  multiplied  by  5.  Again,  in  the 
expression  %[7—  (3  +  f)l,  the  addition  indicated  within  the 
parentheses  is  to  be  performed  first,  the  sum  thus  found  is  to 
be  subtracted  from  7,  and  then  half  of  the  remainder  is  to  be 
found. 

The  vinculum,  ,  is  used  for  the  same  purpose  as  paren- 
theses, brackets,  and  braces,  but  chiefly  in  connection  with  the 
radical  sign  "V  thus,  "V  . 

The  decimal  point  (.)  is  placed  in  a  number  containing  deci- 
mals, to  fix  the  value  of  that  number;  thus,  12.5  is  12  and  r^j; 
1.25  is  1  and  ^;  and  so  on. 

An  exponent  is  a  figure  written  above  and  to  the  right  of  a 
number  to  indicate  the  power  to  which  the  number  is  to  be 


2  MATHEMATICS 

raised.  Thus,  82  means  that  8  is  to  be  squared;  that  is,  8X8 
=  64.  Again,  8"  means  that  8  is  to  be  cubed;  that  is  8X8X8 
=  512. 

The  radical  sign,  V  ,  means  that  some  root  of  the  ex- 
pression under  the  vinculum  is  to  be  found.  If  it  is  used 
without  a  small  index  figure,  it  indicates  square  root;  thus, 
V64  =  8.  The  sign  ^f~  indicates  the  cube  root;  thus,  \27  =  3. 

The  signs  :  :  :  :  indicate  proportion;  thus,  3  : 4  :  :  6  :  8 
is  read  3  is  to  4  as  6  is  to  8.  Instead  of  the  sign  :  :  the  equality 
sign  =  is  often  used;  thus,  3:4  =  6:8. 

The  signs  °  '  "  mean  degrees,  minutes,  and  seconds,  respec- 
tively; thus,  60°  15'  15"  is  read  60  degrees  15  minutes  16  seconds. 

The  signs  '  "  also  mean  feet  and  inches,  respectively;  thus, 
7'  6"  is  read  7  feel  6  inches. 

The  symbol  TC  (pronounced  pi)  means  the  ratio  of  the  cir- 
cumference of  a  circle  to  its  diameter  and  has  a  value,  near 
enough  for  most  practical  purposes,  of  3.1416. 


FRACTIONS 

COMMON  FRACTIONS 

The  numerator  of  a  fraction  is  the  number  above  the  bar, 
and  the  denominator  is  the  number  beneath  it;  thus,  in  the 
fraction  f ,  3  is  the  numerator  and  4  is  the  denominator.  Two 
or  more  fractions  having  the  same  denominator  are  said  to 
have  a  common  denominator.  By  reducing  fractions  to  a  com- 
mon denominator  is'  meant  finding  such  a  denominator  as  will 
contain  each  of  the  given  denominators  without  a  remainder, 
and  multiplying  each  numerator  by  the  number  of  times  its 
denominator  is  contained  in  the  common  denominator.  Thus, 
the  fractions  J,  i,  and  &  have,  as  a  common  denominator, 
16;  then  t  =  A;  i  =  tl;  A  =  &. 

By  reducing  a  fraction  to  its  lowest  terms  is  meant  dividing 
both  numerator  and  denominator  by  the  greatest  number 
that  each  will  contain  without  a  remainder;  for  example,  in 
H,  the  greatest  number  that  will  thus  divide  14  and  16  is  2; 

14-^2 

so  that,  -         =  I,  which  is  jj  reduced  to  its  lowest  terms. 


16-=-2 


MATHEMATICS  3 

A  proper  fraction  is  one  in  which  the  numerator  is  less  than 
the  denominator,  as  3. 

A  mixed  number  is  one  consisting  of  a  whole  number  and  a 
fraction,  as  7f. 

An  improper  fraction  is  one  in  which  the  numerator  is  equal 
to,  or  greater  than,  the  denominator,  as  ¥.  This  is  reduced 
to  a  mixed  number  by  dividing  17  by  8,  giving  2  5. 

A  mixed  number  is  reduced  to  a  fraction  by  multiplying  the 
whole  number  by  the  denominator,  adding  the  numerator 
and  placing  the  sum  over  the  denominator;  thus,  If  becomes, 

(IX  8) +7     15 

by  reduction,  • •=  — . 

8  8 

Addition  of  Fractions  or  Mixed  Numbers. — If  fractions 
only,  reduce  them  to  a  common  denominator,  add  partial 
results,  and  reduce  sum  to  a  whole  or  mixed  number.  If 
mixed  numbers  are  to  be  added,  add  the  sum  of  the  fractions 
to  that  of  the  whole  numbers;  thus,  lf+2J  =  (l  +  2)  +  (i+S) 
=  41, 

Subtraction  of  Two  Fractions  or  Mixed  Numbers. — If  they 
are  fractions  only,  reduce  them  to  a  common  denominator, 
take  less  from  greater,  and  reduce  result;  as,  |  in.  — ^  in. 

1-4-9 

—  =  &  in.      If  they  are  mixed  numbers,  subtract  frac- 
16 

tions  and  whole  numbers  separately,  placing  remainders 
beside  one  another;  thus,  3i-2J  =  (3-2)  +  (f-f)  =  If.  With 
fractions  like  the  following,  proceed  as  indicated:  STS  —  1M 
=  (2+T§+&)-lH  =  2«-lH  =  1«  =  H;  7-4i=(6+*)-4f 
-2i 

Multiplication  of  Fractions. — Multiply  the  numerators 
together,  and  likewise  the  denominators,  and  divide  the  for- 

135     1X3X5     15 

mer  product  by  the  latter;  thus,  ~X~X-  =  —      —  =  — .     If 
248     2X4X8     64 

mixed  numbers  are  to  be  multiplied,  reduce  them  to  fractions 
and  proceed  as  shown  above;  thus,  l|X3J-tXV-V*4|. 

Division  of  Fractions. — Invert  the  divisor,  that  is,  exchange 
places  of  numerator  and  denominator,  and  multiply  the  divi- 
dend by  it,  reducing  the  result  to  lowest  terms  or  to  a  mixed 
number,  as  may  be  found  necessary;  thus,  3-^j  =  jX$  =  3f  =  3 


4  MATHEMATICS 

=  lg.     If  there  are  mixed  numbers,  reduce  them  to  fractions, 
and  then  divide  as  just  shown;  thus,  li^S^-^-J--1^,  or -^XfS 

-4*-*. 

DECIMAL  FRACTIONS 

In  decimals,  whole  numbers  are  divided  into  tenths,  hun- 
dredths,  etc.;  thus,  iV  is  written  .1 ;  .08  is  read  rSff,  the  value  of 
the  number  being  indicated  by  the  position  of  the  decimal 
point;  that  is,  one  figure  after  the  decimal  point  is  read  as 
so  many  tenths;  two  figures  as  so  many  hundredths;  etc. 
Moving  the  decimal  point  to  the  right  multiplies  the  number 
by  10  for  every  place  the  point  is  moved;  moving  it  to  the 
left  divides  the  number  by  10  for  every  place  the  point  is 
moved.  Thus,  in  125.78  (read  125  and  J&),  if  the  decimal 
point  is  moved  one  place  to  the  right,  the  result  is  1,257.8, 
which  is  10  times  the  first  number;  or,  if  the  point  is  moved  to 
the  left  one  place,  the  result  is  12.578,  which  is  rV  the  first  num- 
ber, moving  the  point  being  equivalent  to  dividing  125.78  by  10. 

Annexing  a  cipher  to  the  right  of  a  decimal  does  not  change 
its  value;  but  each  cipher  inserted  between  the  decimal  point 
and  the  decimal  divides  the  decimal  by  10;  thus,  in  125.078, 
the  decimal  part  is  rV  of  .78.  101.257 

Addition  of  Decimals. — Place  the  numbers  so  12.965 

that  the  decimal  points  are  in  a  vertical  line,  and  43.005 

add  in  the  ordinary  way,   placing  the  decimal  920.600 

point  of  the  sum  under  the  other  points.  „_  s__ 

Subtraction  of  Decimals. — Place  the  number  to 
be  subtracted  with  its  decimal  point  under  that 
of  the  other  number,  and  subtract  in  the  ordinary 
way.  434.968 

Multiplication  of  Decimals. — Multiply  in  the  ordinary  way, 
and  point  off  from  the  right  of  the  result  as  many  figures  as  there 
are  figures  to  the  right  of  the  decimal  points  in  21.72 

both  numbers  multiplied;  thus,  in  the  example  34  j 

here  given,  there  are  three  figures  to  the  right  ~2172 

of  the  points  and  that  many  are  pointed  off  in  sfiRS 

the  result.     If  either  number  contains  no  deci-  6516 

mal,  point  off  as  many  places  as  are  in  the  num- 
ber  that  does.  740.652 


MATHEMATICS  5 

If  a  product  has  not  as  many  figures  as  the  sum  of  the  deci- 
mal places  in  the  numbers  multiplied,  prefix  enough  ciphers 
before  the  figures  to  make  up  the  required  number  of  places 
and  place  the  decimal  point  before  the  ciphers.  Thus,  in  .002 
X.002,  the  product  of  2X2  =  4;  but  there  are  three  places  in 
each  number;  hence,  the  product  must  have  six  places,  and 
five  ciphers  must  be  prefixed  to  the  4,  which  gives  .000004; 
that  is,  .002 X.002  =  .000004. 

Division  of  Decimals. — Divide  in  the  usual  way.  If  the 
dividend  has  more  decimal  places  than  the  divisor,  point  off, 
from  the  right  of  the  quotient,  the  number  of  places  in  excess. 
If  it  has  fewer  places  than  the  divisor,  annex  as  many  ciphers 
to  the  decimal  as  are  necessary  to  give  the  dividend  as  many 
places  as  there  are  in  the  divisor;  if  the  dividend  is  a  whole 
number,  annex  as  many  ciphers  as  there  are  decimal  places 
in  the  divisor;  the  quotient  in  either  case  will  be  a  whole  num- 

25.75  82.5     82.50  7.5 

ber.     For  example, =  10.3;  = =  30;  —  =  3. 

2.5  2.75      2.75  2.5 

Carrying  a  Division  to  Any  Number    of    Decimal    Places. 

Annex  ciphers  to  the  dividend  and  divide,  until  the  desired 
number  of  figures  in  the  quotient  is  reached,  which  are  pointed 
off  as  above  shown.  Thus,  36. 5  -5- 18.1  to  three  decimal  places 

36.5000 

= =  2.016 +.     (The  sign  +  thus  placed  after  a  number 

IS.  1 

indicates  that  the  exact  result  would  be  more  than  the  one 
given  if  the  division  were  carried  further;  thus,  if  the  division 
were  carried  to  six  figures,  the  quotient  would  be  2.01657.) 

Reducing  a  Decimal  to  a  Common  Fractioc. — Place  the 
decimal  as  the  numerator;  and  for  the  denominator  put  1  with 
as  many  ciphers  as  there  are  figures  to  the  right  of  the  decimal 
point;  thus,  .375  has  three  figures  to  the  right  of  the  point; 
hence,  .375  =  f$&  =  f. 

Reducing  a  Common  Fraction  to  a  Decimal. — Divide  the 
numerator  by  the  denominator,  and  point  off  as  many  places 
as  there  have  been  ciphers  annexed;  thus,  &  =  3.0000 -^16 
=  .1875. 


6  MATHEMATICS 

INVOLUTION  AND  EVOLUTION 

SIGNIFICANT  FIGURES 

In  any  number,  the  figures  beginning  with  the  first  digit* 
at  the  left  and  ending  with  the  last  digit  at  the  right,  are  called 
the  significant  figures  of  the  number.  Thus,  the  number 
405,800  has  the  four  significant  figures  4,  0,  5,  8  and  the  sig- 
nificant part  of  the  number  is  4058.  The  number  .000090067 
has  five  significant  figures,  9,  0,  0,  6,  and  7,  and  the  significant 
part  is  90067. 

All  numbers  that  differ  only  in  the  position  of  the  decimal  point 
have  the  same  significant  figures  and  the  same  significant  part. 
For  example,  .002103,  21.03,  21,030,  and  210,300  have  the  same 
significant  figures  2,  1,  0,  and  3,  and  the  same  significant  part 
2103. 

The  integral  part  of  a  number  is  the  part  to  the  left  of  the 
decimal  point. 

SQUARE  AND  CUBE  ROOTS 

By  means  of  the  accompanying  table,  the  square,  cube, 
square  root,  cube  root,  and  reciprocal  of  any  number  may  be 
obtained  correct  always  to  five  significant  figures,  and  in  the 
majority  of  cases  correct  to  six  significant  figures. 

If  the  number  whose  root  is  to  be  found  contains  fewer 
than  four  significant  figures,  the  required  'root  can  be  found 
in  the  table,  the  square  root  under  Vn,  or  "VlOw,  and  the  cube 
root  under  3ln,  ^10n,  or  'S'lOOn,  according  to  the  number  of 
significant  figures  in  the  integral  part  of  the  number.  Thus, 
\.;.l  1^1.772;  >/31.4=  \1(>X:U  1  =  r,.C,(«r,7;  V.'U  l  =  1.46434; 
V'.M  =  ^10><3.14  =  3.15484;  %14=  ^100  XiU  4  =  0.79688. 

In  order  to  locate  the  decimal  point,  the  given  number  must 
be  pointed  off  into  periods  of  two  figures  each  for  square  root 
and  three  figures  each  for  cube  root,  beginning  always  at  the 
decimal  point.  Thus,  for  square  root:  12703,  1'27'03;  12.703, 
12.70'30;  220000.  22WOO;  .000442,  .OO'04'42;  and  for  cube 
root:  3141.6,  3'141.ti;  »i7L".Mi428.  67'296'428;  .0000000217, 
.000'000'021'700;  etc. 


*If  ciphers  are  used  simply  to  locate  the  decimal  point,  thev 
must  not  be  counted  as  digits. 


MATHEMATICS  7 

There  are  as  many  figures  preceding  the  decimal  point  in  the 
root  as  there  are  periods  preceding  the  decimal  point  in  the  given 
number;  if  the  number  is  entirely  decimal,  the  root  is  entirely 
decimal,  and  there  are  as  many  ciphers  following  the  decimal 
point  in  the  root  as  there  are  cipher  periods  following  the  decimal 
point  in  the  given  number. 

Applying  this  rule,  \220000  =  469.04,  \.OG0442  =  .021024, 
•^518000  =  80.31 13,  and  ^.003073  =  .04 18. 

If  the  number  has  more  than  three  significant  figures,  point 
off  the  number  into  periods,  place  a  decimal  point  between  the 
first  and  second  periods  of  the  significant  part  of  the  number, 
and  proceed  as  in  the  following  examples: 

EXAMPLE  1. — Find  the  results  of  the  following: 
(a)    \3.1416  =  ?     (b)    A/2342.9  =  ? 

SOLUTION. — (a)  In  this  case,  the  decimal  point  need  hot 
be  moved.  In  the  table  under  n2  find  3.1329  =  1.772  and 
3.1684  =  1.782,  one  of  these  numbers  being  a  little  less  and 
the  other  a  little  greater  than  the  given  number,  3.1416.  The 
first  three  figures  of  the  required  root  are  177.  31 ,684  -  31,329 
=  355  is  the  first  difference;  31,416  (the  number  itself)  — 31,329 
=  87  is  the  second  difference.  87 -4- 355  =  .245,  or  .25,  which 
gives  the  fourth  and  fifth  figures  of  the  root.  Hence,  "V3.1416 
=  1.7725. 

(b)  Pointing  off  and  placing  the  decimal  point  between 
the  first  and  second  periods,  the  number  appears  23.4290. 
Under  n2  find  23.4256  =  4.842  and  23.5225  =  4.852.  The  first 
three  figures  of  the  root  are  484.  The  first  difference  is  235,225 
-234,256  =  969;  the  second  difference  is  234,290-234,256 
=  34;  34-H969  =  .035,  or  .0-4,  which  gives  the  fourth  and  fifth 
figures  of  the  root.  Since  the  integral  part  of  the  number 
23'42.9  contains  two  periods,  the  integral  part  of  the  root 
contains  two  figures,  or  V2342.9  =  48.404. 

EXAMPLE  2. — Find  the  results  of  the  following: 
(a)     ^.0000062417  =  ?     (b)     -$50932676  =  ? 

SOLUTION. — (a)  Pointed  off,  the  number  appears  .000'006'- 
241'700,  and  with  the  decimal  point  placed  between  the  first 
and  second  periods  of  the  significant  parts,  gives  6.2417.  Under 
n*  find  6.22950=1.843  and  6.33163  =  1.853.  The  first  three 
figures  of  the  root  are  1.84.  The  first  difference  is  10,213.  and 


8  MATHEMATICS 

the  second  difference  is  1,220;  1, 220  -5- 10,213  =  .119,  or  .12, 
which  gives  the  fourth  and  fifth  figures.  There  is  one 
cipher  period  after  the  decimal  point  in  the  number;  hence, 
^00000624 17  =  .0184 12. 

(b)  Replace  all  after  the  sixth  figure  with  ciphers,  making 
the  sixth  figure  1  greater  when  the  seventh  figure  is  5  or  greater; 
that  is,  -^50932700  and  %)932676  will  be  the  same.  Placing 
the  decimal  point  between  the  first  and  second  periods  gives 
50.9327.  Under  n?  find  50.6530  =  3.70*  and  5 1.0648  =  3.7 13. 
The  first  three  figures  of  the  root  are  370.  The  second  dif- 
ference 2^797  4- the  first  difference  4. 118  =  .679  or  .68.  Hence, 
^'50932676  =  370.68. 

SQUARES 

If  the  given  number  contains  fewer  than  four  significant 
figures,  the  significant  figures  of  the  square  or  cube  can  be 
found  under  n2  or  n3  opposite  the  given  number  under  n.  The 
decimal  point  can  be  located  by  the  fact  that  if  the  column 
headed  VlOn  is  used,  the  square  will  contain  twice  as  many 
figures  as  the  number  to  be  squared,  while  if  the  column  headed 
Vn  is  used,  the  square  will  contain  twice  as  many  figures  as 
the  number  to  be  squared,  less  1.  If  the  number  contains 
an  integral  part,  the  principle  is  applied  to  the  integral  part 
only;  if  the  number  is  wholly  decimal,  the  square  will  have 
twice  as  many  ciphers,  or  twice  as  many  plus  1,  following  the 
decimal  point  as  in  the  number  itself,  depending  on  whether 
ViOn  or  Vn  column  is  used. 

To  square  a  number  containing  more  than  three  significant 
figures,  place  the  decimal  point  between  the  first  and  second 
significant  figures  and  find  in  the  column  headed  Vn  or  \\()n 
two  consecutive  numbers,  one  a  little  greater  and  the  other 
a  little  less  than  the  given  number.  The  remainder  of  the 
work  is  exactly  as  described  for  extracting  roots.  The  square 
will  contain  twice  as  many  figures  as  the  mfmber  itself,  or 
twice  as  many  less  1,  according  to  whether  the  column  headed 
\10n  or  Vn  is  used.  The  number  of  ciphers  following  the 
decimal  point  in  the  square  of  a  number  wholly  decimal  is 
determined  in  the  same  way. 

EXAMPLE. — Find  the  results  of  the  following: 
(a)  273.42*  =  ?     (b)  .0524362  =  ? 


MATHEMATICS  9 

SOLUTION. — (a)  Placing  the  decimal  point  between  the  first 
and  second  significant  figures,  the  number  is  2.7342,  which 
occurs  between  2.73313=  VrTi?  and  2.73496=^7748,  found 
under  \».  The  first  three  figures  of  the  square  are  747.  The 
second  difference  107 -^  the  first  difference  183  =  .584,  or  .58. 
Hence,  273.422  =  74,758. 

(&)  With  the  position  of  the  decimal  point  changed,  the 
number  is  5.2436,  which  is  between  5.23450  =  \2.74  and 
5.24404  =  V2.75,  both  under  "VlOn.  The  first  three  significant 
figures  of  the  root  are  2.74,  and  the  second  difference  910-;- 
the  first  difference  954  =  .953,  or  .95,  the  next  two  figures.  The 
number  has  one  cipher  following  the  decimal  point,  and  the 
column  headed  VlOn  is  used;  hence,  .0524362  =  .0027495. 

CUBES 

To  cube  a  number,  proceed  in  the  same  way,  but  use  a 
column  headed  ^n,  ^lOn,  or  ^lOOw.  If  the  number  contains 
an  integral  part,  the  number  of  figures  in  the  integral  part 
of  the  cube  will  be  three  times  as  many  as  in  the  given  num- 
ber if  the  column  headed  ^100«  is  used;  it  will  be  three  times 
as  many  less  1  if  the  column  headed  A/lOn  is  used;  and  it  will 
be  three  times  as  many  less  2  if  the  column  headed  3jn  is  used. 
If  the  number  is  wholly  decimal,  the  number  of  ciphers  fol- 
lowing the  decimal  point  in  the  cube  will  be  three  times,  three 
times  plus  1,  or  three  times  plus  2,  as  many  as  in  the  given 
number,  depending  on  whether  the  >/100w,  "VtlOn,  or  3ln  column 
is  used. 

EXAMPLE. — Find  the  results  of  the  following: 

(a)   129.6843  =  ?     (b)     7.64423  =  ?     (c)  .032425'  =  ? 

SOLUTION. — (a)  With  the  position  of  the  decimal 
changed,  the  number  1.29684  is  between  1.29664  = 
and  1.29862=  "fe.19,  found  under  -%».  The  second  difference 
20  -r-  the  first  difference  198  =  . 101 +  ,  or  .10.  Hence,  the  first 
five  significant  figures  are  21810;  the  number  of  figures  in 
the  integral  part  of  the  cube  is  3X3  —  2  =  7;  and  129.684s 
=  2,181,000,  correct  to  five  significant  figures. 

(6)  7.64420  occurs  between  7.64032=^446  and  7.64603 
=  ^447.  The  first  difference  is  571;  the  second  difference  is 
388;  and  388  -4-  571  =  .679  +  ,  or  .68.  Hence,  the  first  five 


10  MATHEMATICS 

significant  figures  are  44668;  the  number  of  ciphers  follow- 
ing the  decimal  point  is  3X0  =  0;  and  7.64423  =  446.68,  correct 
to  five  significant  figures, 

(c)  3.2425  falls  between  3.24278=^10X3.41  and  3.23961 
=  ^10X3.40-  The  first  difference  is  317;  the  second  difference 
is  289;  289 -=-317  =  . 911  +  ,  or  .91.  Hence,  the  first  five  sig- 
nificant figures  are  34091;  the  number  of  ciphers  following  the 
decimal  point  is  3X1  +  1=4;  and  .0324253  =  .000034091,  cor- 
rect to  five  significant  figures. 


RECIPROCALS 

The  reciprocal  of  any  number  is  equal  to  1  divided  by  that 
number;  thus,  the  reciprocal  of  6  is  £,  because  1-4-6=  |.  The 
product  of  a  number  and  its  reciprocal  is  always  1;  thus,  J  is 
the  reciprocal  of  8,  and  8X  J  =  1. 

The  last  column  of  the  following  table  gives  the  reciprocals 
of  all  numbers  expressed  by  three  significant  figures  correct  to 
six  significant  figures.  The  number  of  ciphers  following  the 
decimal  point  in  the  reciprocal  of  a  number  is  1  less  than  the 
number  of  figures  in  the  integral  part  of  the  number;  and  if 
the  number  is  entirely  decimal,  the  number  of  figures  in  the 
integral  part  of  the  reciprocal  is  1  greater  than  the  number 
of  ciphers  following  the  decimal  point  in  the  number. 

EXAMPLE. — Find  the  reciprocal  of  the  following: 

(a)  379.426;   (b)  .0004692  j 

SOLUTION.— (a)  .379426    falls    between    .378788  = and 

1  -'.lit 

.380228  =  — -.     The     first     difference     is     380,228-: 

=  1,440;  the  second  difference  is  380,228-379, 12(1  =  SOL'; 
802-=-l,440=.o">7,  or  .56.  Hence,  the  first  five  significant 
figures  are  26356,  and  the  reciprocal  of  379.426  is  .002- ;:;:,(, 
to  five  significant  figures.  j 

(b)     .469200    falls    between     .469484  = and     .H,72!«i 

1  2-13 

= .     The  first  difference  is  2,194;  the  second  difference  is 

2.14  ! 

284;  284-=- 2,194  =  .129  +  ,  or  .13.     Hence, =  2,131.3, 

.0004692 

correct  to  five  significant  figures. 


MATHEMATICS 


11 


71 

7l2 

7l3 

4H 

ViOtt 

«£ 

•fton 

3lOOn 

1 

n 

1.01 

1.0201 

1.03030 

1.00499 

3.17805 

1.00332 

2.16159 

4.65701 

.990099 

1.02 

1.0404 

1.06121 

1.00995 

3.19374 

1.00662 

2.16870 

4.67233 

.980392 

1.03 

1.0609 

1.09273 

1.01489 

3.20936 

1.00990 

2.17577 

4.68755 

.970874 

1.04 

1.0816 

1.12486 

1.01980 

3.22490 

1.01316 

2.18278 

4.70267 

.961539 

1.05 

1.1025 

1.15763 

1.02470 

3.24037 

1.01640 

2.18976 

4.71769 

.952381 

1.06 

1.1236 

1.19102 

1.02956 

3.25576 

1.01961 

2.19669 

4.73262 

.943396 

1.07 

1  1449 

1.22504 

1.03441 

3.27109 

1.02281 

2.20358 

4.74746 

.934579 

1.08 

1.1664 

1.25971 

1.03923 

3.28634 

1.02599 

2.21042 

4.76220 

.925926 

1.09 

1.1881 

1.29503 

1  .04403 

3.30151 

1.02914 

2.21722 

4.77686 

.917431 

1.10 

1.2100 

1.33100 

1.04881 

3.31662 

1.03228 

2.22398 

4.79142 

.909091 

1.11 

1.2321 

1  36763 

1.05357 

3.33167 

1.03540 

2.23070 

4.80590 

.900901 

1.12 

1.2544 

1.40493 

1.05830 

3.34664 

1.03850 

2.23738 

4.82028 

.892857 

1.13 

1.2769 

1.44290 

1.06301 

3.36155 

1.04158 

2.24402 

4.83459 

.884956 

l.U 

1.2996 

1.48154 

1.06771 

3.37639 

1.04464 

2.25062 

4.84881 

.877193 

1.15 

1.3225 

1.52088 

1.07238 

3.39116 

1.04769 

2.25718 

4.86294 

.869565 

1.16 

1.3456 

1.56090 

1.07703 

3.40588 

1.05072 

2.26370 

4.87700 

.862069 

1.17 

1.3689 

1.60161 

1.08167 

3.42053 

1.05373 

2.27019 

4.89097 

.854701 

1.18 

1.3924 

1.64303 

1  .08628 

3.43511 

1.05672 

2.27664 

4.90487 

.847458 

1.19 

1.4161 

1.68516 

1.09087 

3.44964 

1.05970 

2.28305 

4.91868 

.840336 

1.20 

1.4400 

1.72800 

1.09545 

3.46410 

1.06266 

2.28943 

4.93242 

.833333 

1.21 

1.4641 

1.77156 

1.10000 

3.47851 

1.06560 

2.29577 

4.94609 

.826446 

1.22 

1.4884 

1.81585 

1.10454 

3.49285 

1.06853 

2.30208 

4.95968 

.819672 

1.23 

1.5129 

1.86087 

1.10905 

3.50714 

1.07144 

2.30835 

4.97319 

.813008 

1.24 

1.5376 

1.90662 

1.11355 

3.52136 

1.07434 

2.31459 

4.98663 

.806452 

1.25 

1.5625 

1.95313 

1.11803 

3.53553 

.1.07722 

2.32080 

5.00000 

.800000 

1.26 

1.5876 

2.00038 

1.12250 

3.54965 

1.08008 

2.32697 

5.01330 

.793651 

1.27 

1.6129 

2.04838 

1.12694 

3.56371 

1.08293 

2.33310 

5.02653 

.787402 

1.28 

1.6384 

2.09715 

1.13137 

3.57771 

1.08577 

2.33921 

5.03968 

.781250 

1.29 

1.6641 

2.14669 

1.13578 

3.59166 

1.08859 

2.34529 

5.05277 

.775194 

1.30 

1.6900 

2.19700 

1.14018 

3.60555 

1.09139 

2.35134 

5.06580 

.769231 

1.31 

1.7161 

2.24809 

1.14455 

3.61939 

1.09418 

2.35735 

5.07875 

.763359 

1.32 

1.7424 

2.29997 

1.14891 

3.63318 

1.09696 

2.36333 

5.09164 

.757576 

1.33 

1.7689 

2.35264 

1.15326 

3.64692 

1.09972 

2.36928 

5.10447 

.751880 

1.34 

1.7956 

2.40610 

1.15758 

3.66060 

1.10247 

2.37521 

5.11723 

.74ti2«9 

1.35 

1.8225 

2.46038 

1.16190 

3.67423 

1.10521 

2.38110 

5.12993 

.740741 

1.36 

1.8496 

2.51546 

1.16619 

3.68782 

.10793 

2.38696 

5.14256 

.735294 

1.37 

1.8769 

2.57135 

1.17047 

3.70135 

.11064 

2.3!I280 

5.15514 

.7295)27 

1.38 

1.9044 

2.62807 

1.17473 

3.71484 

.11334 

2.39861 

5.16765 

.724638 

1.39 

1.9321 

2.68562 

1.17898 

3.72827 

.11602 

2.40439 

5.18010 

.719425 

1.40 

1.9600 

2.74400 

1.18322 

3.74166 

.11869 

2.41014 

5.19249 

.714286 

1.41 

1.9881 

2.80322 

1.18743 

3.75500 

.12135 

2.41587 

5.20483 

.709220 

1.42 

2.0164 

2.86329 

1.19164 

3.76829 

.12399 

2.42156 

5.21710 

.704225 

1.43 

2.0449 

2.92421 

1.19583 

3.78153 

.12662 

2.42724 

5.22932 

.699301 

1.44 

2.0736 

2.98598 

1.20000 

3.79473 

.12924 

2.43288 

5.24148 

.694444 

1.45 

2.1025 

3.04863 

1.20416 

3.80789 

.13185 

2.43850 

5.25359 

.689655 

1.46 

2.1316 

3.11214 

1.20830 

3.82099 

.13445 

2.44409 

5.26564 

.684932 

1.47 

2.1609 

3.17652 

1.21244 

3.83406 

.13703 

2.44966 

5.27763 

.680272 

1.48 

2.1904 

3.24179 

1.21655 

3.84708 

.13960 

2.45520 

5.28957 

.675676 

1.49 

2.2201 

3.30795 

1.22066 

3.86005 

.14216 

2.46072 

5.30146 

.671141 

1.50 

2.2500 

3.37500 

1.22474 

3.87298 

.14471 

2.46621 

5.31329 

.666667 

12 


MATHEMATICS 


n 

n« 

7l3 

•VE 

^llQn 

<» 

•ft(r» 

^100  n 

1 

n 

1.51 

2.2801 

3.44295 

1.22882 

3.88587 

1.14725 

2.47168 

5.32507 

.662252 

1.52 

2.3104 

3.51181 

1.23288  3.89872 

1.14978 

2.47713 

5.33680 

.657895 

1.53 

2.3409 

3.58158 

1.23693  3.91152 

1.15230 

2.48255 

5.34848 

.653595 

1.54 

2.3716 

3.65226 

1.24097  3.92428 

1.15480 

2.48794 

5.36011 

.649351 

1.55 

2.4025 

3.72388 

1.24499  3.93700 

1.15729 

2.49332 

5.37169 

.645161 

1.56 

2.4336 

3.79642 

1.24900  3.94968 

1.15978 

2.49866 

5.38321 

.641026 

1.57 

2.4649 

3.86989 

1.25300  3.96232 

1.16225 

2.50399 

5.39469 

.636943 

1.58 

2,1964 

3.94431 

1.25698 

3.97492 

1.16471 

2.50930 

5.40612 

.632911 

1.59 

2.5281 

4.01968 

1.26095 

3.98748 

1.16717 

2.51458 

5.41750 

.62x931 

1.60 

2.5600 

4.09600 

1.26491 

4.00000 

1.16961 

2.51984 

5.42884 

.625000 

1.61 

2.5921 

4.17328 

1.26886 

4.01248 

1.17204 

2.52508 

5.44012 

.621118 

1.62 

2.6244 

4.25153J 

1.27279 

4.02492 

1.17446 

2.53030 

5.45136 

.617264 

1.63 

2.6569 

4.33075 

1.27671 

4.03733 

1.17687 

2.53549 

5.46256 

.613497 

1.64 

2.6896 

4.41094 

1.28062 

4.04969 

1.17927 

2.54067 

5.47370 

.609756 

1.65 

2.7225 

4.49213 

1.28452 

4.06202 

1.18167 

2.54582 

5.48481 

.606061 

1.66 

2.7556 

4.57430 

1.28841 

4.07431 

1.18405 

2.55095 

5.49586 

.602410 

1.67 

2.7889 

4.65746 

1.29228 

4.08656 

1.18642 

2.55607 

5.50688 

.598802 

1.68 

2.8224 

4.74163 

1.29615 

4.09878 

1.18878 

2.56116 

5.51785 

.595238 

1.69 

2.8561 

4.82681 

l.SOOOO 

4.11096 

1.19114 

2.5H623 

5.52877 

.591716 

1.70 

2.8900 

4.91300 

1.30384 

4.12311 

1.19348 

2.57126 

5.53966 

.588235 

1.71 

2.9241 

5.00021 

1.30767 

4.13521 

1.19582 

2.57631 

5.55050 

.584795 

1.72 

2.9584 

5.0x845 

1.31149 

4.14729 

1.19815 

2.58133 

5.56130 

.581395 

1.73 

2.9929 

5.17772 

1.31529 

4.15933 

1.20046 

2.5x632 

5.57205 

.578035 

1.74 

3.0276 

5.26802 

1.31909 

4.17133 

1.20277 

2.59129 

5.58277 

.574713 

1.75 

3.0625 

5.35938 

1.32288 

4.18330 

1.20507 

2.59625 

5.59344 

.571429 

1.76 

3.0976 

5.45178 

1.32665 

4.19524 

1.20736 

2.60118 

5.60408 

.568182 

1.77 

3.1329 

5.54523 

1.33041 

4.20714 

i.-jo'.mi 

2.60610 

5.61467 

.564972 

1.78 

3.1684 

5.63975 

1.33417 

4.21900 

1.21192 

2.61100 

5.62523 

.561798 

1.79 

3.2041 

5.73534 

1.33791 

4.23084 

1.21418 

2.61588 

5.63574 

.558659 

1.80 

3.2400 

5.83200 

1.34164 

4.24264 

1.21644 

2.62074 

5.6462J 

.555556 

1.81 

3.2761 

5.92974 

1.34536 

4.25441 

1.21869 

2.62558 

5.65665 

.552486 

1.82 

3.3124 

6.02857 

1.34907 

4.26615 

1.22093 

2.63041 

5.66705 

.549451 

1.83 

3.3489 

5.13849 

1.35277 

4.27785 

1.22316 

2.63522 

5.67741 

.546448 

1.84 

3.3856 

6.22950 

1.35647 

4.28952 

1.22539 

2.64001 

5.68773 

.643478 

1.85 

3.4225 

6.33163 

1.36015 

4.30116 

1.22760 

2.64479 

5.69802 

.540541 

1.86 

3.4596 

6.43486 

1.36382 

4.31277 

1.22981 

2.64954 

5.70827 

.537634 

1.87 

3.4969 

6.53920 

1.36748 

4.32435 

1.23201 

2.65428 

5.71848 

.534759 

1.88 

3.5344 

6.64467 

1.37113 

4.33590 

1  .23420 

2.65900 

5.  72*65 

.531915 

1.89 

3.5721 

6.76127 

1.37477 

4.34741 

1.23639 

2.66371 

5.73879 

.529101 

1.90 

3.6100 

6.85900 

1.37840 

4.35890 

1.23856 

2.66840 

5.74890 

.526316 

1.91 

3.6481 

6.96787 

1.38203 

4.37035 

1  .24073 

2.67307 

5.75897 

.523560 

1.92 

:j.68C>4 

7.0778'J 

1.3*564 

4.38178 

1.242x9 

2.67773 

5.76900 

.520833 

1.93 

3.7249 

7.18906 

1.38924 

4.39318 

1.24505 

2.68237 

5.77900 

.518135 

1.94 

3.7636 

7.30138 

1  .39284 

4.40454 

1.24719 

2.68700 

6.78896 

.515464 

1.95 

3.8025 

7.41488 

1.39642 

4.41588 

1.24933 

2.69161 

5.79889 

.512821 

1.96 

3.8416 

7.52954 

1.40000 

4.42719 

1.25146 

2.69620 

5.80879 

.510204 

1.97 

3.8809 

7.64537 

1.40357 

4.4:tx47 

1.25359 

2.70078 

5.81865 

.507614 

1.98 

3.9204 

7.76239 

1.40712 

4.44972 

1.25571 

2.70534 

5.82848 

.505051 

1.99 

3.9601 

7.8*060 

1.41067 

4.46094 

1.25782 

2.70989 

5.83827 

.502513 

2.00 

4.0000 

8.00000 

1.41421 

4.47214 

1.25992 

2.71442 

5.84804 

.500000 

MA  THEM  A  TICS 


13 


n 

7*2 

«3 

V^ 

VlOn 

\tt 

$Wn 

-%100n 

1 
71 

2.01 

4.0401 

8.12060 

1.41774 

4.48330 

1.26202 

2.71893 

5.85777 

.497512 

2.02 

4.0804 

8.24241 

142127 

4.49444  1.26411  2.72343  5.86746 

.495050 

2.03 

4.1209 

8.36543 

1.42478  4.50555  1.26619  ,  2.72792  5.87713 

.492611 

2.04 

4.1616 

8.48966 

1.42829  4.51664 

1.26827  2.73239  5.88677  1  .490196 

2.05 

4.2025 

8.61513 

1.43178 

4.52769 

1.27033 

2.73685  5.89637  j  .487805 

2.06 

4.2436 

8.74182 

1.43527 

4.53872 

1.27240 

2.74129  5.90594  .485437 

2.07 

4.2849 

8.86974 

1.43875 

4.54973 

1.27445 

2.74572  5.91548  .483092 

2.08 

4.3264 

8.99891 

1.44222 

4.56070 

1.27650 

2.75014  5.92499  .-JN'T*;!* 

2.09 

4.3681 

9.12933 

1.44568 

4.57165 

1.27854 

2.75454  5.93447  .478*69 

2.10 

4.4100 

9.26100 

1.44914 

4.58258 

1.28058 

2.75893 

5.94392 

.476191 

2.11 

4.4521 

9.39393 

1.45258 

4.59347 

1.28261 

2.76330 

5.95334 

.473934 

2.12 

4.4944 

9.52813 

1.45602 

4.60435 

1.28463 

2.76766 

5.9H273 

.471698 

2.13 

4.5369 

9.66360 

1.45945 

4.61519 

1.28665 

2.77200  i  5.97209 

.469484 

2.H 

4.5796 

9.80034 

1.46287 

4.62601 

1.28866 

2.77633  5.98142 

.467290 

2.15 

4.6225 

9.93838 

1.46629 

4.63681 

1  .29066 

2.78065  5.99073 

.465116 

2.16 

4.6656 

10.0777 

1.46969 

4.64758 

1.29266 

2.78495  I  6.00000 

.462963 

2.  IT 

4.7089 

10.2183 

1.47309 

4.65833 

1.29465 

2.78924  .  6.00925 

.460830 

2.18 

4.7524 

10.3602 

1.47648 

4.66905 

1.29664 

2.79352  !  6.01846 

.458716 

2.19 

4.79K1 

10.5035 

1.47986 

4.67974 

1.29862 

2.79779 

6.02765 

.456621 

2.20 

4.8400 

10.6480 

1.48324 

4.69042 

1.30059 

2.80204 

6.03681 

.454546 

2.21 

4.8841 

10.7939 

1.48661 

4.70106 

1.30256 

2.80628 

6.04594 

.452489 

2.22 

4.9*84 

10.9410 

1  .48997 

4.71169 

1.30452 

2.81051 

6.05505 

.450451 

2.23 

4.9729 

11.0896 

1.49332 

4.72229 

1.30648 

2.81472 

6.06413 

.448431 

2.24 

5.0176 

11.2394 

1.49666 

4.73286 

1.30843 

2.81892 

6.07318 

.446429 

2.25 

5.0625 

11.3906 

1.50000 

4.74342 

1.31037 

2.82311 

6.08220 

.444444 

2.26 

5.1076 

11.5432 

1.50333 

4.75395 

1.31231  !  2.82728 

6.09120 

.442478 

2.27 

5.1529 

11.6971 

1.50665 

4.76445 

1.31424  ;  2.83145 

6.10017 

.440529 

2.28 

5.1984 

11.8524 

1.50997 

4.77493 

1.31617  2.83560 

6.10911 

.438597 

2.29 

5.2441 

12.0090 

1.51327 

4.78539 

1.31809 

2.83974 

6.11803 

.436681 

2.30 

5.2900 

12.1670 

1.51658 

4.79583 

1.32001 

2.84387 

6.12693 

.434783 

2.31 

5.3361 

12.3264 

1.51987 

4.80625 

1.32192 

2.84798 

6.13579 

.432900 

2.32 

5.3824 

12.4872 

1.52315 

4.81664 

1.32382 

2.85209 

6.14463 

.431035 

2.33 

5.4289 

12.6493 

1.52643 

4.82701 

1.32572 

2.85618 

6.15345 

.429185 

2.34 

5.4756 

12.8129 

1.52971 

4.83735 

1.32761 

2.86026 

6.16224 

.427350 

2.35 

5.5225 

12.9779 

1.53297 

4.84768 

1.32950 

2.86433 

6.17101 

.425532 

2.36 

5.5696 

13.1443 

1.53623 

4.85798 

1.33139 

2.86838 

6.17975 

.423729 

2.37 

5.6169 

13.3121 

1.53948 

4.86826 

1  .33326 

2.87243 

6.18846 

.421941 

2.38 

5.6644 

13.4813 

1.54272 

4.87852 

1.33514 

2.87646 

6.19715 

.420168 

2.39 

5.7121 

13.6519 

1.545% 

4.88876 

1.33700 

2.88049 

6.20582 

.418410 

2.40 

5.7600 

13.8240 

1.54919 

4.89898 

1.33887 

2.88450 

6.21447 

.416667 

2.41 

5.8081 

13.9975 

1.55242 

4.90918 

1.34072 

2.88850 

6.22308 

.414938 

2.42 

5.8564 

14.1725 

1.55563 

4.91935 

1.34257 

2.89249 

6.23168 

.413223 

243 

5.9049 

14.3489 

1.55885 

4.92950 

1.34442 

2.89647 

6.24025 

.411523 

2.44 

5.9536 

14.5268 

1.56205 

4.93964 

1.34626 

2.90044 

6.24880 

.409836 

2.45 

6.0025 

14.7061 

1.56525 

4.94975 

1.34810 

2.90439 

6.25732 

.408163 

2.46 

6.0516 

14.8869 

1.56844 

4.95984 

1.34993 

2.90834 

6.26583 

.406504 

2.47 

6.1009 

15.0692 

1.57162 

4.96991 

1.35176 

2.91227 

6.27431 

.404858 

2.48 

6.1504 

15.2530 

1.57480 

4.97996 

1.35358 

2.91620 

6.28276 

.403226 

2.49 

6.2001 

15.4382 

1.57797 

4.98999 

1.35540 

2.92011 

6.29119 

.401606 

2.50 

6.2500 

15.6250 

1.58114 

5.00000 

1.35721 

2.92402 

6.29961 

.400000 

MATHEMATICS 


n 

n* 

|  rcs 

V^ 

VlOM    >« 

^TOnkfOOn   *- 

2.51 

6.3001 

15.8133 

1.58430 

5.00999  1.35902 

2.92791 

6.30799 

.398406 

2.52 

6.3504 

16.0030 

1.58745 

5.019%  1.36082 

2.93179 

6.31636 

.396825 

2.53 

6.4009 

16.1943 

1.59060 

5.02991  1.36262  2.93567 

6.32470 

.395257 

254 

6.4516 

1  16.3871  1.59374 

5.03984  1.36441  2.93953  6.33303 

.393701 

2.55 

6.5025 

!  16.5814 

5.04975  1.36620  2.94338 

6.34133 

.392157 

2.56 

6.5536 

16.7772  1.60000 

.Vor.'.ir.l  1.36798 

2.94723  6.34960 

.390625 

2.57 

6.6049 

16.9746 

1.60312 

5.0(i!»ri2  1.36976 

2.95106 

«.35786 

.389105 

2.58 

6.6564 

17.1735 

1.60624 

5.D7937  1.37153  2.9.'.»>s 

6.36610 

.387597 

2.59 

6.7081 

17.3740 

1.60935 

5.08920  1.37330 

2.95869 

6.37431 

.386100 

2.60 

6.7600 

j  17.5760 

1.61245 

5.09902  1.37J07 

2.96250 

6.38250 

.384615 

2.61 

6.8121 

i  17.7796 

1.61555 

5.10882 

1.37683  2.96629 

6.39068 

.383142 

2.62 

6.8644 

17.9*47  1.6I>61 

5.  11  -.",9  1.37*59  2.97007 

6.39883 

.381679 

2.63 

6.9169 

If.  1914  1.62173 

f,.l-j-:t:,  1  .3-11:14  2.97385 

6.40696 

.380228 

2.64 

6.9696 

18.8W7 

1.62481 

5.13*09  1.38208  2.97761 

6.41507 

.378788 

2.65 

7.0225 

18.6096 

1.62788 

5.14782 

1.38383 

2.98137 

6.42316 

.377359 

2.66 

7.0756 

18.8211 

1.63095 

5.15752 

1.38557 

2.98511 

6.43123 

.375940 

2.67 

7.1289 

19.0342 

1.63401 

5.16720 

1.38730 

2.98885 

6.43928 

.374532 

2.68 

7.1824 

19.2488 

1.63707 

5.17687 

1.38903 

2.99257 

6.44731 

.373134 

2.69 

7.2361 

19.4651 

1.64012 

5.18652 

1.39076 

2.99629 

6.45531 

.371747 

2.70 

7.2900 

19.6830 

1.64317 

5.19615 

1.39248 

3.00000 

6.46330 

.370370 

2.71 

7.3441 

19.9025 

1.64621 

5.20577 

1.39419 

3.00370 

6.47127 

.369004 

2.72 

7.3984 

20.1236  t  1.64924 

5.21536 

l  .:w:>9i 

3.00739 

6.47922 

.367647 

2.73 

7.4529 

20.3464  1.65227 

5.22494 

1.39761 

3.01107 

6.48715 

.366300 

2.74 

7.5076 

20.5708  1.65529 

5.23450 

1.39932 

3.01474 

6.49507 

.364964 

2.75 

7.5625 

20.7969  1.65831 

5.24404 

1.40102 

3.01841 

6.50296 

.363636 

2.76 

7.6176 

21.0246 

1.66132 

5.25357 

1.40272 

3.02206 

6.51083 

.362319 

2.77 

7.6729 

21.2539  1.60433 

5.26308 

1.40141 

3.02571 

6.51X68 

.361011 

2.78 

7.7284 

21.4850  1.66733 

5.27257 

1.40610 

3.02934 

6.52652 

.359712 

3.79 

7.7841 

21.7176  1  1.67033 

5.28205 

1.40778 

3.03297 

6.53434 

.358423 

2.80 

7.8400 

21.9520 

1.67332 

5.29150 

1.40946 

3.03639 

6.54213 

.357142 

2.81 

7.8961 

22.1880 

1.67631 

5.30094 

1.41114 

3.04020 

6.54991 

.355872 

2.82 

7.9.VJ4 

22.4258 

1.67929 

5.31037 

1.41281 

3.04380 

6.55767 

.354610 

2.83 

8.0089 

22.6652 

1.68226 

5.31977 

1.41448 

3.04740 

6.56541 

.353357 

2.84 

8.0656 

22.9063 

1.68523 

5.32917 

1.41614 

8.00096 

6.57314 

.352113 

2.85 

8.1225 

23.1491 

1.  68*19 

5.33854 

1.41780 

3.05456 

6.58084 

.350877 

2.86 

8.1796 

23.3937 

1.69115 

5.34790 

1.41946 

3.05813 

6.58853 

.349650 

•2  -7 

23.0399 

1.69411 

5.35724 

1.42111 

3.116169 

6.59620 

.3IM32 

2.88 

8.2944 

23.8879 

1.0*706 

:,.:t66:><; 

1  .42276 

3.06524 

660385 

2.89 

8.3521 

24.1376 

1.70000 

1.42440 

8.06878 

6.61149 

.3461)21 

2.90 

8.4100 

24.3890 

1.70294 

5.38516 

1.42604 

3.07232 

6.61911 

2.91 

8.4681 

24.6422 

1.70587 

5.39444 

1.42768 

3.07585 

6.62671 

.343643 

2.92 

8.5264 

24.6971 

1.70880 

5.40370 

1.42931 

3.07936 

6.63429 

.342466 

2.93 
2.94 

8.5849 
8.6436 

25.1538 
25.4122 

1.71172 
1.71464 

5.41295 
5.42218 

1.43094 
1.43257 

3.08287  6.64185 
3.08638  I  6.64940 

.341297 
.340136 

3.95 

8.7025 

25.6724 

1.71756 

5.43139 

1.43419 

3.08987 

6.65693 

.338983 

2.96 

8.7616 

25.9343 

1.72047 

5.44059 

1.43581 

3.09336 

6.66444 

.337838 

2.97 

S.H2II9 

26.1981  1.72337 

5.44077 

1.43743 

3.09684  6.67194 

.336700 

2.98 

8.HHH 

26.4684  1.72627 

;'i  4T.-9I   1.43904  3.10031  6.67942  .335571 

299 

8.9401 

l,7-'!l]f, 

5.46809  1.44065  3.10378  6.68688  .334448 

9.00 

9.1HMMI 

1  73205 

5.47723  1.44225  3.10723  6.69433  .333333 

MA  THEM  A  TICS 


15 


n 

«2 

n» 

<& 

VIow 

«! 

Wn 

•^100  n 

JL 

n 

3.01 

9.0601 

27.2709 

1.73494  5.48635 

1.44385 

3.11068 

6.70176 

.332226 

3.02 

9.1204 

27.5436 

1.73781  5.49545 

1.44545 

3.11412 

6.70917 

.331126 

8.03 

9.1809 

27.8181 

1.74069 

5.50454 

1.44704 

3.11755 

6.71657 

.330033 

3.04 

9.2416 

28.0945 

1.74356 

5.51362 

1.44863 

3.12098 

6.72395 

.328947 

S.05 

9.3025 

28.3726 

1.74642 

5.52268 

1  45022 

3.12440 

6.73132 

.327869 

8.06 

9.3636 

28.6526 

1.74929  5.53173 

1.45180 

3.12781 

6.73866 

.326797 

3.07 

9.4249 

28.9344 

1.75214 

5.54076 

1.45338 

3.13121 

6.74600 

.325733 

3.08 

9.4864 

29.2181 

1.75499 

5.54977 

1.45496 

3.13461 

6.75331 

.324675 

8.09 

9.5481 

29.5036 

1.75784 

5.55878 

1.45653 

3.13800 

6.76061 

.323625 

S.10 

9.6100 

29.7910 

1.76068 

5.56776 

1.45810 

3.14138 

6.76790 

.322581 

8.11 

9.6721 

30.0802 

1.76352 

5.57674 

1.45967 

3.14475 

6.77517 

.32154* 

3.12 

9.7344 

30.3713 

1.76635 

5.58570 

1.46123 

3.14812 

6.78242 

.320513 

3.13 

9.7969 

30.6643 

1.76918 

5.59464 

1.46279 

3.15148 

6.78966 

.319489 

3.H 

9.8596 

30.9591 

1.77200 

5.60357 

1.46434 

3.15484 

6.79688 

.318471 

3.15 

9.9225 

31.2559 

1.77482 

5.61249 

1.46590 

3.15818 

6.80409 

.317460 

3.16 

9.9856 

31.5545 

1.77764 

5.62139 

1.46745 

3.16152 

6.81  28 

.316456 

8.17 

10.0489 

31.8550 

1.78045 

5.03028 

1.46899 

3.16485 

6.81846 

.315457 

8.18 

10.1124 

32.1574 

1.78326 

5.63915 

1.47054 

3.16817 

6.82562 

.314465 

8.19 

10.1761 

32.4618 

1.78606 

5.64801 

1.47208 

3.17149 

6.83277 

.313480 

8.20 

10.2400 

32.7680 

1.78885 

5.65685 

1.47361 

3.17480 

6.83990 

.312500 

8.21 

10.3041 

33.0762 

1.79165 

5.66569 

1.47515 

3.17811 

6.84702 

.311527 

8.22 

10.3684 

33.3862 

1.79444 

5.67450 

1.47668 

3.18140 

6.85412 

.310559 

8.23 

10.4329 

33.6983 

1.79722 

5.68331 

1.47820 

3,18469 

6.86121 

.30959& 

3.24 

10.4976 

34.0122 

1.80000 

5.69210 

1.47973 

3.18798 

6.86829 

.308642 

8.25 

10.5625 

34.3281 

1.80278 

5.70088 

1.48125 

3.19125 

6.87534 

.307692 

8.26 

10.6276 

34.6460 

1.80555 

5.70964 

1.48277 

3.19452 

6.88239 

.306749 

8.27 

10.6929 

34.9658 

1.80831 

5.71839 

1.48428 

3.19779 

6.88942 

.305810 

3.28 

10.7584 

35.2876 

1.81108 

5.72713 

1.48579 

3.20104 

6.89643 

.304878 

3.29 

10.8241 

35.6129 

1.81384 

5.73585 

1.48730 

3.20429 

6.90344 

.303951 

8.30 

10.8900 

35.9370 

1.81659 

5.74456 

1.48881 

3.20753 

6.91042 

.303030 

8.31 

10.9561 

36.2647 

1.81934 

5.75326 

1.49031 

3.21077 

6.91740 

.302115 

3.32 

11.0224 

36.5944 

1.82209 

5.76194 

1.49181 

3.21400 

6.92436 

.301205 

3.33 

11.0889 

36.9260 

1.82483 

5.77062 

1.49330 

3.21723 

6.93130 

.300300 

8.34 

11.1556 

37.2597 

1.82757 

5.77927 

1.49480 

3.22044 

6.93823 

.299401 

8.35 

11.2225 

37.5954 

1.83030 

5.78792 

1.49629 

3.22365 

6.94515 

.29850& 

3.36 

11.2896 

37.9331 

1.83303 

5.79655 

1.49777 

3.22636 

6.95205 

.297619 

8.37 

11.3569 

38.2728 

1.83576 

5.80517 

1.49926 

3.23005 

ti.95894 

.296735 

8.38 

11.4244 

38.6145 

1.83848 

5.81378 

1.50074 

3.23325 

6.90582 

.295853 

3.39 

11.4921 

38.9582 

1.84120 

5.82237 

1.50222 

3.23643 

6.97268 

.294985 

3.40 

11.5600 

39.3040 

1.84391 

5.83095 

1.50369 

3.23961 

6.97953 

.294118 

8.41 

11.6281 

39.6518 

1.84662 

5.83952 

1.50517 

3.24278 

6.98637 

.293255 

8.42 

11.6964 

40.0017 

1.84932 

5.84808 

1.50664 

3.24595 

6.99319 

.292398 

8.43 

11.7649 

40.3536 

1.85203 

5.85662 

1.50810 

3.24911 

7.00000 

.29154I> 

844 

11.8336 

40.7076 

1.85472 

5.86515 

1.50957 

3.25227 

7.00680 

.29069S 

8.45 

11.9025 

41.0636 

1.85742 

5.87367 

1.51103 

3.25542 

7.01358 

289855 

8.46 

11.9716 

41.4217 

1.86011 

5.88218 

1.51249 

3.25856 

7.02035 

.289017 

8.47 

12.0409 

41.7819 

1.86279 

5.89067 

1.51394 

3.26169 

7.02711 

.288184 

8.48 

12.1104 

42.1442 

1  .86548 

5.89915 

1.51540 

3.26482 

7.03385 

.287356 

8.49 

12.1801 

42.5085 

1.86815  1  5.90762 

1.51685 

3.26795 

7.04058 

.286533 

3.50 

12.2500 

42.8750 

1.87083  5.91608 

1.51829 

3.27107 

7.04730 

.285714 

16 


MATHEMATICS 


n 

7»2 

W3 

^ 

VlOn 

*s 

•<flOn 

•^Too.n 

1 

n 

3.51 

12.3201 

43.2436 

1.87350 

5.92453 

1.51974 

3.27418 

7.05400 

.284900 

3.52 

12.3904 

43.6142 

1.87617 

5.932% 

1.52118 

3.27729 

7.06070 

.284091 

3.53 

12.4609 

43.9870 

1.87883 

5.94138 

1.52262 

3.28039 

7.06738 

.283286 

3.54 

12.5316 

44.3619 

1.88149 

5.94979 

1.52406 

3.28348 

7.07404 

.282486 

3.55 

12.6025 

44.7389 

1.88414 

5.95819 

1.52549 

3.28657 

7.08070 

.281690 

3.56 

12.6736 

45.1180 

1.88680 

5.96657 

1.52692 

3.28965 

7.08734 

.280809 

3.57 

12.7449 

45.4993 

1.88944 

5.97495 

1.52835 

3.29273 

7.09397 

.280112 

3.58 

12.8164 

45.8827 

1.89209 

5.98331 

1.52978 

3.29580 

7.10059 

.279330 

3.59 

12.8881 

46.2683 

1.89*73 

5.99166 

1.53120 

3.29887 

7.10719 

.278552 

3.60 

12.9600 

46.6560 

1.89737 

6.00000 

1.53262 

3.3019S 

7.11379 

.277778 

3.61 

13.0321 

47.0459 

1.90000 

6.00833 

1.53404 

3.30498 

7.12037 

.277008 

3.62 

13.1044 

47.4379 

1.90263 

6.01664 

1.53545 

3.30803 

7.12694 

.276243 

3.63 

13.1769 

47.8321 

1.90526 

6.02495 

1.53686 

3.31107 

7.13349 

.275482 

3.64 

13.2496 

48.2285 

1.90788 

6.03324 

1.53827 

3.31411 

7.14004 

.274725 

3.65 

13.3225 

48.6271 

1.91050 

6.04152 

1.53968 

3.31714 

7.14657 

.273973 

3.66 

13.3956 

49.0279 

1.91311 

6.04979 

1.54109 

3.32017 

7.15309 

.273224 

3.67 

13.46*9 

49.4309 

1.91572 

ti.OSHOi, 

1.54249 

3.32319 

7.15960 

.272480 

3.68 

13.5424 

49.8360 

1.91833 

6.06630 

1.54389 

3.32621 

7.16610 

.271739 

3.69 

13.6161 

50.2434 

1.92094 

6.07454 

1.54529 

3.32922 

7.17258 

.271003 

3.70 

13.6900 

50.6530 

1.92354 

6.08276 

1.54668 

3.33222 

7.17905 

.270270 

3.71 

13.7641 

51.0648 

1.92614 

6.09098 

1.54807 

3.33522 

7.18552 

.269542 

3.72 

13.8384 

51.4788 

1.92873 

6.09918 

1.54946 

3.33822 

7.19197 

.268817 

3.73 

13.9129 

51.8951 

1.93132 

6.10737 

1.55085 

3.34120 

7.19841 

.268097 

3.74 

13.9876 

52.3136 

1.93391 

6.11555 

1.55223 

3.34419 

7.20483 

.267380 

3.75 

14.0625 

52.7344 

1.93649 

6.12372 

1.55362 

3.34716 

7.21125 

.266667 

3.76 

14.1376 

53.1574 

1.93907 

6.13188 

1.55500 

3.35014 

7.21765 

.265957 

3.77 

14.2129 

53.5826 

1.94165 

6.14003 

1.55637 

3.35310 

7.22405 

.265252 

3.78 

14.2884 

54.0102 

1.94422 

6.14817 

1.55775 

3.35607 

7.23043 

.264550 

3.79 

14.3H41 

54.4399 

1.94679 

6.15630 

1.55912 

3.35902 

7.23680 

.263852 

3.80 

14.4400 

54.8720 

1.94936 

6.16441 

1.56049 

3.36198 

7.24316 

.263158 

3.81 

14.5161 

55.3063 

1.95192 

6.17252 

1.56186 

3.36492 

7.24950 

.262467 

3.82 

14.5924 

55.7430 

1.95448 

6.18061 

1.56322 

3.36786 

7.25584 

.261780 

3.83 

14.6689 

56.1819 

1.95704 

6.18870 

1.56459 

3.37080 

7.26217 

.261097 

3.84 

14.7456 

56.6231 

1.95959 

6.19677 

1.56595 

3.37373 

7.26848 

.260417 

3.85 

14.8225 

57.0666 

1.96214 

6.20484 

1.56731 

3.37666 

7.27479 

.259740 

3.86 

14.8996 

57.5125 

1.96469 

6.21289 

1.56866 

3.37958 

7.28108 

.259067 

3.87 

14.9769 

57.96(16 

1.96723 

6.22093 

1.57001 

3.3H249 

7.28736 

.258393 

3.88 

15.0544 

58.4111 

l.'.lii'.lTi 

6.22H96 

1.57137 

3.38540 

7.29363 

.257732 

3.89 

15.1321 

5.1  8639 

1.97231 

6.23699 

1.57271 

3.38831 

7.29989 

.257069 

3.90 

15.2100 

59.3190 

1.97484 

6.24500 

1.57406 

3.39121 

7.30614 

.256410 

3.91 

15.2881 

59.7765 

1.97737 

6.25300 

1.57541 

3.39411 

7.31238 

.255755 

392 

15.3664 

fio.2:ifi3 

1.97990 

6.26099 

1.57675 

3.39700 

7.81861 

.255102 

3.93 

15.4449 

fid.  69*5 

1.98242 

C.268JJ7 

1.57809 

3.39988 

7.32483 

.254453 

3.94 

15.5236 

61.1630 

1.98494 

6.27694 

1.57942 

3.40277 

7.33104 

.253807 

3.95 

15.6025 

61.6299 

1.98746 

6.28490 

1.58076 

3.40564 

7.33723 

.253165 

3.96 

15.6816 

62.0991 

1.98997 

6.29285 

1.58209 

3.40851 

7.34342 

.252525 

3.97 

15.7609 

62.5708 

1.99249 

6.30079 

1.58342 

3.41138 

7.34960 

.251889 

3.98 

15.8404 

63.0448 

1.99499 

6.30872 

1.58475 

3.41424 

7.35576 

.251256 

3.99 

15.9201 

63.5212 

1.99750 

6.31664 

1.  5*601 

3.41710 

7.36192 

.250627 

4.00 

16.00W 

64.0000 

2.00000 

6.32456 

1.58740 

3.41995 

7.36806 

.250000 

MATHEMATICS 


17 


n 

712 

n» 

vs 

VlOw 

<i 

-^10  n 

"^lOO  n 

1 

n 

4.01 

16.0301 

64.4812 

2.00250 

6.33246 

1.58872 

3.42280 

7.37420 

.249377 

4.02   16.1604 

64.9648 

2.00499  6.34035  1.59004 

3.42564 

7.38032 

.248756 

4.03   16.2409 

65.4508 

2.00749 

6.34823 

1.59136 

3.42848 

7.38644 

.248139 

4.04   16.3216 

65.9393 

2.0099ft 

6.35610 

1.59267 

3.43131 

7.39254 

.247525 

4.05 

16.4025 

66.4301 

2.01246 

6.36396 

1.59399 

3.43414 

7.39864 

.246914 

4.06 

16.4836 

66.9234 

2.01494 

6.37181 

1.59530 

3.43697 

7.40472 

.246305 

4.07 

16.5649 

67.4191 

2.01742 

6.37966 

1.59661 

3.43979 

7.41080 

.245700 

4.08 

16.6464 

67.9173 

2.01990 

6.38749 

1.59791 

3.44260 

7.41686 

.245098 

4.09 

16.7281 

68.4179 

2.02237 

6.39531 

1.59922 

3.44541 

7.42291 

.244499 

4.10 

16.8100 

68.9210 

2.02485 

6.40312 

1.60052 

3.44822 

7.42896 

.243902 

4.11 

16.8921 

69.4265 

2.02731 

6.41093 

1.60182 

3.45102 

7.43499 

.243309 

4.12 

16.9744 

69.9345 

2.02978 

6.41872 

1.60312 

3.45382 

7.44102 

.242718 

4.13 

17.0569 

70.4450 

2.03224 

6.42651 

1.60441 

3.45661 

7.44703 

.242131 

4.14 

17.1396 

70.9579 

2.03470 

6.43428 

1.60571 

3.45939 

7.45304 

.241546 

4.15 

17.2225 

71.4734 

2.03715 

6.44205 

1.60700 

3.46218 

7.45904 

.240964 

4.16 

17.3056 

71.9913 

2.03961 

6.44981 

1.60829 

3.46496 

7.46502 

.240385 

4.17 

17.3889 

72.5117 

2.04206 

6.45755 

1.60958 

3.46773 

7.47100 

.239808 

4.18 

17.4724 

73.0346 

2.04450 

6.46529 

1.61086 

3.47050 

7.47697 

.239234 

4.19 

17.5561 

73.5601 

2.04695 

6.47302 

1.61215 

3.47327 

7.48292 

.238664 

4.20 

17.6400 

74.0880 

2.04939 

6.48074 

1.61343 

3.47603 

7.48887 

.238095 

4.21 

17.7241 

74.6185 

2.05183 

6.48845 

1.61471 

3.47878 

7.49481 

.237530 

4.22 

17.8084 

75.1514 

2.05426 

6.49615 

1.61599 

3.48154 

7.50074 

.236967 

4.23 

17.8929 

75.6870 

2.05670 

6.50385 

1.61726 

3.48428 

7.50666 

.23640T 

4.24 

17.9776 

76.2250 

2.05913 

6.51153 

1.61853 

3.48703 

7.51257 

.235849 

4.2a 

18.0625 

76.7656 

2.06155 

6.51920 

1.61981 

3.48977 

7.51847 

.235294 

4.26 

18.1476 

77.3088 

2.06398 

6.52687 

1.62108 

3.49250 

7.52437 

.234742 

4.27 

18.2329 

77.8545 

2.06640 

6.53452 

1.62234 

3.49523 

7.53025 

.234192 

4.28 

18.3184 

78.4028 

2.06882 

6.54217 

1.62361 

3.49796 

7.53612 

.233645 

4.29 

18.4041 

78.9536 

2.07123 

6.54981 

1.62487 

3.50068 

7.54199 

.233100 

4.30 

18.4900 

79.5070 

2.07364 

6.55744 

1.62613 

3.50340 

7.54784 

.232558 

4.31 

18.5761 

80.0630 

2.07605 

6.56506 

1.62739 

3.50611 

7.55369 

.232019 

4.32 

18.6624 

80.6216 

2.07846 

6.57267 

1.62865 

3.50882 

7.55953 

.231482 

4.33 

18.7489 

81.1827 

2.08087 

6.58027 

1.62991 

3.51153 

7.56535 

.230947 

4.34 

18.8356 

81.7465 

2.08327 

6.58787 

1.63116 

3.51423 

7.57117 

.230415 

4.35 

18.9225 

82.3129 

2.08567 

6.59545 

1.63241 

3.51692 

7.57698 

.229885 

4.36 

19.0096 

82.8819 

2.08806 

6.60303 

1.63366 

3.51962 

7.58279 

.229358 

4.37 

19.0969 

83.4535 

2.09045 

6.61060 

1.63491 

3.52231 

7.58858 

.228833 

4.38 

19.1844 

84.0277 

2.09284 

6.61816 

1.63616 

3.52499 

7.59436 

.228311 

4.39 

19.2721 

84.6045 

2.09523 

6.62571 

1.63740 

3.52767 

7.60014 

.227790 

4.40 

19.3600 

85.1840 

2.09762 

6.63325 

1.63864 

3.53035 

7.60590 

.227273 

4.41 

19.4481 

85.7661 

2.10000 

6.64078 

1.63988 

3.53302 

7.61166 

.226757 

4.42 

19.5364 

86.3509 

2.10238 

6.64831 

1.64112 

3.53569 

7.61741 

.226244 

4.43 

19.6249 

86.9383 

2.10476 

6.655*2 

1.64236 

3.53835 

7.62315 

.225734 

4.44 

19.7136 

87.5284 

2.10713 

6.66333 

1.64359 

3.54101 

7.82888 

.225225 

4.45 

19.8025 

88.1211 

2.10950 

6.67083 

1.64483 

3.54367 

7.63461 

.224719 

4.46 

19.8916 

88.7165 

2.11187 

6.67832 

1.64606 

3.54632 

7.64032 

.224215 

4.47 

19.9809 

89.3146 

2.11424 

6.68581 

1.64729 

3.54897 

7.64603 

.223714 

4.48 

20.0704 

89.9154 

2.11660 

6.69328 

1.64851 

3.55162 

7.65172 

.223214 

4.49 

20.1601 

90.5188 

2.11896 

6.70075 

1.64974 

3.55426 

7.65741 

.222717 

4.50 

20.2500 

91.1250 

2.12132 

6.70820 

1.65096 

3.55689 

7.66309 

.222222 

\IA  Til  EM  A  TICS 


n 

n2 

7*3 

Vn 

VlOw 

*s 

$Wn 

•ftbOn 

1 

n 

4.51 

20.3401 

91.7339 

2.12368 

6.71565 

1.65219 

3.55953 

7.66877 

.221730 

4.52 

20.4304 

92.3454 

2.12603 

6.72309 

1.65341 

3.56215 

7.67443 

.221239 

4.53 

20.5209 

92.9597 

2.12838 

6.73053 

1.65462 

3.56478 

7.68009 

.220751 

4.54 

20.6116 

93.5767 

2.13073 

6.73795 

1.66684 

3.56740 

.220264 

4.55 

20.7025 

94.1964 

2.13307 

6.74537 

1.65706 

3.57002 

7.69137 

.219780 

4.56 

20.7936 

94.8188 

2.13542 

6.75278 

1.6f)827 

3.57263 

7.69700 

.219298 

4.57 

1'0.884<J 

95.4440 

2.13776 

6.76018 

1.85648 

7.701!62 

.218818 

4.58 

20.9764 

96.0719 

2.14009 

6.76757 

1.66069 

8.57788 

7.70824 

.218341 

4.59 

21.0681 

96.7026 

2.14243 

6.77495 

1.66190 

8.58046 

7.71384 

.217865 

4.60 

21.1600 

97.3360 

2.14476 

6.78233 

1.66310 

3.58305 

7.71944 

.217391 

4.61 

21.2521 

97.9722 

2.14709 

6.78970 

166431 

3.58564 

7.72503 

.216920 

4.62 

21.3444 

98.6111 

2.14942 

6.79706 

1.66551 

3.5*823 

7.73061 

.216450 

4.63 

21.4369 

99.2528 

2.15174 

6.80441 

1.66671 

8.59081 

7.73619 

.215983 

4.64 

21.5296 

99.8973 

2.15407 

6.81175 

1.66791 

3.59340 

7.74175 

.215517 

4.65 

21.6225 

100.545 

2.15639 

6.81909 

1.66911 

3.59598 

7.74731 

.215054 

4.66 

21.7156 

Ml.  195 

2.15870 

6.82642 

1.67030 

3.59856 

7.75286 

.214592 

4.67 

21.8089 

101.848 

2.16102 

6.83374 

1.67150 

3.60113 

7.75840 

.214133 

4.68 

21.9024 

102.503 

2.16333 

6.84105 

1.67269 

3.60370 

7.76394 

.213675 

4.69 

21.9961 

103.162 

2.16564 

6.84836 

1  .67388 

3.60626 

7.76946 

.213220 

4.70 

22.0900 

103.823 

2.16795 

6.85565 

1.67507 

3.60883 

7.77498 

.212766 

4.71 

22.1841 

104.487 

2.17025 

6.86294 

1.67626 

3.61138 

7.78049 

.212314 

4.72 

22.2784 

105.154 

2.17256 

6.87023 

1.67744 

3.61394 

7.78599 

.211864 

4.73 

22.3729 

105.824 

2.17486 

6.87750 

1.67863 

3.61649 

7.79149 

.211417 

4.74 

22.4676 

106.496 

2.17715 

6.88477 

1.67981 

3.61904 

7.79697 

.210971 

4.75 

22.5625 

107.172 

2.17945 

6.89202 

1.68099 

3.62158 

7.80245 

.210526 

4.76 

22.6576 

107.850 

2.18174 

6.  89928 

1.68217 

3.62412 

7.80793 

.210084 

4.77 

22.7529 

108.531 

2.18403 

6.90652 

1.68334 

7.*1339 

.'209644 

4.78 

22.8484 

109.215 

2.1X632 

6.91375 

I.I;-I.Y_> 

3.62919 

7.81885 

.209205 

4.79 

22.9441 

109.902 

2.188ft] 

6.92098 

1  .68569 

3.63171 

7.V2429 

.208768 

4.80 

23.0400 

110.592 

2.11)089 

6.92820 

1.68687 

3.63424 

7.82974 

.208333 

4.81 

23.1361 

111.285 

2.19317 

6.93542 

1.68804 

3.63676 

7.83517 

.207900 

4.82 

23.21124 

111.WO 

2.19545 

6.9  42(12 

1.68WO 

3.63928 

7.84059 

.207469 

4.83 

23.3289 

112.679 

2.19773 

6.94982 

1  .69037 

3.64180 

7.-IC.ill 

4.84 

23.4256 

113.380 

2.20000 

6.95701 

1.69154 

3.64431 

7.85142 

.206612 

4.85 

23.5225 

114.084 

2.20227 

6.96419 

1.69270 

3.64682 

7.85683 

.206186 

4.86 

23.6196 

114.791 

2.20454 

6.97137 

1.69386 

3.64932 

7.86222 

.205761 

4.87 

23.7169 

115.501 

2.206M 

6.97854 

1  .6H503 

3.651M2 

4.88 

23.8144 

116.214 

2.20907 

6.98570 

1.69619 

3.65432 

7.872M 

4.89 

23.IM21 

116.930 

2.21133 

1.697*4 

.204»i.'.» 

4.90 

24.0100 

117.649 

2.21359 

7.00000 

1.69850 

3.65931 

,304081 

4.91 

i4.ua 

IWJ71 

2.21585 

7.00714 

1.69965 

3.66179 

7.88909 

.203666 

4.92 

24.2064 

119.095 

•-'.21-11 

7.01427 

1.70081 

3  66428 

7.89446 

.203252 

fcM 

24.3049 

L19.8M 

2.2203C, 

7.02140 

1.70196 

3.66676 

r.899W 

4.94 

24.4036 

120.554 

2  22261 

7.02851 

1.70311 

3.66924 

7.90513 

.202429 

4.95 

24.5025 

121.287 

2.221*6 

7.03562 

1.70426 

3.67171 

7.91046 

.202020 

4.96 

24.6016 

122.024 

2.22711 

7.04273 

1.70540 

3.67418 

7.91578 

.201613 

4.97 

21.71X19 

2.22935 

7.0  IH-'.' 

3.67665 

7.  !H!  110 

.201207 

4.98 

24.8004 

m.506 

2.23159 

7.05691 

1.70769 

3.67911 

7.92641 

.200803 

4.99 

21.90U1 

7.06399 

1.70--4 

3.68157 

7J8171 

.200401 

5.00 

25.0000 

125.000 

2.23607 

7.07107 

1.76998 

3.6x403 

7.93701 

.200000 

MA  THEM  A  TICS 


19 


n 

n2 

n* 

\« 

•VfiTn 

C 

•SllOn 

•9lOO« 

1 

n 

5.01 

25.1001 

125.752 

2.23830 

7.07814 

1.71112 

3.68649 

7.94229 

.199601 

5.02 

25.2004 

126.506 

2.24054 

7.08520 

1.71225 

3.68894 

7.94757 

.199203 

5.03 

25.3009 

127.264 

2.24277 

7.09225 

1.71339 

3.69138 

7.95285 

.198807 

5.04 

25.4016 

128.024 

2.24499 

7.09930 

1.71452 

3.69383 

7.95811 

.198413 

5.05 

25.5025 

128.788 

2.24722 

7.10634 

1.71566 

3.69627 

7.96337 

.198020 

5.06 

25.6036 

129.554 

2.24944 

7.11337 

1.71679 

3.69871 

7.96863 

.197629 

5.07 

25.7049 

130.324 

2.25167 

7.12039 

1.71792 

3.70114 

7.97387 

.197239 

5.08 

25.8064 

131.097 

2.25389 

7.12741 

1.71905 

3.70358 

7.97911 

.196850 

5.09 

25.9081 

131.872 

2.25610 

7.13442 

1.72017 

3.70600 

7.98434 

.196464 

5.10 

26.0100 

132.651 

2.25832 

7.14143 

1.72130 

3.70843 

7.98957 

.196078 

5.11 

26.1121 

133.433 

2.26053 

7.14843 

1.72242 

3.71085 

7.99479 

.195695 

5.12 

26.2144 

134.218 

2,26274 

7.15542 

1.72355 

3.71327 

8.00000 

.195313 

5.13 

26.3169 

135.006 

2.26495 

7.16240 

1.72467 

3.71566 

8.00520 

.194932 

5.14 

26.4196 

135.797 

2.26716 

7.16938 

1.72579 

3.7181C 

8.01040 

.194553 

5.15 

26.5225 

136.591 

2.26936 

7.17635 

1.72691 

3.72051 

8.01559 

.194175 

5.16 

26.6256 

137.388 

2.27156 

7.18331 

1.72802 

3.72292 

8.02078 

.193798 

5.17 

26.7289 

138.188 

2.27376 

7.19027 

1.72914 

3.72532 

8.02596 

.193424 

5.18 

26.8324 

138.992 

2.27596 

7.19722 

1.73025 

3.72772 

8.03113 

.193050 

5.19 

26.9361 

139.798 

2.27816 

7.20417 

1.73137 

3.73012 

8.03629 

.192678 

5.20 

27.0400 

140.608 

2.28035 

7.21110 

1.73248 

3.73251 

8.04145 

.192308 

5.21 

27.1441 

141.421 

2.28254 

7.21803 

1.73359 

3.73490 

8.04660 

.191939 

5.22 

27.2484 

142.237 

2.28473 

7.22496 

1.73470 

3.73729 

8.05175 

.191571 

5.23 

27.3529 

143.056 

2.28692 

7.23187 

1.73580 

3.73968 

8.05689 

.191205 

5.24 

27.4576 

143.878 

2.28910 

7.23878 

1.73691 

3.74206 

8.06202 

.190840 

5.25 

27.5625 

144.703 

2.29129 

7.24569 

1.73801 

3.74443 

8.06714 

.190476 

5.26 

27.6676 

145.532 

2.29347 

7.25259 

1.73912 

3.74681 

8.07226 

.190114 

5.27 

27.7729 

146.363 

2.29565 

7.25948 

1.74022 

3.74918 

8.07737 

.189753 

5.28 

27.8784 

147.198 

2.29783 

7.26636 

1.74132 

3.75158 

8.08248 

.189394 

5.29 

27.9841 

148.036 

2.30000 

7.27324 

1.74242 

3.',5392 

8.08758 

.189036 

5.30 

28.0900 

148.877 

2.30217 

7.28011 

1.74351 

3.75629 

8.09267 

.188679 

5.31 

28.1961 

149.721 

2.30434 

7.28697 

1.74461 

3.75865 

8.09776 

.188324 

5.32 

28.3024 

150.569 

2.30651 

7.29383 

1.74570 

3.76100 

8.10284 

.187970 

5.33 

28.4089 

151.419 

2.30868 

7.30068 

1.74680 

3.76336 

8.10791 

.187617 

5.34 

28.5156 

152.273 

2.31084 

7.30753 

1.74789 

3.76571 

8.11298 

.187266 

5.35 

28.6225 

153.130 

2.31301 

7.31437 

1.74898 

3.76806 

8.11804 

.186916 

6.36 

28.7296 

153.991 

2.31517 

7.32120 

1.75007 

3.77041 

8.12310 

.186567 

5.37 

28.8369 

154.854 

2.31733 

7.32803 

1.75116 

3.77275 

8.12814 

.186220 

5.38 

28.9444 

155.721 

2.31948 

7.33485 

1.75224 

3.77509 

8.13319 

.185874 

5.39 

29.0521 

156.591 

2.32164 

7.34166 

1.75333 

3.77740 

8.13822 

.185529 

5.40 

29.1600 

157.464 

2.32379 

7.34847 

1.75441 

3.77976 

8.14325 

.185185 

5.41 

29.2681 

158.340 

2.32594 

7.35527 

1.75549 

3.78210 

8.14828 

.184843 

5.42 

29.3764 

159.220 

2.32809 

7.36206 

1.75657 

3.78442 

8.15329 

.184502 

5.43 

29.4849 

160.103 

2.33024 

7.36885 

1.75765 

3,78675 

8.15831 

.184162 

5.44 

29.5936 

160.989 

2.33238 

7.37564 

1.75873 

3.78907 

8.16331 

.183824 

5.45 

29.7025 

161.879 

2.33452 

7.38241 

1.75981 

3.79139 

8.16831 

.183486 

5.46 

29.8116 

162.771 

2.33666 

7.38918 

1.76088 

3.79371 

8.17330 

.183150 

5.47 

29.9209 

163.667 

2.33880 

7.39594 

1.76196 

3.79603 

8.17829 

.182815 

5.48 

30.0304 

164.567 

2.34094 

7.40270 

1.76303 

3.79834 

8.18327 

.182482 

5.49 

30.1401 

165.469 

2.34307 

7.40945 

1.76410 

3.80065 

8.18824 

.182149 

5.50 

30.2500 

166.375 

2.34521 

7.41620 

1.76517 

3.80295 

8.19321 

.181818 

20 


MA  THEM  A  TICS 


n 

ns 

W3 

\£ 

VIFn 

« 

$IOn 

•fcbO  n 

1 

» 

5.51 

30.3601 

167.284 

2.34734 

7.42294 

1.76624 

3.80526  8.19818 

.181488 

5.52 

30.4704 

168.197 

2.34947 

7.42967 

1.76731 

380756  8.20313 

.181159 

5.53 

30.5809 

169.112 

2.35160 

7.436*0 

1.76888 

3.80986  8.20808 

.180832 

5.54 

30.6916 

170.031 

2.35372 

7.4*312 

1.76944 

3.80115  8.21303  .180505 

6.55 

30.8025 

170.954 

2.35584 

7.44983 

1.77051 

3.81444 

8.21797 

.180180 

5.56 

30.9136 

171.880 

2.35797 

7.45654 

1.77157 

3.81673 

8.22290 

.179856 

5.57 

31.0249 

172.809 

2.36008 

7.46324 

1.77263 

3.81902 

8.22783 

.179533 

5.58 

31.1364 

173.741 

2.36220 

7.46994 

1.77369 

3.82130 

8.23275 

.179212 

5.59 

31.2481 

174.677 

2.36432 

7.47663 

1.77475 

3.82358 

8.23766 

.178891 

6.60 

31.3600 

175.616 

2.36643 

7.48331 

1.77581 

3.82586 

8.24257 

.178571 

5.61 

31.4721 

176.558 

2.36854 

7.48999 

1.77686 

3.82814 

8.24747 

.178253 

5.62 

31.5844 

177.504 

2.37065 

7.49667 

1.77792 

3.83041 

8.25237 

.177936 

5.63 

31.6969 

178.454 

2.37276 

7.50333 

1.77897 

3.83268 

8.25726 

.177620 

5.64 

31.8096 

179.406 

2.37487 

7.50999 

1.78003 

3.83495 

8.26215 

.177305 

5.65 

31.9225 

180.362 

2.37697 

7.51665 

1.78108 

3.83721 

8.26703 

.176991 

6.66 

32.0356 

181.321 

2.37908 

7.52330 

1.78213 

3.83948 

8.27190 

.176678 

5.67 

32.1189 

182.284 

2.38118 

7.52994 

1.78318 

3.84174 

8.27677 

.176367 

5.68 

32.2624 

183.250 

2.38328 

7.53658 

1.78422 

3.84400 

8.28164 

.176056 

6.69 

32.3761 

184.220 

7.54321 

1.78527 

8.84636 

.175747 

6.70 

32.4900 

185.193 

2!38747 

7.54983 

1.78632 

3.84850 

8.29134 

.175439 

5.71 

32.6011 

186.169 

2.38956 

7.55645 

1.78736 

3.85075 

8.29619 

.175131 

6.72 

32.7184 

187.149 

2.39105 

7.56307 

1.78840 

3.85300 

8.30103 

.174825 

5.73 

32.8329 

188.133 

2.39374 

7.56968 

1.78944 

8.85624 

8.30587 

.174520 

5.74 

32.9476 

189.119 

2.39583 

7.57628 

1.79048 

3.85748 

8.31069 

.171216 

6.75 

33.0625 

190.109 

2.39792 

7.58288 

1.79152 

3.85972 

8.31552 

.173913 

5.76 

33.1776 

191.103 

2.40000 

7.58947 

1.79256 

3.86196 

8.32034 

.173611 

6.77 

33.2929 

192.100 

2.40208 

7.59605 

1.79360 

3.86419 

8.32515 

.173310 

5.78 

33.4084 

193.101 

2.40416 

7.60263 

1.79463 

3.88642 

8.32995 

.173010 

5.79 

33.5241 

194.105 

2.4(1(124 

7.60920 

1.79567 

8.86866 

8.33476 

.172712 

6.80 

33.6400 

195.112 

2.40832 

7.61577 

1.79670 

3.87088 

8.33955 

.172414 

5.81 

33.7561 

196.123 

2.41039 

7.62234 

1.79773 

3.87310 

8.34434 

.172117 

5.82 

33.8721 

197.137 

2.41*47 

7.62389 

1.79876 

3.87532 

8.84818 

.171*21 

5.83 

33.98*9 

198.155 

2.41454 

7.63544 

1.79979 

3.87754 

8.35390 

.171527 

6.84 

34.1056 

199.177 

2.ll(ilil 

7.64199 

1.80082 

3.87975 

8.35868 

.171233 

5.85 

34.2225 

200.202 

2.41868 

7.64853 

1.80185 

3.88197 

8.36345 

.170940 

5.86 

34.3396 

201.230 

2.42074 

7.65506 

1.80288 

3.88418 

8.36821 

.170649 

5.87 

31.4569 

202.262 

2.42281 

7.66159 

1.80390 

3.88639 

8.37297 

.170358 

5J6 

34.5744 

203.297 

2.42487 

7.  r>i;-  12 

1.80492 

8.88859 

8.37772 

.170IIC8 

5.89 

34.6921 

204.336 

2.42693 

7.  67163 

1  .80595 

3.89082 

8.38247 

.169779 

5.90 

34.8100 

205.379 

2.42899 

7.68115 

1.80697 

3.89300 

8.38721 

.169492 

5.91 

34.9281 

206.425 

2.43105 

7.68765 

1.80799 

3.89520 

8.39194 

.169205 

5.92 

35.0164 

207.475 

2.43311 

7.69415 

1.80901 

3.  89739 

8.39(167 

.168919 

6.93 

35.1649 

208.528 

2.43516 

7.70065 

1.81003 

389958 

8.40140 

.168634 

6.94 

35.2836 

209.585 

2.43721 

7.70714 

1.81104 

3.90177 

8.40612 

.168350 

5.95 

35.4025 

210.645 

2.43926 

7.71362 

1.81206 

3.90396 

8.41083 

.168067 

6.96 

35.5216 

211.709 

2.44131 

7.72010 

1.81307 

3.90615 

8.41554 

.167785 

6.87 

36.6409 

212.776 

2.44336 

7.72658 

1.81409 

3.90833 

8.42025 

.167504 

6.98 

35.7604 

213.847 

2.44540 

7.73305 

1.81510 

3.91051 

8.42494 

.167224 

6.99 

35.880P 

214.922 

2.44745 

7.73951 

1.81611 

3.91269 

8.42964 

.166945 

6.00 

36.0000 

216.000 

2.44949 

7.74597 

1.81712 

3.91487 

8.43433 

.166667 

MATHEMATICS 


21 


n 

na 

7*3 

Tfo 

A/10n 

£ 

3lw~n 

•$100  n 

1 

n 

5.01 

36.1201 

217.082 

2.45153 

7.75242 

1.81813 

3.91704 

8.43901 

.166389 

6.02 

36.2404 

218.167 

2.45357 

7.75887 

1.81914 

3.91921 

8.44369 

.16611$ 

6.03 

36.3609 

219.256 

2.45561 

7.76531 

1.82014 

3.92138 

8.44836 

.165838 

6.04 

36.4816 

220.349 

2.45764 

7.77174 

1.82115 

3.92355 

8.45303 

.165563 

6.05 

36.6025 

221.445 

2.45967 

7.77817 

1.82215 

3.92571 

8.45769 

.165289 

6.06 

36.7236 

222.545 

2.46171 

7.78460 

1.82316 

3.92787 

8.46235 

.165017 

6.07 

36.8449 

223.649 

2.46374 

7.79102 

1.82416 

3.93003 

8.46700 

.164745 

6.08 

36.9664 

224.756 

2.46577 

7.79744 

1.82516 

3.93219 

8.47165 

.164474 

6.09 

37.0881 

225.867 

2.46779 

7.80385 

1.82616 

3.93434 

8.47629 

.164204 

6.10 

37.2100 

226.981 

2.46982 

7.81025 

1.82716 

3.93650 

8.48093 

.163934 

6.11 

37.3321 

228.099 

2.47184 

7.81665 

1.82816 

3.93865 

8.48556 

.16366& 

6.12 

37.4544 

229.221 

2.47386 

7.82304 

1.82915 

3.94079 

8.49018 

.163399 

6.13 

37.5769 

230.346 

2.47588 

7.82943 

1.83015 

3.94294 

8.49481 

.16313? 

6.14 

37.6996 

231.476 

2.47790 

7.83582 

1.83115 

3.94508 

8.49942 

.162866 

5.15 

37.8225 

232.608 

2.47992 

7.84219 

1.83214 

3.94722 

8.50404 

.162602 

6.16 

37.9456 

233.745 

2.48193 

7.84857 

1.83313 

3.94936 

8.50864 

.16238ft 

6.17 

38.0689 

234.885 

2.48395 

7.85493 

1.83412 

3.95150 

8.51324 

.162075 

6.18 

38.1924 

236.029 

2.48596 

7.86130 

1.83511 

3.95363 

8.51784 

.161812 

6.19 

38.3161 

237.177 

2.48797 

7.86766 

1.83610 

3.95576 

8.52243 

.161551 

6.20 

38.4400 

238.328 

2.48998 

7.87401 

1.83709 

3.95789 

8.52702 

.161290 

6.21 

38.5641 

239.483 

2.49199 

7.88036 

1.83808 

3.96002 

8.53160 

.161031 

6.22 

38.6884 

240.642 

2.49399 

7.88670 

1.83906 

3.96214 

8.53618 

.160772 

6.23 

38.8129 

241.804 

2.49600 

7.89303 

1.84005 

3.96426 

8.54075 

.160514 

6.24 

38.9376 

242.971 

2.49800 

7.89937 

1.84103 

3.96639 

8.54532 

.160256 

6.25 

39.0625 

244.141 

2.50000 

7.90569 

1.84202 

3.96850 

8.54988 

.160000 

6.26 

39.1876 

245.314 

2.50200 

7.91202 

1.84300 

3.97062 

8.55444 

.159744 

6.27 

39.3129 

246.492 

2.50400 

7.91833 

1.84398 

3.97273 

8.55899 

.159490 

6.28 

39.4384 

247.673 

2.50599 

7.92465 

1.84496 

3.97484 

8.56354 

.159236 

6.29 

39.5641 

248.858 

2.50799 

7.93095 

1.84594 

3.97695 

8.56808 

.158988 

6.30 

39.6900 

250.047 

2.50998 

7.93725 

1.84691 

3.97906 

8.57262 

.158730 

6.31 

39.8161 

251.240 

2.51197 

7.94355 

1.84789 

3.98116 

8.57715 

.158479 

6.32 

33.9424 

252.436 

2.51396 

7.94984 

1.84887 

3.98326 

8.58168 

.15822* 

6.33 

40.0689 

253.636 

2.51595 

7.95613 

1.84984 

3.98536 

8.58620 

.157978 

6.34 

40.1956 

254.840 

2.51794 

7.96241 

1.85082 

3.98746 

8.59072 

.157729 

6.35 

40.3225 

256.048 

2.51992 

7.96869 

1.85179 

3.98956 

8.59524 

.157480 

6.36 

40.4496 

257.259 

2.52190 

7.97496 

1.85276 

3.99165 

8.59975 

.157233 

6.37 

40.5769 

258.475 

2.52389 

7.98123 

1.85373 

3.99374 

8.60425 

.156986 

6.38 

40.7044 

259.694 

2.52587 

7.98749 

1.85470 

3.99583 

8.60875 

.156740 

6.39 

40.8321 

260.917 

2.52784 

7.99375 

1.85567 

3.99792 

8.61325 

.156495 

6.40 

40.9600 

262.144 

2.52982 

8.00000 

1.85664 

4.00000 

8.61774. 

.156250 

6.41 

41.0881 

263.375 

2.53180 

8.00625 

1.85760 

4.00208 

8.62222 

.156006. 

6.42 

41.2164 

264.609 

2.53377 

8.01249 

1.85857 

4.00416 

8.62671 

.155763 

6.43 

41.3449 

265.848 

2.53574 

8.01873 

1.85953 

4.00624 

8.63118 

.155521 

6.44 

41.4736 

267.090 

2.53772 

8.02496 

1.86050 

4.00882 

8.63566 

.155280 

6.45 

41.6025 

268.336 

2.53969 

8.03119 

1.86146 

4.01039 

8.64012 

.155039 

6.46 

41.7316 

269.586 

2.54165 

8.03741 

1.86242 

4.01246 

8.64459 

.154799 

6.47 

41.8609 

270.840 

2.54362 

8.04363 

1.86338 

4.01453 

8.64904 

.154560 

6.48 

41  .9904 

272.098 

2.54558 

8.04984 

1.86434 

4.01660 

8.65350 

.154321 

6.49 

42.1201 

273.359 

2.54755 

8.05605 

1.86530 

4.01866 

8.65795 

.154083 

6.50 

42.2500 

274.625 

2.54951 

8.06226 

1.86626 

4.02073 

8.66239 

.153846 

22 


MATHEMATICS 


n 

n- 

W3 

« 

VlOn 

^ 

tun; 

\100n 

1 

n 

6.51 

42.3801 

275.894 

2.55147 

8.06846 

1.86721 

4.02279 

8.66683 

.153610 

652 

42.5104 

277.168 

2.55343 

8.07465 

1.86817 

4.02485 

8.67127 

.153374 

6.53 

12  6409 

278.445 

2.55539 

8.08084 

1.86912 

4.02690 

8.67570 

.153139 

6.54 

42.7716 

279.726 

2.55734 

8.0«703 

1.87008 

4.02*96 

8.68012 

.152905 

6.55 

42.9025 

281.011 

2.55930 

8.09321 

1.87103 

4.03101 

8.68455 

.152672 

6.56 

43.0336 

282.300 

2.56125 

8.0993S 

1.87198 

4.03306 

•8.68896 

.152439 

6.57 

43.1619 

2*3.593 

2.56320 

8.10555 

1.87293 

4.03511 

8.69338 

.152207 

6.58 

43.2964 

2S4.890 

2.56515 

8.11172 

1.87388 

4.03715 

8.69778 

.151976 

6.59 

4:i.l2-l 

2*6.191 

2.56710 

8.11788 

4.03920 

8.70219 

.151745 

6.60 

43.5600 

2B7.496 

2.56905 

8.12404 

1.87578 

4.04124 

8.70659 

151515 

6.61 

43.6921 

288.805 

2.57099 

8.13019 

1.87672 

4.04328 

8.71098 

.151286 

6.62 

43.8244 

290.118 

2.57294 

8.13634 

1.-7767 

4.04532 

8.71537 

.151057 

6.63 

43.9569 

291.434 

2.57488 

8.14248 

1.87861 

4.04735 

8.71976 

.150830 

6.64 

44.0-96 

292.755 

2.57682 

8.14862 

1.87956 

4.04939 

8.72414 

.150602 

6.65 

44.2225 

294.080 

2.57876 

8.15475 

1.8*050 

4.05142 

8.72852 

.150376 

6.66 

44.3556 

295.408 

2.58070 

8.16088 

1.88144 

4.05345 

8.73289 

.150150 

6.67 

44.4*89 

296.741 

2.58263 

8.16701 

1.8*239 

4.05548 

8.73726 

.149925 

6.68 

44.6224 

298.078 

2.58457 

8.17313 

1.8*333 

4.05750 

8.74162 

.149701 

6.69 

44.7:>61   299.418 

2.  5*650 

8.17924 

1.88427 

4.05953 

8.74598 

.149477 

6.70 

44.8900 

300.763 

2.58844 

8.18535 

1.88520 

4.06155 

8.75034 

.149254 

6.71 

45.0241 

302.112 

2.59037 

8.19146 

1.88614 

4.06357 

8.75469 

.149031 

6.72 

45.1584 

303.464 

2.59230 

8.19756 

1.88708 

4.06558 

8.75904 

.14-10 

6.73 

45.2929 

304.821 

2.59422 

8.20366 

1.88801 

4.06760 

8.76338 

6.74 

45.1276  i  306.182 

2.59615 

8.20975 

1.86896 

4.06961 

8.76772 

.14*368 

«.75 

45.5625  307.547 

2.59808 

8.21584 

1.88988 

4.07163 

8.77205 

.148148 

6.76 

45.6976  !  308.916 

2.60000 

8.22192 

1.89081 

4.07364 

8.77638 

.147929 

6.77 

45.8329 

31(1  2-9 

2.60192 

8.22*00 

1.89175 

8.78071 

.147711 

6.78 

45.9684 

311.666 

1.60884 

8.23408 

4107765 

8.78503 

.147493 

6.79 

46.1041 

313.047 

2.60576 

8.24015 

1  39861 

4.07965 

8.78935 

.147275 

6.80 

46.2400 

314.432 

2.60768 

8.24621 

1.89454 

4.08166 

8.79366 

.147059 

6.81 
6.32 

46.3761 
46.5124 

315.821 
317.215 

2.60960 
2.61151 

8.25227 

8.25833 

1.89546 
1.89689 

4.08365 

4.0*565 

8.79797 
8.80227 

.146843 
.146628 

6.83 

46.6489 

31*612  2.61343 

8.26438 

139789 

4.08765 

8.80657 

.146413 

6.84 

46  7-56 

320.014  2.61534 

8.27043 

1  .-•>•_'  i 

4.0*96* 

8.81087 

.146199 

6.85 

46.9225 

321.419 

2.61725 

8.27647 

1.89917  4.09164 

8.81516 

.145989 

6.86 

T.06M  322.829 

2.61916 

8.28251 

1.90009  4.09362 

8.81945 

.145773 

6.87 

7.1969   ".21.213   2.62107 

8.2**55 

1.90102   4.09561 

8.82373 

.145560 

«.88 

7.3344  325.661   2.62298 

8.29458 

1.90194  4.09760 

8.82*01 

.145349 

6.89 

7.4721   827.083   2.62  l*s 

8.30060 

1.90286  4.09958 

8.83229 

.145138 

«.90 

7.6100 

328.509 

2.62679 

8.30662 

1.90378 

4.10157 

8.83656 

.144928 

6.91 

7.7481 

S29.939 

2.62869 

8.31264 

1.90470 

4.10355 

8.84082 

.144718 

6>2 

331.374  2.63059 

*.31Kti5 

1.90562 

4.10552 

8.84509 

.144509 

6.93 

2.63219 

*.32466 

1.90653 

4.10750 

8.84934 

.144300 

6.94 

2.63439 

H.33067 

1.9H715 

4.10948 

8.85360 

.144092 

6.95 

4BJOSS 

335.702 

2.63629 

8.33667 

1.90837 

4.11145 

8.85785 

.143885 

6.96 

48.4416 

337.154 

263818 

8.34266 

1.90928 

4.11342 

8.86210 

.143678 

6.97 

48.5809  '  338.609  2.6400* 

8.34*65 

1.91019 

4.11539 

H.86634 

.143472 

6.98 

140.068  2.6H97 

8.35464 

1.91111 

4.11736 

8.87058 

.143267 

6.99 

48.8601  i  341.532 

8.36062 

1.91202 

4.11932 

8.874*1 

.143062 

7.00 

49.0000  343.000  2.64575 

8.36660 

1.91293 

4.12129 

8.87904 

.142857 

A/,1  THEM  A  TICS 


23 


n 

11- 

W3 

\7* 

Mo  n 

4S 

•^10  n 

•^IbOn 

1 

n 

7.01   49.1401 

344.472 

2.64764 

8.37257 

1.91384 

4.12325 

8.88327 

.142653 

7.02   49.2804 

345.948 

2.C4953 

8.37854 

1.91475 

4.12521 

8.88749 

.142450 

7.03 

49.4209 

347.429 

2.65141 

8.38451 

1.91566 

4.12716 

8.89171 

.142248 

7.04 

49.5616 

348.914 

2.65330 

8.39047 

1.91657 

4.12912 

8.89592 

.142046 

7.05 

49.7025 

350.403 

2.65518 

8.39643 

1.91747 

4.13107 

8.90013 

.141844 

7.06 

49.8436 

351.896 

2.65707 

8.40238 

1.91838 

4.13303 

8.90434 

.141643 

7.07 

49.9849 

353.393 

2.65895 

8.40833 

1.91929 

4.13498 

8.90854 

.141443 

7.08 

50.1264 

354.895 

2  .6KOS3 

8.41427 

1.92019 

4.13695 

8.91274 

.141243 

7.09 

50.2681 

356.401 

2.66271 

8.42021 

1.92109 

4.13887 

8.91693 

.141044 

7.10 

50.4100 

357.911 

2.66458 

8.42615 

1.92200 

4.14082 

8.92112 

.140845 

7.11 

50.5521 

359.425 

2.66646 

8.43208 

1.92290 

4.14276 

8.92531 

.140647 

7.12 

50.6944 

360.944 

2.66833  1  8.43801 

1.92380 

4.14470 

8.92949 

.140449 

7.13 

50.8369 

362.467 

2.67021  8.44393 

1.92470 

4.14664 

8.93367 

.140253 

7.14 

50.9796 

363.994 

2.67208 

8.44985 

1.92560 

4.14858 

8.93784 

.140056 

7.15 

51.1225 

365.526 

2.67395 

8.45577 

1.92650 

4.15051 

8.94201 

.139860 

7.16 

51.2656 

367.062 

2.67582 

8.46168 

1.92740 

4.15245 

8.94618 

.139665 

7.17 

51.4089 

368.602  2.67769 

8.46759 

1.92829 

4.15438 

8.95034 

.139470 

7.18 

51.5524 

370.146  2.67955 

8.47349 

1.92919 

4.15631  j  8.95450 

.139276 

7.19 

51.6961 

371.695 

2.68142 

8.47939 

1.93008 

4.15824 

8.95866 

.139082 

7.20 

51.8400 

373.248 

2.68328 

8.48528 

1.93098 

4.16017 

8.96281 

.138889 

7.21 

51.9841 

374.805 

2.68514 

8.49117 

1.93187 

4.16209 

8.96696 

.138696 

7.22 

52.1284 

376.367 

2.68701 

8.49706 

1.9327i7 

4.16402 

8.97110 

.138504 

7  23 

52.2729 

377.933 

2.6S887 

8.50294 

1.93366 

4.16594 

8.97524 

.138315 

7.24 

52.4176 

379.503 

2.69072 

8.50882 

1.93455 

4.16786 

8.97938 

.138122 

7.25 

52.5625 

381.078 

2.69258 

8.51469 

1.93544 

4.16978 

8.98351 

.137931 

7.26 

52.7076 

382.657 

2.69444 

8.52056 

1.93633 

4.17169 

8.98764 

.137741 

7.27 

52.8529 

384.241 

2.69629 

8.52643 

1.93722 

4.17361 

8.99176 

.137552 

7.28 

52.9984 

385.828 

2.69815 

8.53229 

1.93810 

4.17552 

8.99588 

.137363 

7.29 

53.1441 

387.420 

2.70000 

8.53815 

1.93899 

4.17743 

9.00000 

.137174 

7.30 

53.2900 

389.017 

2.70185 

8.54400 

1.93988 

4.17934 

9.00411 

.136986 

7.31 

53.4361 

390.618 

2.70370 

8.54985 

1.94076 

4.18125 

9.00822 

.136799 

7.32 

53.5824 

392.223 

2.70555 

8.55570 

1.94165 

4.18315  9.01283 

.136612 

7.33 

53.7289 

393.833 

2.70740 

8.56154 

1.94253 

4.18506  1  9.01643 

.136426 

7.34 

53.8756 

395.447 

2.70924 

8.56738 

1.94341 

4.18696 

9.02053 

.136240 

7.35 

54.0225 

397.065 

2.71109 

8.57321 

1.94430 

4.18886 

9.02462  .136054 

7.36 

54.16% 

398.688 

2.71293 

8.57904 

1.94518 

4.19076  9.02871 

.135870 

7.37  |  54.3169 

400.316 

2.71477 

8.58487 

1.94606 

4.19266  9.03280 

.135685 

7.3s   54.4644 

401.947 

2.71662 

8.59069 

1.94694 

4.19455 

9.03C89 

.135501 

7.39 

54.6121 

403.583 

2.71846 

8.59651 

1  .94782 

4.19644 

9.04097 

.135318 

7.40   54.7600 

405.224 

2.72029 

8.60233 

1.94870 

4.19834 

9.04504 

.135135 

7.41   54.9081 

406.869  2.72213 

8.60814 

1.94957 

4.20023 

9.04911 

.134953 

7.42   55.0564 

408.518  2.72W7 

8.61394 

1.95045 

4.20212 

9.05318 

.134771 

7.43   55.2049 

410.17-2  2.72.XI 

8.61974 

1.95132 

4.20400 

9.05725 

.134590 

7.44   55.353(5 

411.831  2.72764 

8.62554 

1  ."5220 

4.80689 

9.06131 

.134409 

7.45   55.5025 

413.494  2.72947 

8.63134 

1.95307 

4.20777 

9.06537 

.134228 

7.46   55.6516 

415.161 

2.73130  *.63713  1.95395 

4.20965 

9.06942 

.134048 

7.47   55.8009 

416.833 

2.73313  8.64292  1.95482  4.21153  9.07347 

.133869 

7.48   55.9504 

418.509 

2.73496  8.641*70  1.95569  4.21341  j  9.07752 

.133690 

7.49   56.1001 

420.190  2.73679  8.65448  1.95656  4.21529  9.08156 

.133511 

7.50 

56.2500 

421.875  2.73861  8.66025  1.95743  4.21716 

9.08560 

.133333 

MATHEMATICS 


n 

n« 

na 

1K 

VlCfn 

*£ 

•fton 

^lOOri 

k 

7.51 

56.4001 

423.565 

2.74044 

8.66603 

1.95830 

4.21904 

9.08964 

.133156 

7.52 

56.5504 

425.259 

2.74226 

8.67179 

1.95917 

4.22091 

9.09367 

.132979 

7.53 

56.7009 

426.958 

2.74408 

8.67756 

1.96004 

4.22278 

9.09770 

.132802 

7.54 

56.8516 

428.661 

2.74591 

8.68332 

1.96091 

4.22465 

9.10173 

.132626 

7.55 

57.0025 

430.369 

2.74773 

8.68907 

1.96177 

4.22651 

9.10575 

.132450 

T.56 

57.1536 

432.081 

2.74955 

8.69483 

1.96264 

4.22838 

9.10977 

.132275 

7.57 

57.3049 

433.798 

2.75136 

8.70057 

1.96350 

4.23024 

9.11378 

.132100 

7.58 

57.4564 

435.520 

2.75318 

8.70632 

1.96437 

4.23210 

9.11779 

.131926 

7.59 

57.6081 

437.245 

2.75500 

8.71206 

1.96523 

4.23396 

9.12180 

.131752 

7.60 

57.7600 

438.976 

2.75681 

8.71780 

1.96610 

4.23582 

9.12581 

.131579 

7.61 

57.9121 

440.711 

2.75862 

8.72353 

1.96696 

4.23768 

9.12981 

.131406 

7.62 

58.0644 

442.451 

2.76043 

8.72926 

1.96782 

4.23954 

9.13380 

.131234 

7.63 

58.2169 

444.195 

2.76225 

8.73499 

1.96868 

4.24139 

9.13780 

.131002 

7.64 

58.3696 

445.994 

2.76405 

8.74071 

1.96954 

4.24324 

9.14179 

.130i90 

7.65 

58.5225 

447.697 

2.76586 

8.74643 

1.97040 

4.24509 

9.14577 

.130719 

7.66 

58.6756 

449.455 

2.76767 

8.75214 

1.97126 

4.24694 

9.14976 

.130548 

7.67 

58.8289 

451.218 

2.76948 

8.75785 

1.97211 

4.24179 

9.15374 

.130378 

7.68 

58.9824 

452.  9K5 

2.77128 

8.76356 

1.97297 

4.25063 

9.15771 

.130208 

7.69 

59.1361 

454.757 

2.77308 

8.76926 

1.97383 

4.25M8 

9.16169 

.130039 

7.70 

59.2900 

456.533 

2.77489 

8.77496 

1.97468 

4.25432 

9.16566 

.129870 

7.71 

59.4441 

458314 

2.77669 

8.78066 

1.97554 

4.25616 

9.16962 

.129702 

7.72 

59.5984 

460.100 

2.77849 

K.7NJ35 

1.97639 

4.25800  9.17359 

.129534 

7.73 

59.7529 

461  ."'.10 

2.78029 

8.79204 

1.97724 

4.25984  |  9.17754 

.1293C6 

1.74 

59.9076 

M8.68B 

2.78209 

8.79773 

1.97809 

4.26168 

9.18150 

.129199 

7.75 

60.0625 

465.484 

2.78388 

8.80341 

1.97895 

4.26351 

9.18545 

.129032 

7.76 

60.2176 

467.289 

2.78568 

8.80909 

1.97980 

4.26534 

9.18940 

.128866 

7.77 

60.3729 

469.097 

2.78747 

8.81476 

1.98065 

4.26717  1  9.19335 

.128700 

7.78 

60.5284 

470.911 

2.78927 

8.82043 

1.98150 

4.26900  9.19729 

.128535 

7.79 

60.6841 

472.729 

2.79106 

8.82610 

1.98234 

4.27083  9.20123 

.128370 

7.80 

60.8400 

474.552 

2.79285 

8.83176 

1.98319 

4.27266  9.20516 

.128205 

7.81 

60  .9%! 

476.380 

2.79464 

8.83742 

1.98404 

4.27448  '  9.20910 

.128041 

7.82 

61.1524 

478.212 

2.79643 

8.84308 

1  .98489 

4.27113]  9.21303 

.127877 

7.83 

6T.MM 

480  049 

2.79821 

8.81*73 

1.98573 

4.27813  9.21695 

.127714 

7.84 

61.4656 

481.890 

2.  SI  KM  M) 

8.Hf>438 

1  .9st;.-)H 

4.27995  1  9.22087 

.127551 

7.85 

61.6225 

483.737 

2.80179 

8.86002 

1.98742 

4.28177 

9.22479 

.127389 

7.86 

61.7796 

485.588 

2.80357 

8.86566 

1.98826 

4.28359 

9.22871 

.127227 

7.87 

61.9369 

487.443 

2.S0535 

8.87130 

1.98911 

4.28540 

9.23262 

.127065 

7.88 

62.0944 

489.304 

2.80713 

8.87694 

1  .9*995 

4.28722 

».236U 

.126904 

7.89 

62.2521 

491.169 

2.80891 

8.HH257 

1.99079 

4.28903 

9.24043 

.1211743 

7.90 

62.4100 

493.039 

2.81069 

8.88819 

1.99163 

4.29084 

9.24433 

.126582 

7.91 

62.5681 

494.914 

2.81247 

8.89382 

1.99247 

4.29265 

9.24823 

.126422 

7.92 

62.7264 

4!t6.7!>3 

2.81425 

*.«9944 

1.99331 

4.29446 

9.25213 

.126263 

7.93 

62.8849 

4<*H.677 

2.81603 

s.:M)-,05 

1.99415 

4.29627 

9.25602 

.126103 

7.94 

63.o4:m 

500.566 

2.H17M) 

8.9KH17 

1.99499 

4.29807 

9.25991 

.125945 

7.95 

63.2025 

502.460 

2.81957 

8.91628 

1.99582 

4.29987 

9.26380 

.125786 

7.96 

63.3616 

504.358 

2.82135 

8.92188 

1.99666 

4.30168 

9.26768 

.125628 

7.97 

63.5209 

506.262 

2.82312 

8.92749 

1.99750 

4.30348 

9.27156 

.125471 

7.98 

63.6804 

508.170 

h.iwim 

1.99*33 

4.30528 

9.27544 

.125313 

7.99 

63.M401 

510.0*2 

2.KJIK16 

8.'.t3sfiH 

1.99917 

4.30707 

9.27931 

.125156 

8.00 

64.0000 

512.000 

2.82843 

3.94427 

2.00000 

4.30HH7 

9.28318 

.125000 

MATHEMATICS 


25 


71 

«* 

ns 

1ft 

VlOn 

« 

lm 

^<xm 

1 

n 

8.01 

64.1601 

513.922 

2.83019 

8.94986 

2.00083 

4.31066 

9.28704 

.124844 

8.02 

64.3204 

615.850 

2.83196 

8.95545 

2.00167 

4.31246 

9.29091 

.124688 

8.03 

64.4809 

517.782 

2.83373 

8.96103 

2.00250 

4.31425 

9.29477 

.124533 

8.04 

64.6416 

519.718 

2.83549 

8.96660 

2.00333 

4.31604 

9.29862 

.124378 

8.05 

64.8025 

521.660 

2.83725 

8.97218 

2.00416 

4.31783 

9.30248 

.124224 

8.06 

64.9636 

523.607 

2.83901 

8.97775 

2.00499 

4.31961 

9.30633 

.124070 

8.07 

65.1249 

525.558 

2.84077 

8.98332 

2.00582 

4.32140 

9.31018  I  .123916 

8.08 

65.2864 

527.514 

2.84253 

8.98888 

2.00664 

4.32818 

9.31402 

.123762 

8.09 

65.4481 

529.475 

2.84429 

8.99444 

2.00747 

4.32497 

9.31786 

.123609 

8.10 

65.6100 

531.441 

2.84605 

9.00000 

2.00830 

4.32675 

9.32170 

.123457 

8.11 

65.7721 

633.412 

2.84781 

9.00555 

2.00912 

4.32853 

9.32553 

.123305 

8.12 

65.9344 

535.387 

2.84956 

9.01110 

2.00995 

4.S3031 

9.32936 

.123153 

8.13 

66.0969 

537.368 

2.85132 

9.01665 

2.01078 

4.33208 

9.33319 

.123001 

8.14 

66.2596 

539.353 

2.85307 

9.02219 

2.01160 

4.33386 

9.33702 

.122850 

8.15 

66.4225 

641.343 

2.85482 

9.02774 

2.01242 

4.33563 

9.34084 

.122699 

8.16 

66.5856 

543.338 

2.85657 

9.03327 

2.01325 

4.33741 

9.34466 

.122549 

8.17 

66.7489 

545.339 

2.85832 

9.03881 

2.01407 

4.33918 

9.34847 

.122399 

8.18 

66.9124 

547.343 

2.86007 

9.04434 

2.01489 

4.34095 

9.35229 

.122249 

8.19 

67.0761 

549.353 

2.86182 

9.04986 

2.01571 

4.34272 

9.35610 

.122100 

8.20 

67.2400 

551.368 

2.86356 

9.05539 

2.01653 

4.34448 

9.35990 

.121951 

8.21 

67.4041 

553.388 

2.86531 

9.06091 

2.01735 

4.34625 

9.36370 

.121803 

8.22 

67.5684 

555.412 

2.86705 

9.06642 

2.01817 

4.34801 

9.36751 

.121655 

8.23 

67.7329 

557.442 

2.86880 

9.07193 

2.01899 

4.34977 

9.37130 

.121507 

8.24 

67.8976  559.476 

2.87054 

9.07744 

2.01980 

4.35153 

9.37610 

.121359 

8.25 

68.0625 

561.516 

2.87228 

9.08295 

2.02062 

4.35329 

9.37889 

.121212 

8.26 

68.2276 

563.560 

2.87402 

9.08845 

2.02144 

4.35505 

9.38268 

.121065 

8.27 

68.3929 

565.609 

2.87576 

9.09395 

2.02225 

4.35681 

9.38646 

.120919 

8.28 

68.5584 

567.664 

2.87750 

9.09945 

2.02307 

4.35856 

9.39024 

.120773 

8.29 

68.7241 

569.723 

2.87924 

9.10494 

2.02388 

4.36032 

9.39402 

.120627 

8.30 

68.8900 

571.787 

2.88097 

9.11043 

2.02469 

4.36207 

9.39780 

.120482 

8.31 

69.0561 

573.856 

2.88271 

9.11592 

2.02551 

4.36382 

9.40157 

.120337 

8.32 

69.2224 

575.930 

2.88444 

9.12140 

2.02632 

4.36557 

9.40534 

.120192 

8.33 

69.3889 

578.010 

2.88617 

9.12688 

2.02713 

4.36732 

9.40911 

.120048 

8.34 

69.5556 

580.094 

2.88791 

9.13236 

2.02794 

4.36907 

9.41287 

.119904 

8.35 

69.7225 

582.183 

2.88%4 

9.13783 

2.02875 

4.37081 

9.41663 

.119761 

8.36 

69.88% 

584.277 

2.89137 

9.14330 

2.02956 

4.37255 

9.42039 

.119617 

8.37 

70.0569 

586.376 

2.89310 

9.14877 

2.03037 

4.37430 

9.42414 

.119474 

8.38 

70.2244 

588.480 

2.89482 

9.15423 

2.03118 

4.37604 

9.42789 

.119332 

8.39 

70.3921 

590.590 

2.89655 

9.15969 

2.03199 

4.37778 

9.43164 

.119190 

8.40 

70.5600 

592.704 

2.89828 

9.16515 

2.03279 

4.37952 

9.43539 

.119048 

8.41 

70.7281 

594.823 

2.90000 

9.17061 

2.03360 

4.38126 

9.43913 

.118906 

8.42 

70.8964 

596.948 

2.90172 

9.17606 

2.03440 

4.38299 

9.44287 

.118765 

8.43 

71.0649 

599.077 

2.90345 

9.18150 

2.03521 

4.38473 

9.44661 

.118624 

8.44 

71.2336 

601.212 

2.90517 

9.18695 

2.03601 

4.38646 

9.45034 

.118483 

8.45 

71.4025 

603.351 

2.90689 

9.19239 

2.03682 

4.38819 

9.45407 

.118343 

8.46 

71.5716 

605.4% 

2.90861 

9.19783 

2.03762 

4.38992 

9.45780 

.118203 

8.47 

71.7409 

607.645 

2.91033 

9.20326 

2.03842 

4.39165 

9.46152 

.118064 

8.48 

71.9104 

609.800 

2.91204 

9.20869 

2.03923 

4.39338 

9.46525 

.117925 

8.49 

72.0801 

611.960 

2.91376 

9.21412 

2.04003 

4.39511 

9.46897 

.117786 

8.50 

72.2500 

614.125 

2.91548 

9.21954 

2.04083 

4.39683 

9.47268 

.117647 

MATHEMATICS 


n 

n* 

W' 

V^ 

.VlOn 

^ 

•fton 

-^00  n 

I 

n 

8.51 

72.4201 

616.295 

2.91719 

9.22497 

2.04163 

4.39855 

9.47640 

.117509 

8.52 

72.5904 

618.470 

2.91890 

9.2303* 

2.04243 

4.40028 

9.4X011 

.117371 

8.53 

72.7609 

620.650 

2.92062 

9.23580 

2.04323 

4.40200 

9.48381 

.117233 

8.54 

72.9316 

622.836 

2.92233 

9.24121 

2.04402 

4.40372 

9.48763 

.117096 

8.55 

73.1025 

625.026 

2.92404 

9.24662 

2.04482 

4.40543 

9.49122 

.116959 

8.56 

73.2736 

627.222 

2.92575 

9.25203 

2.04562 

4.40715 

9.49492 

.116822 

8.57 

73.4449 

629.423 

2.92746 

9.25743 

2.04641 

4.40887 

9.49*61 

.110686 

8.58 
8.59 

73.6164 
73.7881 

631  .629 
633.840 

2.92916 
2.93087 

9.26283 
9.26823 

2.04721 
2.04801 

4.41058  1  9.50231 
4.41229  9.50000 

.116550 
.116414 

8.60 

73.9600 

636.056 

2.93258 

9.27362 

2.04880 

4.41400 

9.50969 

.116279 

8.61 

74.1321 

638.277 

2.93428 

9.27901 

2.04959 

4.41571 

9.51337  !  .116144 

8.62 

74.3044 

640.504 

2.93598 

9.2*440 

2.05039 

4.41742 

9.51705  1  .116009 

8.63 

74.4769 

642.736 

2.93769 

9.2*978 

2.05118 

4.41913 

9.52073  .115875 

8.64 

74.6196 

644.973 

2.93939 

9.29516 

2.05197 

4.42084 

9.52441 

.115741 

8.65 

74.8225 

647.215 

2.94109 

9.30054 

2.05276 

4.42254 

9.52808 

.115607 

8.66 

74.9956 

649.462 

2.94279 

9.30591 

2.05355 

4.42425 

9.53175 

.115473 

8.67 

75.1689 

651.71  4 

2.94449 

9.31128 

2.05434 

4.42595 

9.53542 

.115340 

8.68 

75.3424 

653.972 

2.94618 

9.31665 

2.05513 

4.42765 

9.68908 

.115207 

8.69 

75.5161 

656.235 

2.94788 

9.32202 

2.05592 

4.42988 

9.54274 

.115075 

8.70 

75.6900 

658.503 

2.94958 

9.32738 

2.05671 

4.43105 

9.54640 

.114943 

8.71 

75.8641 

660.776 

2.95127 

9.33274 

2.05750 

4.43274 

9.55006 

.114811 

8.72 

76.0384 

663.055 

2.95296 

9.33*09 

2.05828 

4.43444 

9.55371 

.114679 

8.73 

76.2129 

665.339 

2.95466 

9.34345 

2.05907 

4.43614 

9.66786 

.114548 

8.74 

76.3876 

667.628 

2.95635 

9.3i>*o 

2.05986 

4.48789 

9.56101 

.114417 

8.75 

76.5625 

669.922 

2.95804 

9.35414 

2.06064 

4.43952 

9.56466 

.114286 

8.76 

76.7376 

672.221 

2.95973 

9.35949 

2.06143 

4.44121 

9.56830 

.114155 

8.77 

76.9129 

674.526 

2.96142 

9.364*3 

2.06221 

4.  11290 

9.57194 

.114025 

8.78 

77.0*84 

2.96311 

9.37017 

2.06299 

4.44459 

9.57557 

.113*95 

8.79 

77.2641 

679.151 

2.96479 

9.37550 

1.06378 

4.44091 

9  57921 

.113766 

8.80 

77.4400 

f,.-1.472 

2.96648 

9.38083 

2.06456 

4.44796 

9.58284 

.113636 

8.81 

77.6161 

683.798 

2.96816 

9.38616 

2.06534 

4.44964 

9.58647 

.113507 

8.82 

77.7921 

nun 

0.89149 

2.06612 

4.  4  5133 

9.69009 

.113379 

8.83 

77.9689 

68*.  465 

2.97153 

9.396*1 

2.06690 

4.45301 

9.59372 

.113250 

8.84 

78.1456 

690.807 

2.97321 

9.40213 

2.06768 

I.4846S 

9.59784 

.113122 

8.85 

78.3225 

693.154 

2.97489 

9.40744 

2.06846 

4.45637 

9.60095 

.112994 

8.86 

78.4996 

695.506 

2.97658 

9.41276 

2.  0692  I 

4.45805 

9.60457 

.112867 

8.87 

78.6769 

697.864 

2.97*25 

9.41807 

•2  07002 

4.45972 

9.00818 

.112740 

8.88 

700.227 

2.  97993 

9.4233H 

2.070*0 

4.46140 

9.61179 

.112613 

8.89 

79.o:-,2i 

702.595 

2.98161 

9.42*6* 

2.07157 

4.46307 

9.61540 

.112486 

8.90 

79.2100 

704.969 

2.98329 

9.43398 

2.07235 

4.46474 

9.61900 

.112360 

8.91 

79.3-M 

707.348 

2.98496 

9.43928 

2.07313 

4.46642 

9.62260 

.112233 

8.92 

79.5664 

709.7:12 

2  9-061 

9.i4i5* 

2.07390 

4.46-09 

9  62620 

.112108 

8.93 

79.7449 

712.122 

9.44981 

2.07468 

4.16976 

9.63980 

.1119*2 

8.94 

79.9236 

714.617 

MOM 

9.45516 

1.07648 

4.47142 

9.63339 

.111*57 

8.96 

MM  If.';-) 

716.917 

2.99166 

9.46044 

2.07622 

4.47309 

9.63698 

.111732 

8.96 

80.2816 

719.323 

2.99333 

9.46573 

2.07700 

4.47476 

9.64067 

.111607 

8.97 

*o.n;o9 

7'-'  1.  734 

2.99500 

9.47101 

2.07777 

4.47642 

9.64415 

.111483 

8.98 

80.6404 

7-Jt.ir,i 

2.990(,0 

9.47629 

9.64774 

.111359 

8.99 

MI>1'01 

726.573 

9.481M 

2.o:9:il 

4.47974 

9.6S132 

.111236 

9.00 

81.0000 

729.000 

3.00000 

2.0*00* 

4.48140 

9.65489 

.111111 

MATHEMATICS 


•21 


n 

W2 

7l3 

^ 

Vio^i 

« 

fto^ 

•^100  n 

2, 

n 

9.01 

81.1801 

731.433 

3.00167 

9.49210 

2.08085 

4.48306 

9.65847 

.110988 

9.02 

81.3604  733.871 

3.00333 

9.49737 

2.08162 

4.48472 

9.66204 

.110865 

9.03 

81.5409 

736.314 

3.00500 

9.50263 

2.08239 

4.48638 

9.66561 

.110742 

9.01 

81.7216 

738.763 

3.00666 

9.50789 

2.08316 

4.48803 

9.66918 

.110620 

9.05 

81.9025 

741.218 

3.00832 

9.51315 

2.08393 

4.48968 

9.67274 

.110497 

9.06 

82.0836 

743.677 

3.00998 

9.51840 

2.08470 

4.49134 

9.67630 

.110375 

9.07 

82.2649 

746.143 

3.01164 

9.52365 

2.08546 

4.49299 

9.67986 

.110254 

9.08 

82.4464 

748.613 

3.01330 

9.52890 

2.08623 

4.49464 

9.68342 

.110132 

9.09 

82.6281 

751.089 

3.01496 

9.53415 

2.08699 

4.49629 

9.68697 

.110011 

9.10 

82.8100 

753.571 

3.01662 

9.53939 

2.08776 

4.49794 

9.69052 

.109890 

9.11 

82.9921 

756.058 

3.01828 

9.54463 

2.08852 

4.49959 

9.69407 

.109770 

9.12 

83.1744 

758.551 

3.01993 

9.54987 

2.08929 

4.50123 

9.69762 

.109649 

9.13 

83.3569 

761.048 

3.02159 

9.55510 

2.09005 

4.50288 

9.70116 

.109529 

9.14 

83.5396 

763.552 

3.02324 

9.56033 

2.09081 

4.50452 

9.70470 

.109409 

9.15 

83.7225 

766.061 

3.02490 

9.56556 

2.09158 

4.50616 

9.70824 

.109290 

9.16 

83.9056 

768.575 

3.02655 

9.57079 

2.09234 

4.50780 

9.71177 

.109170 

9.17 

84.0889 

771.095 

3.02820 

9.57601 

2.09310 

4.50945 

9.71531 

.109051 

9.18 

84.2724 

773.621 

3.02985 

9.58123 

2.09386 

4.51108 

9.71884 

.108933 

9.19 

84.4561 

776.152 

3.03150 

9.58645 

2.09462 

4.51272 

9.72236 

.108814 

9.20 

84.6400 

778.688 

3.03315 

9.59166 

2.09538 

4.51436 

9.72589 

.108696 

9.21 

84.8241 

781.230 

3.03480 

9.59687 

2.09614 

4.51599 

9.72941 

.108578 

9.22 

85.0084 

783.777 

3.03645 

9.60208 

2.09690 

4.51763 

9.73293 

.108460 

9.23 

85.1929 

786.330 

3.03809 

9.60729 

2.09765 

4.51926 

9.73645 

.108342 

9.24 

85.3776 

788.889 

3.03974 

9.61249 

2.09841 

4.52089 

9.73996 

.108225 

9.25 

85.5625 

791.453 

3.04138 

9.61769 

2.09917 

4.52252 

9.74348 

.108108 

9.26 

85.7476 

794.023 

3.04302 

9.62289 

2.09992 

4.52415 

9.74699 

.107991 

9.27 

85.9329 

796.598 

3.04467 

9.62808 

2.10068 

4.52578 

9.75049 

.107875 

9.28 

86.1184 

799.179 

3.04631 

9.63328 

2.10144 

4.52740 

9.75400 

.107759 

9.29 

86.3041 

801.765 

3.04795 

9.63846 

2.10219 

4.52903 

9.75750 

.107643 

9.30 

86.4900 

804.357 

3.04959 

9.64365 

2.10294 

4.53065 

9.76100 

.107527 

9.31 

86.6761 

806.954 

3.05123 

9.64883 

2.10370 

4.53228 

9.76450 

.107411 

9.32 

86.8624 

809.558 

3.05287 

9.65401 

2.10445 

4.53390 

9.76799 

.107296 

9.33 

87.0489 

812.166 

3.05450 

9.65919 

2.10520 

4.53552 

9.77148 

.107181 

9.34 

87.2356 

814.781 

3.05614 

9.66437 

2.10595 

4.53714 

9.77497 

.107066 

9.35 

87.4225 

817.400 

3.05778 

9.66954 

2.10671 

4.53876 

9.77846 

.106952 

9.36 

87.6096 

820.026 

3.05941 

9.67471 

2.10746 

4.54038 

9.78195 

.106838 

9.37 

87.7969 

822.657 

3.06105 

9.67988 

2.10821 

4.54199 

9.78543 

.106724 

9.38 

87.9844 

825.294 

3.06268 

9.68504 

2.10896 

4.54361 

9.78891 

.106610 

9.39 

88.1721 

827.936 

3.06431 

9.69020 

2.10971 

4.54522 

9.79239 

.106496 

9.40 

88.3600 

830.584 

3.06594 

9.69536 

2.11045 

4.54684 

9.79586 

.106383 

9.41 

88.5481 

833.238 

3.06757 

9.70052 

2.11120 

4.54845 

9.79933 

.106270 

9.42 

88.7364 

835.897 

3.06920 

9.70567 

2.11195 

4.55006 

9.80280 

.106157 

9.43 

88.9249 

838.562 

3.07083 

9.71082 

2.11270 

4.55167 

9.80627 

.106045 

9.44 

89.1136 

841.232 

3.07246 

9.71597 

2.11344 

4.55328 

9.80974 

.105932 

9.45 

89.3025 

843.909 

3.07409 

9.72111 

2.11419 

4.55488 

9.81320 

.105820 

9.46 

89.4916 

846.591 

3.07571 

9.72625 

2.11494 

4.55649 

9.81666 

.105708 

9.47 

89.6809 

849.278 

3.07734 

9.73139 

2.11568 

4.55809 

9.82012 

.105597 

9.48 

89.8704 

851.971 

3.07896 

9.73653 

2.11642 

4.55970 

9.82357 

.105485 

9.49 

90.0601 

854.670 

3.08058 

9.74166 

2.11717 

4.56130 

9.82703 

.105374 

3.50 

90.2500 

857.375 

3.08221 

9.74679 

2.11791 

4.56290 

9.83048 

.105263 

28 


MA  THEM  A  TICS 


n 

71* 

n3 

V^ 

VlOn 

ft 

•fton 

«S55|  i 

9.51 

90.4401 

860.085 

3.08383 

9.75192 

2.11865 

4.56450 

9.83392 

.105153 

9.52 

90.6304 

862.801 

3.08545 

9.75705 

2.11940 

4.56610 

9.83737 

.105042 

9.53 

90.8209 

865.523 

3.08707 

9.76217 

2.12014 

4.56770 

9.84081 

.104932 

9.54 

91.0116 

868.251 

3.08869 

9.76729 

2.12088 

4.56930 

9.84425 

.104822 

9.55 

91.2025 

870.984 

3.09031 

9.77241 

2.12162 

4.57089 

9.84769 

.104712 

9.56 

91.3936 

873.723 

3.09192 

9.77753 

2.12236 

4.57249 

9.85113 

.104603 

9.57 

91.5849 

876.467 

3.09354 

9.78264 

2.12310 

4.57408 

9.85456 

.104493 

9.58 

91.7764 

879.218 

3.09516 

9.78775 

2.12384 

4.57568 

9.85799 

.104384 

9.59 

91.9681 

881.974 

3.09677 

9.79285 

2.12458 

4.57727 

9.86142 

.104275 

9.60 

92.1600 

884.736 

3.09839 

9.79796 

2.12532 

4.57886 

9.86485 

.104167 

9.61 

92.3521 

887.504 

3.10000 

9.80306 

2.12605 

4.58045 

9.86827 

.104058 

9.62 

92.5444 

890.277 

3.10161 

9.80816 

2.12679 

4.58203 

9.87169 

.103950 

9.63 

92.7369 

893.056 

3.10322 

9.81326 

2.12753  4.58362 

9.87511 

.103842 

9.64 

92.9296 

895.841 

3.10483 

9.81835 

2.12826  4.58521 

9.87853 

.103734 

9.65 

93.1225 

898.632 

3.10644 

9.82344 

2.12900 

4.58679 

9.88195 

.103627 

9.66 

93.3156 

901.429 

3.10805 

9.82853 

2.12974 

4.58838 

9.88536 

.103520 

9.67 

93.5089 

904.231 

3.10966 

9.«3:it>2 

2.13047 

4.58996 

9.88877 

.103413 

9.68 

93.7024 

907.039 

3.11127 

9.83870 

2.13120 

4.59154 

9.89217 

.103306 

9.69 

93.8961 

909.853 

3.11288 

9.84378 

2.13194 

4.59312 

9.89558 

.103199 

9.70 

94.0900 

912.673 

3.11448 

9.84886 

2.13267 

4.59470 

9.89898 

.103093 

9.71 

94.2841 

915.499 

3.11609 

9.85393 

2.13340 

4.59628 

9.90238 

.102987 

9.72 

94.4784 

918.330 

3.11769 

9.85901 

2.13414 

4.59786 

9.90578 

.102881 

9.73 

94.6729 

921.167 

3.11929 

9.S6408 

2.13487 

4.59943 

9.90918 

.102775 

9.74 

94.8676 

924.010 

3.12090 

9.86914 

2.13560 

4.60101 

9.91257 

.102669 

9.75 

95.0625 

926.859 

3.12250 

9.87421 

2.13633 

4.60258 

9.91596 

.102564 

9.76 

95.2576 

929.714 

3.12410 

9.87927 

2.13706 

4.60416 

9.91935 

.102459 

9.77 

95.45-29 

932.575 

3.12570 

9.88433 

2.13779 

4.60573 

9.92274  j  .102354 

9.78 

95.6484 

935.441 

3.12730 

9.88939 

2.13852 

4.60730 

9.92612 

.102250 

9.79 

95.8441 

938.314 

3.12890 

9.89444 

2.13925 

4.60887 

9.92950 

.102145 

9.80 

96.0400 

941.192 

3.13050 

9.89949 

2.13997 

4.61044 

9.93288 

.102041 

9.81 

96.2361 

944.076 

3.13209 

9.90454 

2.14070 

4.61200 

.101937 

9.82 

96.4324 

946.966 

3.13369 

9.90959 

2.14143 

4.61357 

9.93'.t«4  .101833 

9.83 

96.62*9 

949.862 

3.13528 

9.91464 

2.14216 

4.61513 

9.94801   .101729 

9.84 

96.*256 

952.764 

3.136*8 

9.91968 

2.14288 

4.61670 

9.94638  .101626 

9.85 

97.0225 

955.672 

3.13847 

9.92472 

2.14361 

4.61826 

9.94975 

.101528 

9.86 

97.2196 

958.585 

3.14006 

9.92975 

2.14433 

4.61983 

9.95311 

.101420 

9.87 

97.4169 

961.505 

3.14166 

9.93479 

2.14506 

4.62139 

0.96648 

.101317 

9.88 

97.6144 

964.430 

3.14325 

9.93982 

2.14578 

4.62295 

9.95984 

.101215 

9.83 

97.8121 

967.362 

3.144H4 

9.94485 

2.14651 

4.62451 

9.96320 

.101112 

9.90 

98.0100 

970.299 

3.14643 

9.94987 

2.14723 

4.62607 

9.96655 

.101010 

9.91 

98.2081 

973.242 

3.14802 

9.95490 

2.14795 

4.62762 

9.96991 

.100908 

9.92 

98.4064 

976.191 

3.14960 

9.95992 

2.14867 

4.62918 

9.97326 

.100807 

9.93 

98.6049 

979.147 

3.15119 

9.96494 

2.14940 

4.63073 

9.97661 

.100705 

9.94 

9H.H036 

982.108 

3.15278' 

9.96995 

2.15012 

4.63229 

9.97996 

.100604 

9.95 

99.0025 

985.075 

3.15436 

9.97497 

2.15084 

4.63384 

9.98331 

.100503 

9.96 

99.2016 

988.048 

3.15595 

9.97998 

2.15156 

4.63539 

9.98665 

.100402 

9.97 

99.4009 

991.027 

3.15753 

<t.98499 

2.15228 

4.63694 

<».98999 

.100301 

9.98 

99.6004 

994.012 

3  15911 

9.9*999 

2.15300 

4.63849 

9.99333 

.100200 

0.99 

99.*001 

997.003 

3.16070 

9.99.MK) 

2.15372 

4.64004 

9.99667 

.100100 

10.00 

100.000 

1000.00 

3.16228 

10.0000 

2.15443 

4.64159 

10.0000 

.100000 

MATHEMATICS  29 

FORMULAS 

A  formula  is  a  brief  statement  of  a  rule,  in  which  letters  or 
other  symbols  are  used  to  denote  the  different  quantities 
involved.  For  example,  the  rule  for  finding  the  volume  of  a 
rectangular  prism  is  as  follows:  The  volume  of  a  rectangular 
prism  is  equal  to  the  product  of  the  length,  width,  and  height  of 
the  prism.  If  the  dimensions  of  the  prism  are  taken  in  inches, 
the  volume  will  be  in  cubic  inches;  if  they  are  taken  in  feet, 
the  volume  will  be  in  cubic  feet;  and  so  on.  Suppose,  however, 
that  the  volume  is  denoted  by  v,  the  length  by  I,  the  width 
by  w,  and  the  height  by  h.  Then,  the  foregoing  rule  may 
be  stated  much  more  simply  and  concisely  by  the  formula 
v  =  lXwXh.  This  formula  indicates  that  the  volume  v  is 
equal  to  the  product  of  the  length  I,  the  width  w,  and  the  height 
h  of  the  prism.  Where  several  letters  are  multiplied  together 
in  a  formula,  it  is  customary  to  omit  the  multiplication  signs, 
the  multiplication  then  being  taken  for  granted.  The  fore- 
going formula,  therefore,  would  ordinarily  be  written  v  =  lwh, 
The  multiplication  sign  must  not  be  omitted  between  numbers 
that  are  to  be  multiplied  together. 

As  may  be  seen  from  the  example  just  given,  a  formula 
consists  of  two  parts  separated  by  the  sign  of  equality.  The 
letters  or  symbols  denoting  the  quantities  that  are  known  are 
usually  placed  at  the  right  of  the  equality  sign,  and  the  letter 
or  symbol  designating  the  value  to  be  found  is  placed  at  the 
left  of  the  equality  sign.  To  apply  a  formula  to  the  solution 
of  an  example  a  numerical  value  is  substituted  for  each  letter 
that  denotes  a  known  quantity,  and  the  indicated  mathematical 
operations  are  then  performed.  Care  must  be  observed,  in 
using  a  formula,  to  have  all  weights,  dimensions,  or  other 
values  expressed  in  the  units  required  by  the  formula. 

Letters  with  additional  marks,  such  as  O ',  a",  di,  Ta,  etc., 
are  often  found  in  formulas  when  similar  quantities  are  to  be 
represented  by  the  same  letter  and  yet  to  be  distinguished 
from  one  another.  The  marks  '  "  are  termed  prime  and 
second,  respectively,  and  the  marks  i  and  a  are  termed  sub- 
scripts or  subs.  The  four  examples  just  given  are  read  large 
C  prime,  a  second,  d  sub  one,  and  large  T  sub  a.  Parentheses 
4 


30  MA  THEM  A  TICS 

and  brackets  are  used  in  formulas  to  indicate  that  the  quan- 
tities enclosed  by  them  are  to  be  subjected  to  the  same  opera- 
tion. The  sign  —  before  an  expression  in  parentheses  or 
brackets  affects  the  entire  expression,  and  if  the  parentheses  or 
brackets  are  removed,  the  signs  +  and  —  within  them  must 
be  interchanged;  but  if  the  sign  +  precedes  the  brackets, 
they  may  be  removed  without  changing  any  signs.  For 
example,  the  expression  212— (36+75  — 49)  becomes,  when 
the  parentheses  are  removed,  212-36-75+49;  but  the 
removal  of  the  brackets  from  the  expression  65 +  [20 +9— 14] 
gives  65+20+9  —  14.  The  multiplication  sign  is  ordinarily 
omitted  before  and  after  parentheses  or  brackets,  and  before 
the  radical  sign;  thus,  the  expressions  36 X(  18 +22) ,[760  —  315J 
X1.07,  and  .21 X  VT40  —  27  would  ordinarily  be  written 
36(18+22),  [760-315]1.07,  and  .21A/140-27.  The  following 
examples  will  serve  to  illustrate  the  use  of  formulas. 

EXAMPLE. — What  is  the  volume  of  a  block  of  cast  iron  28  in. 
long,  15  in.  wide,  and  12  in.  high? 

SOLUTION. — Applying  the  formula  previously  given,  and 
substituting  28  for  /,  15  for  w,  and  12  for  h,  the  volume  is 
r  =  28X15X12  =  5,040cu.  in. 

One  of  the  most  familiar  formulas,  to  the  operating  engineer, 
is  that  used  for  finding  the  indicated  horsepower  of  an  engine. 
This  formula,  as  usually  stated,  is 

PLAN 

33,000 

in  which  H  =  indicated  horsepower; 

P  =  mean  effective  pressure  on  piston,  in  pounds  per 
square  inch; 

L  =  length  of  stroke,  in  feet; 

A  =area  of  piston,  in  square  inches; 

N  =  number  of  working  strokes  per  minute. 
The  formula  as  stated  may  be  used  to  find  the  horsepower 
of  any  engine,  provided  the  values  of  the  quantities  denoted 
by  P,  L,  A,  and  N  are  known.  But  sometimes  it  is  desired 
to  find  some  other  quantity,  as  for  example,  the  diameter  of 
cylinder  required  to  produce  a  certain  horsepower,  or  the  mean 
effective  pressure  necessary  to  produce  the  desired  power. 


MATHEMATICS  31 

To  find  these  quantities,  the,  order  of  the  terms  in  the  fore- 
going formula  must  be  altered,  bringing  the  values  to  be 
found  to  the  left  of  the  equality  sign  and  the  remainder  to 
the  right.  This  operation  is  called  a  transformation  of  a 
formula.  The  horsepower  formula,  transformed  so  as  to  give 
the  values  of  the  piston  area  and  the  mean  effective  pressure 
necessary  to  produce  a  desired  horsepower,  are 

33,0007? 
=     PLN 
and 

33.00Qg 

LAN 

EXAMPLE.  —  Find  the  diameter  of  the  piston  of  a  steam  engine 
that  is  designed  to  produce  40  H.  P.,  if  the  stroke  is  30  in., 
the  mean  effective  pressure  is  28  Ib.  per  sq.  in.,  and  the  speed 
is  75  R.  P.  M. 

SOLUTION.  —  The  length  of  stroke  in  feet  is  L  =  30-=-12 
=  2.5  ft.;  the  mean  effective  pressure  is  P  —  2S  Ib.  per  sq.  in.; 
as  there  are  two  working  strokes  to  each  revolution,  2V  =  2X75 
=  150;  and  //  =  40.  Substituting  these  values  in  the  formula 
for  the  area  of  the  piston, 

33,000X40 


The  diameter  of  a  circle  having  an  area  of  125.7  sq.  in,  is 
about  12f  in.  The  required  diameter  of  the  piston,  or  of  the 
cylinder,  therefore,  is  12|  in. 

If  a  segment  of  a  circle  is  not  greater  than  a  semicircle,  its 
area  may  be  found  by  the  formula 

irrzE     c 

A=  ---  (r-h), 
360     2 

in  which  A  =  area  of  segment  ; 
7r  =  3.1416; 
r  =  radius  of  circle; 

E  =  angle,  in  degrees,  obtained  by  drawing  lines  from 
the  center  to  the  extremities  of  arc  of  segment; 
c  =  chord  of  segment; 
h  =  height  of  segment. 


52  MA  THEM  A  TICS 

EXAMPLE. — A  segment  of  a  circle  having  a  radius  of  7.5  in. 
is  1.91  in.  high  and  its  chord  is  10  in.  long.  If  the  angle 
subtended  by  the  chord  is  83.46°,  what  is  the  area  of  the 
segment? 

SOLUTION. — Substituting  the  given  values  in  the  foregoing 
formula, 

3.1416X7.52X83.46      10 
360  2 

=  40.97  —  27.95  =  13.02  sq.  in.,  nearly. 

If  the  lengths  of  the  sides  of  a  triangle  are  known,  the  area 
may  be  found  by  the  formula 
b 


in  which  A  denotes  the  area  of  the  triangle  and  a,  b,  and  c 
•denote  the  lengths  of  the  three  sides. 

EXAMPLE. — What  is  the  area  of  a  triangle  whose  sides  are 
21  ft.,  46  ft.,  and  50  ft.  long? 

SOLUTION. — In  order  to  apply  the  formula,  let  a  represent 
the  side  that  is  21  ft.  long;  b,  the  side  that  is  50  ft.  long;  and 
-c,   the  side  that  is  46  ft.   long.     Then,   substituting  in  the 
formula, 
50 


_ 

=  25  V441  -8.252  =  25  \441  -  68.0625  =  25  \372.9375 

=  25X19.312  =  482.8  sq.  ft.,  nearly. 

EXAMPLE.—  When  x  =  8  and  y  =  6,  what  is  the  value  of  m  in 
the  following:  _ 


SOLUTION.  —  Substituting, 
m 


4X8X6 
16+2.02  =  18.02 


MA  THEM  A  TICS 


33 


MENSURATION 

MEANINGS  OF  SYMBOLS 

In  the  following  formulas,  the  letters  have  the  meanings 
here  given,  unless  otherwise  stated: 
D  =  larger  diameter; 
d  =  smaller  diameter; 
R  —  radius  corresponding  to  D ; 
r  =  radius  corresponding  to  d\ 
p  —  perimeter  or  circumference ; 
C  =  area  of  convex  surface  =  area  of  flat  surface  that  can  be 

rolled  into  the  shape  shown; 

5  =  area  of  entire  surf  ace  =  C+ area  of  the  end  or  ends; 
A  =  area  of  plane  figure ; 
IT  =  3. 1416,  nearly  =  ratio    of    circumference  of  any  circle  to 

its  diameter; 
V  =  volume  of  solid. 
The  other  letters  used  will  be  found  on  the  illustrations. 

TRIANGLES 

Using  letters  to  denote  the  angles, 
D  =B+C 
B  =D-C 

E'  =  E  B'  =  B 

For  a  right  triangle,  c  being  the  hypotenuse, 


If  c  =  length  of  side  opposite  an 
acute  angle  of  an  oblique  triangle, 
and  the  distance  e  is  known, 

-2be 
h 


If  c  =  length  of  side  opposite  an  obtuse  angle 
of  an  oblique  triangle, 


34 


MA  I II  EM  A  TICS 


Any  triangle  inscribed  in  a  semicircle  is  a  right  triangle,  and 

c:b  =  a:h 
fci\«.  J 


ab     ce 
c      a 


For  any  triangle, 


2b 


A1so.  A  = 

in  which  s=$(a+b  +  c). 


-  a)  (s  -  b)  (s  -  c) 


RECTANGLE  AND  PARALLELOGRAM 

-7  A  =  ab 

TRAPEZOID 


TRAPEZIUM 

Divide  the  figure  into  two  triangles  and  a  trapezoid;  then, 


or,  A  =  \[bh' 

Or,  divide  into  two  triangles  by  drawing  a 
diagonal.  Considering  the  diagonal  as  the  base 
of  both  triangles,  call  its  length  /,  and  call 
the  altitudes  of  the  triangles  hi  and  fo;  then, 


REGULAR  POLYGONS 

Divide  the  polygon  into  equal  triangles  and 
find  the  sum  of  the  partial  areas.  Otherwise, 
square  the  length  of  one  side  and  multiply  by 
proper  number  from  the  following  table: 


MATHEMATICS 


35 


Name 
Triangle 

No. 
Sides 
3 

Multi- 
plier 
.433 

Name 
Heptagon.  . 

No. 
Sides 

7 

Multi- 
plier 
3.634 

Square 

4 

1.000 

Octagon 

8 

4.828 

Pentagon 

5 

1.720 

Nonagon.  .  . 

9 

6.182 

Hexagon  

6 

2.598 

Decagon  .  .  . 

..      10 

7.694 

IRREGULAR  AREAS 

Divide  the  area  into  trapezoids,  triangles,  parts 
of  circles,  etc.,  and  find  the  sum  of  the  partial 
areas. 

If  the  figure  is  very  irregular,  the  approximate 
area  may  be  found  as  follows:  Divide  the  figure 
into  trapezoids  by  equidistant  parallel  lines  b,  c,  d, 
etc.,  and  measure  the  lengths  of  these  lines.  Then, 
calling  a  the  first  and  n  the  last  length,  and  y  the  width  of  strips, 


SECTOR 

If  I  denotes  the  length  of  the  arc,  and  E*  the  angle  in  degrees 
and  decimals  of  a  degree, 

Er 

••  .0175  Er,  nearly 


V 


Then, 


57.296 


A  =  --  =  .008727r2£ 
360 


CIRCLE 


*If  the  angle  E  is  stated  in  degrees,  minutes,  and  seconds, 
the  minutes  and  seconds  must  be  reduced  to  decimals  of  a 
degree.  To  do  this,  divide  the  number  of  minutes  by  60  and 
the  number  of  seconds  by  3,600  and  add  the  sum  of  the  quo- 
tients to  the  number  of  degrees.  Thus,  28°  42'  18"  =  28 
8+.7+.005  =  28.7050. 


36  MATHEMATICS 

=  3.5449  ^A 
2A     4A  > 


RING 

77 
4 

SEGMENT 
A  =  Wr-c(r-h)} 


>^-°™E 
B.«!!.WW- 

wr  r 


ELLIPSE 


P*-»Y 


£)2-|_d2        (D-d)* 

8.8 


A  =  -Z?d  =  .7854Dd 


CYLINDER 

C  =  7rdA 

S  =  2nrh+2*r* 


4  7T 

*The  perimeter  of  an  ellipse  cannot  be  exactly  determined 
without  a  very  elaborate  calculation,  and  this  formula  is 
merely  an  approximation  giving  close  results. 


MATHEMATICS 


37 


FRUSTUM  OF  CYLINDER 

h  =  5  sum  of  greatest  and  least  heights 


=  Trdh+-d2+area  of  elliptic  top 


PRISM  OR  PARALLELOPIPED 

C  =  Ph 

S  =  Ph+2A 

For  prisms   with   regular   polygons    as 
bases,   P  —  length  of  one  side  X  number  of  sides. 

To  obtain  area  of  base,  if  it  is  a  polygon,  divide  it  into  tri- 
angles and  find  sum  of  partial  areas. 


FRUSTUM  OF  PRISM 

If  a  section  perpendicular  to  the  edges  is  a 
triangle,  square,  parallelogram,  or  regular  poly- 


gon,  V 


sum  of  lengths  of  edges 


number  of  edges 


—  X  area  of  right 


section. 


SPHERE 


=  4.1888r3 

CIRCULAR  RING 

D  =  mean  diameter; 
R  =  mean  radius. 


V  =  27r2#r2  =  2.4674Dd2 
WEDGE 


MATHEMATICS 


CIRCUMFERENCES   AND    AREAS   OF    CIRCLES    FROM 
1-64  TO  100 


Diam. 

Circum  . 

Area 

Diam. 

Circum. 

Area 

A 

.0491 

.0002 

4 

12.5664 

12.5664 

A 

.0982 

.0008 

*i 

12.9591 

13.3641 

A 

.1963 

.0031 

4: 

13.3518 

14.1863 

.3927 

.0123 

4 

13.7445 

15.0330 

TS 

.5890 

.0276 

4 

14.1372 

15.9043 

£ 

.7854 

.0491 

4 

14.5299 

16.8002 

-fg 

.9817 

.0767 

4 

14.9226 

17.7206 

• 

1.1781 

.1104 

4 

• 

15.3153 

18.6555 

JL 

1.3744 

.1503 

5 

15.7080 

19.6350 

I 

1.5708 

.1963 

5j 

16.1007 

20.6290 

JL 

1.7671 

.2485 

5 

16.4934 

21.6476 

I 

1.9635 

.3068 

5 

16.8861 

22.6907 

1  h 

2.1598 

.3712 

5 

17.2788 

23.7583 

• 

2.3562 

.4418 

5 

17.6715 

24.8505 

H 

2.5525 

.5185 

5 

18.0642 

25.9673 

£ 

2.7489 

.6013 

5 

18.4569 

27.1086 

!  •' 

2.9452 

.6903 

6 

18.8496 

28.2744 

1 

3.1416 

.7854 

61 

19.2423 

29.4648 

l 

3.5343 

.9940 

6 

19.6350 

30.  (1797 

3.9270 

1.2272 

6 

20.0277 

31.9191 

4.3197 

1.4849 

6J 

20.4204 

33.1831 

4.7124 

1.7671 

6 

20.8131 

3-1.-4717 

5.1051 

2.0739 

61 

21.2058 

35.7848 

5.4978 

2.4053 

6 

21.5985 

37.1224  " 

5.8905 

2.7612 

7 

21.9912 

38.4846 

2 

6.2832 

3.1416 

7 

22.3839 

39.8713 

2 

6.6759 

3.5466 

7 

22.7766 

41.2826 

2 

7.0686 

3.9761 

7 

23.1693 

42.7184 

2 

7.4613 

4.4301 

7 

23.5620 

44.1787 

2 

7.8540 

4.9087 

7 

23.9547 

•{.->.  <;<;;w 

2 

8.2467 

5.4119 

7- 

24.3474 

47.173] 

2 

8.6394 

5.9396 

7 

• 

24.7401 

48.7071 

2 

9.0321 

6.4918 

8 

25.1328 

50.2656 

3 

9.4248 

7.0686 

8} 

255255 

51.8487 

3 

9.8175 

7.6699 

8 

25.9182 

53.4563 

3 

10.2102 

8.2958 

8^ 

26.3109 

55.0884 

3 

10.6029 

8.9462 

8^ 

26.7036 

56.7451 

3 

10.  w-,r, 

9.6211 

8! 

27.0963 

58.4264 

3 

1  l  3883 

10.  :•(_'<)») 

8; 

27.4890 

60.1322 

3 

11.7810 

11.0447 

8 

27.8817 

61.8625 

3 

12.1737 

11.7933 

9 

28.2744 

63.6174 

MATHEMATICS 
TABLE — (Continued) 


39 


Diam. 

Circurn  . 

Area 

Diam. 

Circum. 

Area 

9J 

28.6671 

65.3968 

194 

61.2612 

298.648 

91 

29.0598 

67.2008 

191 

62.0466 

306.355 

91 

29.4525 

69.0293 

20 

62.8320 

314.160 

94 

29.8452 

70.8823 

201 

63.6174 

322.063 

91 

30.2379 

72.7599 

204 

64.4028 

330.064 

9| 

30.6306 

74.6621 

20  1 

65.1882 

338.164 

31.0233 

76.589 

21 

65.9736 

346.361 

ios 

31.4160 

78.540 

211 

66.7590 

354.657 

101 

32.2014 

82.516 

214 

67.5444 

363.051 

104 

32.9868 

86.590 

211 

68.3298 

371.543 

101 

33.7722 

90.763 

22 

69.1152 

380.134 

11 

34.5576 

95.033 

221 

69.9006 

388.822 

11* 

35.3430 

99.402 

224 

70.6860 

397.609 

•  114 

36.1284 

103.869 

22| 

71.4714 

406.494 

ill 

36.9138 

108.434 

23 

72.2568 

415.477 

12 

37.6992 

113.098 

231 

73.0422 

424.558 

12J 

38.4846 

117.859 

234 

73.8276 

433.737 

124 

39.2700 

122.719 

23| 

74.6130 

443.015 

121 

40.0554 

127.677 

24 

75.3984 

452.390 

13 

40.8408 

132.733 

241 

76.1838 

461.864 

13J 

41.6262 

137-887 

244 

76.9692 

471.436 

134 

42.4116 

143.139 

24J 

77.7546 

481.107 

131 

43.1970 

148.490 

25 

78.5400 

490.875 

14 

43.9824 

153.938 

251 

79.3254 

500.742 

141 

44.7678 

159.485 

254 

80.1108 

510.706 

144 

45.5532 

165.130 

251 

80.8962 

520.769 

14f 

46.3386 

170.874 

26 

81.6816 

530.930 

15 

47.1240 

176.715 

261 

82.4670 

541.190 

151 

47.9094 

182.655 

264 

83.2524 

551.547 

154 

48.6948 

188.692 

261 

84.0378 

562.003 

15* 

49.4802 

194.828 

27 

84.8232 

572.557 

16 

50.2656 

201.062 

271 

85.6086 

583.209 

161 

51.0510 

207.395 

274 

86.3940 

593.959 

164 

51.8364 

213.825 

271 

87.1794 

604.807 

16f 

52.6218 

220.354 

28 

87.9648 

615.754 

17 

53.4072 

226.981 

281 

88.7502 

626.798 

171 

54.1926 

233.706 

284 

89.5356 

637.941 

174 

54.9780 

240.529 

28f 

90.3210 

649.182 

171 

55.7634 

247.450 

29 

91.1064 

660.521 

18 

56.5488 

254.470 

291 

91.8918 

671.959 

181 

57.3342 

261.587 

294 

92.6772 

683.494 

184 

58.1196 

268.803 

291 

93.4626 

695.128 

18} 

58.9050 

276.117 

30 

94.2480 

706.860 

19 

59.6904 

283.529 

301 

95.0334 

718.690 

191 

60.4758 

291.040 

304 

95.8188 

730.618 

40 


MATHEMATICS 
TABLE — (Continued) 


Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

30| 

96.6042 

742.645 

42 

131.947 

1,385.45 

31 

97.3896 

754.769 

42* 

132.733 

,401  .99 

3li 

98.1750 

766.992 

42* 

133.518 

,418.63 

31* 

98.9604 

779.313 

422 

134.303 

,435.37 

311 

99.7458 

791.732 

43 

135.089 

,452.20 

32 

100.5312 

804.250 

43* 

135.874 

,469.14 

32* 

101.3166 

816.865 

43* 

136.660 

,486.17 

32* 

102.1020 

829.579 

43  i 

137.445 

,503.30 

32J 

102.8874 

842.391 

44 

138.230 

,520.53 

33 

103.673 

855.301 

44* 

139.016 

,537.86 

33* 

104.458 

868.309 

44* 

139.801 

,555.29 

33* 

105.244 

881.415 

44  J 

140.587 

,572.81 

33J 

106.029 

894.620 

45 

141.372 

,590.43 

34 

106.814 

907.922 

45* 

142.157 

,608.16 

34* 

107.600 

921.323 

45* 

142.943 

,625.97 

34* 

108.385 

934.822 

452 

143.728 

,643.89 

34J 

109.171 

948.420 

46 

144.514 

,661.91 

35 

109.956 

962.115 

46* 

145.299 

,680.02 

35* 

110.741 

975.909 

46* 

146.084 

,698.23 

35* 

111.527 

989.800 

46J 

146.870 

,716.54 

351 

112.312 

1,003.790 

47 

147.655 

,734.95 

36 

113.098 

1,017.878 

47* 

148.441 

1,753.45 

36* 

113.883 

1,032.065 

47* 

149.226 

1,772.06 

36* 

114.668 

1,046.349 

47| 

150.011 

1,790.76 

36J 

115.454 

1,060.732 

48 

150.797 

1,809.56 

37 

116.239 

1,075.213 

48* 

151.582 

1,828.46 

37* 

117.025 

1,089.792 

48* 

152.368 

1  ,847.46 

37* 

117.810 

1,104.469 

48J 

153.153 

1  ,866.55 

37J 

118.595 

,119.244 

49 

153.938 

1,885.75 

38 

119.381 

,134.118 

49* 

154.724 

1,905.04 

38* 

120.166 

,149.089 

49* 

155.509 

1,924.43 

38* 

120.952 

,164.159 

49| 

156.295 

1,943.91 

38  i 

121.737 

,179.327 

50 

157.080 

1,963.50 

39 

122.522 

,194.593 

50* 

158.651 

2,002.97 

39* 

123.308 

,209.958 

51 

160.222 

2,042.83 

39* 

124.093 

,225.420 

51* 

161.792 

2,083.08 

39j 

124.879 

.240.981 

52 

163.363 

2,123.72 

40 

125.664 

,256.640 

52* 

164.934 

2,164.76 

40* 

126.449 

,272.400 

53 

166.505 

2,206.19 

40* 

127.235 

,288.250 

53* 

168.076 

2,248.01 

40| 

128.020 

,304.210 

54 

169.646 

2,290.23 

41 

128.806 

,320.260 

54* 

171.217 

2,332.83 

41* 

129.591 

,336.410 

55 

172.788 

2,375.83 

41* 

130.376 

,352.660 

55* 

174.359 

2,419.23 

41! 

131.162 

1  ,369.000 

56 

175.930 

2,463.01 

MA  THEM  A  TICS 
TABLE — (Continued) 


41 


Diam. 

Circum. 

Area 

Diam. 

Circum. 

Area 

56* 

177.500 

2,507.19 

78* 

246.616 

4,839.83 

57 

179.071 

2,551.76 

79 

248.186 

4,901.68 

57* 

180.642 

2,596.73 

79* 

249.757 

4,963.92 

58 

182.213 

2,642.09 

80 

251.328 

5,026.56 

58* 

183.784 

2,687.84 

80* 

252.899 

5,089.59 

59 

185.354 

2,733.98 

81 

254.470 

5,153.01 

59* 

186.925 

2,780.51 

81* 

256.040 

5,216.82 

60 

188.496 

2,827.44 

82 

257.611 

5,281.03 

60* 

190.067 

2,874.76 

82* 

259.182 

5,345.63 

61 

191.638 

2,922.47 

83 

260.753 

5,410.62 

61* 

193.208 

2,9.0.58 

83* 

262.324 

5,476.01 

62 

194.779 

3,019.08 

84 

263.894 

5,541.78 

62* 

196.350 

3,067.97 

84* 

265.465 

5,607.95 

63 

197.921 

3,117.25 

85 

267.036 

5,674.51 

63* 

199.492 

3,166.93 

85* 

268.607 

5,741.47 

64 

201.062 

3,217.00 

86 

270.178 

5,808.82 

64* 

202.633 

3,267.46 

86* 

271.748 

5,876.56 

65 

204.204 

3,318.31 

87 

273.319 

5,944.69 

65* 

205.775 

3,369.56 

87* 

274.890 

6,013.22 

66 

207.346 

3,421.20 

88 

276.461 

6,082.14 

66* 

208.916 

3,473  24 

88* 

278.032 

6,151.45 

67 

210.487 

3,525.66 

89 

279.602 

6,221.15 

67* 

212.058 

3,578.48 

89* 

281.173 

6,291.25 

68 

213.629 

3,631.69 

90 

282.744 

6,361.74 

68* 

215.200 

3,685.29 

90* 

284.315 

6,432.62 

69 

216.770 

3,739.29 

91 

285.886 

6,503.90 

69* 

218.341 

3,793.68 

91* 

287.456 

6,575.56 

70 

219.912 

3,848.46 

92 

289.027 

6,647.63 

70* 

221.483 

3,903.63 

92* 

290.598 

6,720.08 

71 

223.054 

3,959.20 

93 

292.169 

6,792.92 

71* 

224.624 

4,015.16 

93* 

293.740 

6,866.16 

72 

226.195 

4,071.51 

94 

295.310 

6,939.79 

72* 

227.766 

4,128.26 

94* 

296.881 

7,013.82 

73 

229.337 

4,185.40 

95 

298.452 

7,088.24 

73* 

230.908 

4,242.93 

95* 

300.023 

7,163.04 

74 

232.478 

4,300.85 

96 

301.594 

7,238.25 

74* 

234.049 

4,359.17 

96* 

303.164 

7,313.84 

75 

235.620 

4,417.87 

97 

304.735 

7,389.83 

75* 

237.191 

4,476.98 

97* 

306.306 

7,466.21 

76 

238.762 

4,536.47 

98 

307.877 

7.542.98 

76* 

240.332 

4,596.36 

98* 

309.448 

7,620.15 

77 

241.903 

4,656.64 

99 

311.018 

7.697.71 

77* 

243.474 

4,717.31 

99* 

312.589 

7,775.66 

78 

245.045 

4,778.37 

100 

314.160 

7,854.00 

42  USEFUL  TABLES 


USEFUL  TABLES 


UNITS  OF  MEASUREMENT 

LINEAR  MEASURE 

12    inches  (in.) =1  foot ft. 

3    feet =1  yard yd. 

5}  yards =1  rod rd. 

40    rods =1  furlong ....  I fur. 

8    furlongs =1  mile mi. 

mi.  fur.  rd.        yd.         ft.          in. 

1  =  8  =  320=1,760  =  5,280  =  63,360 

There  are  various  other  units  of  length,  such  as  the  league 
=  3  mi.;  the  nautical  mile  =  6,080  ft.;  the  fathom  =  6  ft.;  the 
hand  =  4  in.;  the  span  =  Q  in.;  the  cubit  =  18  in. 

SQUARE  MEASURE 

144    square  inches  (sq.  in.) =1  square  foot sq.  ft. 

9    square  feet =1  square  yard sq.  yd. 

30  J  square  yards =1  square  rod sq.  rd. 

160    square  rods =1  acre A. 

640    acres =1  square  mile sq.  mi. 

sq.  mi.  A.     sq.  rd.        sq.  yd.  sq.  ft.  sq.  in. 

1  =  640  =  102,400  =  3,097,600  =  27,878,400  =  4,014,489,600 

CUBIC  MEASURE 

1,728  cubic  inches  (cu.  in.) =1  cubic  foot cu. 

27  cubic  feet =  1  cubic  yard cu.  yd. 

128  cubic  feet =1  cord cd. 

24  J  cubic  feet =1  porch P. 

1  cu.  yd.  =  27  cu.  ft.  =  46,656  cu.  in. 

MEASURES  OF  ANGLES  OR  ARCS 

60  seconds  (") =1  minute ' 

60  minutes =1  degree ° 

90  degrees =  1  rt.  angle  or  quadrant .  .  D 

360  degrees =1  circle 

1  cir.  =  300° -21, COO' =  1,296,000" 


USEFUL  TABLES  43 

A  quadrant  is  one-fourth  the  circumference  of  a  circle,  or 
90°;  a  sextant  is  one-sixth  of  a  circle,  or  60°.  A  right  angle 
contains  90°.  The  unit  of  measurement  is  the  degree,  or  ^  of 
the  circumference  of  a  circle. 

AVOIRDUPOIS  WEIGHT 

437J  grains  (gr.) =1  ounce oz. 

16    ounces =1  pound Ib. 

100    pounds =1  hundredweight cwt. 

20    cwt.,  or  2,000  Ib =  1  ton T. 

1  T.  =  20  cwt.  =  2,000  Ib.  =  32,000  oz.  X  14,000,000  gr. 
The  avoirdupois  pound  contains  7,000  gr. 

LONG-TON  TABLE 

16  ounces  (oz.) =1  pound Ib. 

112  pounds =  1  hundredweight cwt. 

20  cwt.,  or  2,240  Ib =1  ton T. 

TROY  WEIGHT 

24  grains  (gr.) =1  pennyweight pwt. 

20  pennyweights =1  ounce oz. 

12  ounces =1  pound Ib. 

1  Ib.  =  12  oz.  =  240  pwt.  =  5,760  gr. 

DRY  MEASURE 

2  pints  (pt.) =1  quart qt. 

8  quarts =1  peck pk. 

4  pecks =1  bushel bu. 

1  bu.  =  4  pk.  =  32  qt.  =  64  pt. 

The  U.  S.  struck  bushel  contains  2,150.42  cu.  in.  =  1.2444 
cu.  ft.  By  law,  its  dimensions  are  those  of  a  cylinder  18|  in. 
in  diameter  and  8  in.  deep.  The  heaped  bushel  is  equal  to 
1J  struck  bushels,  the  cone  being  6  in.  high.  The  dry  gallon 
contains  268.8  cu.  in.,  being  f  struck  bushel. 

For  approximations,  the  bushel  may  be  taken  as  1J  cu.  ft.; 
or  1  cu.  ft.  may  be  considered  I  bu. 

The  British  bushel  contains  2,218.19  cu.  in.  =  1.2837  cu.  ft. 
=  1.032  U.S.  bushels. 


44  USEFUL  TABLES 

LIQUID  MEASURE 

4    gills  (gi.) =  1  pint pt. 

2    pints =1  quart qt. 

4    quarts =  1  gallon gal. 

31*  gallons =1  barrel bbl. 

2    barrels,  or  63  gallons ,  =  1  hogshead hhd. 

1  hhd.  =  2  bbl.  =  63  gal.  =  252  qt.  =  504  pt.  =  2,016  gi. 
The  U.  S.  gallon  contains  231  cu.  in.  =  .134  cu.  ft.,  nearly, 
or  1  cu.  ft.  contains  7.481  gal. 

When  water  is  at  its  maximum  density,  1  cu.  ft.  weighs 
62.425  Ib.  and  1  gal.  weighs  8.345  Ib. 

For  approximations,  1  cu.  ft.  of  water  is  considered  equal 
to  7i  gal.,  and  1  gal.  as  weighing  8$  Ib. 

The  British  imperial  gallon,  both  liquid  and  dry,  contains 
277.463  cu.  in.  =  .16057  cu.  ft.,  and  is  equivalent  to  the  volume 
of  10  Ib.  of  pure  water  at  62°  F.  To  reduce  British  to  U.  S. 
liquid  gallons,  multiply  by  1.2.  Conversely,  to  convert  U.  S. 
into  British  liquid  gallons,  divide  by  1.2;  or,  increase  the 
number  of  gallons  $. 

MEASURES  OF  UNITED  STATES  MONEY 

10  mills  (m.) =1  cent c. 

10  cents =1  dime d. 

10  dimes =1  dollar $. 

10  dollars =1  eagle E. 

m.  c.        d.      $     E. 

10=         1 
100=       10=      1 
1,000=     100=    10=   1 
10,000=1,000=100=10=1 

The  term  legal  tender  is  applied  to  money  that  may  be 
legally  offered  in  payment  of  debts.  All  gold  coins  are  legal 
tender  for  their  face  value  to  any  amount,  provided  their 
weight  has  not  diminished  more  than  ifor.  Silver  dollars  also 
are  legal  tender  to  any  amount,  but  silver  coins  of  a  lower 
denomination  than  $1  are  legal  tender  only  for  sums  not 
exceeding  $10.  Nickel  and  copper  coins  are  legal  tender  for 
sums  not  exceeding  25c. 


USEFUL  TABLES 


45 


MEASURES  OF  TIME 

60  seconds  (sec.) =1  minute min. 

60  minutes =1  hour hr. 

24  hours =1  day da. 

7  days =1  week wk. 

4  weeks =1  month mo. 

12  months =1  year yr. 

100  years =1  century C. 

yr.  wk.    da.        hr.          min.  sec. 

1  =  52  =  365  =  8,765  =  525,948  =  31,556,936 

DECIMAL  EQUIVALENTS  OF  PARTS  OF  1  IN. 


1-64 

.015625 

17-64 

.265625 

33-64 

.515625 

49-64 

.765625 

1-32 

.031250 

9-32 

.281250 

17-32 

.531250 

25-32 

.781250 

3-64 

.046875 

19-64 

.296875 

35-64 

.546875 

51-64 

.796875 

1-16 

.062500 

.5-16 

.312500 

9-16 

.562500 

13-16 

.812500 

5-64 

.078125 

21-64 

.328125 

37-64 

.578125 

53-64 

.828125 

3-32 

.093750 

11-32 

.343750 

19-32 

.593750 

27-32 

.843750 

7-64 

.109375 

23-64 

.359375 

39-64 

.609375 

55-64 

.859375 

1-8 

.125000 

3-8 

.375000 

5-8 

.625000 

7-8 

.875000 

9-64 

.140625 

25-64 

.390625 

41-64 

.640625 

57-64 

.890625 

5-32 

.156250 

13-32 

.406250 

21-32 

.656250 

29-32 

.906250 

11-64 

.171875 

27-64 

.421875 

43-64 

.671875 

59-64 

.921875 

3-16 

.187500 

7-16 

.437500 

11-16 

.687500 

15-16 

.937500 

13-64 

.203125 

29-64 

.453125 

45-64 

.703125 

61-64 

.953125 

7-32 

.218750 

15-32 

.468750 

23-32 

.718750 

31-32 

.968750 

15-64 

.234375 

31-64 

.484375 

47-64 

.734375 

63-64 

.984375 

1-4 

.250000 

1-2 

.500000 

3-4 

.750000 

1 

1 

WEIGHTS  AND  SIZES  OF  MATERIALS 

SPECIFIC  GRAVITY 

The  specific  gravity  of  a  substance  is  the  ratio  of  the  weight 
of  any  volume  of  the  substance  to  the  weight  of  an  equal 
volume  of  water  with  solids  and  liquids,  and  air  with  gases. 
The  weight  of  1  cu.  ft.  of  any  solid  or  liquid,  in  pounds  avoir- 
dupois, is  found  by  multiplying  its  specific  gravity  by  62.425. 
The  weight,  in  pounds  avoirdupois,  of  1  cu.  ft.  of  any  gas  at 
atmospheric  pressure  and  at  32°  F.  is  found  by  multiplying 
its  specific  gravity  by  .08073. 
5 


46  USEFUL  TABLES 

WEIGHTS  OF  VARIOUS  SUBSTANCES 


Metals 


Aluminum 

Antimony 

Bismuth 

Brass,  common 

Copper,  cast 

Copper,  rolled 

Gold,  pure  cast 

Iron,  cast 

Iron,  wrought 

Lead,  pure 

Mercury,  at  60°  F 

Silver,  pure 

Steel,  hard 

Steel,  soft 

Tin 

Zinc.. 


Stones  and  Earth 


Asbestos 1110 

Brick 0723 

Chalk 1006 

Clay .0686 

Coal,  anthracite 

Coal,  bituminous .0488 

Earth,  loose 0491 

Emery 1450 

Glass,  flint 

Granite,  Quincy 0958 

Gypsum,  opaque .0783 

Limestone 

Marble,  common 0970 

1012 

Quartz 0961 

Salt,  common 0769 

Sand 0957 

1012 

Soil,  common .0717 

Stone,  common .0910 

Sulphur,  native <>7:<1 


Weight  per 
Cu.  In. 
Pound 


.096 
.242 
.352 

.307 
.314 
.321 
.696 
.260 
.281 
.409 
.491 
.378 
.286 
.283 
.256 
.260 


Weight  per 
Cu.  In. 
Pound 


Specific 
Gravity 


2.660 

6.712 

9.746 

8.500 

8.700 

8.878 

19.258 

7.207 

7.780 

11.330 

13.580 

10.474 

7.919 

7.833 

7.351 

7.101 


Specific 
Gravity 


3  to  3.2 
2.000 
2.784 
1.900 
1.640 
1.436 
1.350 
1.360 
4.000 
3.500 
2.662 
2.168 
2.700 
2.688 
2.800 
2.660 
2.130 
2.660 
2.800 
1.984 
2.520 
2.033 


USEFUL  TABLES 


47 


TABLE — (Continued) 


Dry  Woods 

Weight  per 
Cu.  In. 

Pound 

Specific 
Gravity 

Ash                                   

.0305 

.845 

Beech 

.0308 

.852 

Cedar   American   

.0203 

.561 

Cork                                                 

.0090 

.250 

.0441 

1.220 

Elm                                  

.0202 

.560 

.0481 

1.330 

Mahogany   Honduras  

.0202 

.560 

Maple                                               .    ... 

.0285 

.790 

Oak 

.0343 

.950 

Pine   Southern                

.0260 

.720 

Pine  White 

.0144 

.400  " 

Poplar             

.0138 

.383 

Spruce  

.0181 

.500 

Liquids 

Weight 
per  Cu.  In. 
Pound 

Specific 
Gravity 

Acid,  nitric  
Acid,  sulphuric  
Acid,  muriatic,  or  hydrochloric  
Alcohol,  commercial  

.0440 
.0665 
.0434 
.0301 

1.217 
1.841 
1.200 
.833 

.0286 

.792 

Oil  linseed 

.0340 

.940 

Oil  turpentine   .  .         

.0314 

.870 

Water,  distilled  (62.425  Ib.  per  cu.  ft.)  . 

.0361 

1.000 

Gases  and  Vapors 
At  32°  and  a  Tension  of  1  Atmosphere 

Weight 
per  Cu.  Ft. 
Grains 

Specific 
Gravity 

565.11 

1.0000 

333.10 

.."»894 

Carbonic  acid  

859.00 

1.5201 

Carbonic  oxide  

546.60 
39  10 

.9673 
.0692 

Oxygen  
Sulphureted  hydrogen  

624.80 
663.80 
548.90 

1.1056 
1.1747 
.9713 

Steam  at  21  2°  F  

275.80 

.4880 

48  USEFUL  TABLES 

STANDARD  PIPE  FOR  STEAM,  GAS,  AND  WATER 


Nominal 
Inside 
Diameter 
Inches 

Actual 
Inside 
Diameter 
Inches 

Thick- 
ness 

Inch 

Internal 
Area 
Square 
Inches 

Threads 
Per 
Inch 

Per 
Foot 
Pounds 

| 

.27 

.068 

.06 

27 

.24 

.36 

.088 

.10 

18 

.42 

| 

.49 

.091 

.19 

18 

.56 

i 

.62 

.109 

.30 

14 

.84 

i 

.82 

.113 

.53 

14 

1.12 

1 

1.05 

.134 

.86 

111 

1.67 

H 

1.38 

.140 

1.50 

111 

2.24 

ll 

1.61 

.145 

2.04 

11* 

2.68 

2 

2.07 

.154 

3.36 

lit 

3.61 

2* 

2.47 

.204     . 

4.78 

8 

5.74 

3 

3.07 

.217 

7.39 

8 

7.54 

3i 

3.55 

.226 

9.89 

8 

9.00 

4 

4.03 

.237 

12.73 

8 

10.66 

4J 

4.51 

.246 

15.96 

8 

12.49 

5 

5.05 

.259 

19.99 

8 

14.50 

6 

6.07 

.280 

28.89 

8 

18.76 

7 

7.02 

.301 

38.74 

8 

23.27 

8 

7.98 

.322 

50.02 

8 

28.18 

9 

8.94 

.344 

62.72 

8 

33.70 

10 

10.02 

.366 

78.82 

8 

40.00 

11 

11.00 

.375 

95.03 

8 

45.00 

12 

12.00 

.375 

113.10 

8 

49.00 

WEIGHT  OF  SHEET  IRON  PER  SQUARE  FOOT 


Galvan- 

Num- 

Thick- 

Black 

Num- 

Thick- 

Black 

ized 

ber  of 
Gauge 

ness 
Inch 

Iron 
Pounds 

ber  of 
Gauge 

ness 
Inch 

Iron 
Pounds 

Iron 
Pounds 

1 

.300 

12.0 

16 

.065 

2.6 

3.0 

2 

.284 

11.4 

17 

.058 

2.3 

2.7 

3 

.259 

10.4 

18 

.049 

2.0 

2.3 

4 

.238 

9.5 

19 

.042 

1.7 

2.1 

5 

.220 

8.8 

20 

.035 

1.4 

1.7 

8 

.203 

8.1 

21 

.032 

1.3 

1.5 

7 

.180 

7.2 

22 

.028 

1.1 

1.3 

8 

.165 

6.6 

23 

.025 

1.0 

1.2 

9 

.148 

5.9 

24 

.022 

0.9 

1.1 

10 

.134 

5.4 

25 

.020 

0.8 

1.0 

11 

.120 

4.8 

26 

.018 

0.7 

1.0 

12 

.109 

4.4 

27 

.016 

0.6 

0.9 

18 

.095 

3.8 

28 

.014 

0.6 

0.7 

14 

.083 

3.3 

29 

.013 

0.5 

0.7 

Ifl 

.072 

2.9 

30 

.012 

0.5 

0.6 

USEFUL  TABLES 


49 


EXTRA-STRONG  WROUGHT-IRON  PIPE 


Size      ,  Nominal 
of             Inside 
Pipe     1  Diameter 
Inches    '.     Inches 

Actual 
Outside 
Diameter 
Inches 

Thick- 
ness 

Inch 

Weight 

Foot 
Pounds 

Internal 
Area 
Square 
Inches 

i 

.205 

.405 

.100 

.29 

.03 

| 

•  .294 

.540 

.123 

.54 

.07 

4 

.421 

.675 

.127 

.74 

.14 

i 

.542 

.840 

.149 

1.09 

.23 

3 

.736 

1.050 

.157 

1.39 

.43 

1 

.951 

1.315 

.182 

2.17 

.71 

H 

1.272 

1.660 

.194 

3.00 

1.27 

11 

1.494 

1.900 

.203 

3.63 

1.75 

2 

1.933 

2.375 

.221 

5.02 

2.94 

2i 

2.315 

2.875 

.280 

7.67 

4.21 

3 

2.892 

3.500 

.304 

10.25 

6.57 

3* 

3.358 

4.000 

.321 

12.47 

8.86 

4 

3.818 

4.500 

.341 

14.97 

11.46 

4J 

4.280 

5.000 

.360 

18.22 

14.39 

5 

4.813 

5.563 

.375 

20.54 

18.19 

6 

5.750 

6.625 

.437 

28.58 

25.98 

7 

6.625 

7.625 

.500 

37.67 

34.47 

8 

7.625 

8.625 

.500 

43.00 

45.66 

9 

8.625 

9.625 

.500 

48.73 

58.43 

\0 

9.750 

10.750 

.500 

54.74 

74.66 

11 

10.750 

11.750 

.500 

60.08 

90.76 

12 

11.750 

12.750 

.500 

65.42 

108.43 

WEIGHT  OF  IRON-PIPE  SIZES  OF  SEAMLESS-DRAWN 
BRASS  AND  COPPER  TUBES 


Nominal 
Size 

Outside 
Diameter 

Inside 
Diameter 

Weight,  in  Pounds 
per  Linear  Foot 

Inches 

Inches 

Inches 

Brass 

Copper 

.27 

.30 

.31 

.36 

.43 

.45 

.49 

.58 

.61 

i 

H 

.62 

.80 

.84 

! 

1& 

.82 

1.17 

1.23 

l 

1A 

1.04 

1.67 

1.75 

u 

1- 

1.38 

2.42 

2.54 

li 

1- 

1.61 

2.92 

3.07 

2 

2 

2.06 

4.17 

4.38 

2J 

2 

2.46 

5.00 

5.25 

3 

3 

3.06 

8.00 

8.40 

4 

4 

4.02 

12.00 

12.00 

50  USEFUL  TABLES 

WEIGHT  OF  ROUND  AND  SQUARE  ROLLED  IRON  PER 
LINEAR  FOOT 


Side  or 
Diameter 

Inches 

Weight  Pounds 
per  Foot 

Side  or 
Diameter 

Inches 

Weight  Pounds 
per  Foot 

Round 

Square 

Round 

Square 

A 

.010 

.013 

3J 

39.864 

50.756 

i 

.041 

.053 

4 

42.464 

54.084 

JL. 

.093 

.118 

4 

45.174 

57.517 

i 

.165 

.211 

4 

47.952 

61.055 

.373 

.475 

4 

50.815 

64.700 

?, 

.663 

.845 

4 

53.760 

68.448 

I 

1.043 

1.320 

4f 

56.788 

72.305 

i 

1.493 

1.901 

4? 

59.900 

1 

2.032 

2.588 

4  1 

63.094 

80.333 

1 

2.654 

3.380 

5 

66.350 

84.480 

11 

3.359 

4.278 

5i 

69.731 

88.784 

1: 

4.147 

5.280 

5 

73.172 

93.168 

1! 

5.019 

6.390 

5 

76.700 

97.657 

1 

5.972 

7.604 

5 

80.304 

102.2  10 

1 

7.010 

8.926 

5 

84.001 

io<i.  <);>;•! 

li 

8.128 

10.352 

5 

87.776 

in.  r.-.r. 

1, 

9.333 

11.883 

5 

91.634 

L16.671 

2 

10.616 

13.520 

6 

95.552 

121.664 

2 

11.988 

15.263 

6 

103.704 

132.040 

2 

13.440 

17.112 

6 

112.160 

142.816 

2 

14.975 

19.066 

6 

120.960 

154.012 

2 

16.588 

21.120 

7 

130.048 

165.632 

2 

18.293 

23.292 

7i 

139.544 

177.C.72 

2 

20.076 

25.560 

7i 

149.328 

190.130 

2 

21.944 

27.939 

7J 

L59.456 

203.024 

3 

23.888 

30.416 

8 

169.856 

21<i.33li 

3j 

25.926 

33.010 

8i 

180.696 

230.068 

3 

28.040 

35.704 

84 

1  '.U.  SOS 

244.220 

30.240 

38.503 

8f 

203.260 

2f>S.sOO 

3 

32.512 

41.408 

9 

215.040 

27:-S.7<>2 

3 

34.886 

44.418 

9 

227.152 

2S9.220 

3 

37.332 

47.534 

9 

239.600 

305.056 

WEIGHT  OF  SHEET  LEAD  PER  SQUARE  FOOT 


Thick- 
ness 
Inch 

Weight 
Pounds 

Thick- 
ness 
Inch 

Weight 
Pounds 

Thick- 
ness 
Inch 

Weight 
Pounds 

.017 

.o:5t 
.051 

.Olis 

1 
2 
3 
4 

.085 
.101 
.118 
.135 

5 

(i 
7 
8 

.152 
.169 
.186 
.203 

9 
10 
11 
12 

USEFUL  TABLES 


g.s  s 

So* 


CO  00  CO  •*  iO  CO  t^       | 


'OOMOOXOONNININSCCO 


C  O  O  -*  T)<  00  00 

04  -M  01  01  04  01  01 


Sss 


10  «o  o  t^  oo  o  o  O  •-< 


0  CO  «O  O  00  "-H  CO  ; 

01  O)  Ol  Ol  OJ  ^  CO  : 


P.5 

rtfe 


Tj(Tj<iO<Ot»t>.aOOJO>O-H<NM«.'5®OS'-'       «  MS 


222S3o1ol^cv 


^-S.x 

•*  Ov-     o 


;oi?J^ 


52 


USEFUL  TABLES 


DIMENSIONS  OF  PIPE  FLANGES 

The  table  on  page  51  gives  the  dimensions  of  standard  and 
extra-heavy  pipe  flanges,  the  former  being  the  pressure  up  to 
125  Ib.  per  sq.  in.,  and  the  latter  for  pressures  above  125  and 

STANDARD  AND  EXTRA-GAUGE  STEEL  BOILER 
TUBES 


r\..4. 

Standard 

Nominal  Weight  per  Foot 

Uut- 
side 

Thickness 

Pounds 

Di- 

am- 
eter 

Near- 

Stand- 

One 

Two 

Three 

Four 

est 

ard 

Extra 

Extra 

Extra 

Extra 

In- 

Birm. 

Wirp 

Inch 

Thick- 

Wire 

Wire 

Wire 

Wire 

ches 

w  ire 
Gauge 

ness 

Gauge 

Gauges 

Gauges 

Gauges 

1 

13 

.095 

.90 

1.04 

1.13 

1.24 

1.35 

11 

13 

.095 

1.15 

1.33 

1.45 

1.60 

1.74 

H 

13 

.095 

1.40 

1.62 

1.77 

1.96 

2.14 

11 

13 

.095 

1.66 

1.91 

2.09 

2.31 

2.53 

2 

13 

.095 

1.91 

2.20 

2.41 

2.67 

2.93 

21 

13 

.095 

2.16 

2.49 

2.73 

3.03 

3.32 

2i 

12 

.109 

2.75 

3.05 

3.39 

3.72 

4.12 

2| 

12 

.109 

3.04 

3.37 

3.74 

4.11 

4.56 

3 

12 

.109 

3.33 

3.69 

4.10 

4.51 

5.00 

31 

11 

.120 

3.96 

4.46 

4.90' 

5.44 

5.90 

8| 

11 

.120 

4.28 

4.82 

5.30- 

5.88 

6.38 

31 

11 

.120 

4.60 

5.18 

5.69 

6.32 

6.86 

4 

10 

.134 

5.47 

6.09 

6.76 

7.34 

8.23 

4} 

10 

.134 

6.17 

6.88 

7.64 

8.31 

9.32 

5 

9 

.148 

7.58 

8.52 

9.27 

10.40 

11.23 

6 

8 

.165 

10.16 

11.19 

12.57 

13.58 

14.65 

7 

8 

.165 

11.90 

13.11 

14.74 

15.93 

17.19 

8 

8 

.165 

13.65 

15.04 

16.91 

18.28 

19.73 

0 

7 

.180 

16.76 

19.07 

20.63 

22.27 

24.18 

10 

6 

.203 

21.00 

22.98 

24.82 

26.95 

29.47 

11 

5 

.220 

25.00 

27.30 

29.71 

32.51 

34.29 

12 

4i 

.229 

28.50 

31.19 

34.01 

36.52 

39.92 

13 

4 

.238 

32.06 

35.25 

38.57 

40.70 

45.98 

not  over  250  Ib.  per  sq.  in.  The  dimensions  of  flanges  and  fit- 
tings were  arranged  by  joint  committees  from  the  American 
Society  of  Mechanical  Engineers  and  the  National  Association 
of  Master  Steam  and  Hot-Water  Fitters,  and  after  revision 
and  amplification  were  adopted  by  the  latter  body  and  officially 


USEFUL  TABLES 


e 

as 


T 

-O'-iTt<'-HOt^d>~  r-xcNO'-'r^-t^o-^c: 

-^  r.  —  —  -'  ~  ••'  :•:  n  —  c:  c  5  x  b  io  TJI  -5  co 


II 
* 


^1  O  C5  O  C2  "-O  <-"  L-5  O  •*  LO  Tf  iO  CC  t-  O 

'*t^~-r 
i-<  c;  ci  ~ 


CO  i-i  O  X  l>  ^  '-t  T«I  L-  TT  -M  M  C5 1^.  1-1  >-~  C5  Tf  T*< 
^3  "H  C5  '-C  •*  ^H       l>  TJH  (N  C  t>  (N  t-.  X       O  I-H  ^H 


II 


c  •*  >oo  »-  »oo  -H 

i-ll-Hi-Hi-(C^CvlM'?0 


Li  C5  C5  C5  O  O  O  "*  •*  X  O  »O  1C  O 

2  —  — :  s  ^  ^  ^  w  M  "*  ~  "-^  "^  x 


54  CHEMISTRY  AND  HEAT 

recommended  by  the  former.  Also,  the  American  Society  of 
Heating  and  Ventilating  Engineers  recommended  the  values 
for  the  use  of  its  members.  The  table  gives  the  dimensions 
of  flanges,  but  not  of  fittings.  Another  series  of  values  is  the 
Manufacturers'  1912  Schedule,  which  was  adopted  July  10, 
lltli',  to  take  effect  Oct.  1,  1912.  The  latter  schedule  agrees 
with  the  table  on  page  51,  so  far  as  standard  flanges  are  con- 
cerned, but  has  slightly  different  values  for  extra-heavy  flanges 
for  pipes  over  8  in.  in  diameter. 


CHEMISTRY  AND  HEAT 


CHEMISTRY 

Divisions  of  Matter. —  Matter  is  anything  that  occupies 
space,  and  it  exists  in  three  states,  namely,  solid,  liquid,  and 
gaseous.  It  is  made  up  of  molecules  and  atoms.  A  molecule 
is  the  smallest  portion  of  matter  into  which  a  body  can  be 
divided  and  exist  without  changing  its  nature.  An  atom  is 
an  indivisible  portion  of  matter,  or  the  smaller  particle  pro- 
duced by  dividing  a  molecule.  A  molecule  is  simply  a  group 
of  two  or  more  atoms  that  are  held  together  by  their  natural 
attraction  for  one  another. 

Elements  and  Compounds. — Every  body,  or  every  portion 
of  matter,  is  either  an  element,  a  compound,  or  a  mixture. 
Iron,  silver,  sulphur,  and  oxygen  are  elements;  wood,  coal, 
salt,  and  water  are  compounds;  and  atmospheric  air  is  a  mix- 
ture. An  element  is  a  substance  that  cannot  be  divided  or 
broken  up  into  other  substances;  thus,  if  a  piece  of  silver  is 
divided  and  subdivided,  each  particle  will  still  be  silver.  A 
compound  is  a  substance  that  can  be  divided  into  other  sub- 
stances; thus,  if  an  electric  current  is  passed  through  water, 
the  water  is  decomposed  into  two  gases,  hydrogen  and  oxygen. 
A  mixture  is  simply  a  combination  of  elements  or  compounds 
in  which  each  preserves  its  own  nature;  thus,  air  is  a  mix- 
ture of  oxygen  and  nitrogen  and  minute  proportions  of 
other  gases. 


CHEMISTRY  AND  HEAT 


Symbols  and  Formulas. — Each  of  the  known  elements  is 
designated  by  a  symbol,  which  is  a  letter  or  a  pair  of  letters, 
oftentimes  the  initial  letter  of  the  name  of  the  element.  Thus, 
O  is  the  symbol  for  oxygen,  H  for  hydrogen,  C  for  carbon,  and 
so  on.  When  two  or  more  elements  unite  to  form  a  compound, 
the  symbols  representing  the  elements  in  the  compound  may 
be  connected  in  a  formula,  which  will  show  how  the  atoms  of 
the  elements  combined  to  form  the  compound.  Thus,  H  and 
O  are  the  symbols  of  the  elements  hydrogen  and  oxygen. 
When  these  two  gases  unite  in  certain  proportions,  they  form 
water,  a  compound  whose  formula  is  HiO.  This  formula 
indicates,  first,  that  water  is  composed  of  hydrogen,  H,  and 
oxygen,  O;  and  second,  it  indicates,  by  the  subscript  2,  that  2 
atoms  of  hydrogen  unite  with  1  atom  of  oxygen  to  form  1 

ATOMIC  WEIGHTS  OF  ELEMENTS 


Name  of 

Sym- 

Atomic 

Name  of 

Sym- 

Atomic 

Element 

bol 

Weight 

Element 

bol 

Weight 

Calcium  

Ca 

40.10 

Nitrogen  .... 

.V 

14.04 

Carbon  

C 

12.00 

Oxygen  

0 

16.00 

Chlorine  

Cl 

35.45 

Potassium  .  . 

K 

39.15 

Hydrogen  .  .  . 

H 

1.00 

Sodium  

Xa 

23.05 

Magnesium.  . 

Mg 

24.36 

Sulphur.  .... 

S 

32.06 

molecule  of  water.  The  formula  for  carbon  dioxide  is  COi, 
which  indicates  that  a  molecule  of  carbon  dioxide  consists  of 
1  atom  of  carbon,  C,  and  2  atoms  of  oxygen,  O. 

Atomic  Weight  and  Molecular  Weight. — The  ratio  between 
the  weight  of  an  atom  of  any  element  and  the  weight  of  an 
atom  of  hydrogen  is  termed  the  atomic  weight  of  that  element. 
The  symbols  and  the  atomic  weights  of  a  number  of  the  ele- 
ments most  commonly  met  with  in  steam  engineering  are 
given  in  the  accompanying  table.  By  the  aid  of  the  atomic 
weights,  the  composition  of  any  substance,  by  weight,  may  be 
determined.  For  example,  water  contains  2  atoms  of  hydrogen 
and  1  atom  of  oxygen.  Multiplying  the  number  of  atoms  of 
each  by  the  atomic  weight,  it  is  seen  that  there  are  2X1=2 
parts  of  hydrogen,  by  weight,  and,  IX 16=  16  parts  of  oxygen, 


56  CHEMISTRY  AND  HEAT 

COMMON  NAMES  OF  CHEMICAL  COMPOUNDS 


Chemical  Compound 

Common  Name 

Formula 

Ammonium  chloride.  . 
Ammonium  hydrate  .  . 
Calcium  hydroxide  
Calcium  chloro-hypo- 
chlorite 

Sal  ammoniac  
Liquor  ammonia  
Slaked  lime  

Bleaching  powder  or 

NHtCl 

NH*OH 

Ca(OH)i 

Calcium  oxide.  .  . 

chloride  of  lime  .... 
Quicklime 

Ca(ClO}Cl 
CaO 

Calcium  sulphate  ...  . 
Hydrochloric  acid 

Plaster  of  Paris  
Muriatic  acid 

2CaSOi-H£> 
HCl 

Magnesium  sulphate  . 
Nitric  acid 

Epsom  salts  
Aquafortis 

MgSOi 
HNOt 

Potassium  hydrate  .  . 
Potassium  nitrate  ...  . 
Sodium  carbonate  .  .  . 
Sodium  carbonate 

Caustic  potash  
Niter,  or  saltpeter  
Washing  soda  
Soda  ash 

KOH 
KNOt 

NazCOs'lOHiO 
NaiCOi 

Sodium  chloride  

Common  salt  

NaCl 

Sodium  hydrate  

Caustic  soda  

NaOH 

Sulphuric  acid  

Oil  of  vitriol  

//•2.SOl 

by  weight,  and  the  molecule  contains  2 -f  16  =  18  parts.     The 
weight  of  the  molecule  of  a  substance  is  termed  the  molec 
weight. 


HEAT 


TEMPERATURE 

Thermometric  Scales. — Three  different  scales  are  used 
designating  temperatures,  namely,  the  Fahrenheit  scale,  the 
centigrade  scale,  and  the  Reaumur  scale.  The  last-named 
is  little  used,  however.  Temperatures  on  these  scales  are 
usually  indicated  by  the  abbreviations  F.  or  Fahr.,  C.  or  Cent., 
and  R.  or  Reau.,  respectively.  There  are  three  standard  points 
on  each  scale,  namely,  the  boiling  point  of  water,  at  sea  level, 
the  melting  point  of  ice,  and  the  absolute  zero  of  temperature. 
The  last  indicates  the  point  of  complete  absence  of  heat.  On 
the  Fahrenheit  scale,  the  melting  point  of  ice  is  marked  32 
and  the  boiling  point  of  water  is  marked  212,  and  the  inter- 
vening space  is  divided  into  180  equal  parts,  called  degrees. 


CHEMISTRY  AND  HEAT 


57 


On  the  centigrade  scale,  the  melting  point  of  ice  is  zero,  and  the 
boiling  point  of  water  is  100,  and  there  are  100  divisions,  or 
degrees,  between  these  points.  On  the  Reaumur  scale,  zero 
marks  the  melting  point  of  ice,  and  80  the  boiling  point  of  water. 
Absolute  Zero. — It  has  been  found  by  experiment  that  all 
perfect  gases  will  expand  I\R  of  their  volume  when  heated 
from  zero  to  1°  above  it.  It  is  inferred,  therefore,  that  the 

CENTIGRADE  AND  FAHRENHEIT  DEGREES 


Deg. 
C. 

Deg. 

F. 

Deg. 
C. 

Deg. 
F. 

Deg. 
C. 

Deg. 
F. 

Deg. 
C. 

Deg. 
F. 

0 

32.0 

26 

78.8 

51 

123.8 

76 

168.8 

1 

33.8 

27 

80.6 

52 

125.6 

77 

170.6 

2 

35.6 

28 

82.4 

53 

127.4 

78 

172.4 

3 

37.4 

29 

84.2 

54 

129.2 

79 

174.2 

4 

39.2 

30 

86.0 

55 

131.0 

80 

176.0 

5 

41.0 

31 

87.8 

56 

132.8 

81 

177.8 

6 

42.8 

32 

89.6 

57 

134.6 

82 

179.6 

7 

44.6 

33 

91.4 

58 

136.4 

83 

181.4 

8 

46.4 

34 

93.2 

59 

138.2 

84 

183.2 

9 

48.2 

35 

95.0 

60 

140.0 

85 

185.0 

10 

50.0 

36 

96.8 

61 

141.8 

86 

186.8 

11 

51.8 

37 

98.6 

62 

143.6 

87 

188.6 

12 

53.6 

38 

100.4 

63 

145.4 

88 

190.4 

13 

55.4 

39 

102.2 

64 

147.2 

89 

192.2 

14 

57.2 

40 

104.0 

65 

149.0 

90 

194.0 

15 

59.0 

41 

105.8 

66 

150.8 

91 

195.8 

16 

60.8 

42 

107.6 

67 

152.6 

92 

197.6 

17 

62.6 

43 

109.4 

68 

154.4 

93 

199.4 

18 

64.4 

44 

111.2 

69 

156.2 

94 

201.2 

19 

66.2 

45 

113.0 

70 

158.0 

95 

203.0 

20 

68.0 

46 

114.8 

71 

159.8 

96 

204.8 

21 

69.8 

47 

116.6 

72 

161.6 

97 

206.6 

22 

71.6 

48 

118.4 

73 

163.4 

98 

208.4 

23 

73.4 

49 

120.2 

74 

165.2 

99 

210.2 

24 

75.2 

50 

122.0 

75 

167.0 

100 

212.0 

25 

77.0 

ultimate  limit  of  contraction  will  be  found  at  460°  below  zero 
on  the  Fahrenheit  scale,  and  that  at  this  point  all  motion  of 
the  molecules  ceases.  This  point  is  called  the  absolute  zero, 
and  temperatures  measured  therefrom  are  called  absolute 
temperatures. 


58  CHEMISTRY  AND  HEAT 

The  temperature  that  is  indicated  by  the  Fahrenheit  ther- 
mometer may  be  converted  into  absolute  temperature  by 
adding  it  to  460°.  Thus,  a  temperature  of  85°  by  the  Fahren- 
heit thermometer  corresponds  to  the  absolute  temperature 
of  85+460  =  545°.  On  the  centigrade  scale  the  absolute  zero 
is  273  J°  below  the  zero  point.  On  the  Reaumur  scale  it  is 
2 18 1°  below  zero.  When  the  thermometer  indicates  tem- 
peratures below  the  zero  point  of  its  graduation,  the  indicated 
temperature  must  be  subtracted  from  460,  273 i  or  218 §, 
respectively,  to  find  the  absolute  temperature;  that  is,  absolute 
zero  is  -460°  F.,  -273|°  C.,  and  -218f°  R. 

Conversion  of  Temperatures. — A  degree  on  the  Fahrenheit 
scale  is  equal  to  TS&  =  I  of  a  degree  centigrade  and  to  /&  =  $  of 
a  degree  Reaumur.  Temperatures  according  to  any  one  of 
these  scales,  therefore,  may  be  converted  into  the  correspond- 
ing temperatures  on  the  other  scales  by  using  the  following 
simple  formulas: 

Temp.  F.  =  f    Temp.  C.+320  =|  Temp.  R.  +  320. 

Temp.  C.  =  |  (Temp.  F.-32°)=f  Temp.  R. 

Temp.  R.  =  a  (Temp.  F.-32°)=^  Temp.  C. 

The  table  on  page  57  shows  the  equivalents  of  centigrade 
temperatures  on  the  Fahrenheit  scale. 

COEFFICIENTS  OF  LINEAR  EXPANSION 

The  coefficient  of  expansion  of  a  body  is  its  expansion  per 
degree  rise  of  temperature.  The  coefficient  of  surface  expan- 
sion is  double,  and  that  of  cubic  expansion  three  times  the 
coefficient  of  linear  expansion.  The  table  on  page  59  shows 
the  coefficient  of  linear  expansion  for  various  substances. 

For  example,  a  30-ft.  steel  rail  in  warming  from  20°  F.  below 
zero  to    100°   F.   will   expand    (20+100)  X  .0000059!) X30X  12 
38  in. 

MEASUREMENT  OF  HEAT 

British  Thermal  Unit. — The  unit  most  commonly  used  for 
the  measurement  of  heat  is  the  British  Thermal  Unit,  abbre- 
viated B.  T.  U.  This  is  the  amount  of  heat  required  to  raise 
the  temperature  of  1  Ib.  of  pure  water  1°  F.  at  or  near  the  tem- 
perature 39.1°  F.,  whi,ch  is  the  point  of  maximum  density  of 
water.  Heat  is  a  form  of  energy,  and  it  may  be  transformed 


CHEMISTRY  AND  HEAT 


59 


into  other  forms  of  energy.  The  equivalent  of  1  B.  T.  U.  in 
foot-pounds  is  778  ft.-lb.,  and  this  value,  778  ft.-lb.,  is  termed 
the  mechanical  equivalent  of  heat.  It  is  the  number  of  foot- 
pounds of  mechanical  energy  that  would  be  produced  by 
transforming  1  B.  T.  U.  without  any  losses. 

COEFFICIENTS  OF  EXPANSION  FOR  VARIOUS 
SUBSTANCES 


Substance 


Coefficient  of  Linear 

Expansion  in  Inches  per 

Degree  F. 


Aluminum 

Brass '. 

Brick 

Cement  and  Concrete {£ro™ 

c°PPer 

Glass 

Gold 

Granite 

Iron,  cast 

Iron,  wrought 

Lead 

Marble 

Masonry 

Mercury 

Platinum 

Porcelain 

Sandstone {fro™ 

Steel,  untempered 

Steel,  tempered 

Tin 

Wood,  pine 

Zinc... 


.00001140 
.00001040 
.00000306 
.00000550 
.00000780 
.00000961 
.00000399 
.00000521 
.00000841 
.00000460 
.00000587 
.00000677 
.00001580 
.00000400 
.00000206 
.00000490 
.00003334 
.00000494 
.00000200 
.00000400 
.00000670 
.00000599 
.00000702 
.00001160 
.00000276 
.00001634 


Latent  Heat. — The  heat  expended  in  changing  a  body  from 
the  solid  to  the  liquid  state,  or  from  the  liquid  to  the  gaseous 
state,  without  change  of  temperature,  is  called  its  latent  heat. 

The  temperature  at  which  a  body  changes  from  a  solid  to 
a  liquid  state  is  called  its  temperature  of  fusion,  or  its  fusing 
point;  and  the  number  of  B.  T.  U.  required  to  effect  this  change 
in  a  body  weighing  1  Ib.  is  called  its  latent  heat  of  fusion.  The 


CHEMISTRY  AND  HEAT 


temperature  at  which  a  body  changes  from  a  liquid  state  to  a 
vapor  or  a  gas  is  called  its  temperature  of  vaporization;  and  the 
heat  required  to  effect  this  change  in  1  Ib.  of  the  liquid  is  called 
its  latent  heat  of  vaporization. 

When  a  vapor  changes  back  to  a  liquid,  it  is  said  to  con- 
dense, and  when  a  liquid  changes  back  to  a  solid,  it  is  said  to 
freeze;  in  either  case,  an  amount  of  heat,  equal  to  the  latent 
heat  of  vaporization  or  of  fusion,  as  the  case  may  be,  must  be 
abstracted  from,  or  given  up,  by  the  body. 

TEMPERATURES    AND    LATENT    HEATS    OF    FUSION 
AND  OF  VAPORIZATION 


Substance 

Temper- 
ature 
of 
Fusion 
Deg.  F. 

Latent 
Heat 
of 
Fusion 
B.  T.  U. 

Temper- 
ature of 
Vapori- 
zation 
Deg.  F. 

Latent 
Heat  of 
Vapori- 
zation 
B.  T.  U. 

Aluminum  

1,160.0 

51.4 

Carbon  
Copper              .... 

Infusible 
1.930.0 

Ice 

32  0 

144  0 

212 

Iron,  cast  
Iron,  wrought  
Lead  
Mercury 

2,192.0 
2,912.0 
626.0 
—  37.8 

233.0 

9.7 
5.1 

662 

157 

Platinum  
Steel  
Sulphur 

3,227.0 
2,520.0 
2390 

46.0 
16.9 

824 

Tin  .  .  . 

446.0 

25.7 

Zinc   

6&0.0 

50.6 

1  900 

493 

The  accompanying  table  shows  the  latent  heats  of  fusion 
and  of  vaporization  for  1  Ib.  of  various  substances,  they  having 
first  been  raised  to  the  temperature  at  which  the  change  takes 
place,  and  the  pressure  being  one  atmosphere,  or  14.7  Ib.  per 
sq.  in.  The  temperature  of  vaporization  in  the  table  is  the 
boiling  point  of  the  liquid  under  the  ordinary  atmospheric 
pressure  of  14.7  Ib.  per  sq.  in. 

Specific  Heat. — The  specific  heat  of  a  body  is  the  ratio  be- 
tween the  quantity  of  heat  required  to  warm  that  body  1° 
and  the  quantity  of  heat  required  to  warm  an  equal  weight  of 


CHEMISTRY  AND  HEAT 


61 


water  1°.  The  number  of  B.  T.  U.  required  in  order  to  raise 
or  required  to  be  abstracted  in  order  to  lower,  the  temperature 
of  a  body  a  certain  number  of  degrees  may  be  found  by  the 
formula  Q=Ws  (ti-h), 

in  which  Q  =  number  of  B.  T.  U.  required; 

W= weight  of  body,  in  pounds; 

s  =  specific  heat  of  body; 

ll  =  higher  temperature,  in  degrees  P.; 

tz  =  lower  temperature,  in  degrees  P. 

The  specific  heats  of  various  solids,  liquids,  and  gases  are 
given  in  the  accompanying  tables. 

SPECIFIC  HEATS  OF  SOLIDS  AND  LIQUIDS 


Substance 

Specific 
Heat 

Substance 

Specific 
Heat 

Aluminum  

.2143 

Lead,  melted  

.0402 

Ashes,  average  
Brass 

.2100 
.0939 

Mercury  
Platinum 

.0333 
0324 

Charcoal   

.2410 

Steel  

.1170 

Copper  
Glass  
Ice... 

.0951 
.1937 
.5040 

Sulphur  
Sulphur,  melted  
Tin  

.2026 
.2340 
.0562 

.1298 

Tin   melted 

0637 

Iron,  wrought.  .  . 

.1138 

Water  

1.0000 

Lead   .    .. 

.0314 

Zinc  

.0956 

SPECIFIC  HEATS  OF  GASES 


Specifi 

:Heat 

Name  of  Gas 

Constant 
Pressure 

Constant 
Volume 

Air  .. 

23751 

16902 

Carbon  dioxide  

.21700 

.15350 

Carbon  monoxide  

.24500 

.17580 

Hydrogen 

3  40900 

2  41226 

24380 

17273 

Oxygen  

.21751 

.15507 

62  MECHANICS 

MECHANICS 


WORK  AND  POWER 

Work  is  the  overcoming  of  resistance  through  a  distance. 
The  unit  of  work  is  the  foot-pound;  that  is,  it  equals  1  Ib. 
raised  vertically  1  ft.  The  amount  of  work  done  is  equal  to 
the  resistance  in  pounds  multiplied  by  the  distance  in  feet 
through  which  it  is  overcome.  If  a  body  is  lifted,  the  resist- 
ance is  the  weight  or  the  overcoming  of  the  attraction  of  grav- 
ity, the  work  done  being  the  weight  in  pounds  multiplied  by 
the  height  of  the  lift  in  feet.  If  a  body  moves  in  a  horizontal 
direction,  the  work  done  is  the  friction  overcome,  or  the  force 
needed  to  move  a  resistant  body  or  combination  of  bodies, 
multiplied  by  the  distance  moved  through. 

It  must  always  be  kept  in  mind  that  motion  in  itself  is  not 
work  and  that  the  mere  application  of  a  force  also  is  not  work ; 
a  force  must  act  through  a  distance  overcoming  resistance  in 
order  that  work  be  done. 

Power  is  the  rate  of  doing  work,  or  the  quantity  of  work 
done  in  unit  time.  The  ordinary  unit  of  mechanical  power 
is  the  horsepower,  which  is  equivalent  to  33,000  ft.-lb.  per  min., 
or  :>:»<)  ft.-lb.  per  sec.  The  term  horsepower  is  commonly 
abbreviated  H.  P. 

The  work  necessary  to  be  done  in  raising  a  body  weighing 
W  Ib.  through  a  height  of  h  ft.  equals  W  h  ft.-lb.  The  total 
work  that  any  moving  body  is  capable  of  doing  in  being  brought 

i  iv 

to  rest  equals  its  kinetic  energy,  or  -      ,  in  which  v  is  the  velocity 

of  the  body,  in  feet  per  second,  and  g  =  32.16. 

The  kinetic  energy  of  a  200,000-lb..  train  running  at  40  mi. 
per  hr.,  or  .r>S.7  ft.  per  sec.,  is  200,000X58.7^(2X32.16) 
=  10,714,220  ft.-lb.;  the  retarding  force  necessary  to  stop 
the  train  within  2.000  ft.  is  10,714.220H-2,000  =  5,357.1  Ib., 
and  the  average  power  required  to  stop  the  train  in  i  min. 
is  10,714.220-5-}  =  21.  l-'s.  tin  ft.-lb.  per  min.,  or  21,428,440 
-^  33,000  =  649.3  H.  P. 


MECHANICS  63 

CENTRIFUGAL  FORCE 

If  a  ball  is  fastened  to  a  string  and  is  whirled  so  as  to  give 
it  a  circular  motion,  there  will  be  a  pull  of  greater  or  less  amount 
on  the  string,  according  as  the  speed  of  the  ball  increases  or 
decreases.  If  the  string  is  cut  while  the  ball  is  in  motion, 
the  ball  will  fly  off,  away  from  the  center  of  the  circle  in  which 
it  is  whirling.  The  force  that  acts  to  draw  a  body  away  from 
the  center  around  which  it  revolves  is  termed  the  centrifugal 
force  of  the  body.  It  may  be  found  by  the  formula 

F  =  . 00034  WRN*, 
in  which   F  =  centrifugal  force,  in  pounds; 

IT' =  weight  of  revolving  body,  in  pounds; 

R  =  radius,  in  feet,  of  circle  in  which  the  center  of 

gravity  of  the  revolving  body  moves; 
2V  =  revolutions  per  minute  of  revolving  body. 


MACHINE   ELEMENTS 

LEVERS 

A  lever  is  a  bar  that  may  be  turned  about  a  pivot,  or  point, 
as  shown  in  Figs.  1,  2,  and  3.     In  each  case,  the  object  W  to 


FIG.  1  FIG.  2  FIG.  3 


be  lifted  is  called  the  load  ,  or  weight;  the  force  that  accomplishes 
the  lifting  is  represented  by  F;  and  the  fulcrum,  or  pivot,  is 
indicated  by  C.  The  distance  /  from  the  weight  to  the  fulcrum 
is  termed  the  -weight  arm  and  the  distance  L  from  the  force 
to  the  fulcrum  is  termed  the  force  arm.  •  The  distance  between 
the  force  and  the  weight  is  denoted  by  a.  Whenever  the  force 
f  is  just  great  enough  to  balance  the  load  lifted,  it  will  be 
found  that  the  force  times  the  length  of  the  force  arm  is  equal 


€4  MECHANICS 

to  the  weight  times  the  length  of  the  weight  arm.     That  is, 
in  each  of  the  forms  of  levers  shown  in  Figs.  1  to  3,  F:W  =  l:L, 

or  FL=Wl.     From  this  it  follows  that  F  =  —  and  W=  —  . 

L  I 

If  the  force  and  the  weight  are  known,  and  it  is  desired  to 
calculate  the  lengths  of  the  weight  and  force  arms  so  that  the 
lever  may  balance,  the  following  formulas  may  be  used: 
For  the  style  of  lever  shown  in  Fig.  1, 
Fa  Wa 


For  the  style  of  lever  shown  in  Fig.  2, 
Fa  Wa 


For  the  style  of  lever  shown  in  Fig.  3, 
Fa  Wa 


FIXED  AND  MOVABLE  PULLEYS 

A  pulley  consists  of  a  grooved  wheel  on  an  axle  held  in  a 
frame,  or  block,  and  is  very  useful  in  moving  or  hoisting  loads. 
A  fixed  pulley  is  one  whose  block  is  not  movable.  Such  a  pulley 
is  shown  in  Fig.  1.  A  rope  passes  over  the  pulley  and  carries 
the  load  W  at  one  end,  the  hoisting  force  F  being  applied 


FIG.  1  FIG.  2  FIG.  3  FIG.  4 


at  the  other  end  of  the  rope.  Neglecting  the  friction  of  the 
pulley  in  its  block,  the  force  required  to  lift  a  load  is  equal 
to  the  load;  that  is,  F  =  W. 

A  movable  pulley  is  one  whose  block  is  movable,  such  as  that 
shown  in  Fig.  2.     In  this  case,  one  end  of  the  rope  is  fastened 


MECHANICS  65 

to  an  overhead  support  and  the  hoisting  force  is  applied  at  the 
other  end  in  an  upward  direction.  With  this  arrangement,  a 
pull  of  1  Ib.  at  F  will  lift  a  weight  of  2  Ib.  at  W.  If  the  free 
end  of  the  rope  is.  carried  up  over  a  fixed  pulley,  as  shown  in 
Fig.  3,  the  effect  will  still  be  the  same;  that  is,  a  weight  of 
2  Ib.  can  be  raised  by  a  force  F  of  1  Ib.;  that  is,  in  Figs.  2 
and  3,  F=±W. 

A  double  movable  pulley  is  shown  in  Fig.  4;  that  is,  the 
movable  block  attached  to  the  load  W  carries  two  pulleys. 
A  similar  pulley  is  fixed  to  an  overhead  support,  and  one  end 
of  the  rope  is  attached  to  it,  the  other  end  being  carried  around 
the  several  pulleys  as  shown.  With  this  arrangement,  a  force 
F  of  1  Ib.  is  sufficient  to  raise  a  weight  W  of  4  Ib.;  that  is, 
F  =  \W. 

Combination  of  Pulleys. — By  increasing  the  number  of  fixed 
and  movable  pulleys  over  which  the  hoisting  rope  or  chain 
passes,  the  force  required  to  lift  a  given  load  may  be  lessened. 
In  Fig.  5  is  shown  a  quadruple  movable  pulley,  or  one  hi  which 
the  movable  block  has  four  pulleys,  and  a  force  of  1  Ib.  at  F 
will  lift  a  weight  of  8  Ib.  at  W.  The  following  general  rule 
applies  to  any  combination  of  pulleys: 

Rule. — When  a  single  rope  is  used  with  a  combination  of 
pulleys,  a  pull  on  the  free  end  will  balance  a  load  on  the  movable 
block  as  many  times  as  great  as  the  pull  as  there  are  parts  of  the 
rope  supporting  the  movable  block 

For  instance,  in  Figs.  2  and  3,  there  are  two  parts  of  the 
rope  supporting  the  movable  block,  and  the  load  balanced  by 
the  pull  F  is  twice  as  great  as  the  pull  F.  In  Fig.  4  there  are 
four  parts  of  the  rope  supporting  the  movable  block,  so  that 
W=±F,  or  F  =  %W.  In  Fig.  5,  W=8F,  as  there  are  eight 
parts  of  the  rope  supporting  the  movable  block. 

Differential  Pulley. — The  arrangement  shown  in  Fig.  6  is 
known  as  a  differential  pulley.  The  two  fixed  pulleys  have 
different  radii  r  and  R.  The  hoisting  chain  passes  around  the 
larger  of  the  fixed  pulleys,  then  around  the  movable  pulley 
carrying  the  weight  W,  and  then  around  the  smaller  fixed 
pulley.  The  chain  is  joined  at  its  ends,  thus  forming  a  con- 
tinuous piece.  The  two  fixed  pulleys  are  fastened  together 
so  that  they  must  turn  as  one  piece  on  their  axle.  When  a 


66  MECHANICS 

pull  P  is  exerted  on  a  chain,  the  fixed  pulleys  are  rotated. 
The  chain  winds  up  on  one  side  of  the  large  pulley  and 
unwinds,  at  a  slower  rate,  from  the  small  pulley.  As  a  result. 


FIG.  5 


FIG.  6 


FIG.  7 


the  load  W  is  lifted  slightly  at  each  turn  of  the  fixed  pulleys. 
The  weight  W  that  can  be  lifted  by  a  force  P  is  found  by  the 
formula 


R-r 

the  letters  R  and  r  designating  the  radii  of  the  large  and  small 
fixed  pulleys,  respectively. 

Wheel  and  Axle. — The  device  known  as  the  wheel  and  axle 
consists  of  two  cylinders  of  different  sizes  connected  rigidly, 
so  that  they  turn  together.  The  rope  carrying  the  load  to 
be  raised  is  fastened  to  the  smaller  cylinder  and  the  rope  on 
which  the  pulling  force  is  exerted  is  wound  on  the  larger  cylin- 
der, as  shown  in  Fig.  7.  The  pull  F  causes  the  larger  cylinder 
to  turn,  rotating  the  smaller  cylinder  at  the  same  rate.  The 
rope  attached  to  the  weight  W  is  thus  caused  to  wind  on  the 
smaller  cylinder,  and  the  load  is  raised.  If  R  and  r  represent, 
respectively,  the  radii  of  the  large  and  small  cylinders,  the 
force  F  required  to  lift  a  weight  W,  and  the  weight  W  that  may 
be  lifted  by  a  force  F,  are  given  by  the  formulas 

F  =  —     and     W  = 
R  r 


BELT  PULLEYS 

Solid  and  Split  Pulleys. — Besides  being  used  with  ropes  or 
chains  for  the  hoisting  of  loads,  pulleys  are  extensively  employed 
with  belts  for  transmitting  power.  Belt  pulleys  may  be  divided 


MECHANICS 


67 


into  two  classes,  namely,  solid  pulleys  and  split  pulleys.  A 
solid  pulley  is  one  in  which  the  arms,  hub,  and  rim  are  cast 
in  one  solid  piece,  as  shown  in  Fig.  1.  A  split  pulley  is  one  that 
is  cast  in  halves  that  are  afterwards  bolted  together,  as  shown 
in  Fig.  2.  The  latter  style  of  pulley  is  more  readily  placed  on 
or  removed  from  a  shaft  than  is  the  solid  pulley.  Pulleys  are 
generally  cast  in  halves  or  parts  when  they  are  more  than 
6  ft.  in  diameter.  This  is  done  on  account  of  the  shrinkage 
strains  in  large  pulley  castings,  which  renders  the  pulleys  liable 
to  crack  as  a  result  of  unequal  cooling  of  the  metal. 


FIG.  1 


FIG.  2 


Wooden  Pulleys. — Although  most  belt  pulleys  are  made  of 
cast  iron,  wrought  iron,  and  steel,  wooden  pulleys  have  come 
into  extensive  use.  These  are  built  of  segments  of  wood 
securely  glued  together,  maple  being  the  wood  ordinarily 
used.  It  is  possible  to  procure  wooden  split  pulleys  that  are 
fitted  with  removable  bushings,  thus  allowing  the  same  pulley 
to  be  adapted  readily  to  shafting  of  different  diameters. 
Wooden  pulleys  are  somewhat  lighter  than  cast-iron  pulleys 
for  the  same  service. 

Driving  and  Driven  Pulleys. — The  pulley  that  imparts 
motion  to  the  belt  is  called  the  driving  pulley,  or  the  driver, 
and  the  one  that  receives  motion  from  the  belt  is  called  the 
driven  pulley,  or  simply  the' driven.  When  two  pulleys  are 
connected  by  a  belt,  the  speeds  at  which  the  pulleys  run  are 
inversely  proportional  to  their  diameters.  Thus,  if  two 
pulleys  have  diameters  of  12  in.  and  24  in.,  the  speed  of  the 
smaller  is  to  the  speed  of  the  larger  as  24  to  12,  or  as  2  to  1« 


68  MECHA  NICS 

The  speed  of  a  pulley  or  of  a  shaft  is  usually  stated  in  revo- 
lutions per  minute,  abbreviated  R.  P.  M. 

Diameter  and  Speed  of  Driver. — It  often  becomes  necessary 
to  calculate  the  size  or  the  speed  of  a  pulley  that  drives  or  is 
being  driven  by  a  machine. 

Let    D  =  diameter  of  driving  pulley,  in  inches; 
d  =  diameter  of  driven  pulley,  in  inches ; 
N  =  number  of  R.  P.  M.  of  driving  pulley; 
«  =  number  of  R.  P.  M.  of  driven  pulley. 
Then,  if  the  diameter  of  the  driven  and  the  required  speeds 
of  both  pulleys  are  given,  the  diameter  of  the  driver  may  be 
found  by  the  formula 

dn 
D--  U> 

If  the  speed  of  the  driver  is  to  be  found,  it  is  necessary  to 
use  the  formula 

dn 
X--  (2) 

EXAMPLE. — A  12-in.  pulley  on  a  certain  machine  is  to  run 
at  160  R.  P.  M.  and  is  to  be  driven  by  belt  from  a  pulley  on 
the  shaft  of  an  engine  that  makes  96  R.  P.  M.  What  must 
be  the  diameter  of  the  pulley  on  the  engine  shaft? 

SOLUTION. — Substituting  in  formula  1, 

12X160 
D  = =20  in. 

Diameter  and  Speed  of  Driven. — If  the  diameter  of  the 
driving  pulley  and  the  desired  speeds  of  both  pulleys  are 
known,  the  required  diameter  of  the  driven  pulley  may  be 
found  by  the  formula 

DN 

d=  (1) 

n 

If  the  speed  of  the  driven  pulley  is  to  be  found,  it  is  necessary 
to  use  the  formula 

DN 

n  =  -~  (2) 

a 

EXAMPLE  1. — A  30-in.  pulley  on  a  line  shaft  running  at 
120  R.  P.  M.  is  to  drive  a  pulley  on  a  machine  at  300  R.  P.  M. 
What  must  be  the  diameter  of  the  pulley  on  the  machine? 


MECHANICS  69 

SOLUTION. — Substituting  in  formula  1, 
30X120 

i=^T-12ta' 

EXAMPLE  2. — A  driving  pulley  48  in.  in  diameter  makes 
175  R.  P.  M.  and  is  connected  by  belt  to  a  driven  pulley  14  in. 
in  diameter.  What  is  the  speed  of  the  driven  pulley? 

SOLUTION. — Substituting  in  formula  2, 

48X175 

»  =  — 600  R.  P.M. 

14 

BELTING 

A  belt  is  a  flexible  band  by  which  motion  is  transmitted 
from  one  pulley  to  another.  The  materials  most  commonly 
used  for  belts  are  leather,  cotton,  and  rubber,  although  thin, 
flat  bands  of  steel  are  coming  into  use.  Leather  belts  are 
usually  made  either  single  or  double.  A  single  belt  is  one 
composed  of  a  single  thickness  of  leather,  and  a  double 
belt  is  one  composed  of  two  thicknesses  of  leather  cemented 
and  riveted  together  throughout  the  whole  length  of  the  belt. 
Still  heavier  belts,  consisting  of  three  or  four  thicknesses  of 
leather,  and  known  as  triple  or  quadruple  belts,  are  sometimes 
made  for  heavy  drives.  Cotton  belts  are  made  up  of  a  number 
of  layers,  or  plies,  sewed  together  and  treated  with  a  water- 
proofing substance.  They  are  termed  two-ply,  three-ply,  etc., 
according  to  the  number  of  plies  they  contain.  Four-ply  cot- 
ton belting  is  usually  considered  equal  to  single  leather  belting. 
Rubber  belts  are  particularly  adapted  for  use  in  damp  or 
wet  places.  They  withstand  changes  of  temperature  without 
injury,  are  durable,  and  are  claimed  to  be  less  liable  to  slip 
than  are  leather  belts. 

Sag  of  Belts. — The  distance  between  pulley  centers  depends 
on  the  size  of  the  pulleys  and  of  the  belt;  it  should  be  great 
enough  so  that  the  belt  will  run  with  a  slight  sag  and  a  gently 
undulating  motion,  but  not  great  enough  to  cause  excessive 
sag  and  an  unsteady  flapping  motion  of  the  belt.  In  general, 
the  centers  of  small  pulleys  carrying  light  narrow  belts  should 
be  about  15  ft.  apart  and  the  belt  sag  1J  to  2  in.;  for  large 
pulleys  and  heavy  belts  the  distance  should  be  20  to  30  ft. 
and  the  sag  2£  to  5  in.  Loose-running  belts  will  last  much 


70  MECHANICS 

longer  than  tight  ones,  and  will  be  less  likely  to  cause  heating 
and  wear  of  bearings. 

Speed  of  Belts. — The  higher  the  speed  of  a  belt,  the  less 
may  be  its  width  to  transmit  a  given  horsepower;  consequently, 
it  follows  that  a  belt  should  be  run  at  as  high  a  speed  as  con- 
ditions will  permit.  The  greatest  allowable  speed  for  a  belt 
joined  by  lacing  is  about  3,500  ft.  per  min.,  for  ordinary  single 
and  double  leather  belts.  For  belts  joined  by  cementing, 
when  the  joint  has  about  the  same  strength  as  the  solid  belt, 
the  velocity  may  be  as  high  as  5,000  ft.  per  min.  Higher 
speeds  than  these  have  been  used,  but  there  is  little  to  be  gained 
by  exceeding  about  4,800  ft.  per  min.  In  choosing  a  proper 
belt  speed,  due  regard  must  be  paid  to  commercial  conditions. 
Although  a  high  speed  of  the  belt  means  a  narrow  and  cheaper 
belt,  the  increased  cost  of  the  larger  pulleys  that  may  be 
required  may  offset  the  gain  due  to  the  high  speed  of  the  belt, 
at  least  so  far  as  the  first  cost  is  concerned.  The  speed  of  a 
belt,  in  feet  per  minute,  may  be  found  by  multiplying  the 
number  of  revolutions  per  minute  of  the  pulley  by  3.1416 
times  the  diameter  of  the  pulley,  in  inches,  and  dividing  the 
product  by  12. 

Horsepower  of  Belts. — The  pull  on  a  belt  is  greatest  on  the 
tight,  or  driving,  side,  and  least  on  the  slack  side.  The  dif- 
ference between  the  tensions,  or  pulls,  in  these  two  sides  is 
called  the  effective  pull.  The  effective  pull  that  may  be  allowed 
per  inch  of  width  for  single  leather  belts  with  different  arcs 
of  contact  is  given  in  the  accompanying  table.  The  arc  of 
contact  is  the  portion  of  the  circumference  of  the  smaller  pulley 
that  is  covered  by  the  belt.  The  horsepower  that  can  be 
transmitted  by  a  single  leather  belt  may  be  found  by  the 
formula 

cwv 

~  33, 000* 
in  which  //  =  horsepower  of  belt; 

C  =  effective  pull,  taken  from  table; 
H'  =  width  of  belt,  in  inches; 
T'  =  speed  of  belt,  in  feet  per  minute. 
If  it  is  desired  to  find  the  width  of  single  belt  required 
transmit  a  given  horsepower,  the  formula  becomes 


MECHANICS 


71 


W-- 


33,000  H 


CV 


(2) 


EXAMPLE  1. — What  horsepower  can  be  transmitted  by  a 
single  leather  belt  4  in.  wide  running  at  a  speed  of  2,500  ft. 
per  min.,  if  the  belt  covers  one-third  of  the  circumference  of 
the  small  pulley? 

SOLUTION. — The  fraction  of  the  circumference  covered  by 
the  belt  is  |  =  .333.  From  the  table,  the  allowable  effective 
pull  corresponding  to  this  value  is  28.8.  Substituting  in 
formula  1, 


EXAMPLE  2. — A  single  leather  belt  is  to  run  at  a  speed  of 
3,000  ft.  per  min.  and  is  to  transmit  18  H.  P.  Find  the  width 
of  the  belt,  if  the  arc  of  contact  is  150°. 

SOLUTION. — The  effective  pull  corresponding  to  an  arc  of 
contact  of  150°,  from  the  table,  is  33.8.  Substituting  in 
formula  2, 

33,000X18 

W=—  —  =  5.9  in. 

33.8X3,000 

A  6-in.  belt  would  be  used. 

ALLOWABLE  EFFECTIVE  PULL 


Arc  of  Contact 

Allowable 

Effective  Pull 

Degrees 

Fraction  of 
Circumference 

Pounds  per 
Inch  of  tyidlh 

90 

.250 

23.0 

112| 

.312 

27.4 

120 

.333 

28.8 

135 

.375 

31.3 

150 

.417 

33.8 

157£ 

.437 

34.9 

180  or  over 

.500  or  over 

38.1 

The  horsepower  of  a  double  leather  belt  may  be  taken  as 
1^  times  that  of  a  single  leather  belt  of  the  same  width  running 


72 


MECHANICS 


under  the  same  conditions.  Accordingly,  the  width  of  a  double 
leather  belt  required  for  any  service  is  only  T^  that  of  a  single 
belt  for  the  same  service. 

Lacing  of  Belts. — A  very  satisfactory  way  of  lacing  belts 
less  than  3  in.  wide  is  shown  in  Fig.  1,  in  which  A  is  the  outside 
of  the  belt  and  B  is  the  side  that  runs  against  the  face  of  the 
pulley.  The  ends  of  the  belt  are  first  cut  square,  and  then 
holes  are  punched  in  the  ends,  in  corresponding  positions 
opposite  one  another.  The  number  of  holes  in  each  row 
should  always  be  odd,  in  the  style  of  lacing  shown,  using  3 
holes  in  belts  up  to  2  in.  wide  and  5  holes  in  belts  between 
2  and  3  in.  wide.  The  lacing  is  first  drawn  through  one  of 
the  middle  holes  from  the  under  side,  or  pulley  side,  as  at  1. 
Then  it  is  drawn  across  the  upper  side  and  is  passed  down 
through  2,  across  under  the  belt  to  3,  up  through  3,  across  and 
down  again  through  2,  back  under  the  belt  and  up  through  3 
again,  then  across  and  down  through  4  and  finally  up  through 
5,  where  a  barb  is  cut  in  the  edge  of  the  lacing  to  prevent  it 
from  pulling  out.  This  completes  the  lacing  of  one  half. 
The  other  end  of  the  lacing  is  then  carried  through  the  holes 
in  the  other  half,  in  the  same  order. 


tt  \N\V\\\V 


FIG.  1 


FIG.  2 


For  belts  wider  than  3  in.,  the  lacing  shown  in  Fig.  2  may  be 
used.  In  this  case,  there  are  two  rows  of  holes  in  each  end  of 
the  belt  to  be  joined.  The  row  nearer  the  end  of  the  belt  should 
have  one  more  hole  than  the  row  farther  away.  For  belts 
up  to  4}  in.  wide,  use  3  holes  in  the  first  row  and  2  holes  in 
the  second  row.  For  belts  up  to  6  in.  wide,  use  4  and  3  holes, 
respectively.  For  wider  belts,  make  the  total  number  of  holes 


MECHANICS  73 

in  both  rows  either  one  or  two  more  than  the  number  of  inches 
of  width  of  the  belt,  the  object  being  to  get  an  odd  total  number 
of  holes.  For  example,  a  10-in.  belt  would  have  10+1  =  11 
holes,  and  a  13-in.  belt  would  have  13+2  =  15  holes.  The 
outside  holes  of  the  first  row  should  not  be  nearer  the  side 
edges  of  the  belt  than  f  in.  and  not  nearer  the  joint  edge  than 
|  in.  The  second  row  should  be  at  least  If  in.  from  the  joint 
edge.  In  Fig.  2,  A  is  the  outside  face  and  B  the  face  next  the 
pulley.  The  lacing  is  first  drawn  up  through  1  from  the  pulley 
side,  and  then  is  carried  through  2,  3,  4,  5,  6,  7,  6,  7,  4,  5, 
2,  3,  8,  and  out  at  9  to  be  fastened.  The  other  end  of  the 
lacing  is  used  on  the  other  half  of  the  belt  in  the  same  way. 


HYDRAULICS 

Pressure  Due  to  Head  of  Water. —  Hydraulics  treats  of 
liquids  in  motion.  When  a  tank  is  filled  with  water,  its 
bottom  and  its  sides  are  subjected  to  pressure  due  to  the 
weight  of  the  water.  The  distance  from  a  point  at  any  given 
level  in  the  tank  to  the  surface  of  the  water,  measured  vertically, 
is  termed  the  head  of  water  for  that  level.  The  pressure 
exerted  by  the  water  is  directly  proportional  to  the  head.  A 
cubic  foot  of  water  weighs  approximately  62.5  lb.,  so  that,  if 
a  tank  1  sq.  ft.  in  cross-section  were  filled  with  water  to  a 
depth  of  1  ft.,  it  would  contain  1  cu.  ft.,  or  62.5  lb.,  of  water. 
The  pressure  on  the  bottom,  having  an  area  of  1  sq.  ft.,  would 
be  62.5  lb.,  or  the  weight  of  1  cu.  ft.  of  water;  consequently, 
the  pressure  per  square  inch  would  be  62.5  =  144  =  .434  lb.  In 
other  words,  a  column  of  water  1  ft.  deep,  or  having  a  head  of 
1  ft.,  exerts  a  pressure  of  .434  lb.  per  sq.  in.  Knowing  this 
fact,  the  pressure  due  to  any  given  head  of  water  may  be 
found  by  the  formula 

p  =  .434  h, 

in  which  p  =  pressure  in  pounds  per  square  inch ; 
h  =  head  of  water,  in  feet. 

If  it  is  desired  to  find  the  head  of  water  necessary  to  produce 
a  certain  pressure,  the  formula  becomes 


74  MECHANICS 

Velocity  of  Flow.  —  If  a  hole  is  made  in  the  side  of  a  tank 
filled  with  water,  the  water  will  issue  therefrom  with  a  velocity 
depending  on  the  head  of  water  above  the  opening. 

When  water  flows  in  a  pipe,  a  ditch,  or  a  channel  of  any 
kind,  the  velocity  is  not  the  same  at  all  points,  because  the 
cross-section  of  the  channel  is  not  the  same  at  all  points,  and 
also  because  of  friction.  In  such  cases,  the  mean  velocity  is 
taken  in  all  calculations.  The  mean  velocity  is  that  velocity 
which,  being  multiplied  by  the  area  of  the  cross-section  of 
the  stream,  will  equal  the  total  quantity  discharged. 

Flow  of  Water  in  Pipes.  —  For  straight  cylindrical  pipes  of 
uniform  diameter,  the  mean  velocity  of  discharge  may  be  calcu- 
lated by  the  formula 


in  which  Vm  =  mean  velocity  of  discharge  in  feet  per  second  ; 
h   =  total  head   in   feet  =  vertical   distance   between 
the  level  of  water  in  reservoir  and  the  point 
of  discharge; 

I   =  length  of  pipe,  in  feet; 
d   =  diameter  of  pipe,  in  inches; 
/  =  coefficient  of  friction. 

The  head  is  always  taken  as  the  vertical  distance  between 
the  point  of  discharge  and  the  level  of  the  water  at  the  source, 
or  point  from  which  it  is  taken,  and  is  always  measured  in 
feet.  It  matters  not  how  long  the  pipe  is,  whether  vertical  or 
inclined,  whether  straight  or  curved,  nor  whether  any  part  of 
the  pipe  goes  below  the  level  of  the  point  of  discharge  or  not; 
the  head  is  always  measured  as  stated  above. 

EXAMPLE.  —  What   is   the   mean   velocity   of  efflux  from   a 
C-in.  pipe,  5.780  ft.  long,  if  the  head  is  170  ft.?    Take  /=.  021. 
SOLUTION.  —  Substituting  in  formula  1, 

Fm  =  2.315  \/  —  --  =6.69  ft.  per  sec. 

\.021X5,780+(.125X6) 

When  the  pipe  is  very  long  compared  with  the  di 
as  in  the  foregoing  example,  use  may  be  made  of  the  formula 


iameter, 
y  be  made  of  the 

fu 
V? 


Vm  =  '-'.:;  I  >\    ..          (2) 


MECHANICS 


75 


in  which  the  letters  have  the  same  meaning  as  in  the  preceding 
formula.  This  formula  may  be  used  when  the  length  of  the 
pipe  exceeds  10,000  times  its  diameter. 

The  actual  head  necessary  to  produce  a  certain  velocity 
Vm  may  be  calculated  by  the  formula 


(3) 


If  the  head,  the  length  of  the  pipe,  and  the  diameter  of  the 
pipe  are  given,  to  find  the  discharge,  use  the  formula 


Q  =  . 09445  <# 


hd 


(•*) 


'/H-.125<* 

in  which  Q  =  discharge  in  U.  S.  gallons  per  second. 

To  find  the  value  of  /,  calculate  Vm  by  formula  2,  assuming 
that  /=  .025,  and  get  the  final  value  of /from  the  following  table: 


Y 

/ 

Vm 

/ 

Vm 

/ 

.1 

.0686 

.7 

.0349 

2 

.0265 

.2 

.0527 

.8 

.0336 

3 

.0243 

.3 

.0457 

.9 

.0325 

4 

.0230 

.4 

.0415 

1 

.0315 

6 

.0214 

.0 

.0387 

H 

.0297 

8 

.0205 

.6 

•  .0365 

H 

.0284 

12 

.0193 

EXAMPLE. — The  length  of  a  pipe  is  6,270  ft.,  its  diameter  is 
8  in.  and  the  total  head  at  the  point  of  discharge  is  215  ft. 
How  many  gallons  are  discharged  per  minute? 


7.67  ft.  per  sec., 
«  =  8  (see  table), 


1.025X6.270 

nearly.     Using  the  value   of  /=  .0205  for  V-, 


.  09455X82 


215X8 


•-  22.03  gal.  per  sec. 


.0205X6,270 +  (.125X8) 
=  22.03X60  =  1,321.8  gal.  per  min. 

If  it  is  desired  to  find  the  head  necessary  to  give  a  discharge 
of  a  certain   number  of  gallons  per  second   through  a   pipe 


76  COMBUSTION  AND  FUELS 

whose  length  and  diameter  are  known,  calculate  the  mean 
velocity  of  efflux  by  using  the  formula 

24.51Q 
Vm  =  --  -;  (5) 

d2 

find  the  value  of  /  from  the  table,  corresponding  to  this  value 
of  Vm  ,  and  substitute  these  values  of  /  and  Vm  in  the  formula 
for  the  head. 

EXAMPLE.  —  A  4-in.  pipe,  2,000  ft.  long,  is  to  discharge  24,000 
gal.  of  water  per  hr.;  what  head  is  necessary? 

24,000  24.51X61 

SOLUTION.—     Q  =  -  =  6  j  gal.  per  sec.     V 


=  10.2  ft.  per  sec.     From  the  table,  /=.0205  for  Vm  =  S,  and 
.0193  for  Vm  =  12;  assume  that  /=  .02  for  Vm  =  10.2.     Then 

ft. 


COMBUSTION  AND  FUELS 


COMBUSTION 

Nature  of  Combustion.  —  Combustion  is  the  very  rapid 
chemical  combination  of  two  or  more  elements,  accompanied 
by  the  production  of  light  and  heat.  The  atoms  of  some  of 
the  elements  have  a  very  great  affinity  or  attraction  for  those 
of  other  elements,  and  when  they  combine  they  rush  together 
with  such  rapidity  and  force  that  heat  and  light  are  produced. 
Oxygen,  for  example,  has  a  great  attraction  for  nearly  all  the 
other  elements.  For  carbon,  oxygen  has  a  particular  liking, 
and  whenever  these  two  elements  come  into  contact  at  a 
sufficiently  high  temperature,  they  combine  with  great  rapidity. 
The  combustion  of  coal  in  the  furnace  of  a  boiler  is  of  this 
nature.  The  temperature  of  the  furnace  is  raised  by  kindling 
the  fire,  and  then  the  carbon  of  the  coal  begins  to  combine 
with  oxygen  taken  from  the  air. 

Products  of  Combustion. — When  carbon  and  oxygen  com- 
bine they  form  CO*,  or  carbon  dioxide;  when  hydrogen  and 


COMBUSTION  AND  FUELS  77 

oxygen  combine  they  form  water,  HzO.  These  are  called  the 
products  of  combustion.  The  oxygen  required  for  combustion 
is  usually  obtained  from  the  air,  which  is  a  mixture  composed 
of  approximately  23  parts  of  oxygen  and  77  parts  of  nitrogen 
by  weight.  The  nitrogen  that  enters  the  furnace  with  the- 
oxygen  takes  no  part  in  the  combustion,  but  passes  through 
the  furnace  and  up  the  chimney  without  any  change  in  its 
nature. 

Air  Required  for  Combustion. — When  carbon  is  burned  to 
carbon  dioxide,  COz,  1  atom  of  carbon  unites  with  2  atoms  of 
oxygen.  Carbon  has  an  atomic  weight  of  12  and  oxygen  has 
an  atomic  weight  of  16,  so  that  the  molecular  weight  of  COi  is 
(1 X 12)  +  (2  X 16)  =  44 ;  hence  COi  is  composed  of  12  -^  44  =  27.27 
per  cent,  of  carbon  and  32 -=-44  =  72. 73  %  of  oxygen.  To 
burn  a  pound  of  carbon  to  COz,  therefore,  requires  32 -hi 2 
=  2f  Ib.  of  oxygen.  If  the  oxygen  is  taken  from  the  air,  it 
will  take  2f  -h. 23  =  11.6  Ib.  of  air  to  supply  the  2f  Ib.  of  oxy- 
gen. This  is  because  only  23%  of  air  is  oxygen.  The  com- 
bustion of  a  pound  of  carbon  to  COz  may  be  represented  as 
follows: 

Mixture  Elements  Products 

in  Pounds  in  Pounds  in  Pounds 

Carbon,      1.0  Carbon,       l.OOl       _    , 

Air  1,6  -I0"""'      2.6r)-Carbo"d'-de'      3'67 

I  Nitrogen,    8.93        Nitrogen,  8.93 

12.6  12.60  12.60 

That  is,  1  Ib.  of  carbon  requires  11.6  Ib.  of  air  for  complete 
combustion.  Of  this  air,  2.67  Ib.  is  oxygen  which  combines 
with  the  pound  of  carbon,  forming  3.67  Ib.  of  carbon  dioxide. 
The  8.93  Ib.  of  nitrogen  contained  in  the  air  passes  off  with 
the  CO-i  as  a  product  of  combustion. 

Take,  next,  the  complete  combustion  of  1  Ib.  of  hydrogen. 
The  product  of  the  combustion  is  water,  HiO.  It  has  been 
shown  that  HzO  is  composed  by  weight  of  2  parts  hydrogen 
to  16  parts  oxygen.  Hence  1  Ib.  of  H  requires  16 -=-2  =  8  Ib. 
of  O  to  unite  with  it.  The  air  required  to  furnish  8  Ib.  of  O  is 
8 -T-. 23  =  34.8  Ib.  The  process  of  combustion  is,  therefore,  as 
follows: 


78  COMBUSTION  AND  FUELS 

Mixture  Elements  Products 

in  Pounds  in  Pounds  in  Pounds 

Hydrogen,     1.0         Hydrogen,         1.0 1 

Air  348=(°Xygen'  8-0/-Water' 

\Nitrogen,        26.8        Nitrogen,  26.8 

35.8  35.8  35.8 

Incomplete  Combustion. — There  is  one  other  case  that  may 
occur;  the  combustion  of  carbon  may  not  be  complete.  If 
insufficient  air  or  oxygen  is  supplied  to  the  burning  carbon, 
it  is  possible  for  the  carbon  and  oxygen  to  form  another  gas, 
carbon  monoxide,  CO,  instead  of  carbon  dioxide,  COz.  The  com- 
bustion of  1  Ib.  of  carbon  to  form  CO,  of  course,  requires  only 
one-half  the  oxygen  that  would  be  necessary  to  form  COz.  This 
is  because  in  CO  gas  1  atom  of  carbon  seizes  1  atom  of  oxygen 
instead  of  2.  To  burn  1  Ib.  of  carbon  to  COz  requires  11.6  Ib.  of 
.air.  To  burn  it  to  CO  would,  therefore,  require  but  5.8  Ib.  of  air. 
Calorific  Value  of  Fuels. — The  amount  of  heat,  in  B.  T.  U., 
developed  by  the  complete  combustion  of  1  Ib.  of  a  fuel  is 
termed  the  calorific  value  of  that  fuel;  it  is  also  sometimes 
called  the  heat  value  or  the  heat  of  combustion.  It  may  be 
determined  most  accurately  by  burning  a  known  weight  of 
the  fuel  with  oxygen  in  an  instrument  known  as  a  calorimeter. 
The  gases  resulting  from  the  combustion  are  passed  through  a 
known  weight  of  water  and  give  up  their  heat  to  the  water. 
By  noting  the  rise  of  temperature  of  the  water,  it  is  possible 
to  calculate  the  amount  of  heat  absorbed,  and  thus  to  determine 
the  heat  that  would  be  produced  by  the  combustion  of  1  Ib. 
of  the  fuel.  The  calorific  values  of  the  elements  most  commonly 
found  in  fuels  are  as  follows: 

B.  T.  U.  per  Lb. 

Hydrogen,  burned  to  water,  H->O 62,000 

Carbon,  burned  to  COi 14,600 

Carbon,  burned  to  CO 4,400 

Sulphur,  burned  to  SOi 4,000 

If  the  various  percentages,  by  weight  of  the  elements,  com- 
posing a  fuel  are  known,  the  approximate  calorific  value  of 
that  fuel  may  easily  be  calculated  by  the  formula 

X=14,600C+62,000   \H )  +4,0005, 


H 


COMBUSTION7  AND  FUELS  79- 

in  which  X  =  calorific  value  of  fuel,  in  B.  T.  U.  per  pound; 
C  =  percentage  of  carbon,  expressed  as  a  decimal; 
H  =  percentage  of  hydrogen,  expressed  as  a  decimal; 
O  =  percentage  of  oxygen,  expressed  as  a  decimal; 
5  =  percentage  of  sulphur,  expressed  as  a  decimal. 
EXAMPLE. — A  coal  contains  85%  of  carbon,  4%  of  oxygen, 
6%  of  hydrogen,  1%  of  sulphur,  and  4%  of  ash.     What  is 
the  heat  of  combustion  per  pound? 

SOLUTION.— Applying  the  formula,  X  =  14, 600  X. 85+62,000 

-  — I  +4,000 X. 01  =  15,860  B.  T.  U. 


FUELS 

SOLID  FUELS 

Fuels  for  Steam  Making. — The  fuels  used  in  the  generation- 
of  steam  are  chiefly  coal,  coke,  wood,  petroleum,  and  natural 
gas.  Other  fuels,  such  as  the  waste  gases  from  blast  furnaces, 
straw,  bagasse,  dried  tan  bark,  green  slabs,  sawdust,  peat,  etc., 
are  also  used.  All  these  fuels  are  composed  either  of  carbon 
alone  or  carbon  in  combination  with  hydrogen,  oxygen,  sulphur, 
and  non-combustible  substances. 

Classes  of  Coal. — Coal  is  the  fuel  most  extensively  used  in 
steam-plant  work.  Its  different  varieties  may  be  classed  in 
four  main  groups,  namely,  anthracite,  semianthracite,  semi- 
bituminous,  and  bituminous  coal. 

Anthracite  Coal. — Anthracite  coal  contains  from  92.31  to- 
100%  of  fixed  carbon  and  from  0  to  7.69%  of  volatile  hydro- 
carbons. It  is  rather  hard  to  ignite  and  requires  a  strong 
draft  to  burn  it.  It  is  quite  hard  and  shiny;  in  color  it  is  a 
grayish  black.  It  burns  with  almost  no  smoke,  and  this  fact 
gives  it  a  peculiar  value  in  places  where  smoke  is  objectionable. 
Anthracite  coal  is  known  to  the  trade  by  different  names, 
according  to  the  size  into  which  the  lumps  are  broken.  These 
names,  with  the  generally  accepted  dimensions  of  the  screens 
over  and  through  which  the  lumps  of  coal  will  pass,  are  as 
follows:  Culm  passes  through  A-in.  round  mesh.  Rice  passes 
over  Ts-in.  mesh  and  through  j-in.  square  mesh.  Buckwheat 


SO  COMBUSTION  AND  FUELS 

No.  2  passes  over  J-in.  mesh  and  through  &-in.  mesh.  Buck- 
wheat No.  1  passes  over  ^-in.  mesh  and  through  J-in.  square 
mesh.  Pea  passes  over  £-in.  mesh  and  through  f-in.  square 
mesh.  Chestnut  passes  over  f-in.  mesh  and  through  If-in. 
square  mesh.  Stove  passes  over  If -in.  mesh  and  through  2-in. 
square  mesh.  Egg  passes  over  2-in.  mesh  and  through  2  f-in. 
square  mesh.  Broken  passes  over  2  f-in.  mesh  and  through 
3i-in.  square  mesh.  Steamboat  passes  over  3J-in.  mesh  and  out 
of  screen.  Lump  passes  over  bars  set  from  3J  to  5  in.  apart. 

Semianthracite  Coal. — Semianthracite  coal  contains  from 
87.5  to  92.31%  of  fixed  carbon  and  from  7.69  to  12.5%  of  vola- 
tile hydrocarbons.  It  kindles  easily  and  burns  more  freely 
than  the  true  anthracite  coal;  hence,  it  is  highly  esteemed  as 
a  fuel.  It  crumbles  readily  and  may  be  distinguished  from 
anthracite  coal  by  the  fact  that  when  just  fractured  it  will  soil 
the  hand,  while  anthracite  will  not  do  so.  It  burns  with  very 
little  smoke.  Semianthracite  coal  is  broken  into  different  sizes 
for  the  market;  these  sizes  are  the  same  and  are  known  by  the 
same  trade  names  as  the  corresponding  sizes  of  anthracite  coal. 

Semibituminous  Coal. — Semibituminous  coal  contains  from 
75  to  87.5%  of  fixed  carbon  and  from  12.5  to  25%  of  volatile 
hydrocarbons.  It  differs  from  Semianthracite  coal  only  in 
having  a  smaller  percentage  of  fixed  carbon  and  more  volatile 
hydrocarbons.  Its  physical  properties  are  practically  the 
same,  and  since  it  burns  without  the  smoke  and  soot  emitted 
by  bituminous  coal,  it  is  a  valuable  steam  fuel.  Semibitumi- 
nous and  bituminous  coals  are  known  to  the  trade  by  the  fol- 
lowing names:  Lump  coal  includes  all  coal  passing  over  screen 
bars  1J  in.  apart.  Nut  coal  passes  over  bars  f  in.  apart  and 
through  bars  li  in.  apart.  Pea  coal  passes  over  bars  |  in. 
apart  and  through  bars  f  in.  apart.  Slack  includes  all  coal 
passing  through  bars  f  in.  apart. 

Bituminous  Coal. — Bituminous  coal  contains  from  0  to 
75%  of  fixed  carbon  and  from  25  to  100%  of  volatile  hydro- 
carbons. It  may  be  divided  into  three  classes,  whose  names 
and  characteristics  are  as  follows:  Caking  coal  is  the  name 
given  to  coals  that,  when  burned  in  the  furnace,  swell  and  fuse 
together,  forming  a  spongy  mass  that  may  cover  the  whole 
surface  of  the  grate.  These  coals  are  difficult  to  burn,  because , 


COMBUSTION  AND  FUELS  81 

the  fusing  prevents  the  air  from  passing  freely  through  the 
bed  of  burning  fuel.  When  caking  coals  are  burned,  the  spongy 
mass  must  be  frequently  broken  up  with  the  slice  bar,  in  order 
to  admit  the  air  needed  for  its  combustion.  Free-burning 
coal  is  a  class  of  bituminous  coal  that  is  often  called  non-caking 
coal  from  the  fact  that  it  has  no  tendency  to  fuse  together 
when  burned  in  a  furnace.  Cannel  coal  is  a  grade  of  bituminous 
coal  that  is  very  rich  in  hydrocarbons.  The  large  percentage 
of  volatile  matter  makes  it  valuable  for  gas  making,  but  it  is 
little  used  for  the  generation  of  steam,  except  near  the  places 
where  it  is  mined. 

Lignite. — Lignite,  or  brown  coal,  contains  from  30  to  60%  of 
carbon,  a  small  quantity  of  hydrocarbons,  and  a  large  amount 
of  oxygen.  It  occupies  a  position  between  peat  and  bituminous 
coal,  being  probably  of  a  later  origin  than  the  latter.  It  has 
an  uneven  fracture  and  a  dull  luster.  Its  value  as  a  steam 
fuel  is  limited,  since  it  will  easily  break  in  transportation. 
Exposure  to  the  weather  causes  it  to  absorb  moisture  rapidly, 
and  it  will  then  crumble  quite  readily.  It  is  non-caking  and 
yields  but  a  moderate  heat,  and  is  in  this  respect  inferior  to 
even  the  poorer  grades  of  bituminous  coal. 

Miscellaneous  Fuels. — Coke  is  made  from  bituminous  coal 
by  driving  off  the  volatile  matter.  It  consists  of  from  88  to 
95%  of  carbon,  i  to  2%  of  sulphur,  and  from  4  to  12%  of  ash. 
It  is  little  used  for  steam-boiler  fuel. 

Wood  is  used  for  fuel  in  localities  where  it  is  plentiful.  It 
contains  from  20  to  50%  of  moisture  when  cut,  and  this  per- 
centage is  not  reduced  much  below  20%  by  drying.  Wood 
has  a  calorific  value  of  6,000  to  7,000  B.  T.  U.  per  Ib. 

Peat  consists  of  vegetable  matter  that  is  partly  carbonized  and 
is  found  at  the  surface  of  the  earth.  It  contains  from  75  to  80% 
water  when  cut,  and  must  be  dried  before  it  can  be  used  as  fuel. 

Bagasse  is  the  refuse  left  after  the  juice  has  been  extracted 
from  the  sugar  cane  by  means  of  the  rolls.  It  is  used  to  some 
extent  in  tropical  and  semitropical  countries.  Naturally,  its 
use  is  limited  to  the  places  where  the  sugar  cane  is  grown. 

Dried  tan  bark,  straw,  slabs,  and  sawdust  being  refuse,  their 
use  is  local  and  usually  confined  to  tanneries,  planing  and  saw- 
mills, and  threshing  outfits. 


82  COMBUSTION  AND  FUELS 

The  Babcock  &  Wilcox  Company  state  that  on  the  average 
1  Ib.  of  good  bituminous  coal  may  be  considered  as  the  equiva- 
lent of  2  Ib.  of  dry  peat,  2£  Ib.  of  dry  wood,  2£  to  3  Ib.  of  dry 
tan  bark  or  sun-dried  bagasse,  3  Ib.  of  cotton  stalks,  3J  Ib.  of 
straw,  6  Ib.  of  wet  bagasse,  and  from  6  to  8  Ib.  of  wet  tan  bark. 

LIQUID    FUEL 

Nature  of  Petroleum. — The  fuel  most  extensively  employed 
in  the  generation  of  steam  is  coal,  the  most  valuable  of  the  solid 
fuels.  In  some  parts  of  the  world,  however,  it  has  been  found 
convenient  and  economical  to  use  liquid  fuel.  This  is  obtained 
chiefly  from  petroleum,  which  is  a  natural  oil  obtained  from  the 
earth.  In  its  original  state  it  is  usually  of  a  dark-green  color 
when  viewed  in  the  sunlight;  but  when  held  up  to  the  light,  so 
that  the  light  passes  through  it,  it  has  a  reddish-brown  color. 
The  appearance  of  the  oil  will  vary  somewhat,  depending  on 
the  locality  from  which  it  is  derived.  In  some  cases  it  is 
almost  as  clear  and  colorless  as  water,  and  in  other  cases  it  is 
black;  but  American  petroleum  is  commonly  brown  or  red- 
dish-brown with  a  green  luster. 

Composition  of  Crude  Oil. — Petroleum  in  the  form  in  which 
it  issues  from  the  earth  is  known  as  crude  oil.  It  usually  con- 
tains from  83  to  87%  of  carbon,  from  10  to  16%  of  hydrogen, 
and  small  percentages  of  oxygen,  nitrogen,  and  sulphur.  Some 
crude  oils  are  devoid  of  sulphur  and  nitrogen,  but  all  those 
obtained  along  the  Pacific  coast  contain  oxygen,  sulphur, 
nitrogen,  and  a  small  percentage  of  moisture.  The  presence  of 
sulphur  in  an  oil  is  manifested  by  a  very  disagreeable  odor. 
The  following  analyses  of  crude  oils  from  Beaumont,  Texas, 
and  Bakersfield,  Cal.,  will  serve  to  give  an  idea  as  to  the  compo- 
sition of  the  oils  from  these  fields. 


Constituents 
of  Crude  Oil 

Carbon  
Hydrogen  

Texas      California 
Per  Cent.    Per  Cent. 

84.60          85.0 
10.90          12.0 
1  63               8 

Oxygen  
Nitrogen  
Moisture  .  . 

2.87            1.0 
.2 
1.0 

COMBUSTION  AND  FUELS  83 

Properties  of  Fuel  Oil. — Owing  to  the  great  demand  for 
gasoline  in  all  its  various  grades,  the  better  grades  of  petroleum, 
such  as  those  obtained  in  Pennsylvania,  are  treated  so  as  to 
recover  the  lighter  hydrocarbons.  Of  these,  gasoline  is  among 
the  early  distillates,  and  when  the  gasoline,  naphtha,  and  kero- 
sene have  been  separated,  the  residue  contains  the  lubricating 
oils,  paraffin,  and  coke.  This  residue  may  be  further  dis- 
tilled, so  as  to  obtain  the  several  products  named;  or,  it  may  be 
used  as  a  fuel,  being  then  termed  fuel  oil.  In  other  words,  fuel 
oil  is  simply  the  heavier  compounds  of  carbon  and  hydrogen 
contained  in  crude  petroleum,  the  lighter  compounds  having 
been  driven  off  by  distillation.  The  analysis  of  a  fuel  oil 
derived  from  Beaumont  crude  oil  is  as  follows: 

Constituents  Per  Cent. 

Carbon 83.26 

Hydrogen 12.41 

Sulphur .50 

Oxygen 3.83 

On  comparing  this  analysis  with  that  of  Beaumont  crude  oil 
previously  given,  it  will  be  seen  that  the  relative  proportions 
of  hydrogen  and  carbon  have  been  changed  and  that  a  large 
part  of  the  sulphur  has  been  eliminated  by  the  treatment  of 
the  crude  oil. 

Calorific  Values  of  Oil  Fuels. — The  combustible  elements 
contained  in  oil  fuels  are  the  same  as  those  in  coal,  namely, 
carbon  and  hydrogen,  and  possibly  a  small  proportion  of  sul- 
phur. The  heat  of  combustion  per  pound  of  oil,  or  the  calorific 
value,  may  be  found  approximately  from  the  chemical  analysis 
of  the  oil  by  the  same  formula  as  that  used  for  rinding  the  heat 
value  of  coal.  A  more  accurate  method,  however,  is  to  burn  a 
known  weight  of  oil  in  a  calorimeter  and  to  measure  the  heat 
generated,  from  which  the  heat  per  pound  of  the  oil  may  readily 
be  calculated.  From  the  results  of  available  tests  it  is  found 
that  the  heat  of  combustion  per  pound  of  oil  fuel  varies  between 
17,000  and  21,000  B.  T.  U.  The  average  calorific  value  of 
Texas  and  California  crude  oils  seems  to  be  about  18,600 
B.  T.  U.  per  Ib. 

Atomization  of  Oil. — When  coal  is  used  under  steam  boilers, 
the  furnace  contains  a  considerable  amount  of  fuel;  but  early 


84  COMBUSTION  AND  FUELS 

experiments  with  liquid  fuel  soon  proved  that  the  methods 
adopted  for  solid  fuel  were  not  applicable  to  liquid  fuel,  and 
that  the  latter  could  not  be  burned  successfully  in  bulk.  To 
insure  satisfactory  burning  of  oil  fuel,  it  must  first  be  changed 
to  a  vapor,  and  this  is  now  accomplished  by  atomizing  the  oil, 
or  converting  it  into  the  form  of  a  very  minutely  divided 
spray.  It  is  the  vapor  that  burns,  and  not  the  liquid  oil 
itself.  If  a  sliver  of  burning  wood  is  thrust  into  an  open  pan 
of  fuel  oil,  the  oil  will  not  ignite,  and  the  flame  of  the  stick 
will  be  extinguished.  The  reason  is  that  insufficient  oil  sur- 
face is  exposed  to  the  action  of  heat,  and  vaporization  does 
not  occur  rapidly  enough  to  supply  the  necessary  quantity  of 
inflammable  gases  to  support  combustion.  By  atomizing  the 
oil,  each  minute  particle  is  exposed  to  the  air,  thus  providing 
for  rapid  evaporation  and  complete  combustion. 

Mixture  of  Oil  Spray  and  Air. — Having  changed  the  oil  to 
a  spray  or  to  a  vapor,  it  is  next  necessary  to  mix  it  intimately 
with  air  in  the  correct  ratio  to  produce  complete  combustion. 
There  are  different  methods  by  which  the  air  is  admitted  so 
as  to  accomplish  the  mixing.  Sometimes  it  is  allowed  to  enter 
through  holes  surrounding  the  spraying  devices  and  some- 
times through  openings  from  the  ash-pit  into  the  furnace; 
combinations  of  both  methods  may  also  be  used.  In  any  event, 
the  main  object  to  be  attained  is  the  thorough  mixing  of  the 
spray  and  the  air,  so  that  each  particle  of  oil  shall  be  surrounded 
by  the  oxygen  required  for  its  perfect  combustion. 

Comparison  of  Steam  and  Air  for  Atomizing. — In  stationary- 
boiler  practice  the  agent  most  extensively  used  for  the  atomi- 
zation  of  oil  fuel  is  steam,  air  being  used  in  rare  or  special  cases. 
There  seems  to  be  little,  if  any,  saving  of  fuel  by  using  com- 
pressed air  for  atomizing,  for  the  reason  that  it  requires 
about  the  same  amount  of  steam  to  operate  the  air  compressor 
as  to  atomize  the  oil  directly.  Moreover,  with  the  direct  use 
of  steam  there  is  less  complication  of  apparatus  than  when  a 
compressor  is  installed,  and  there  is  a  correspondingly  smaller 
risk  of  accidents  that  may  interrupt  the  service.  Also  the 
installation  required  for  atomization  by  air  is  considerably 
more  expensive  than  that  required  for  the  application  of 
steam. 


COMBUSTION  AND  FUELS  85 

Amount  of  Steam  Used  for  Atomizing. — During  1902  and 
1903  the  Bureau  of  Steam  Engineering  of  the  U.  S.  Navy 
Department  made  an  extensive  series  of  tests  of  oil  burners 
using  steam  and  air  as  atomizing  agents.  From  the  results  of 
these  tests  it  is  found  that  the  atomization  of  each  pound  of  oil 
required  the  use  of  from  .15  to  1  Ib.  of  steam,  the  average  value 
being  about  .55  Ib.  For  good  performance,  the  value  should  lie 
between  .3  and  .5  Ib.  The  amount  of  steam  used  for  atomiza- 
tion, expressed  as  a  percentage  of  the  total  amount  of  steam 
generated  by  the  boiler,  ranged  from  1  to  10%,  but  the  aver- 
age was  approximately  2%.  The  foregoing  values  refer  to  the 
steam  used  for  atomization  only,  whether  directly  or  through 
the  medium  of  the  compressor,  and  are  representative  of  aver- 
age practice.  They  do  not  include  the  steam  required  for  the 
oil-pressure  pumps,  which  amounts  to  another  2%,  approxi- 
mately. Hence,  in  calculating  capacities  for  an  installation, 
it  will  be  safe  to  assume  that  5%  of  the  steam  generated  will 
be  utilized  by  the  atomizing  and  pressure  systems. 

Effect  of  Steam  on  Combustion. — The  steam  that  is  used 
for  the  purpose  of  atomizing  the  oil  does  not  increase  the  total 
heat  resulting  from  combustion,  although  it  may  affect  the 
character  of  the  chemical  changes  in  certain  parts  of  the 
flame  so  as  to  produce  a  higher  temperature  at  those  points. 
An  impression  that  seems  to  have  gained  credence  is  that  the 
steam,  under  the  effects  of  the  high  furnace  temperature,  is 
dissociated  into  its  elements,  oxygen  and  hydrogen,  and  that 
the  combustion  of  the  hydrogen  thus  set  free  increases  the  heat 
of  combustion.  The  impression  is  wrong,  for  it  takes  just  as 
much  heat  to  break  the  steam  up  into  its  elements  as  is  obtained 
by  the  subsequent  uniting  of  those  elements.  Consequently, 
if  the  combustion  is  perfect,  the  steam  that  enters  the  furnace 
passes  up  the  stack  as  steam,  carrying  away  heat  with  it,  and 
the  greater  the  amount  of  steam  introduced,  the  greater  will 
be  the  heat  loss.  Thus,  the  introduction  of  steam  into  the 
furnace  decreases  the  available  heat  rather  than  increases  it. 

Excess  of  Air  in  Oil  Burning. — A  pound  of  oil  fuel  of  average 
composition  requires  about  13  or  14  Ib.  of  air  for  its  complete 
combustion;  however,  a  greater  amount  must  be  admitted  to 
the  furnace  to  insure  complete  combustion,  as  the  mixture  of 


M,  COMBUSTION  AND  FUELS 

the  air  and  the  oil  is  not  perfect.  The  excess  of  air  is  required 
in  order  that  the  combustible  elements  may  be  surrounded 
by  sufficient  oxygen  during  the  subsequent  mixing  in  the  com- 
bustion chamber.  The  percentage  of  this  excess  should  be  as 
small  as  can  be  obtained  without  forming  smoke.  In  some 
boiler  tests  the  excess  has  amounted  to  only  10%,  which  is 
extremely  low;  but  under  average  conditions  the  excess  of  air 
is  usually  over  15%.  When  coal  is  used  as  fuel,  the  excess  of 
air  is  from  50  to  100%,  or  more;  therefore,  it  is  not  surprising 
that  a  fireman  accustomed  to  burning  coal  should  admit  too 
much  air  when  burning  oil  fuel.  To  serve  as  a  guide  to  the 
fireman  in  the  regulation  of  combustion,  it  is  a  good  plan  to 
install  a  COz  recorder,  which  will  give  a  continuous  record  of 
the  percentage  of  COz  in  the  flue  gases.  The  amount  of  COt 
formed  bears  a  known  relation  to  the  amount  of  air  admitted, 
and  by  instructing  the  fireman  to  obtain  as  high  a  percentage 
of  COz  as  possible,  the  economy  of  operation  may  be  increased. 
In  practice,  about  15%  of  COz  indicates  the  best  performance 
obtainable,  and  an  average  of  from  12  to  13%  may  be  consid- 
ered very  satisfactory. 

Evaporative  Power  of  Oil  Fuel. — Owing  to  its  higher  calo- 
rific value,  oil  fuel  has  a  greater  evaporative  capacity,  per  lb., 
than  is  possessed  by  coal.  Moreover,  the  conditions  under 
which  oil  fuel  is  burned  enable  a  greater  proportion  of  the 
heating  value  to  be  obtained  for  evaporation  of  the  water  than 
is  the  case  with  coal.  As  a  consequence,  the  number  of  pounds 
of  water  evaporated  per  lb.  of  oil  is  greater  than  the  evapora- 
tion per  lb.  of  coal.  Tests  of  boilers  using  a  good  grade  of 
coal  have  shown  an  evaporation  of  slightly  more  than  1 1  lb. 
of  water  per  lb.  of  coal  and,  under  particularly  favorable  condi- 
tions, even  better  results  have  been  obtained.  On  the  other 
hand,  an  average  evaporation  of  from  12  to  13  lb.  of  water  per 
lb.  of  oil  has  frequently  been  obtained  with  oil  fuel,  and  in  some 
cases  an  evaporation  of  16  lb.  has  been  reached. 

Effect  of  Sulphur  in  Oil. — The  presence  of  sulphur  in  oil 
fuels,  particularly  in  crude  oils,  has  caused  some  engineers  to 
fear  that  the  plates  and  tubes  of  oil-burning  boilers  would  be 
pitted  and  corroded  by  the  sulphurous  gases  generated.  Their 
fears,  however,  seem  to  have  been  groundless,  inasmuch  as  the 


COMBUSTION  AND  FUELS  87 

boiler  inspection  and  insurance  companies,  who  would  be  most 
likely  to  know,  have  made  mention  of  no  cases  of  excessive 
pitting  or  corrosion  directly  traceable  to  the  presence  of  sul- 
phur in  oil  fuel.  Some  of  the  lower  grades  of  bituminous- 
coal,  containing  from  2  to  4%  of  sulphur,  have  been  used  in 
steam-boiler  furnaces  without  detriment  to  the  boilers,  although 
the  grate  bars  may  have  been  affected.  Consequently,  there 
seems  to  be  no  good  reason  why  oil  containing  sulphur  cannot 
be  burned  with  the  same  freedom  from  deteriorating  effects 
on  the  boiler. 

Flash  Point  and  Firing  Point. — If  a  sample  of  fuel  oil  or  of 
crude  oil  is  placed  in  an  open  cup  and  heat  is  applied,  the  oil 
will  begin  to  vaporize  and  inflammable  gases  will  be  driven 
off.  If,  while  the  heating  proceeds,  a  lighted  match  is  passed 
at  intervals  over  the  surface  of  the  oil  and  about  §  in.  from  it,  a 
point  will  be  reached  at  which  the  vapor  rising  from  the  oil 
will  ignite  and  burn  with  a  flicker  of  blue  flame.  The  tempera- 
ture of  the  oil  when  this  flame  first  becomes  apparent  is 
termed  the  flash  point  of  the  oil.  If  the  heating  of  the  sample 
is  continued,  the  vapors  will  be  given  off  more  rapidly  and 
eventually  they  will  ignite  and  burn  continuously  at  the  sur- 
face of  the  oil  when  the  lighted  match  is  brought  near.  The 
temperature  of  the  oil  when  the  burning  becomes  continuous 
is  termed  the  firing  point  of  the  oil.  The  flash  point  and  the 
firing  point  of  an  oil  depend  on  the  composition,  specific  grav- 
ity, and  source  of  the  oil. 

Specifications  for  Oil  Fuel. — An  oil  to  be  used  as  a  fuel  for 
steam  boilers  may  be  either  a  crude  oil  of  uniform  composition 
or  a  fuel  oil.  If  it  is  the  latter,  all  constituents  having  a  low 
flash  point  will  have  been  removed  by  distillation.  The  dis- 
tillation should  not  have  been  carried  on  at  a  temperature  high 
enough  to  burn  the  oil  or  to  cause  particles  of  carbon  to  sepa- 
rate from  the  oil;  for  these  carbon  particles  will  eventually  clog 
the  pipes  and  burners  and  cause  trouble.  The  flash  point  of 
an  oil  fuel,  as  determined  by  a  standard  testing  apparatus, 
should  not  be  below  140°  F.;  otherwise,  there  will  be  danger 
from  the  inflammable  vapors  given  off.  The  percentage  of 
water  in  the  oil  should  be  less  than  2,  and  the  percentage  of 
sulphur  should  not  exceed  about  1.  If  these  proportions  are 


88  COMBUSTION  AND  FUELS 

exceeded,  the  oil  will  be  more  troublesome  to  use  and  should 
be  purchasable  at  a  correspondingly  lower  price. 

Firebrick  Lining  of  Furnaces. — It  is  possible  to  burn  oil  fuel 
by  spraying  the  oil  directly  into  the  metallic  firebox  of  an 
internally  fired  boiler  or  the  ordinary  furnace  of  an  externally 
fired  boiler;  but,  although  it  may  be  done  and  .occasionally  is 
done,  it  is  not  good  practice  and  is  not  recommended.  The 
spray  of  oil  issuing  from  the  burner  should  not  strike  the  tubes 
or  the  comparatively  cold  metal  surfaces  of  the  boiler,  but 
should  first  be  completely  burned  in  a  combustion  chamber  of 
ample  size,  after  which  the  hot  gases  may  be  led  into  contact 
with  the  heating  surface  of  the  boiler.  A  carefully  designed 
furnace  is  either  partly  or  wholly  lined  with  firebrick,  which 
protects  the  boiler  from  the  direct  action  of  the  flames,  prevents 
the  hot  gases  from  being  chilled  before  combustion  is  complete, 
and  tends  to  produce  a  more  uniform  transmission  of  heat  to 
the  boiler. 

Effect  of  Firebrick  Lining  on  Combustion. — Under  the  effect 
of  the  high  temperature  of  combustion  of  oil  fuel,  the  firebrick 
lining  of  the  furnace  is  maintained  in  an  incandescent  state, 
which  is  of  advantage  in  that  it  tends  to  promote  a  more  nearly 
uniform  flow  of  heat  to  the  boiler.  If  there  is  dirt  or  water  in 
the  oil  supply,  or  if  the  oil  pumps  do  not  act  properly,  so  that 
the  oil  supply  is  variable  in  pressure  or  not  continuous,  the 
burners  will  act  in  a  gusty,  erratic  manner.  Under  such  cir- 
cumstances, with  an  unlined  firebox  or  furnace,  it  would  be 
difficult  and  troublesome,  if  not  impossible,  to  maintain  com- 
bustion; but  with  a  lining  of  incandescent  firebrick  there  is  a 
reserve  of  heat  in  the  furnace,  so  that  combustion  will  be 
restarted  in  case  the  fuel  supply  is  momentarily  interrupted 
by  dirt  or  water.  Moreover,  the  firebrick,  acting  as  a  heat 
reservoir,  makes  the  flow  of  heat  to  the  boiler  more  regular, 
without  seriously  reducing  the  heat-transmitting  efficiency  of 
the  plates  or  tubes  that  it  covers. 

Furnace  Proportions  for  Oil  Fuel. — It  is  not  necessary  to 
observe  any  definite  ratio  of  length  to  breadth  or  length 
to  depth  of  the  combustion  space.  The  important  point  is  to 
provide  ample  volume,  and  then  to  insure  that  the  gases  fill  it  in 
all  parts  and  have  the  same  velocity  of  flow  throughout  it. 


STEAM 


STEAM 


PROPERTIES  OF  STEAM 

Saturated  Steam. — If  water  is  put  in  a  closed  vessel  and 
heat  is  applied  until  boiling  occurs  and  steam  is  given  off,  the 
pressure  and  the  temperature  of  the  steam  will  be  the  same  as 
those  of  the  water.  The  steam  thus  produced  is  known  as 
saturated  steam;  that  is,  saturated  steam  is  steam  whose  tem- 
perature is  the  same  as  that  of  boiling  water  subjected  to  the 
same  pressure.  Its  nature  is  such  that  any  loss  of  heat  will 
cause  some  of  the  steam  to  condense,  provided  the  pressure  is 
not  changed.  Saturated  steam  that  carries  no  water  particles 
with  it  is  called  dry  saturated  steam;  if  it  contains  moisture, 
it  is  called  wet  steam.  At  every  different  pressure,  saturated 
steam  has  certain  definite  values  for  the  temperature,  the 
weight  per  cubic  ft.,  the  heat  per  lb.,  and  so  on.  These  various 
values,  collected  and  arranged  in  order,  form  the  table  of  the 
Properties  of  Saturated  Steam,  more  commonly  termed  the 
Steam  Table.  This  table  is  shown  on  the  following  pages. 

The  various  properties  of  steam,  with  their  symbols,  as  given 
in  the  Steam  Table,  are  as  follows: 

1.  The  temperature,  t,  of  the  steam,  which  is  the  boiling 
point  of  the  water  from  which  the  steam  is  formed. 

2.  The  heat  of  the  liquid,  q,  which  is  the  number  of  B.  T.  U. 
required  to  raise  the  temperature  of  1  lb.  of  water  from  32°  F. 
to  the  boiling  point  corresponding  to  the  given  pressure. 

3.  The  latent  heat  of  vaporization,  r,  often  termed  the  latent 
heat,   which  is  the  number  of  B.   T.  U.  required  to  change 
1  lb.  of  water  at  the  boiling  point  into  steam  at  the  same 
temperature. 

4.  The  total  heat  of  vaporization,  H,  often  termed  the  total 
heat,  which  is  the  number  of  B .  T.  U.  required  to  raise  1  lb.  of 
water  from  32°  F.  to  the  boiling  point  for  any  given  pressure 
and  to  change  it  into  steam  at  that  pressure.     It  is  the  sum  of 
the  heat  of  the  liquid  and  the  latent  heat. 


90 


STEAM 


PROPERTIES  OF  SATURATED  STEAM 


Abso- 

British  Thermal  Units 

I 

lute 

Wpiaht 

Press. 
Lb. 

E 

In. 

Fahren- 
heit 
Temper- 
ature 

Heat 
of  the 
Liquid 
from 
32°  F. 

Total 
Heat 
from 
32°  F. 

Latent 
Heat  of 
Vapori- 
zation 

Volume 
of  1  Ib. 
in 
Cu.  Ft. 

w  t  ignt 
of  1 
Cu.  Ft. 
in 
Pounds 

P 

f 

Q 

H 

r 

V 

w 

1 

101.99 

70.0 

1,113.1 

1,043.0 

334.6 

.00299 

2 

126.27 

94.4 

1,120.5 

1,026.1 

173.6 

.00576 

3 

141.62 

109.8 

1,125.1 

1,015.3 

118.4 

.00844 

4 

153.09 

121.4 

1,128.6 

1,007.2 

90.31 

.01107 

5 

162.34 

130.7 

1,131.5 

1,000.8 

73.22 

.01366 

6 

170.14 

138.6 

1,133.8 

995.2 

61.67 

.01622 

7 

176.90 

145.4 

1,135.9 

990.5 

53.37 

.01874 

8 

182.92 

151.5 

1,137.7 

986.2 

47.07 

.02125 

9 

188.33 

156.9 

1,139.4 

982.5 

42.13 

.02374 

10 

193.25 

161.9 

1,140.9 

979.0 

38.16 

.02621 

11 

197.78 

166.5 

1,142.3 

975.8 

34.88 

.02866 

12 

201.98 

170.7 

1,143.6 

972.9 

32.14 

.03111 

13 

205.89 

174.6 

1,144.7 

970.1 

29.82 

.03355 

14 

209.57 

178.3 

1.145.8 

967.5 

27.79 

.03600 

14.7 

212.0 

180.8 

1,146.6 

965.8 

26.60 

.03760 

16 

216.32 

185.1 

1,147.9 

962.8 

24.59 

.1110117 

18 

222.40 

191.3 

1,149.8 

958.5 

22.00 

.04547 

20 

227.95 

196.9 

1,151.5 

954.6 

19.91 

.05023 

22 

233.06 

202.0 

1,153.0 

951.0 

18.20 

.05495 

24 

237.79 

206.8 

1.154.4 

947.6 

16.76 

.05966 

26 

242.21 

211.2 

1,155.8 

944.6 

15.55 

.06432 

28 

246.36 

215.4 

1.157.1 

941.7 

14.49 

.06899 

30 

250.27 

219.4 

1,158.3 

938.9 

13.59 

.07360 

32 

253.98 

223.1 

1,159.4 

936.3 

12.78 

.07820 

34 

257.50 

226.7 

1,160.4 

933.7 

12.07 

.OS2XO 

36 

260.85 

230.0 

1,161.5 

931.5 

11.45 

.08736 

38 

264.06 

233.3 

1.162.5 

929.2 

10.88 

.09191 

40 

267.13 

236.4 

1,163.4 

927.0 

10.37 

.09644 

42 

270.08 

239.3 

1,134.3 

925.0 

9.906 

.1009 

44 

272.91 

242.2 

1.165.2 

923.0 

9.484 

.1054 

46 

275.65 

245.0 

1,166.0 

921.0 

9.907 

.1099 

48 

278.30 

247.6 

1,166.8 

919.2 

8.740 

.11  H 

50 

2x0.  sr, 

2.50.2 

1,167.6 

917.4 

8.414 

.1188 

52 

283.32 

252.7 

1.168.4 

915.7 

8.110 

.1233 

54 

285.72 

255.1 

1,169.1 

914.0 

7.829 

.1277 

56 

2XX.O:> 

257.5 

1,169.8 

912.3 

7>>f,8 

.1321 

58 

200.31 

259.7 

1,170.5 

910.8 

7.323 

.1366 

60 

292.51 

261.9 

1.171.2 

909.3 

7.096 

.1  10'.) 

62 

294.65 

264.1 

1,171.8 

907.7 

6.882 

.1453 

64 

2W.74 

266.2 

1.172.1          '.«)<;._>       6.680 

.1497 

STEAM 
TABLE — (Continued) 


91 


p 

t 

Q 

H 

r 

V 

w 

66 

298.78 

268.3 

1,173.0 

904.7 

6.490 

.1541 

68 

300.76 

270.3 

1,173.6 

903.3 

6.314 

.1584 

70 

302.71 

272.2 

,174.3 

902.1 

6.144 

.1628 

72 

304.61 

274.1 

,174.9 

900.8 

5.984 

.1671 

74 

306.46 

276.0 

,175.4 

899.4 

5.834 

.1714 

76 

308.28 

277.8 

,176.0 

898.2 

5.691 

.1757 

78 

310.06 

279.6 

,176.5 

896.9 

5.554 

.1801 

80 

311.80 

281.4 

,177.0 

895.6 

5.425 

.1843 

82 

313.51 

283.2 

,177.6 

894.4 

5.301 

.1886 

85 

316.02 

285.8 

,178.3 

892.5 

5.125 

.1951 

90 

320.04 

290.0 

,179.6 

889.6 

4.858 

.2058 

95 

323.89 

294.0 

,180.7 

886.7 

4.619 

.2165 

100 

327.58 

297.9 

,181.9 

884.0 

4.403 

.2271 

105 

331.13 

301.6 

,182.9 

881.3 

4.206 

.2378 

110 

334.56 

305.2 

,184.0 

878.8 

4.026 

.2484 

115 

337.86 

308.7 

,185.0 

876.3 

3.862 

.2589 

120 

341.05 

312.0 

,186.0 

874.0 

3.711 

.2695 

125 

344.13 

315.2 

,186.9 

871.7 

3.572 

.2800 

130 

347.12 

318.4 

,187.8 

869.4 

3.444 

.2904 

135 

350.03 

321.4 

,188.7 

867.3 

3.323 

.3009 

140 

352.85 

324.4 

,189.5 

865.1 

3.212 

.3113 

145 

355.59 

327.2 

1,190.4 

863.2 

3.107 

.3218 

150 

358.26 

330.0 

1,191.2 

861.2' 

3.011 

.3321 

155 

360.86 

332.7 

1,192.0 

859.3 

2.919 

.3426 

160 

363.40 

335.4 

1,192.8 

857.4 

2.833 

.3530 

165 

365.88 

338.0 

1,193.6 

855.6 

2.751 

.3635 

170 

368.29 

340.5 

1,194.3 

853.8 

2.676 

.3737 

175 

370.65 

343.0 

1,195.0 

852.0 

2.603 

.3841 

180 

372.97 

345.4 

1,195,7 

850.3 

2.535 

.3945 

185 

375.23 

347.8 

1,196.4 

848.6 

2.470 

.4049 

190 

377.44 

350.1 

1,197.1 

847.0 

2.408 

.4153 

195 

379.61 

352.4 

1,197.7 

845.3 

2.349 

.4257 

200 

381.73 

354.6 

1,198.4 

843.8 

2.294 

.4359 

205 

383.82 

356.8 

1,199.0 

842.2 

2.241 

.4461 

210 

385.87 

358.9 

1,199.6 

840.7 

2.190 

.4565 

215 

387.88 

361.0 

1,200.2 

839.2 

2.142 

.4669 

220 

389.84 

363.0 

1,200.8 

837.8 

2.096 

.4772 

225 

391.79 

365.1 

1,201.4 

836.3 

2.051 

.4876 

230 

393.69 

367.1 

1,202.0 

834.9 

2.009 

.'4979 

235 

395.56 

369.0 

1,202.6 

833.6 

1.968 

.5082 

240 

397.41 

371.0 

1,203.2 

832.2 

1.928 

.5186 

250 

400.99 

374.7 

1,204.2 

829.5 

1.854 

.5393 

260 

404.47 

378.4 

1,205.3 

826.9 

1.785 

.5601 

275 

409.50 

3S3.6 

1,206.8 

823.2 

1.691 

.5913 

300 

417.42 

391.9 

1,209.3 

817.4 

1.554 

.644 

325 

424.82 

399.6 

1,211.5 

811.9 

1,437 

.696 

92  STEAM 

5.  The  specific  volume,  V,  which  is  the  volume,  in  cubic  ft., 
of  1  Ib.  of  steam  at  the  given  pressure. 

6.  The  density,  w,  which  is  the  weight,  in  pounds,  of  1  cu.  ft. 
of  steam  at  the  given  pressure.     It  is  the  reciprocal  of  the 
specific  volume. 

The  pressures,  p,  given  in  the  first  column  of  the  Steam 
Table,  are  absolute  pressures.  The  pressure  registered  by  the 
gauge  on  the  boiler  is  the  gauge  pressure,  or  the  pressure  of  the 
steam  above  that  of  the  atmosphere.  The  pressure  of  the 
atmosphere  at  sea  level,  with  the  barometer  at  about  30  in., 
is  approximately  14.7  Ib.  per  sq.  in.  Therefore,  the  abso- 
lute pressure  at  sea  level  is  equal  to  the  gauge  pressure 
plus  14.7.  In  using  the  Steam  Table,  the  atmospheric  pres- 
sure, 14.7  Ib.  per  sq.  in.,  must  always  be  added  to  the  gauge 
pressure. 

Use  of  Steam  Table. — For  any  absolute  pressure  p  given  in 
the  first  column  of  the  Steam  Table,  the  corresponding  temper- 
ature /,  total  heat  H,  or  other  property  is  found  in  the  same 
horizontal  line,  under  the  proper  column  heading;  but  if  the 
pressure  lies  between  two  of  the  values  given  in  the  first  column, 
the  corresponding  temperature,  total  heat,  etc.  must  be  found 
by  the  process  known  as  interpolation,  as  illustrated  in  the 
following  examples: 

EXAMPLE  1. — Find  the  temperature  corresponding  to  a 
pressure  of  147  Ib.  per  sq.  in.,  absolute. 

SOLUTION. — Referring  to  the  Steam  Table, 

for/>=1501b.,  /  =  358.26° 

and  for  p  =  145  Ib.,  t  -  355.59° 

Difference,  5  Ib.,        2.67° 

2.67° 

Difference  for  1  Ib.  difference  of  pressure  is =  .534°. 

5 

147  lb.^145  lb.  =  2  Ib.,  the  given  difference  of  pressure;  and 
for  this,  the  difference  in  temperature  is  2 X. 534°=  1.068°  or 
1.07°,  taking  two  decimal  places.  Hence,  the  increase  of  2  Ib. 
from  145  Ib.  to  147  Ib.  is  accompanied  by  an  increase  in  temper- 
ature of  1.07°.  Therefore,  adding  the  increase  1.07°  to  the 
temperature  355.59°  corresponding  to  145  Ib.,  the  temperature 
for  147  Ib.  is  355.59°  +1.07°  =  356.66°. 


STEAM  93 

EXAMPLE  2. — The  pressure  in  a  steam  boiler  as  shown  by 
the  gauge  is  87  Ib.  per  sq.  in.  What  is  the  temperature  of 
the  steam? 

SOLUTION. — The  absolute  pressure  is  87+14.7  =  101.7  Ib. 
per  sq.  in.  This  pressure,  in  the  Steam  Table,  lies  between, 
the  values  100  and  105. 

for  £  =  1051b.,  f  =  331.13° 
for  £  =  100  Ib..  *  =  327.58° 
Difference,  5  Ib.,        3.55° 
For  1  Ib.  change  of  pressure,  the  difference  in  temperature 

3.55° 

is  —  —  =  .71°.     From  100  Ib.  to  101.7  Ib.,  the  change  of  pres- 
5 

sure  is  1.7  Ib.,  and  the  corresponding  change  of  temperature 
is  .71°X  1.7  =  1.207°,  or  1.21°  as  the  values  in  the  Steam 
Table  contain  but  two  decimal  places.  For  101.7  Ib.,  therefore, 
the  temperature  is  327.58°  + 1.21°  =  328.79°. 

EXAMPLE  3. — What  is  the  pressure  of  steam  at  a  temperature 
of  285°  P.? 

SOLUTION. — From  the  Steam  Table, 

for/ =  285.72°,  £  =  541b. 
for  /  =  283.32°,  p  =  52  Ib. 
Difference,  2.40°,  2  Ib. 

From  t  =  283.32°  to  /  =  285°,  the  increase  of  temperature 
is  1.68°.  Now,  since  an  increase  of  temperature  of  2.40°  gives 
an  increase  of  pressure  of  2  Ib.,  the  increase  of  1.68°  must  give 

1.68 
an  increase  of  pressure  of  —  X2  lb.  =  1.4  Ib.     Hence,  the 

required  pressure  is  52  lb.  +  1.4  lb.  =  53.4  Ib. 

EXAMPLE  4. — Find,  from  the  Steam  Table,  the  total  heat  of 
a  pound  of  saturated  steam  at  a  pressure  of  63  Ib.  per  sq.  in., 
gauge. 

SOLUTION. — The  absolute  pressure  is  63  +  14.7  =  77.7  Ib.  per 
sq.  in.  From  the  Steam  Table, 

for  p  =  78  Ib.,  H  =  1,176.5  B.  T.  U. 

for  p  =  76  Ib.,  H  =  1.176.0  B.  T.  U. 

Difference,   2  Ib.,  .5    B.  T.  U. 

Difference,    1  Ib.,  .25  B.  T.  U. 

8 


«J4  STEAM 

The  difference  between  the  given  pressure  and  76  Ib.  is  77.7 
—  76  =  1.7  Ib.  For  a  difference  of  1.7  Ib.,  the  change  of  total 
heat  is  1.7  X  .25  =  .425  B.  T.  U.  Hence,  for  77.7  Ib.,  H  =  1,176.0 
+  .425=1,176.425,  say  1,176.4  B.  T.  U. 

EXAMPLE  5. — Find  the  volume  occupied  by  14  Ib.  of  steam  at 
30  Ib.  gauge  pressure. 

SOLUTION. — Absolute  pressure  =  30+14.7  =  44.7  Ib.  per  sq.  in. 
From  the  Steam  Table, 

for  £  =  44  Ib.,  V  =  9.484  cu.  ft. 

for  £  =  46  Ib.,  F  =  9.097  cu.  ft. 

Difference,    2  Ib.,          .387  cu.  ft. 

.387 
The  difference  for  1  Ib.  is  =  .1935.     44.7-44  =  .7    Ib. 

actual  difference  in  pressure.  .  1935 X. 7  =  .135  difference  in 
volume.  As  the  pressure  increases,  the  volume  decreases; 
and  to  obtain  the  volume  at  44.7  Ib.,  it  is  necessary  to  sub- 
tract the  difference  .135  from  the  volume  at  44  Ib.;  thus,  for  p 
=  44.7,  v  =  9.484 -.135  =  9.349  cu.  ft.  The  volume  of  14  Ib. 
is  14X9.349  cu.  ft.  =  130.89  cu  ft. 

EXAMPLE  6. — Find  the  weight  of  40  cu.  ft.  of  steam  at  a 
temperature  of  25-4°  F. 

SOLUTION. — From  column  10  of  the  Steam  Table,  the  weight 
w  of  1  cu.  ft.  of  steam  at  253.98  is  .07820  Ib:  254  —  253.98  =  .02. 
Neglecting  the  .02°,  the  weight  of  40  cu.  ft.  is  therefore 
,07820X40-3.128  Ib. 

EXAMPLE  7. — How  many  pounds  of  steam  at  64  Ib.  pressure, 
absolute,  are  required  to  raise  the  temperature  of  300  Ib.  of 
water  from  40°  to  130°  P.,  the  water  and  steam  being  mixed 
together? 

SOLUTION. — The  number  of  heat  units  required  to  raise  1  Ib. 
from  40°  to  130°  is  130° -40°  =  90  B.  T.  U.  Actually,  a  little 
more  than  90  would  be  required  but  the  above  is  near  enough 
for  all  practical  purposes.  Then,  to  raise  300  Ib.  from  40° 
to  130°  requires  90X300  =  27,000  B.  T.  U.  This  quantity  of 
heat  must  necessarily  come  from  the  steam.  Now,  1  Ib.  of  steam 
at  64  Ib.  pressure  gives  up,  in  condensing,  its  latent  heat  of 
vaporization,  or  906.2  B.  T.  U.;  but,  in  addition  to  its  latent 
heat,  each  pound  of  steam  on  condensing  must  give  up  an 


STEAM  95 

additional  amount  of  heat  in  falling  to  130°.  Since  the  original 
temperature  of  the  stealn  was  296.74°  F.  (see  Steam  Table), 
each  pound  gives  up  by  its  fall  of  temperature  296.74  — 130 
=  166.74  B.  T.  U.  Consequently,  each  pound  of  the  steam 
gives  up  a  total  of  906.2+166.74  =  1,072.94  B.  T.  U.,  and 

'- =  25.16  Ib.   of  steam  will  therefore  be  required  to 

1,072.94 

accomplish  the  desired  result. 

SUPERHEATED  STEAM 

If  saturated  steam  is  contained  in  a  vessel,  out  of  contact 
with  water,  and  heat  is  added  to  it,  its  temperature  will  begin 
to  rise  and  its  weight  per  cu.  ft.  will  begin  to  decrease,  pro- 
vided the  pressure  remains  constant.  As  more  heat  is  added, 
the  temperature  rises  farther  above  that  of  saturated  steam 
at  that  pressure,  and  the  steam  is  then  called  superheated 
steam.  Superheated  steam  cannot  exist  in  contact  with  water. 

The  following  distinction  is  usually  made  between  saturated 
and  superheated  steam:  For  a  given  pressure,  saturated  steam 
has  one  temperature  and  one  weight  per  cu.  ft.,  neither  of 
which  can  change  so  long  as  the  steam  remains  in  immediate 
contact  with  water.  Superheated  steam  at  the  same  pressure 
has  a  greater  temperature  and  less  weight  per  cu.  ft.  than  sat- 
urated steam,  and  both  the  temperature  and  weight  per  cu.  ft. 
may  vary  while  the  pressure  remains  constant  if  the  volume 
increases  or  decreases  accordingly.  In  other  words,  .both  the 
pressure  and  the  volume  of  superheated  steam  must  be  con- 
stant in  order  to  maintain  a  constant  temperature  and  a  con- 
stant weight  per  cu.  ft. 

QUALITY  OF  STEAM 

Moisture  in  Steam. — The  steam  furnished  by  the  average 
steam  boiler  is  not  dry  saturated  steam,  but  is  usually  wet 
steam.  A  good  boiler  should  not  show  more  than  2  or  3% 
of  water  in  the  steam.  In  a  quantity  of  wet  steam,  or  a  mix- 
ture of  steam  and  water,  the  percentage  of  dry  steam,  expressed 
as  a  decimal,  is  called  the  quality  of  the  steam.  For  example, 
suppose  that  a  certain  boiler  generates  wet  steam  that  con- 
tains 3%,  or  .03,  of  moisture;  then  the  quality  of  the  steam. 


36  STEAM 

•or  the  percentage  of  dry  steam,  is  .97.  In  other  words,  the 
quality  of  the  steam  is  equal  to  1  minus  the  percentage  of 
moisture,  expressed  decimally.  This  rule  may  be  stated 
simply  by  the  formula 

Q=l-m, 
in  which     Q  =  quality  of  the  steam; 

m  =  percentage  of  moisture,  expressed  decimally. 

EXAMPLE. — What  is  the  quality  of  steam  that  contains  2.7% 
of  moisture? 

SOLUTION. — Expressed  as  a  decimal,  2.7%  =  .027.  Then, 
substituting  this  value  for  m  in  the  formula,  Q  =  1  —  .027  =  .973. 

Heat  in  Wet  Steam. — The  total  heat  contained  in  1  Ib.  of 
dry  steam  is  the  sum  of  the  heat  required  to  raise  1  Ib.  of  water 
from  32°  F.  to  the  boiling  point  and  the  heat  required  to  change 
the  boiling  water  into  steam  of  the  same  temperature.  That 
is,  in  the  Steam  Table,  each  value  given  in  the  fourth  column 
is  the  sum  of  the  values  given  in  the  third  and  fifth  columns 
and  lying  in  the  same  horizontal  row.  In  a  mixture  of  1  Ib.  of 
steam  and  water  at  the  same  temperature  there  is  less  heat  than 
in  1  Ib.  of  dry  steam  at  the  same  temperature;  for  all  the  water 
has  not  been  changed  to  steam,  and  consequently  the  latent 
heat  of  1  Ib.  of  steam  has  not  been  utilized.  Instead,  there  is 
present  only  that  part  of  the  latent  heat  which  is  used  to  evap- 
orate the  portion  of  the  mixture  that  is  dry  steam,  which  is 
represented  by  the  quality  of  the  steam.  Thus,  using  the 
symbols  given  in  the  Steam  Table, 

H  =  q+r  (1) 

which  is  the  formula  for  the  total  heat  of  1  Ib.  of  dry  steam. 
But  if  the  steam  is  wet,  and  Q  represents  the  quality  of  the 
steam,  expressed  decimally,  the  total  heat  of  1  Ib.,  represented 
by//',  is  Hl  =  q+Qr  (2) 

EXAMPLE.— What  is  the  total  heat  of  10  Ib.  of  steam  at 
150  Ib.  gauge  pressure,  if  the  steam  contains  5%  of  moisture? 

SOLUTION. — From  the  Steam  Table,  the  heat  of  the  liquid 
of  lib.  of  dry  steam  at  150  Ib.,  gauge,  or  150+14.7  =  164.7  Ib., 
absolute,  is  q  =  337.84  B.  T.  U.,  and  the  latent  heat  of  1  Ib.  at 
the  same  pressure  is  r  =  855.71  B.  T.  U.  As  the  moisture  is  5%, 
the  quality  of  the  steam  is  1.00  — .05  =  .95.  Then,  applying 
formula  2,  //'  =337.84  +  .95X855.7 1  =  1,150.76  B.  T.  U. 


STEAM 


97 


Barrel  Calorimeter. — It  is  a  rather  difficult  matter  to  make 
a  very  exact  determination  of  the  moisture  contained  in  steam. 
The  apparatus  or  instrument  used  for  this  purpose  is  called  a 
calorimeter.  There  are  many  more  or  less  complicated  calori- 
meters, but  about  the  simplest  and  most  available  one  for 
general  use  is  the  so-called  barrel  calorimeter,  shown  in  the 
accompanying  illustration.  A 
barrel  or  tank  a  holding  400 
or  500  Ib.  of  water  is  placed  on 
a  platform  scales  b,  filled  with 
water,  and  weighed.  The  tem- 
perature of  the  water  is  regis- 
tered by  a  thermometer  inserted 
in  the  side  of  the  barrel.  Steam 
from  the  boiler  is  led  through 
a  hose  c  into  the  barrel  until 
the  temperature  of  the  water 

reaches  130°  to  140°  F.  The  steam  is  then  turned  off  and  the 
barrel  and  its  contents  are  again  weighed.  The  difference 
between  this  weight  and  the  original  weight  is  the  weight  of 
the  steam  led  in  from  the  boiler  and  condensed  in  the  barrel. 
The  average  steam  pressure  throughout  the  process  must  be 
observed.  It  is  well  to  have  the  tube  bent  as  shown  in  the 
figure. 

The  weight  of  the  cold  water  and  the  rise  in  its  temperature 
are  known,  and  so  also  is  the  weight  of  the  mixture  of  steam 
and  water  that  is  led  in  from  the  boiler.  From  the  Steam 
Table,  the  temperature  of  the  steam  can  be  found,  since  the 
average  pressure  is  known.  Now,  if  dry  steam  comes  through 
the  hose  c,  the  condensation  of  this  steam  should  raise  the 
temperature  of  the  cold  water  in  the  barrel  a  certain  amount. 
If  the  temperature  is  not  raised  that  much,  it  must  be  because 
some  of  the  mixture  led  into  the  barrel  was  water. 

Let  Q  =  quality  of  steam; 

W  =  weight  of  cold  water  in  barrel,  in  pounds; 
w  =  weight  of  mixture  run  into  the  barrel,  in  pounds; 
t  =  temperature  of  steam  corresponding  to  the  observed 

pressure ; 
ti  =  original  temperature  of  water,  in  barrel; 


98  STEAM 

tz  =  temperature  of  water  in  barrel  after  steam  is  con- 

densed; 
L  =  latent  heat  of  1  Ib.  of  steam  at  observed  pressure. 


Then,  Q  =  —        - 

EXAMPLE.  —  In  a  calorimetric  test,  the  weight  of  cold  water 
was  420  Ib.,  and  of  steam  condensed,  36  Ib.  The  initial 
temperature  of  the  cold  water  was  40°  F.,  the  final  tempera- 
ture was  130°  F.,  and  the  average  steam  pressure  was  60  Ib. 
Find  the  quality  of  the  steam. 

SOLUTION.  —  Absolute  pressure  =  60+  14.7  =  74.7  Ib.  per  sq.  in. 
Latent  heat  of  steam  at  this  pressure,  from  Steam  Table,  is 
898.5.  The  temperature  of  steam  at  this  pressure  is  307.2°. 
Hence,  by  the  formula 


--  .9714 


898.5 

That  is,  the  boiler  generates  a  mixture  that  is  composed  of 
97.14%  of  dry  steam  and  2.86%  of  water. 

If  the  result  found  by  the  foregoing  formula  shows  that  Q 
is  greater  than  1,  the  conclusion  is  that  the  steam,  instead  of 
being  wet,  was  superheated,  and  therefore  gave  up,  in  con- 
densing, a  greater  amount  of  heat  per  pound  than  would  have 
been  given  up  by  1  Ib.  of  dry  saturated  steam  at  the  same 
pressure. 

The  barrel  calorimeter  must  be  used  very  carefully  in  order 
to  obtain  accurate  results.  The  operation  should  be  repeated 
once  or  twice  before  the  actual  test  is  made  so  as  to  warm  up 
the  barrel.  The  most  important  observation  is  the  tempera- 
ture. This  should  be  taken  by  a  thermometer  graduated  to 
fifths  or  tenths  of  a  degree.  The  weights  should  be  as  accu- 
rate as  possible.  The  chief  merit  of  the  barrel  calorimeter  is 
its  availability.  It  can  be  rigged  up  in  almost  any  situation. 

The  quality  of  the  steam  having  been  determined,  the  actual 
amount  of  water  evaporated  by  a  steam  boiler  is  found  by 
multiplying  the  observed  amount  of  feedwater  by  the  quality 
of  the  steam  expressed  decimally. 


STEAM  99 

FLOW  OF  STEAM 

Weight  of  Steam  Discharged. — The  number  of  pounds  of 
steam  that  will  flow  continuously  through  a  pipe  of  given 
diameter  in  1  min.  at  specified  pressure  may  be  calculated 
by  the  formula 


in  which    W = weight  of  steam  discharged ,  in  pounds  per  minute ; 

w  =  weight  of  1  cu.  ft.  of  steam  at  the  pressure  Pi ; 
Pi  =  pressure  of  steam  at  entrance  to  pipe,  in  pounds 

per  square  inch; 

P2  =  pressure  of  steam   at   discharge,  in  pounds  per 
square  inch; 

L  =  length  of  pipe,  in  feet; 

d  =  diameter  of  pipe,  in  inches. 

In  applying  the  preceding  formula  in  determining  the  diam- 
eter of  the  steam  pipe  for  an  engine,  it  must  be  remembered 
that,  in  steam-engine  work,  the  steam  is  drawn  intermittently 
from  the  pipe.  Thus,  assume  that  an  engine  of  100  H.  P.,  con- 
suming 30  Ib.  of  steam  per  horsepower  per  hour,  cuts  off  at  J 
stroke.  In  that  case,  the  steam  consumption  per  hour  would 
be  100 X  30  =  3,000  Ib.  But  as  the  steam  used  at  each  stroke  is 
drawn  into  the  cylinder  during  only  one-fourth  of  the  time 
required  to  complete  the  stroke,  the  3,000  Ib.  of  steam  flows 
through  the  pipe  in  J  hr.  Then,  in  order  to  determine  the 
quantity  of  steam  that  would  flow  continuously  at  the  same 
velocity  at  which  it  flows  during  admission  to  the  cylinder, 
the  actual  steam  consumption  per  hour  should  be  divided  by 
the  fraction  representing  the  cut-off  and  the  quotient  should  be 
taken  as  the  weight  of  steam  discharged  per  hour.  This  value, 
divided  by  60,  should  be  substituted  for  w  in  the  formula. 
Thus,  in  the  case  mentioned,  the  amount  of  steam  discharged 
per  hour,  flowing  continuously  at  the  same  velocity  as  during  the 
admission  period,  is  3,000 -f- i  =  12,000,  and  the  value  of  W  to 
be  used  in  the  formula  is  therefore  12, 000 -=-60  =  200  Ib.  per 
min.  Knowing  the  pressures,  the  length  of  pipe,  and  the 


100  STEAM 

•weight  of  the  entering  steam  per  cubic  foot,  different  values 
of  d  may  be  assumed,  until  a  value  is  found  that  will  give  the 
necessary  discharge  W.  This  is  the  required  pipe  diameter. 

The  approximate  weights  of  steam  delivered  per  minute 
through  100  ft.  of  pipe  of  various  diameters,  with  a  drop  of 
pressure  of  1  lb.,  are  given  in  the  accompanying  table.  On 
the  whole,  these  values  are  slightly  higher  than  those  which 
would  be  obtained  by  the  foregoing  formula  for  the  same  con- 
ditions. If  the  drop  of  pressure  is  more  or  less  than  1  lb.,  the 
value  in  the  table  must  be  multiplied  by  the  square  root  of  the 
drop,  to  obtain  the  discharge.  Also,  if  the  length  of  the  pipe  is 
more  or  less  than  100  ft.,  divide  100  by  the  length,  in  feet,  and 
multiply  the  square  root  of  this  quotient  by  the  value  given 
in  the  table.  The  following  example  illustrates  this  point. 

EXAMPLE. — How  many  pounds  of  steam  will  be  discharged 
per  minute,  with  an  initial  gauge  pressure  of  120  lb.  per  sq.  in., 
through  a  pipe  3  in.  in  diameter  and  400  ft.  long,  with  a  drop  of 
pressure  of  2  lb.  ? 

SOLUTION. — From  the  table,  the  amount  discharged  through 
100  ft.  of  3-in.  pipe  with  a  drop  of  1  lb.  and  an  initial  pressure 
of  120  lb.  per  sq.  in.,  is  53.6  lb.  per  min.  But  as  the  drop 
is  2  lb.,  the  table  value  must  be  multiplied  by  ^2  and  as  the 
length  is  400  ft.,  it  must  also  be  multiplied  by  "V^.  Hence, 
the  discharge  for  the  given  conditions  will  be  53.6 X  "V2X  \igg 
=  37.9  lb.  per  min. 

Resistance  of  Elbows  and  Valves. — The  presence  of  elbows, 
bends,  and  valves  in  a  steam  pipe  increases  the  resistance  to 
the  flow  of  steam  and  thus  increases  the  drop  of  pressure 
between  the  inlet  and  outlet  ends.  It  has  been  found  that  the 
resistance  caused  by  an  elbow  or  a  sharp  bend  is  approxi- 
mately the  same  as  the  resistance  of  a  length  of  pipe  equal  to 
60  times  the  diameter,  and  that  a  stop-valve  has  a  resistance 
equal  to  that  of  a  length  of  pipe  of  40  diameters.  In  using 
the  foregoing  formula  for  the  weight  of  steam  discharged, 
therefore,  the  value  of  L  should  be  the  equivalent  length  of  pipe, 
taking  into  account  the  bends  and  valves.  The  method  of 
doing  this  is  illustrated  by  the  following  example: 

EXAMPLE. — What  is  the  equivalent  length  of  300  ft.  of  3-in. 
pipe  containing  four  elbows  and  six  stop-valves? 


STEAM 


101 


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102  STEAM 

SOLUTION.  —  Each  elbow  has  a  resistance  the  same  as  that 
of  60  diameters  of  pipe,  or  60X3  =  180  in.  =  15  ft.,  and  four 
elbows  have  the  resistance  of  4X15  =  60  ft.  of  pipe.  Each 
stop-valve  has  a  resistance  that  is  equivalent  to  adding  40X3 
=  120  in.  =  10  ft.  of  pipe,  and,  as  there  are  six  valves,  their  com- 
bined resistance  is  that  of  6  X  10  =  60  ft.  of  pipe.  The  equiva- 
lent length  of  pipe  is,  therefore,  300  +  60+60  =  420  ft. 

Steam  Pipes  for  Engines.  —  In  practice,  the  velocity  of  flow 
of  steam  in  the  supply  pipes  of  engines  and  pumps  is  usually 
not  greater  than  6,000  ft.  per  min.,  although  it  is  increased  to 
as  much  as  8,000  ft.  per  min.  in  some  cases.  For  exhaust 
pipes,  a  common  value  is  4,000  ft.  per  min.  The  assumptions 
made  are  that  the  cylinder  is  rilled  with  steam  at  boiler  pressure 
at  each  stroke  and  that  a  volume  of  steam  equal  to  the  volume 
of  the  cylinder  is  released  at  each  stroke,  so  that  the  flow  is 
practically  continuous.  The  areas  of  the  steam  and  exhaust 
pipes  may  then  be  calculated  by  the  formula 

A  S 

a  —  —, 
s 

in  which  a  =area  of  steam  or  exhaust  pipe,  in  square  inches; 
A  =area  of  cylinder,  in  square  inches; 
5  =  piston  speed,  in  feet  per  minute; 
s  =  velocity  of  steam  in  pipe,  in  feet  per  minute. 
EXAMPLE.  —  Find  the  areas  of  the  steam  and  exhaust  pipes 
for  an  engine  whose  cylinder  is*20  in.  in  diameter  and  whose 
piston  speed  is  450  ft.  per  min. 

SOLUTION.  —  By  the  formula,  the  area  of  the  steam  pipe, 
assuming  that  5  =  6,000  ft.  per  min.,  is 
.7854X202X450 


600 

Similarly,  for  the  exhaust  pipe,  assuming  that  5  =  4,000,  the 
area  is 

.7854X202X450 


4,000 


=  35.3  sq.  in. 


STEAM  BOILERS  103 


STEAM  BOILERS 


FURNACE  FITTINGS 

Bridge  Wall. — The  bridge,  also  termed  the  bridge  wall,  is  a 
low  wall  at  the  back  end  of  the  grate;  it  forms  the  rear  end 
of  the  furnace  and  causes  the  flame  to  come  in  close  contact 
with  the  heating  surface  of  the  boilei  It  is  usually  built  of 
common  brick  and  faced  with  firebi  :k.  The  passage  between 
the  bridge  and  the  boiler  shell  should  lot  be  too  small;  its  area 
may  be  approximately  one-sixth  the  ar;?a  of  the  grate.  The 
space  between  the  grate  and  the  shell  should  be  ample  for  com- 
plete combustion,  and  the  distance  between  the  grate  and  the 
boiler  shell  may  be  made  about  one-half  the  diameter  of  the 
shell. 

Fixed  Grates. — The  grate,  which  is  nearly  always  made  of 
cast  iron,  furnishes  a  support  for  the  fuel  to  be  burned  and 
must  be  provided  with  spaces  for  the  admission  of  air.  The 
area  of  the  solid  portion  of  the  grate  is  usually  made  nearly 
equal  to  the  combined  area  of  the  air  spaces. 


FIG.  1 

The  common  type  of  fixed  grate  is  made  of  single  bars  a, 
Fig.  1 ,  placed  side  by  side  in  the  furnace.  The  thickness  of 
the  lugs  cast  on  the  sides  of  the  bars  determines  the  width  of  the 
open  spaces  of  the  grate.  It  is  the  general  practice  to  make 
the  thickness  across  the  lugs  twice  the  thickness  of  the  top  of  the 
bar.  For  long  furnaces,  the  bars  are  generally  made  in  two 
lengths  of  about  3  ft.  each,  with  a  bearing  bar  in  the  middle 
of  the  grate.  Long  grates  are  generally  set  with  a  downward 
slope  toward  the  bridge  wall  of  about  f  in.  per  foot  of  length. 


104 


STEAM  BOILERS 


For  the  larger  sizes  of  anthracite  and  bituminous  coal,  the 
air  space  may  be  from  f  to  f  in.  wide,  and  the  grate  bar  may 
have  the  same  width.  For  pea  and  nut  coal,  the  air  space  may 
be  from  f  to  $  in.,  and  for  finely  divided  fuel,  like  buckwheat 
coal,  rice  coal,  bird's-eye  coal,  crlm;  and  slack,  air  spaces  from 
&  to  |  in.  may  be  used. 


FIG.  2 

The  grate  bar  shown  n  Fig.  2,  and  known  as  the  herring- 
bone grate  bar,  has  in  r.iany  places  superseded  the  ordinary 
grate  bar,  because  they  will  usually  far  outlast  a  set  of  ordi- 
nary grate  bars.  Herring-bone  grate  bars  can  be  obtained  in 
a  great  variety  of  styles  and  with  different  widths  of  air  spaces. 
They  are  usually  supported  on  cross-bars,  and,  like  many 


FIG.  3 


other  forms  of  grate  bars,  may  be  arranged  with  trunnions,  so 
as  to  rock  the  individual  bars  by  means  of  hand  levers. 

A  form  of  cast-iron  grate  bar  for  the  burning  of  sawdust  is 
shown  in  Fig.  3.  The  bar  is  semicircular  in  cross-section  and 
is  provided  with  circular  openings  for  the  introduction  of  air. 
Lugs  are  cast  on  each  side  of  the  bar  to  serve  as  distance  pieces 

in  providing  air  spaces  between 

the  bars. 

Dead  Plate.— The  front  ends 

of  the  grate  bars  are  usually 
FIG.  4  supported   on   the   dead    plate, 

which  is  a  flat  cast-iron  plate 

placed  across  the  furnace  just  inside  the  boiler  front  and  on  a 
level  with  the  bottom  of  the  furnace  door.  The  purpose  of 
the  dead  plate  is  twofold:  It  forms  a  support  for  the  firebrick 


STEAM  BOILERS  105 

lining  of  the  boiler  front,  and  a  resting  place  on  which  bitumi- 
nous coal  may  be  coked  before  it  is  placed  on  the  fire.  To 
support  the  grate  bars,  the  inner  edge  of  the  dead  plate  is 
either  beveled  or  a  lip  is  provided,  as  at  a,  Fig.  4. 

Objection  to  Stationary  Grate  Bars. — The  greatest  objec- 
tion to  stationary  grate  bars  is  that  with  them  the  furnace 
door  must  be  kept  open  for  a  considerable  length  of  time 
when  the  fire  is  being  cleaned.  Cleaning  fires  when  the  boiler 
has  a  stationary  grate  not  only  severely  taxes  the  fireman,  but 
the  inrush  of  cold  air  chills  the  boiler  plates,  thus  producing 
stresses  that  in  the  course  of  time  will  crack  them. 

Shaking  Grates. — There  are  on  the  market  many  designs  of 
shaking  grates  for  large  steam  boilers,  differing  chiefly  in  detail 
and  arrangement.  Usually  the  grate  bars  are  hung  on  trun- 
nions at  each  end  and  are  connected  together  with  bars  to 
which  are  attached  shaking  rods  that  extend  forwards  through 
the  furnace  front.  Levers  or  handles  are  attached  to  the 
shaking  rods,  and  by  working  them  back  and  forth  the  grats 
bars  receive  a  rocking  motion  that  breaks  up  the  bed  of  coal 
on  the  grate  and  serves  to  shake  the  ashes  through  into  the 
ash-pit.  The  fires  may  thus  be  kept  clean  without  the  neces- 
sity of  opening  the  fire-doors. 

Classes  of  Mechanical  Stokers. — A  mechanical  stoker  is  a 
power-driven  rocking  grate  arranged  so  as  to  give  a  uniform 
feed  of  coal  and  to  rid  itself  continuously  of  ashes  and  clinkers. 
The  principal  designs  of  mechanical  stokers  and  automatic 
furnaces  may  be  divided  into  two  general  classes,  overfeed  and 
underfeed. 

Overfeed  Stoker. — In  overfeed  stokers  the  fixed  carbon  of 
the  coal  is  burned  on  inclined  grates.  The  coal  is  pushed  on 
to  these  grates,  which  are  given  a  sufficiently  rapid  vibratory 
motion  to  feed  it  down  at  such  a  rate  that  practically  all 
the  carbon  is  burned  before  reaching  the  lower  end,  where 
the  ashes  and  clinkers  are  discharged.  In  Fig.  5  is  shown 
a  sectional  view  of  a  stoker  of  this  class.  The  coal  is  fed  into 
the  hopper  a,  from  which  it  is  pushed  by  the  pusher  plate  b 
on  to  the  dead  plate  c,  where  it  is  heated.  From  c  it  passes 
to  the  grate  d.  Each  bar  is  supported  at  its  ends  by  trunnions 
and  is  connected  by  an  arm  to  a  rocker  bar  i,  which  is  slowly 


106 


STEAM  BOILERS 


moved  to  and  fro  by  an  eccentric  on  the  shaft  s,  so  as 
rock  the  grates  back  and  forth;  the  grates  thus  gradually 
move  the  burning  fuel  downwards.  The  ashes  and  clinkers 
are  discharged  from  the  lower  grate  bar  on  to  the  dumping 
grate  e.  A  guard  /  may  be  raised,  as  shown  by  the  dotted 
lines,  so  as  to  prevent  coke  or  coal  from  falling  from  the  grate 
bars  into  the  ash-pit  when  the  dumping  grate  is  lowered.  Air 
for  burning  the  gases  is  admitted  in  small  jets  through  holes  in 
the  air  tile  g,  and  the  mixture  of  gas  and  air  is  burned  in  the 


FIG. 


hot  chamber  between  the  firebrick  arch  h  and  the  bed  of  burning 
coke  below. 

Underfeed  Stoker. — The  stoker  shown  in  Fig.  f>  illustrates 
the  principle  of  operation  and  the  construction  of  the  under- 
feed stoker.  Coal  is  fed  into  the  hopper  a,  from  which  it  is 
drawn  by  the  spiral  conveyer  b  and  forced  into  the  magazine  d. 
The  incoming  supply  of  fresh  coal  forces  the  fuel  upwards  to  the 
surface  and  over  the  sides  of  the  magazine  on  the  grates,  where 
it  is  burned.  A  blower  forces  air  through  a  pipe  /  into  the 


STEAM  BOILERS 


107 


chamber  g  surrounding  the  magazine.  From  g  the  air  passes 
upwards  through  hollow  cast-iron  tuyere  blocks  and  out  through 
the  openings,  or  tuyeres  e.  The  gas  formed  in  the  magazine, 
mixed  with  the  jets  of  air  from  the  tuyeres,  risdfe  through  the 
burning  fuel  above,  where  it  is  subjected  to  a  sufficiently  high 
temperature  to  secure  its  combustion.  Nearly  all  the  air  for 
burning  the  coal  is  supplied  through  the  tuyeres,  only  a  very 
small  portion  of  the  supply  coming  through  the  grate.  The 


FIG. 


ashes  and  clinkers  are  gradually  forced  to  the  sides  of  the  grate 
against  the  side  walls  of  the  furnace,  from  which  they  are 
removed  from  time  to  time  through  doors  in  the  furnace  front 
similar  to  the  fire-doors  of  an  ordinary  furnace.  In  other 
words,  owing  to  the  construction  of  the  underfeed  stoker, 
the  fire  must  periodically  be  cleaned  from  clinkers  and  the 
ashes  removed  by  hand. 


108 


STEAM  BOILERS 


CHIMNEYS 

Production  of  Draft. — It  is  well  known  that  any  volume  of 
gas  is  lighter  when  heated  than  the  same  volume  of  gas  when 
cool.  When  hot  gases  pass  into  the  chimney,  they  have  a  tem- 
perature of  from  400°  to  600°  P.,  while  the  air  outside  the  chim- 
ney has  a  temperature  of  from  40°  to  90°  F.  Roughly  speak- 
ing, the  air  weighs  twice  as  much,  bulk  for  bulk,  as  the  hot 
gases.  Naturally,  then,  the  pressure  in  the  chimney  is  less 
than  the  pressure  of  the  outside  air.  The  production  of  draft 
and  the  satisfactory  operation  of  a  chimney 
depend  on  this  pressure  difference.  The  pres- 
sure of  the  draft  depends  on  the  temperature 
of  the  furnace  gases  and  the  height  of  the 
chimney.  Chimney  draft  is  affected  by  so 
many  varying  conditions  that  no  absolutely 
reliable  rules  can  be  given  for  proportioning 
chimneys  to  give  a  certain  desired  draft  pres- 
sure. The  rules  given  for  chimney  proportions 
are  based  on  successful  practice  rather  than  on 
pure  theory. 

Measurement   of   Draft. — The  intensity 
the    draft  may  be   measured  by  means  of 
water  gauge  such   as  is  shown  in  the  accom- 
panying illustration.     As  will  be  seen,  it  is  a 
glass  tube  open  at  both  ends,  bent  to  the  shape 
of  the  letter  U ;  the  left  leg  communicates  with 
the  chimney.     The  difference  in  the  two  water 
levels  H  and  Z  in  the  legs  represents  the  intensity  of  the  draft, 
and  is  expressed  in  inches  of  water. 

The  draft  produced  by  a  chimney  may  vary  from  J  in.  to 
2  in.  of  water,  depending  on  the  temperature  of  the  chimney 
gases  and  on  the  height  of  the  chimney.  Generally  speaking, 
it  is  advantageous  to  use  a  high  chimney  and  as  low  a  chimney 
temperature  as  possible.  The  draft  pressure  required  depends 
on  the  kind  of  fuel  used.  Wood  requires  but  little  draft, 
say  J  in.  of  water  or  less;  bituminous  coal  generally  requires 
less  draft  than  anthracite.  To  burn  anthracite,  slack,  or  culm, 
the  draft  pressure  should  be  about  H  in.  of  water. 


STEAM  BOILERS  109 

Form  of  Chimney. — The  form  of  a  chimney  has  a  pronounced 
effect  on  its  capacity.  A  round  chimney  has  a  greater  capacity 
for  a  given  area  than  a  square  one.  If  the  flue  is  tapering,  the 
area  for  calculation  is  measured  at  its  smallest  section.  The 
flue  through  which  the  gases  pass  from  the  boilers  to  the.  chim- 
ney should  have  an  area  equal  to,  or  a  little  larger  than,  the 
area  of  the  chimney.  Abrupt  turns  in  the  flue  or  contractions 
of  its  area  should  be  carefully  avoided.  Where  one  chimney 
serves  several  boilers,  the  branch  flue  from  each  furnace  to 
the  main  flue  must  be  somewhat  larger  than  its  proportionate 
part  of  the  area  of  the  main  flue. 

Brick  Chimneys. — Chimneys  are  usually  built  of  brick, 
though  concrete,  iron,  and  steel  are  often  used  for  those  of 
moderate  height.  Brick  chimneys  are  usually  built  with  a  flue 
having  parallel  sides  and  a  taper  on  the  outside  of  the  chimney 
of  from  ^  to  j  in.  per  ft.  of  height.  A  round  chimney  gives 
greater  draft  area  for  the  same  amount  of  material  in  its 
structure  and  exposes  less  surface  to  the  wind  than  a  square 
chimney.  Large  brick  stacks  are  usually  made  with  an  inner 
core  and  an  outer  shell,  with  a  space  between  them.  Such 
chimneys  are  usually  constructed  with  a  series  of  internal 
pilasters,  or  vertical  ribs,  to  give  rigidity.  The  top  of  the 
chimney  should  be  protected  by  a  coping  of  stone  or  a  cast-iron 
plate  to  prevent  the  destruction  of  the  bricks  by  the  weather. 

Iron  and  Steel  Chimneys. — Iron  or  steel  stacks  are  made  of 
plates  varying  from  £  to  |  in.  thick.  The  larger  stacks  are 
made  in  sections,  the  plates  being  about  J  in.  thick  at  the  top 
and  increasing  to  £  in.  at  the  bottom;  they  are  lined  with  fire- 
brick about  18  in.  thick  at  the  bottom  and  4  in.  at  the  top. 
Sometimes  no  lining  is  used  on  account  of  the  likelihood  of 
corrosion  and  the  difficulty  of  inspection,  and  also  because 
the  inside  of  lined  stacks  cannot  be  painted. 

Chimney  Foundations. — On  account  of  the  great  concentra- 
tion of  weight,  the  foundation  for  a  chimney  should  be  care- 
fully designed.  Good  natural  earth  will  support  from  2,000 
to  4,000  Ib.  per  sq.  ft.  The  footing  beneath  the  chimney 
foundation  should  be  made  of  large  area,  in  order  to  reduce 
the  pressure  due  to  the  weight  of  the  chimney  and  its  founda- 
tion to  a  safe  limit. 


110  STEAM  BOILERS 

Height  of  Chimney. — The  relation  between  the  height  of 
the  chimney  and  the  pressure  of  the  draft,  in  inches  of  water,  is 
given  by  the  formula 

_./7.6     7.9^ 
P  =  - 


in  which  P  =  draft  pressure,  in  inches  of  water; 

H  =  height  of  chimney,  in  feet; 
Ta  and  Tc  =  absolute  temperatures  of  the  outside  air  and  of 

the  chimney  gases,  respectively. 

EXAMPLE. — What    draft   pressure    will    be   produced   by   a 
chimney  120  ft.  high,  the  temperature  of  the  chimney  gases 
being  600°  P.,  and  of  the  external  air  60°  F.? 
SOLUTION. — Substituting  in  the  formula, 

/     7.6  7.9      \ 

^  =  120  (—  —I  =.859  in. 

\460+60      460+600/ 

To  find  the  height  of  chimney  to  give  a  specified  draft  pres- 
sure, the  preceding  formula  may  be  transformed.     Thus, 
P 


7.G     7.9 


U 


EXAMPLE.  —  Required,  the  height  of  the  chimney  to  produce 
a  draft  of  \\  in.  of  water,  the  temperature  of  the  gases  and  of 
the  external  air  being,  respectively,  550°  and  62°  F. 

SOLUTION.  —  Substituting  in  the  formula, 


„, 


7.6      7.9 
522  ~  1,010 

In  determining  the  height  of  a  chimney  in  cities,  it  should 
be  borne  in  mind  that  it  must  almost  always  be  carried  to  a 
height  above  the  roofs  of  surrounding  buildings,  partly  in 
order  to  prevent  a  nullification  of  the  draft  by  opposing  air- 
currents  and  partly  to  prevent  the  commission  of  a  nuisance. 

Area  of  Chimney.  —  The  height  of  the  chimney  being  decided 
on,  its  cross-sectional  area  must  be  sufficient  to  carry  off 
readily  the  products  of  combustion.  The  following  for- 
mulas for  rinding  the  dimensions  of  chimneys  are  in  common 
use: 


STEAM  BOILERS  111 

Let  H  =  height  of  chimney,  in  feet; 
H.  P.  =  horsepower  of  boiler  or  boilers; 

A  =  actual  area  of  chimney,  in  square  feet; 
£  =  effective  area  of  chimney,  in  square  feet; 
5  =side  of  square  chimney,  in  inches; 
d  =  diameter  of  round  chimney,  in  inches. 

o  rr    r> 

Then,  E=^p  =  A-.6VZ  (1) 

H.  P.  =  3.33E  Vff  (2) 

S=12V£+4  (3) 

d  =13.54  Vfi+4  (4) 

The  accompanying  table  has  been  computed  from  these 
formulas. 

EXAMPLE  1. — What  should  be  the  diameter  of  a  chimney 
100  ft.  high  that  furnishes  draft  for  a  600-H.  P.  boiler  ? 

.3X600 
SOLUTION. — Substituting    in    formula    1,    E  =  —  ——  =  18. 

VlOO 
Now,  using  formula  4,  d=  13.54 Vis +4  =  61.44  in. 

EXAMPLE  2. — For  what  horsepower  of  boilers  will  a  chimney 
64  in.  sq.  and  125  ft.  high  furnish  draft  ? 

SOLUTION. — By  simply  referring  to  the  table,  the  horsepower 
is  found  to  be  934. 

Maximum  Combustion  Rate. — The  maximum  rates  of  com- 
bustion attainable  under  natural  draft  are  given  by  the 
following  formulas,  which  have  been  deduced  from  the 
experiments  of  Isherwood: 

Let  F  =  weight,  in  pounds  of  coal  per  hour  per  square  foot 

of  grate  area; 

H  =  height,  in  feet,  of  chimney  or  stack. 
Then,  for  anthracite  burned  under  the  most  favorable  con- 
ditions, 

F  =  2\//-l  (1) 

and  under  ordinary  conditions, 

F=1.5V//-1  (2) 

For  best  semianthracite  and  bituminous  coals, 

F  =  2.25V'//  (3) 

and  for  less  valuable  soft  coals, 

F  =  3\//  (4) 


112 


STEAM  BOILERS 


11 


>     §          8 

i*J    ! 


Ill    IS 


^ 


s. "~  c  —  c  i- 
r-i  o  —  rc  i-  c-i 


STEAM  BOILERS  113 

The  maximum  weight  of  combustion  is  thus  fixed  by  the 
height  of  the  chimney;  the  minimum  rate  may  be  anything 
less. 

EXAMPLE. — Under  ordinary  conditions,  what  is  the  maxi- 
mum rate  of  combustion  of  anthracite  coal  if  the  chimney  is 
120  ft.  high  ? 

SOLUTION. — By  formula  2, 

F  =  1.5>/120- 1  =  15|  Ib.  per  sq.  ft.  per  hr. 


BOILER  FITTINGS 

Types  of  Safety  Valve. — The  safety  valve  is  a  device 
attached  to  the  boiler  to  prevent  the  steam  pressure  from  rising 
above  a  certain  point.  When  steam  is  made  more  rapidly  than 
it  is  used,  its  pressure  must  necessarily  rise;  and  if  no  means  of 
escape  is  provided  for  it,  the  result  must  be  an  explosion. 
Briefly  described,  the  safety  valve  consists  of  a  plate,  or  disk, 
fitting  over  a  hole  in  the  boiler  shell  and  held  to  its  place  by  a 
dead  weight,  by  a  weight  on  a  lever,  or  by  a  spring.  The 
weight  or  the  spring  is  so  adjusted  that  when  the  steam  reaches 
the  desired  pressure  the  disk  is  raised  from  its  seat,  and  the 
surplus  steam  escapes  through  the  opening  in  the  shell. 


FIG.  1 


Weight  of  Ball  for  Lever  Safety  Valve. — A  simple  diagram 
of  a  lever  safety  valve  is  shown  in  Fig.  1.  The  valve  stem  and 
the  bail  are  attached  to  the  lever  at  C  and  B,  respectively, 
and  the  fulcrum  is  at  F. 


114  STEAM  BOILERS 

Let  d  =  F  B  =  distance  from  fulcrum  to  weight,  in  inches; 
c  =  F  G  =  distance  from  fulcrum  to  center  of  gravity 

of  lever,  in  inches; 
a  =  F  C  =  distance    from    fulcrum    to    center    line    of 

valve,  in  inches; 
A  =area  of  orifice  beneath  bottom  of  valve,  in  square 

inches  ; 

W  =  weight  of  ball  P,  in  pounds; 
Wi  =  weight  of  valve  and  stem,  in  pounds; 
Wt  =  weight  of  lever,  in  pounds; 

p  =  blow-off  pressure,  in  pounds  per  square  inch. 
Then,  if  the  position  of  the  ball  P  on  the  lever  is  fixed,  the 
required  weight  of  the  ball  may  be  found  by  the  formula 
a(pA-Wi)-Wic 

~7~ 

EXAMPLE.  —  The  area  of  the  orifice  is  10  sq.  in.,  the  distance 
from  the  valve  to  the  fulcrum  is  3  in.,  and  the  length  of  the 
lever  is  32  in.  The  valve  and  stem  weigh  5  lb.,  the  lever 
weighs  12  lb.,  and  the  gauge  pressure  is  90  lb.  What  should 
be  the  weight  W,  if  placed  2  in.  from  the  end  of  the  lever, 
assuming  the  lever  to  be  straight  ? 

SOLUTION.  —  In  this  case,  c  =  3£=lG  in.,  and  d  =  32  —  2  =  30  in. 
Then,  substituting  in  the  formula, 


Position  of  Ball  for  Lever  Safety  Valve.—  If  the  ball  of  a 
lever  safety  valve  has  a  known  weight  and  it  is  desired  to  find 
at  what  distance  from  the  fulcrum  it  must  be  placed  so  as  to 
give  a  required  blow-off  pressure,  the  formula  to  be  used  is 


in  which  the  various  letters  have  the  same  meanings  as  before. 
EXAMPLE.  —  Suppose  all  the  quantities  to  remain  the  same 
as  in  the  solution  of  the  preceding  example,  except  that  it  is 
desired  that  the  boiler  should  blow  off  at  75  lb.  gauge  pressure, 
instead  of  90  lb.  What  will  be  the  distance  of  the  weight 
from  the  fulcrum  ? 


STEAM  BOILERS  115 

SOLUTION.  —  Applying  the  formula 


83.1 

Roper's  Safety-Valve  Rules.  —  Some  inspectors  of  the  United 
States  Steamboat  Inspection  Service  prefer  to  have  lever 
safety-valve  problems  worked  out  by  the  rules  that  follow, 
known  among  American  marine  engineers  as  Roper's  rules. 
A  candidate  for  a  marine  engineer's  license  should  always  use 
Roper's  rules  when  he  knows  that  they  are  preferred  by  the 
examining  inspector. 

Let    A  =  area  of  valve,  in  square  inches; 

D  =  distance  from  center  line  of  valve  to  fulcrum,  in 

inches; 

L  =  distance  of  weight  from  fulcrum,  in  inches; 
P  =  steam  pressure  in  pounds,  per  square  inch; 
W=  weight  of  load  or  weight  on  lever,  in  pounds; 
V  =  weight  of  valve  and  stem,  in  pounds; 
w  =  weight  of  lever,  in  pounds  ; 
1  =  distance  from  fulcrum  to  center  of  gravity  of  lever, 

in  inches. 

Then,  the  pressure  at  which  the  safety-valve  will  blow  off  is 
found  by  the  formula 

r_WL+wl+VD 

A  D 

If  the  distance  L  is  known,  the  weight  W  to  be  hung  on 
the  lever  is  found  by  the  formula 


L 

The  distance  L  from  the  fulcrum  to  the  point  at  which  the 
weight  W  is  hung  is  found  by  the  formula 
APD-(wl+VD) 
W 

Area  of  Safety  Valve.  —  By  area  of  safety  valve  is  meant  the 
area  of  the  opening  in  the  valve  seat;  that  is,  the  area  of  the 
surface  of  the  valve  in  contact  with  steam  when  the  valve 
is  closed.  The  size  of  the  valve  relative  to  the  size  of  the 
boiler  and  the  working  pressure  is  prescribed  by  law  in 
many  localities,  and  must  be  made  to  conform  to  the  law 


11G  STEAM  BOILERS 

wherever  such  law  is  in  existence.     In  localities  having  no 
law  governing  this  matter,  the  size  of  the  safety  valve  may  be 
calculated  by  the  accompanying  formulas,  which  are  based  on 
practice  and  recommended  by  leading  authorities. 
For  natural  draft, 


For  artificial  draft, 

1.406  w 


in  which  G  =  grate  surface,  in  square  feet; 

p  =  steam  pressure,  gauge,  in  pounds  per  square  inch; 
w  =  weight  of  coal  burned  per  hour  in  pounds; 
A  =  least  area  of  safety  valve,  in  square  inches. 

Location  of  Safety  Valve.  —  The  safety  valve  should  be 
placed  in  direct  connection  with  the  boiler,  so  that  there  can  be 
no  possible  chance  of  cutting  off  the  communication  between 
them.  A  stop-  valve  placed  between  the  boiler  and  safety  valve 
is  a  very  fruitful  cause  of  boiler  explosions.  Again,  the  safety 
valve  must  be  free  to  act,  and  to  prevent  it  from  corroding 
fast  to  its  seat,  it  should  be  lifted  from  the  seat  occasionally. 
Care  must  be  taken  to  prevent  persons  ignorant  of  the  impor- 
tance of  safety  valves  from  raising  the  blow-off  pressure  by 
adding  to  the  weights  or  increasing  the  tension  of  the  sprir 
To  this  end,  the  weights  of  lever  safety  valves  are  often  loci 
in  position  by  the  boiler  inspector. 

Use  of  Fusible  Plugs.  —  Fusible  plugs  are  devices  placed 
the  crown  sheets  of  furnaces  or  in  similar  places  to  obviate 
danger  from  overheating  through  lack  of  water.  The  plug 
often  consists  of  an  alloy  of  tin,  lead,  and  bismuth,  which  melts 
at  a  comparatively  low  temperature.  In  many  localities,  the 
law  requires  that  fusible  plugs  shall  be  attached  to  all  high- 
pressure  boilers. 

Forms  of  Fusible  Plugs.  —  The  fusible  plugs  in  common 
are  shown  in  section  in  Fig.  2.     They  consist  of  brass  or  ir 
shells  threaded  on  the  outside  with  a  Standard  pipe  thi 
The  plugs  have  some  form  of  conical  filling,  the  larger  end  of  1 
filling  receiving  the  steam  pressure.     The  conical  form  of  the 


STEAM  BOILERS 


117 


filling  prevents  it  from  being  blown  out  by  the  pressure  of  the 
steam.  Fusible  plugs  applied  from  the  outside  differ  from 
those  applied  from  the  inside,  as  Fig.  2  clearly  shows. 

Location  of  Fusible  Plugs. — According  to  the  rules  issued  by 
the  Board  of  Boiler  Rules  of  the  State  of  Massachusetts, 
fusible  plugs  must  be  filled  with 
pure  tin,  and  the  least  diameter 
shall  not  be  less  than  $  in., 
except  for  working  pressures 
over  175  lb.,  gauge,  or  when  it 
is  necessary  to  place  a  fusible 
plug  in  a  tube,  in  which  cases 
the  least  diameter  of  fusible 
metal  shall  not  be  less  than 
f  in.  The  location  of  fusible  pIG 

plugs  shall  be  as  follows: 

In  horizontal  return-tubular  boilers,  in  the  back  head,  not 
less  than  2  in.  above  the  upper  row  of  tubes  and  projecting 
through  the  sheet  not  less  than  1  in. 

In  horizontal  flue  boilers,  in  the  back  head,  on  a  line  with 
the  highest  part  of  the  boiler  exposed  to  the  products  of  com- 
bustion, and  projecting  through  the  sheet  not  less  than  1  in. 

In  locomotive-type  or  star  water-tube  boilers,  in  the  highest 
part  of  the  crown  sheet  and  projecting  through  the  sheet  not 
less  than  1  in. 

In  vertical  fire-tube  boilers,  in  an  outside  tube,  placed  not 
less  than  one-third  the  length  of  the  tube  above  the  lower 
tube-sheet. 

In  vertical  submerged -tube  boilers,  in  the  upper  tube-sheet. 

In  water-tube  boilers  of  the  Babcock  &  Wilcox  type,  in  the 
upper  drum,  not  less  than  6  in.  above  the  bottom  of  the  drum 
and  projecting  through  the  sheet  not  less  than  1  in. 

In  Stirling  boilers  of  standard  type,  in  the  front  side  of  the 
middle  drum,  not  less  than  6  in.  above  the  bottom  of  the  drum 
and  projecting  through  the  sheet  not  less  than  1  in. 

In  Stirling  boilers  of  the  superheated  type,  in  the  front 
drum,  not  less  than  6  in.  above  the  bottom  of  the  drum,  and 
exposed  to  the  products  of  combustion,  projecting  through  the 
sheet  not  less  than  1  in. 


118  STEAM  BOILERS 

In  water-tube  boilers  of  the  Heine  type,  in  the  front  course 
of  the  drum,  not  less  than  6  in.  from  the  bottom  of  the  drum, 
and  projecting  through  the  sheet  not  less  than  1  in. 

In  Robb-Mumford  boilers  of  standard  type,  in  the  bottom 
of  the  steam  and  water  drum,  24  in.  from  the  center  of  the  rear 
neck,  and  projecting  through  the  sheet  not  less  than  1  in. 

In  water-tube  boilers  of  the  Almy  type,  in  a  tube  directly 
exposed  to  the  products  of  combustion. 

In  vertical  boilers  of  the  Climax  or  Hazelton  type,  in  a 
tube  or  center  drum,  not  less  than  one-half  the  height  of  the 
shell,  measuring  from  the  lowest  circumferential  seam. 

In  Cahall  vertical  water-tube  boilers,  in  the  inner  sheet  of 
the  top  drum,  not  less  than  6  in.  above  the  upper  tube  sheet. 

In  Scotch  marine-type  boilers,  in  the  combustion-chamber 
top,  and  projecting  through  the  sheet  not  less  than  1  in. 

In  dry-back  Scotch-type  boilers,  in  the  rear  head,  not  less 
than  2  in.  above  the  top  row  of  tubes,  and  projecting  through 
the  sheet  not  less  than  1  in. 

In  Economic-type  boilers,  in  the  rear  head,  above  the  upper 
row  of  tubes. 

In  cast-iron  sectional  heating  boilers,  in  a  section  over 
in  direct  contact  with  the  products  of  combustion  in 
primary  combustion  chamber. 

In  other  types  and  new  designs,  fusible  plugs  shall  be  pi 
at  the  lowest  permissible  water  level,  in  the  direct  path  of 
products   of   combustion,    as    near   the    primary    combusti 
chamber  as  possible. 

Connection  of  Steam  Gauge. — A  steam  gauge  should 
connected  to  the  boiler  in  such  a  manner  that  it  will  neither 
injured  by  heat  nor  indicate  incorrectly  the  pressure  to  which 
it  is  subjected.  To  prevent  injury  from  heat,  a  so-called 
siphon  is  placed  between  the  gauge  and  the  boiler.  This' 
siphon  in  a  short  time  becomes  filled  with  water  of  condensa- 
tion, which  protects  the  spring  of  the  gauge  from  the  injury 
the  hot  steam  would  cause.  Care  should  be  taken  not  to 
locate  the  steam-gauge  pipe  near  the  main  steam  outlet  of  the 
boiler,  as  this  may  cause  the  gauge  to  indicate  a  lower  pressure 
than  really  exists.  In  locating  the  steam  gauge,  care  must 
also  be  taken  not  to  run  the  connecting  pipe  in  such  a  manner 


STEAM  BOILERS  119 

that  the  accumulation  of  water  in  it  will  cause  an  extra  pressure 
to  be  shown. 

Bottom  Blow-Off. — For  the  double  purpose  of  emptying 
the  boiler  when  necessary  and  of  discharging  the  loose  mud  and 
sediment  that  collect  from  the  feedwater,  each  boiler  is  pro- 
vided with  a  pipe  that  enters  the  boiler  at  its  lowest  point. 
This  pipe,  which  is  provided  with  a  valve  or  a  cock,  is  com- 
monly known  as  the  bottom  blow-off.  The  position  of  the  blow- 
off  pipe  varies  with  the  design  of  the  boiler;  in  ordinary  return- 
tubular  boilers,  it  is  usually  led  from  the  bottom  of  the  rear  end 
of  the  shell  through  the  rear  wall.  Where  the  boiler  is  fitted 
with  a  mud-drum,  the  blow-off  is  attached  to  the  drum. 

Blow-Off  Cocks  and  Valves. — While  in  many  boiler  plants 
globe  valves  are  used  on  the  blow-off  pipe,  their  use  is  objection- 
able, because  the  valve  may  be  kept  from  closing  properly  by  a 
chip  of  incrustation  or  similar  matter  getting  between  the  valve 
and  its  seat.  As  a  result,  the  water  may  leak  out  of  the  boiler 
unnoticed. 

Plug  cocks  packed  with  asbestos  are  widely  used,  the  asbestos 
packing  obviating  the  objectionable  features  of  the  ordinary 
plug  cock.  Gate  valves  are  also  used  to  some  extent,  but  are 
open  to  the  same  objection  as  globe  valves.  In  the  best  modern 
practice,  the  blow-off  pipe  is  fitted  with  two  shut-off  devices. 
The  one  shut-off  may  be  an  asbestos-packed  cock  and  the  other 
some  form  of  valve,  or  both  may  be  cocks  or  valves,  the  idea 
underlying  this  practice  being  that  leakage  past  the  shut-off 
nearest  the  boiler  will  be  arrested  by  the  other. 

Protection  of  Blow-Off  Pipe. — When  exposed  to  the  gases  of 
combustion,  the  bottom  blow-off  pipe  should  always  be  pro- 
tected by  a  sleeve  made  of  pipe,  by  being  bricked  in,  or  by  a 
coil  of  plaited  asbestos  packing.  If  this  precaution  is  neglected, 
the  sediment  and  mud  collecting  in  the  pipe,  in  which  there  is 
no  circulation,  will  rapidly  become  solid.  The  blow-off  pipe 
should  lead  to  some  convenient  place  entirely  removed  from 
the  boiler  house  and  at  a  lower  level  than  the  boiler.  Some- 
times it  may  be  connected  to  the  nearest  sewer.  In  many 
localities,  however,  ordinances  prohibiting  this  practice  are  in 
force;  the  blow-off  is  then  connected  to  a  cooling  tank,  whence 
the  water  may  be  discharged  into  the  sewer. 


120  STEAM  BOILERS 

BOILER  PIPING 

Principal  Considerations. — The  piping  of  an  engine  and 
boiler  plant  requires  that  careful  attention  be  paid  to  all  the 
details  as  well  as  to  the  general  design,  not  only  in  order  to 
make  it  suitable  for  the  purpose,  but  also  in  order  to  reduce  the 
likelihood  of  a  breakdown.  The  main  considerations  regarding 
steam  piping  are  the  size  of  the  pipes;  the  arrangement  and 
construction  of  the  piping  system;  the  method  of  providing  for 
expansion;  and  proper  drainage. 

Materials  for  Pipes. — Most  of  the  piping  for  steam  and 
water  is  built  up  of  wrought-iron  or  steel  pipe  of  standard  size. 
The  various  grades  of  wrought-iron  and  steel  pipe  are  known 
as  standard,  extra  strong,  and  double  extra  strong.  Both  wrought- 
iron  and  steel  pipe  are  used  in  the  piping  systems  of  power 
plants.  Formerly,  wrought  iron  was  chiefly  used,  but  of  late 
steel  has  been  employed,  especially  for  the  larger  sizes  of  steam 
pipes.  The  two  kinds  are  equally  reliable  when  made  into 
expansion  bends,  copper  bends  as  a  general  rule  being  used 
only  for  very  heavy  work. 

Expansion  Joints. — In  installing  steam  piping,  provision 
must  be  made  for  expansion  and  contraction,  which  ordinarily 
amounts  to  about  li  in.  per  100  ft.  of  pipe.  Generally,  this 
may  be  provided  for  in  the  arrangement  of  the  piping;  but 
for  great  lengths  that  are  straight,  or  nearly  so,  it  is  necessary 
to  use  expansion  joints,  which  may  be  made  in  various  ways. 

One  form,  shown  in  Fig.  1, 
is  called  the  slip  joint.  The 
ends  a  and  b  of  the  sections 
of  pipe  come  together  in  a 
stuffingbox  c  in  order  to 

_,  make   a  steam-tight  joint. 

The  stud  bolts   are  extra 

long,  so  as  to  extend  through  holes  in  a  flange  d  riveted  to  the 
pipe  b.  Check-nuts  e  on  the  ends  of  the  studs  prevent  the  two 
ends  of  the  pipe  from  being  forced  apart  by  the  steam  pressure. 
The  nuts  e  are  not  intended  ordinarily  to  be  in  contact  with  the 
flange;  their  distance  from  the  flange  is  adjusted  so  that  the 
proper  expansion  may  occur. 


STEAM  BOILERS  121 

In  Fig.  2  is  shown  a  corrugated  expansion  joint,  which  is  some- 
times used  on  large  exhaust  pipes.  It  consists  of  a  short 
section  of  flanged  corrugated 
pipe,  usually  copper,  which  is 
put  in  the  steam  pipe  wherever 
necessary.  The  elasticity  of  FIG.  2 

this  section,  due  to  the  corrugations,  permits  expansion  and 
contraction. 

Expansion  Bends. — The  best  way  of  allowing  for  expan- 
sion is  by  using  expansion  bends,  or  bent  pipes;  but  the  space 
they  occupy  often  limits  their  use.  The  forms  of  bends  more 
commonly  used  are  shown  in  Fig.  3,  the  trade  name  being  given 
below  each  bend.  Where  a  bent  pipe  is  used,  the  radius  r  of 
the  bend  should  not  be  less  than  six  times  the  diameter  of  the 
pipe,  for  wrought  iron  or  steel;  to  secure  the  proper  spring  in 
bends  used  on  long  lines  of  piping,  the  radius  should  be  greater 
than  this.  Bends  of  copper  pipe  may  be  of  shorter  radius, 
as  copper  yields  more  readily  than  iron  or  steel. 

Bends  made  from  iron  or  steel  pipe  must  be  bent  while  red 
hot.  Iron  and  steel  pipe  bends  generally  have  iron  flanges 
fastened  on;  copper  bends  either  have  composition  flanges  riv- 
eted and  brazed  on,  or  have  steel  flanges,  the  edges  of  the  pipe 
being  turned  over.  The  piping  is  usually  installed  so  that  it  is 
under  a  slight  tension  when  cold;  when  filled  with  steam,  the 
expansion  of  the  pipes  removes  the  tension,  and  there  is  no 
stress  on  the  pipe  except  that  due  to  the  steam  pressure. 

Pipe  Coverings. — To  prevent  loss  of  heat  by  radiation,  steam 
pipes  are  covered  with  various  kinds  of  materials  that  are  poor 
conductors  of  heat.  As  a  rule,  the  covering  is  manufactured 
in  short  sections  molded  in  halves  to  fit  the  pipe,  the  valves  and 
fittings  being  covered  with  the  same  material  in  a  plastic  state. 
After  the  covering  is  properly  secured  in  place,  it  is  frequently 
covered  with  a  heavy  duck  or  canvas  jacket  sewed  on  and 
painted,  and  sometimes  ornamented  by  brass  bands  placed  at 
regular  intervals. 

The  substances  used  for  covering  steam  pipes  for  this  pur- 
pose are  very  numerous  and  vary  considerably  in  efficiency. 
Among  the  best  and  most  widely  used  non-conducting  materials 
are  hair  felt,  cork,  magnesia,  asbestos,  and  mineral  wool. 


122 


STEAM  BOILERS 


Frequently,  pipe  cover- 
ings are  made  up  of 
combinations  of  two  or 
more  of  these  sub- 
stances. For  pipes  laid 
in  trenches,  where  a 
cheap  covering  is  de- 
sired, such  materials  as 
sawdust,  charcoal,  coal 
ashes,  coke,  loam,  and 
slaked  lime  are  some- 
times used. 

Arrangement  of  Pi- 
ping.— The  pipes  and 
fittings  must  be  so  pro- 
portioned as  to  permit 
a  free  flow  of  steam  or 
water.  Water  pockets 
should  be  avoided;  and 
where  such  pockets  are 
unavoidable,  they  must 
be  drained  to  free  them 
from  water.  By-pass 
pipes  should  be  arranged 
around  feedwater  heat- 
ers,  economizers, 
pumps,  etc.  The  sys- 
tem must  be  so  designed 
as  to  give  perfect  free- 
dom for  expansion  and 
contraction. 

Perfect  drainage  must 
be  provided  in  order  that 
all  water  of  condensa- 
tion shall  be  fully  sepa- 
rated from  the 
Reliability  is 
by  careful  design  and 
superior  workmanship, 


STEAM  BOILERS  123 

combined  with  the  use  of  high-class  materials  and  fit- 
tings and  the  judicious  placing  of  cut-out  and  by-pass  valves. 
Drainage  is  best  effected  by  arranging  the  piping  so  that  all 
the  water  of  condensation  will  flow  by  gravity  toward  a  point 
close  to  the  delivery  end  of  the  pipe,  and  then  providing  a  drip 
pipe  at  that  point.  A  trap  may  be  placed  at  the  end  of  the 
drip  pipe  for  automatic  draining. 


BOILER  FEEDING  AND  FEEDWATER 
INJECTORS 

Classification  of  Injectors. — Injectors  may  be  divided  into 
two  general  classes,  namely,  non-lifting  and  lifting  injectors. 
Non-lifting  injectors  are  intended  for  use  where  there  is  a  head 
of  water  available.  When  the  water  comes  to  a  non-lifting 
injector  under  pressure,  as  from  a  city  main,  it  can  be  placed 
in  almost  any  convenient  position  close  to  the  boiler.  Lifting 
injectors  are  of  two  distinct  types,  called  automatic  injectors 
and  positive  injectors.  As  positive  injectors  generally  have 
two  sets  of  tubes,  they  are  frequently  called  double-tube  inject- 
ors. Automatic  injectors  are  so  called  from  the  fact  that  they 
will  automatically  start  again  in  case  the  jet  of  water  is  broken 
by  jarring  or  other  means.  Positive,  or  double-tube,  injectors 
are  provided  with  two  sets  of  tubes,  one  set  of  which  is  used  for 
lifting  the  water,  and  the  other  set  for  forcing  the  water  thus 
delivered  to  it  into  the  boiler.  A  positive  injector  has  a  wider 
range  than  an  automatic  injector  and  will  handle  a  hotter 
feed-water  supply;  it  will  also  lift  water  to  a  greater  height  than 
the  automatic  injector. 

Size  of  Injector. — Most  engineers  prefer  to  select  a  size  of 
injector  having  a  capacity  per  hour  about  one-half  greater 
than  the  maximum  evaporation  per  hour  in  order  to  have  some 
reserve  capacity.  The  maximum  evaporation,  when  not 
known,  may  be  estimated  in  U.  S.  gallons  by  one  of  the  follow- 
ing rules,  which  hold  good  for  ordinary  combustion  rates 
under  natural  draft: 

Rule  I. — For  plain  cylindrical  boilers,  multiply  the  Product  of 
the  length  and  diameter  in  feet  by  1.3. 


124  STEAM  BOILERS 

Rule  II. — For  tubular  boilers,  either  horizontal  or  vertical, 
multiply  the  product  of  the  square  of  the  diameter  in  feet  and 
the  length  in  feet  by  1.9. 

Rule  in. — For  water-tube  boilers,  multiply  the  heating  sur- 
face in  square  feet  by  .4- 

Rule  IV. — For  boilers  not  covered  by  the  foregoing  rules, 
multiply  the  grate  surface  in  square  feet  by  12. 

Rule  V. — //  the  coal  consumption  in  pounds  per  hour  is 
known,  it  may  be  taken  as  representing  the  number  of  gallons 
evaporated  per  hour. 

No  standard  method  of  designating  the  size  of  an  injector  is 
followed  by  all  makers;  therefore,  such  an  instrument  must  be 
selected  from  the  lists  of  capacities  published  by  the  different 
makers. 

Location  of  Injector. — An  injector  must  always  be  placed  in 
the  position  recommended  by  the  maker.  There  must  always 
be  a  stop-valve  in  the  steam-supply  pipe  to  the  injector. 
While  lifting  injectors,  when  working  as  such,  scarcely  need  a 
stop-valve  in  the  suction  pipe,  it  is  advisable  to  supply  it. 
When  the  water  flows  to  the  injector  under  pressure,  a  stop- 
valve  in  the  water-supply  pipe  is  a  necessity.  A  stop-valve 
and  a  check-valve  must  be  placed  in  the  feed-delivery  pipe, 
with  the  stop-valve  next  to  the  boiler.  The  check-valve 
should  never  be  omitted,  even  if  the  injector  itself  is  supplied 
with  one.  No  valve  should  ever  be  placed  in  the  overflow 
pipe,  nor  should  the  overflow  be  connected  directly  to  the 
overflow  pipe,  but  a  funnel  should  be  placed  on  the  latter  so 
that  the  water  can  be  seen.  This  direction  does  not  apply  to 
the  inspirator  or  to  any  other  injector  that  has  a  hand-operated, 
separate  overflow  valve.  In  the  inspirator,  the  overflow  pipe 
is  connected  directly  to  the  overflow,  but  the  end  of  the  pipe 
must  be  open  to  the  air.  In  general,  where  the  injector  lifts 
water  it  is  not  advisable  to  have  a  foot-valve  in  the  suction 
pipe,  as  it  is  desirable  that  the  injector  and  pipe  may  drain 
themselves  when  not  in  use.  A  strainer  should  be  placed  on 
the  end  of  the  suction  pipe. 

Steam  Supply  to  Injector. — The  steam  for  the  injector  must 
be  taken  from  the  highest  part  of  the  boiler,  as  it  must  be 
sup'plied  with  dry  steam.  Under  no  consideration  should  the 


STEAM  BOILERS  125 

steam  be  taken  from  another  steam  pipe.  The  suction  pipe 
should  be  as  straight  as  possible  and  must  be  air-tight.  In 
connecting  up  an  injector,  the  pipes  should  be  cleaned  by 
blowing  them  out  with  steam  before  making  the  connection, 
"because  if  a  small  bit  of  dirt  gets  into  the  injector  it  will  inter- 
fere seriously  with  its  operation. 

Injector  Troubles. — In  the  discussion  of  injector  troubles  as 
given  in  succeeding  paragraphs,  the  suction  pipe,  strainer, 
feed-delivery  pipe,  and  check- valve  are  considered  as  parts  of 
the  injector.  In  searching  for  the  cause  of  a  trouble,  therefore, 
the  suction  and  delivery  pipes  should  be  carefully  inspected  as 
well  as  the  injector. 

Failure  to  Raise  Water. — The  causes  that  prevent  an  injector 
from  raising  water  are: 

1.  Suction  Pipe  Stopped  Up. — This  is  due,  generally,  to  a 
clogged  strainer  or  to  the  pipe  itself  being  stopped  up  at  some 
point.     In  case  the  suction  pipe  is  clogged,  steam  should  be 
blown  back  through  the  pipe  to  force  out  the  obstruction. 

2.  Leaks  in  Suction  Pipe. — This  prevents  the  injector  form- 
ing the  vacuum  required  to  raise  the  water.     To  test  the 
suction  pipe  for  air  leaks,  plug  up  the  end  and  turn  the  full 
steam  pressure  on  the  pipe;  leaks  will  then  be  revealed  by 
the  steam  issuing  therefrom.     Have  the  suction  pipe  full  of 
water  before  steam  is  turned  on,  as  the  presence  of  small 
leaks  will  be  revealed  better  by  water  than  by  steam. 

3.  Water  in  the  Suction  Pipe  Too  Hot. — A    leaky    steam 
valve  or  leaky  boiler  check- valve  and  leaky  injector  check- 
valve  may  be  the  cause  of  hot  water  or  steam  entering  the 
source  of  supply  and  heating  the  water  so  hot  that  the  injector 
refuses  to  handle  it. 

4.  Obstruction  in  Tubes. — There  may  be  an  obstruction  in 
the  lifting  or  combining  tubes;  or,  the  spills  (or  openings)  in 
the  tubes  through  which  the  steam  and  water  escape  to  the 
overflow  may  be  clogged  up  with  dirt  or  lime. 

Injector  Primes,  but  Will  Not  Force. — In  some  cases  an 
injector  will  lift  water,  but  will  not  force  it  into  the  boiler;  or, 
it  may  force  part  of  it  into  the  boiler  and  the  rest  out  of  the 
overflow.  When  it  fails  to  force,  the  trouble  may  be  due  to 
one  or  the  other  of  the  following  causes: 
10 


126  STEAM  BOILERS 

1.  Choked  Suction  Pipe  or  Strainer. — If  the  suction  pipe  or 
the  strainer  is  partly  choked,  the  injector,  in  either  case,  will 
be  prevented  from  lifting  sufficient  water  to  condense  all  the 
steam  issuing  from  the  steam  valve.     The  uncondensed  steam, 
therefore,  will  gradually  decrease  the  vacuum  in  the  combining 
tube  until  it  is  reduced  so  much  that  the  injector  will  not  work. 
The  remedy  in  case  the  supply  valve  is  partly  closed  is  to  open 
it.     In  the  case  of  a  choked  suction  pipe,  the  obstruction  should 
be  blown  out. 

2.  Suction  Pipe  Leaking. — The  leak  may  not  be  sufficient 
entirely  to  prevent  the  injector  from  lifting  water,  but  the 
quantity  lifted  may  be  insufficient  to  condense  all  the  steam, 
which,  therefore,  destroys  the  vacuum  in  the  combining  tube. 
A  slight  leak  may  exist  that  will  simply  cut  down  the  capacity 
of  the  injector.     In  such  a    case  an    automatic    injector  will 
work  noisily,  on  account  of  the  overflow  valve  seating  and 
unseating  itself  as  the  pressure  in  the  combining  tube  varies, 
due  to  the  leak. 

3.  Boiler  Check-Valve  Stuck  Shut.—U  the  boiler  check-valve 
is  completely  closed,  the  injector  may  or  may  not  continue  to 
raise  water  and  force  it  out  of  the  overflow;  this  depends  on 
the  design  of  the  injector.     If  the  boiler  check  is  partly  open, 
the  injector  will  force  some  of  the  water  into  the  boiler  and  the 
remainder  out  of  the  overflow.     In  case  the  check-valve  cannot 
be  opened  wide,  water  may  be  saved  by  throttling  both  steam 
and  water  until  the  overflow  diminishes,  or,  if  possible,  ceases. 
The  steam  should  be  throttled  at  the  valve  in  the  boiler  steam 
connection.     If  a  check-valve  sticks,  it  can  sometimes  be  made 
to  work  again  by  tapping  lightly  on  the  cap  or  on  the  bottom 
of  the  valve  body. 

4.  Obstruction  in  Delivery  Tube. — Any    obstruction  in  the 
delivery  tube  will  cause  a  heavy  waste  of  water  from  the  over- 
flow.    To  remedy  this,  the  tube  will  have  to  be  removed  and 
cleaned. 

5.  Leaky  Overflow  Valve. — A  leaky  overflow  valve  is  indi- 
cated by  the  boiler  check  chattering  on  its  seat.    To  remedy  this 
defect,  grind  the  valve  on  its  seat  until  it  forms  a  tight  joint. 

6.  Injector  Choked  \Vilk  Lime. — It  is  essential  to  the  proper 
working   of    an   injector   that    the    interior  of    the   tubes   be 


STEAM  BOILERS  127 

perfectly  smooth  and  of  the  proper  bore.  As  in  course  of  time 
they  become  clogged  with  lime,  the  capacity  of  the  injector 
decreases  until,  finally,  it  refuses  to  work  at  all.  If  the  water 
used  is  very  bad,  it  becomes  necessary  frequently  to  cleanse 
the  tubes  of  the  accumulated  lime.  This  may  be  done  by 
putting  the  parts  in  a  bath  consisting  of  1  part  of  muriatic 
acid  to  10  parts  of  water.  The  tubes  should  be  removed  from 
it  as  soon  as  the  gas  bubbles  cease  to  be  given  off. 

Advantages  and  Disadvantages  of  Injectors. — The  advan- 
tages of  the  injector  as  a  boiler  feeding  apparatus  are  its  cheap- 
ness, as  compared  with  a  pump  of  equal  capacity;  it  occupies 
but  little  space;  the  repair  bills  are  low,  owing  to  the  absence 
of  moving  parts;  no  exhaust  piping  is  required,  as  with  a 
steam  pump;  it  delivers  hot  water  to  the  boiler.  The  dis- 
advantages of  the  injector  are  that  it  will  not  start  with  a 
steam  pressure  less  than  that  for  which  it  is  designed,  and 
that  it  will  stand  but  little  abuse,  being  poorly  adapted  for 
handling  water  containing  grit  or  other  matter  liable  to  cut 
the  nozzles. 

INCRUSTATION  AND  CORROSION 

Incrustation. — Broadly  speaking,  any  deposit  that  is  formed 
on  the  plates  and  tubes  of  a  boiler  is  termed  scale,  or  incrusta- 
tion; it  is  caused  by  impurities  that  enter  with  the  water  and 
that  are  left  behind  in  the  boiler  when  the  water  is  evaporated. 
In  passing  through  the  soil,  water  dissolves  certain  mineral 
substances,  the  most  important  of  which  are  carbonate  of 
lime  and  sulphate  of  lime.  Other  substances  frequently  pres- 
ent in  small  quantities  are  chloride  of  sodium,  or  common 
salt,  and  chloride  of  magnesium.  It  also  often  contains  other 
troublesome  substances. 

Impurities  in  Feedwater. — Some  of  the  more  common  impu- 
rities found  in  feedwater,  together  with  their  properties,  are 
given  in  the  following  paragraphs: 

Carbonate  of  lime  will  not  dissolve  in  pure  water,  but  will 
dissolve  in  water  that  contains  carbonic-acid  gas.  It  becomes 
insoluble  and  is  precipitated  in  the  solid  form  when  the  water 
is  heated  to  about  212°  F.,  the  carbonic-acid  gas  being  driven 
off  by  the  heat. 


128  STEAM  BOILERS 

Sulphate  of  lime  dissolves  readily  in  cold  water,  but  not  in 
hot  water.  It  precipitates  in  the  solid  form  when  the  water 
is  heated  to  about  290°  F.,  corresponding  to  a  gauge  pressure 
of  45  Ib. 

Chloride  of  sodium  will  not  be  precipitated  by  the  action  of 
heat  unless  the  water  has  become  saturated  with  it.  Since  it 
generally  is  present  in  but  very  small  quantities  in  fresh  water, 
it  will  take  a  very  long  time  for  the  water  in  a  boiler  to  become 
troublesome,  and  with  the  ordinary  blowing  down  of  a  boiler 
once  a  week  or  every  2  wk.,  there  is  little  danger  of  the  water 
becoming  saturated  with  it.  Consequently,  it  is  one  of  the 
least  troublesome  scale-forming  substances  contained  in  fresh 
water. 

Chloride  of  magnesium  is  one  of  the  worst  impurities  in  water 
intended  for  boilers,  for  while  not  dangerous  as  long  as  the  water 
is  cold,  it  makes  the  water  corrosive  when  heated,  and  when 
present  in  large  quantities,  it  becomes  dangerously  corrosive, 
attacking  the  metal  of  the  boiler  and  rapidly  corroding  it. 

Organic  mailer  by  itself  may  or  may  not  cause  the  water  to 
become  corrosive,  but  will  often  cause  foaming;  when  it  is 
present  in  small  quantities  in  water  containing  carbonate  or 
sulphate  of  lime,  or  both,  it  usually  serves  to  keep  the  deposits 
from  becoming  hard. 

Earthy  mailer,  like  organic  matter,  is  not  dissolved  in  the 
water,  but  is  in  mechanical  suspension.  It  is  very  objection- 
able, especially  when  the  earthy  matter  is  clay,  and  when  other 
scale-forming  substances  are  present  is  liable  to  form  a  hard 
scale  resembling  Portland  cement. 

Acids,  such  as  sulphuric  acid,  nitric  acid,  tannic  acid,  and 
acetic  acid,  are  often  present  in  the  feedwater.  The  sulphuric 
acid  is  the  most  dangerous  one  of  these  acids,  attacking  the 
metal  of  which  the  boiler  is  composed  and  corroding  it  very 
rapidly.  The  other  acids,  while  not  so  violent  in  their  action 
as  the  sulphuric  acid,  are  also  dangerous,  and  water  contain- 
ing any  one  should  be  neutralized  when  it  must  be  used. 

Formation  of  Scale. — The  small  solid  particles,  due  to  pre- 
cipitation of  substances  in  solution  or  matter  in  mechanical 
suspension,  remain  for  a  time  suspended  in  the  water,  especially 
the  carbonate  of  lime  that  for  some  time  after  precipitation 


STEAM  BOILERS  129 

floats  on  the  surface  of  the  water.  These  particles  will  gradu- 
ally settle  on  the  plates,  tubes,  and  other  internal  surfaces.  A 
large  part  of  the  impurities  will  be  carried  by  the  circulation 
of  the  water  to  the  most  quiet  part  of  the  boiler  and  there 
settle  and  form  a  scale.  In  a  few  weeks,  if  no  means  of  pre- 
vention are  used,  the  inner  parts  of  the  boiler  will  be  covered 
with  a  crust  from  rj  to  -|  in.  in  thickness. 

Danger  of  Scale. — A  scale  &  in.  or  less  in  thickness  is 
thought  by  many  to  be  an  advantage,  as  it  protects  the  plates 
from  the  corrosive  action  of  acids  in  the  water.  When,  how- 
ever, the  scale  becomes  J  in.  thick  or  more,  heat  is  transmitted 
through  the  plates  and  tubes  with  difficulty,  more  fuel  is 
required,  and  there  is  danger  of  overheating  the  plates.  The 
chief  danger  from  a  heavy  incrustation  is  the  danger  of  over- 
heating the  plates  and  tubes;  it  also  prevents  a  proper  examina- 
tion of  the  inside  of  the  boiler,  since  it  may  hide  a  dangerously 
corroded  piece  of  plate  or  a  defective  rivet  head  that  would 
otherwise  be  discovered. 

Scale  Containing  Lime. — The  carbonate  of  lime  forms  a 
soft,  muddy  scale,  which  when  dry,  becomes  fluffy  and  flour- 
like.  This  scale  may  be  easily  swept  or  washed  out  of  the 
boiler  by  a  hose,  provided  it  is  not  baked  hard  and  fast.  A  car- 
bonate scale  is  much  harder  to  deal  with  when  grease  is  allowed 
to  enter  the  boiler.  The  grease  settles  and  mixes  with  the 
floury  scale,  making  a  spongy  crust  that  remains  in  contact 
with  the  plates,  being  too  heavy  to  be  carried  off  by  the  natural 
circulation  of  the  water.  The  sulphate  of  lime  forms  a  scale 
that  soon  bakes  to  the  plates. 

Kerosene  as  Scale  Remover. — Some  substances  seem  to 
soften  and  aid  in  detaching  scale.  Of  these,  kerosene  oil  has 
met  with  much  favor.  Its  action  appears  to  be  mechanical 
rather  than  chemical,  the  oil  penetrating  or  soaking  through 
the  scale  and  softening  and  loosening  it.  It  is  somewhat 
useful,  too,  in  preventing  the  formation  of  scale,  enveloping 
the  fine  particles  of  the  scale-forming  substances  that,  after 
precipitation,  float  on  the  surface  of  the  water  for  a  little 
while.  It  seems  that  this  prevents  the  particles  from  adher- 
ing firmly  to  one  another  and  to  the  metal  when  they  finally 
settle. 


130 


STEAM  BOILERS 


Removal  of  Scale  by  Chipping. — A  hard  scale,  when  once 
formed,  is  generally  removed  by  chipping  it  off  with  scaling 
hammers  and  scaling  bars;  soft  scale  can  be  largely  removed 
during  running  by  a  periodic  use  of  the  bottom  and  surface 
blow-offs,  and  the  remainder  can  usually  be  washed  out  and 
raked  out  when  the  boiler  is  blown  down  and  opened.  In 
order  to  prevent  the  scale-forming  substances  deposited  on 
the  metal  from  baking  hard,  it  is  advisable  to  let  the  boiler 
cool  down  slowly  until  entirely  cold  preparatory  to  blowing 
off,  whenever  circumstances  permit  this  to  be  done.  This 
cooling  process  will  generally  take  from  24  to  36  hr. 

Removal  of  Mud. — Mud  and  earthy  matter  by  itself  will 
not  form  any  hard  scale,  but  will  often  do  so  when  carbonate 
of  lime  and  sulphate  of  lime  are  present.  An  accumulation 
of  such  matter  can  be  prevented,  and  most  of  it  can  be 
removed,  by  a  periodic  use  of  the  bottom  blow-off,  removing 
the  remainder  whenever  the  boiler  is  opened. 

Internal  Corrosion. — Corrosion  of  boiler  plates  may  be  defined 
as  the  eating  away  or  wasting  of  the  plates  due  to  the  chemical 
action  of  water.  Corrosion  may  be  internal  and  external. 


FIG.  1 


FIG.  2 


Internal    corrosion  may  present    itself  as  uniform  corrosion, 
pitting  or  honeycombing,  and  grooving. 

Uniform  Corrosion. — In  cases  of  uniform  corrosion  large  areas 
of  plate  are  attacked  and  eaten  away.  There  is  no  sharp  line 
of  division  between  the  corroded  part  and  the  sound  plate. 


STEAM  BOILERS  131 

Corrosion  often  violently  attacks  the  staybolts  and  rivet  heads. 

Pitting  or  Honeycombing. — Pitting  or  honeycombing  is 
readily  perceived.  The  plates  are  indented  in  spots  with 
holes  and  cavities  from  3*5  to  \  in.  deep.  The  appearance  of  a 
pitted  plate  is  shown  in  Fig.  1.  On  the  first  appearance  of 
pitting,  the  surface  so  affected  should  be  thoroughly  cleaned 
and  a  good  coating  of  thick  paint  made  of  red  lead  and  boiled 
linseed  oil  should  be  applied.  This  treatment  should  be  given 
from  time  to  time  to  insure  protection  to  the  metal. 

Grooving. — Grooving,  which  means  the  formation  of  a  dis- 
tinct groove,  is  generally  caused  by  the  buckling  action  of  the 
plates  when  under  pressure.  Thus,  the  ordinary  longitudinal 
lap  joint  of  a  boiler  slightly  distorts  the  shell  from  a  truly 
cylindrical  form,  and  the  steam  pressure  tends  to  bend  the 
plates  at  the  joint.  This  bending  action  is  liable  to  start  a 
small  crack  along  the  lap,  which,  being  acted  on  by  corrosive 
agents  in  the  water,  soon  deepens  into  a  groove,  as  shown  in 
Fig.  2. 

External  Corrosion. — External  corrosion  frequently  attacks 
stationary  boilers,  particularly  those  set  in  brickwork.  The 
causes  of  external  corrosion  are  dampness,  exposure  to  weather, 
leakage  from  joints,  moisture  arising  from  the  waste  pipes  or 
blow-off,  etc.  External  corrosion  should  be  prevented  by 
keeping  the  boiler  shell  free  from  moisture,  and  the  stoppage  of 
all  leaks  as  soon  as  they  appear. 

Leakage  of  rivets  and  the  calking  edges  of  seams  may  be 
caused  by  the  delivery  of  the  cold  feedwater  on  to  the  hot 
plates;  another  cause  is  the  practice  of  emptying  the  boiler 
when  hot  and  then  filling  it  with  cold  water.  The  leakage  in 
both  cases  is  due  to  the  sudden  contraction  of  the  plates. 

In  horizontal  water-tube  boilers  of  the  inclined-tube  type, 
external  corrosion  principally  attacks  the  ends  of  the  tubes, 
especially  the  back  ends,  close  up  to  the  headers  into  which 
they  are  expanded.  In  the  course  of  time  the  tubes  will  leak 
around  the  expanded  portion  in  the  headers. 

If  leaks  are  attended  to  as  soon  as  they  occur,  no  corrosion 
will  take  place,  as  the  gases  of  combustion  are  harmless  unless 
acting  in  conjunction  with  water  or  dampness,  or  unless  the 
coal  is  rich  in  sulphur.  Should,  however,  the  ends  of  several 


132 


STEAM  BOILERS 


tubes  be  found  badly  corroded  but  not  yet  leaking  from  that 
cause,  the  tubes  should  by  all  means  be  removed  and  replaced. 
Lamination. — Sometimes  what  is  called  lamination,  or  the 
splitting  of  a  plate  into  thin  layers,  is  revealed  by  the  action  of 
the  fire  in  causing  a  bag  or  blister  to  appear.  Laminations 
due  to  slag  and  other  impurities  in  the  metal,  which  become 


FIG.  3 

flattened  out  when  the  plates  are  rolled,  are  shown  at  a,  Fig.  3. 
Under  the  action  of  the  heat  the  part  exposed  to  the  fire  will 
form  a  blister,  which  may  finally  open  at  the  point  b  or  c.  If 
the  laminated  portion  of  the  plate  is  small,  it  may  be  cut  out 
and  a  patch  put  in  its  place.  If  there  are  a  number  of  lamina- 
tions in  the  same  plate,  it  is  advisable  to  put  in  a  new  plate. 

Overheating. — The  heating  of  a  plate  beyond  its  normal 
temperature  is  called  overheating,  and  may  be  caused  by  low 
water  or  by  incrustation.  When  the  plate  is  covered  by  a 
heavy  scale,  the  plate  becomes  overheated,  so  that  it  yields  to 
the  steam  pressure,  forming  a  pocket,  as  shown  in  Fig.  4, 
which  represents  the  shell  sheet,  or  the  sheet  of  a  horizontal 
return-tubular  boiler  directly  over  the  fire.  If  the  pocket  is 


FIG.  4 

not  discovered  in  time  for  the  plate  to  be  repaired,  it  stretches 
until  finally  the  material  becomes  too  thin  to  withstand  the 
steam  pressure;  the  pocket  then  bursts  with  more  or  less  lia- 
bility of  an  explosion.  The  vegetable  or  animal  oils  carried 
into  the  boiler  from  a  surface  condenser  are  particularly  liable 
to  cause  the  formation  of  pockets. 


STEAM  BOILERS 


133 


Prevention  of  Incrustation  and  Corrosion. — Incrustation 
can  best  be  prevented  by  purifying  the  feedwater  prior  to  its 
entering  the  boiler,  and  can  be  fairly  satisfactorily  prevented 
by  a  chemical  treatment  of  the  water  in  case  there  is  no  puri- 
fication of  the  water  prior  to  its  entering  the  boiler.  When 

SCALE-FORMING  SUBSTANCES  AND  THEIR 
REMEDIES 


Troublesome  Substance 

Trouble 

Remedy  or  Palliation 

Sediment,  mud,  clay,  etc. 

Incrustation 

Filtration 

Blowing  off 

Readily  soluble  salts 

Incrustation 

Blowing  off 

Heating  feed 

Bicarbonates  of  lime,  mag- 
nesia, iron 

Incrustation 

Addition    of    caustic 
soda,  lime,  or  mag- 
nesia 

Addition  of  carbon- 

Sulphate of  lime 

Incrustation 

ate  of  soda  or  ba- 

rium chloride 

Chloride  and  sulphate  of 
magnesium 

Corrosion 

Addition  of  carbon- 
ate of  soda,  etc. 

Carbonate  of  soda  in  large 
amounts 

Priming 

Addition    of   barium 
chloride 

Acid  (in  mine  water) 

Corrosion 

Alkali 

Heating  feed 

Dissolved    carbonic    acid 
and  oxygen 

Corrosion 

Addition    of    caustic 
soda,  slaked  lime, 
etc. 

Grease    (from   condensed 

Corrosion 

Slaked  lime  and   fil- 
tering.   Carbonate 

water) 

of  soda 

Substitute      mineral 

oil 

Precipitate       with 

Organic  matter  (sewage) 

Priming 

alum  or  chloride  of 

iron  and  filter 

Organic  matter 

Corrosion 

Same  as  last 

the  water  contains  large  quantities  of  substances  that  float 
on  the  surface,  mechanical  means  may  be  resorted  to,  using 
the  surface  blow-off  at  frequent  intervals  or  some  equivalent 
skimming  device.  Corrosion  is  prevented  by  neutralizing 
the  corrosive  acids  by  an  alkali;  corrosion  due  to  a  perfectly 


134  STEAM  BOILERS 

fresh  water  can  be  prevented  by  giving  a  protective  coating  to 
the  metal,  which  may  be  a  thick  red -lead  paint  made  up  with 
boiled  linseed  oil,  or  a  thin  coating  of  scale.  Sometimes  organic 
substances  containing  tannic  acid,  such  as  oak  bark,  hemlock, 
or  sumac,  are  used  to  loosen  or  prevent  scale.  They  are  liable 
to  injure  the  plates  by  corrosion  and  hence  should  not  be 
used.  The  preceding  table  gives  a  list  of  troublesome  scale- 
forming  substances  and  the  means  of  preventing  or  neutralizing 
them. 

Use  of  Zinc  in  Boilers. — Zinc  is  much  used  in  marine  boilers 
for  the  prevention  of  both  incrustation  and  corrosion.  The 
scale  may  acquire  thickness  and  hardness,  but  can  easily  be 
removed  from  the  plates.  The  zinc  is  distributed  through  the 
boiler  in  the  form  of  slabs.  About  1  sq.  in.  of  zinc  surface 
should  be  supplied  for  every  50  Ib.  of  water  in  the  boiler. 

TESTING  OF  FEEDWATER 

Testing  for  Corrosiveness. — It  is  a  good  plan  to  test  the 
feedwater  and  also  the  water  in  the  boiler  occasionally  for  cor- 
rosiveness.  This  may  be  done  by  placing  a  small  quantity  in 
a  glass  and  adding  a  few  drops  of  methyl  orange.  If  the  sam- 
ple of  water  is  acid,  and  hence  corrosive,  it  will  turn  pink.  If 
it  is  alkaline,  and  hence  harmless,  it  will  be  yellow.  The 
acidity  may  also  be  tested  by  dipping  a  strip  of  blue  litmus 
paper  in  the  water.  If  it  turns  red,  the  water  is  acid.  This 
method  is  not  so  sensitive  as  the  previous  one,  which  should  be 
used  in  preference.  If  litmus  paper  is  kept  in  stock,  it  should 
be  kept  in  a  bottle  with  a  glass  stopper,  as  exposure  to  the 
atmosphere  will  cause  the  paper  to  deteriorate.  If  the  water 
in  the  boilers  has  become  corrosive  and  corrosion  has  set  in, 
the  water  in  the  gauge  glass  will  show  red  or  even  black.  As 
soon  as  the  color  is  beyond  a  dirty  gray  or  straw  color,  it  is 
advisable  to  introduce  lime  or  soda  to  neutralize  the  acid. 

Testing  for  Carbonate  of  Lime. — Pour  some  of  the  water 
to  be  tested  into  an  ordinary  tumbler.  Add  a  little  ammonia 
and  ammonium  oxalate,  and  then  heat  to  the  boiling  point. 
If  carbonate  of  lime  is  present,  a  precipitate  will  be  formed. 

Testing  for  Sulphate  of  Lime. — Pour  some  of  the  feedwater 
into  a  tumbler  and  add  a  few  drops  of  hydrochloric  acid. 


STEAM  BOILERS  135 

Add  a  small  quantity  of  a  solution  of  barium  chloride  and  slowly 
heat  the  mixture.  If  a  white  precipitate  is  formed,  which  will 
not  redissolve  when  a  little  nitric  acid  is  added,  sulphate  of  lime 
is  present. 

Testing  for  Organic  Matter. — Add  a  few  drops  of  pure  sul- 
phuric acid  to  the  sample  of  water.  To  this  add  enough  of  a 
pink-colored  solution  of  potassium  permanganate  to  make  the 
whole  mixture  a  faint  rose  color.  If  the  solution  retains  its 
color  after  standing  a  few  hours,  no  organic  substances  are 
present. 

Testing  for  Matter  in  Mechanical  Suspension. — Keep  a 
tumblerful  of  the  feedwater  in  a  quiet  place.  If  no  sediment 
is  formed  in  the  bottom  of  the  tumbler  after  standing  for 
a  day,  there  is  no  mechanically  suspended  matter  in  the  water. 

PURIFICATION  OF  FEEDWATER 

Means  of  Purification. — Water  intended  for  boilers  may  be 
purified  by  settlement,  by  filtration,  by  chemical  means,  and 
by  heat.  Filtration  will  remove  impurities  in  mechanical  sus- 
pension, such  as  oil  and  grease,  and  earthy  matter,  but  will 
not  remove  substances  dissolved  in  the  water.  Chemical 
treatment  of  the  water  will  render  the  scale-forming  substances 
and  corrosive  acids  harmless,  and  may  be  applied  either  before 
or  after  the  water  enters  the  boilers,  but  preferably  the  former. 
Purification  by  heat  is  based  on  the  fact  that  most  of  the  scale- 
forming  substances  become  insoluble  and  precipitate  when 
the  water  containing  them  in  solution  is  heated  to  a  high 
temperature. 

Purification  by  Settlement. — For  feedwater  containing  much 
matter  in  mechanical  suspension,  one  of  the  simplest  methods 
of  purifying  it  is  to  provide  a  relatively  large  reservoir,  or  a 
large  tank  for  small  steam  plants,  where  the  impurities  can 
settle  to  the  bottom.  While  this  method  is  fairly  satisfactory, 
as  far  as  earthy  matter  is  concerned,  it  will  not  clear  the  water 
of  finely  divided  organic  matter,  which  is  usually  lighter  than 
the  water  and  often  so  finely  divided  as  to  be  almost  dissolved 
in  it. 

Purification  by  Filtration. — Organic  and  earthy  matter  in 
mechanical  suspension  is  most  satisfactorily  removed  by  a 


136  STEAM  BOILERS 

filter,  passing  the  water  through  layers  of  sand,  gravel,  hay,  or 
equivalent  substances,  or  through  layers  of  cloth.  Hay  and 
cloth  are  of  service  especially  where  the  feedwater  contains  oil 
or  grease,  as  is  the  case  where  a  surface  condenser  is  used  and 
the  condensed  steam  is  used  over  again. 

Purification  by  Chemicals. — Chemical  purification  may 
take  place  before  or  after  the  water  enters  the  boiler,  the  former 
method  being  somewhat  more  expensive.  However,  the 
purification  is  better  carried  out  before  the  water  enters  the 
boiler  for  the  reason  that  the  amount  of  impurities  enter- 
ing the  boiler  will  be  greatly  reduced.  The  chemical  pro- 
cess to  be  adopted  depends  on  the  substances  present  in  the 
water. 

Use  of  Quicklime. — When  the  water  contains  only  car- 
bonate of  lime,  it  may  be  treated  with  slaked  quicklime, 
using  28  gr.  of  lime  for  every  50  gr.  of  carbonate  of  lime  present 
in  the  water,  the  quicklime  precipitating  the  carbonate  of 
lime  and  being  transformed  into  carbonate  of  lime  itself  during 
the  process. 

Use  of  Caustic  Soda. — Water  containing  carbonate  of  lime 
may  be  treated  with  caustic  soda,  which  precipitates  the  car- 
bonate of  lime  and  leaves  carbonate  of  soda,  which  is  harmless. 
For  every  100  gr.  of  carbonate  of  lime  80  gr.  of  caustic  soda 
should  be  added. 

Use  of  Sal  Ammoniac. — Sal  ammoniac  is  sometimes  added 
to  water  containing  carbonate  of  lime  and  will  cause  the  latter 
to  precipitate.  Its  use  is  not  advisable,  however,  on  account 
of  the  danger  of  the  formation  of  hydrochloric  acid,  which  will 
attack  the  boiler.  The  formation  of  this  acid  is  due  to  the  use 
of  an  excessive  quantity  of  sal  ammoniac. 

Treatment  of  Sulphate  of  Lime. — While  slaked  lime  will 
precipitate  carbonate  of  lime,  it  will  have  no  effect  on  sulphate 
of  lime,  and  water  containing  the  latter,  either  alone  or  in  con- 
junction with  carbonate  of  lime,  must  be  treated  with  other 
chemicals.  The  most  available  ones  for  water  containing  both 
are  carbonate  of  soda  and  caustic  soda.  These  are  often  fed 
into  the  boiler  and  will  precipitate  the  carbonate  of  lime  and 
sulphate  of  lime  there,  requiring  the  sediment  to  be  blown  out 
or  otherwise  removed  periodically. 


STEAM  BOILERS  137 

Quantity  of  Chemicals  to  Use. — When  treating  water  con- 
taining carbonate  of  lime  and  sulphate  of  lime,  caustic  soda 
may  be  used  either  by  itself  or  in  combination  with  carbonate 
of  soda,  depending  on  the  relative  proportions  of  carbonate  of 
lime  and  sulphate  of  lime  present  in  the  water.  The  amount 
of  caustic  soda  or  carbonate  of  soda  to  be  used  per  gallon  of 
feedwater  can  be  found  as  follows: 

Rule  I. — Multiply  the  number  of  grains  of  carbonate  of 
lime  per  gallon  by  1.36.  If  this  product  is  greater  than  the 
number  of  grains  of  sulphate  of  lime  per  gallon,  only  caustic 
soda  is  to  be  used.  To  find  the  quantity  of  caustic  soda  required 
per  gallon,  multiply  the  number  of  grains  of  carbonate  of  lime 
in  a  gallon  by  .8. 

Rule  n. — Multiply  the  number  of  grains  of  carbonate  of  lime 
per  gallon  by  1.36.  If  this  product  is  less  than  the  number  of 
grains  of  sulphate  of  lime  per  gallon,  take  the  difference  and 
multiply  it  by  .78  to  obtain  the  number  of  grains  of  carbonate  of 
soda  required  per  gallon.  To  find  the  amount  of  caustic  soda 
required  per  gallon,  multiply  the  number  of  grains  of  carbonate  of 
lime  in  a  gallon  by  .8. 

EXAMPLE. — A  quantitative  analysis  of  a  certain  feedwater 
shows  it  to  contain  23  gr.  of  sulphate  of  lime  and  14  gr.  of  car- 
bonate of  lime  per  gallon.  How  much  caustic  soda  and  carbon- 
ate of  soda  should  be  used  per  gallon  to  precipitate  the  scale- 
forming  substances? 

SOLUTION. — By  rule  I,  14X1.36  =  19  gr.  As  this  product 
is  less  than  the  number  of  grains  of  sulphate  of  lime  per 
gallon,  rule  II  is  to  be  used.  Applying  rule  II,  (23  — 19)  X. 78 
=  3.12  gr.  of  carbonate  of  soda,  and  14  X  .8  =  11.2  gr.  of  caustic 
soda. 

Use  of  Carbonate  of  Soda. — Water  containing  sulphate  of 
lime,  but  no  carbonate  of  lime,  may  be  treated  with  carbonate 
of  soda.  The  amount  of  the  latter  that  is  required  per  gallon 
to  precipitate  the  sulphate  of  lime  is  found  by  multiplying  the 
number  of  grains  per  gallon  by  .78.  When  using  soda,  it  is 
well  to  keep  in  mind  that  it  will  not  remove  deposited  lime  from 
the  inside  of  a  boiler.  All  that  the  soda  can  do  is  to  facilitate 
the  separating  of  the  lime,  that  is,  cause  it  to  deposit  in  a  soft 
state.  This  sediment  must  be  removed  periodically 


138  STEAM  BOILERS 

Use  of  Trisodium  Phosphate. — For  decomposing  sulphate  of 
lime,  tribasic  sodium  phosphate,  more  commonly  known  as 
trisodium  phosphate,  is  often  used.  This  is  claimed  to  act  on 
the  sulphate  of  lime,  forming  sulphate  of  sodium  and  phos- 
phate of  lime,  the  former  of  which  remains  soluble  and  is 
harmless,  and  the  latter  of  which  is  a  loose,  easily  removed 
deposit.  Trisodium  phosphate  also  acts  on  carbonate  of  lime 
and  carbonate  of  magnesia,  forming  phosphate  of  lime  and 
phosphate  of  magnesia,  at  the  same  time  neutralizing  the  car- 
bonic acid  released  from  the  carbonate  of  lime  and  magnesia, 
and  the  sulphuric  acid  released  from  the  sulphates. 

Neutralization  of  Acids. — Acid  water  can  be  neutralized  by 
means  of  an  alkali,  soda  probably  being  the  best  one.  The 
amount  of  soda  to  be  used  can  best  be  found  by  trial,  adding 
soda  until  the  water  will  turn  red  litmus  paper  blue. 

Purification  by  Heat. — Carbonate  of  lime  and  sulphate  of 
lime  become  insoluble  if  the  water  is  heated,  the  former  pre- 
cipitating at  about  212°  P.  and  the  latter  at  about  290°  P. 
This  fact  is  taken  advantage  of  in  devices  that  may  be  called 
combined  feed  water  heaters  and  purifiers;  as  they  generally 
use  live  steam,  they  are  also  called  live-steam  feed-water  heaters. 
Since  no  feedwater  heater  can  effect  a  direct  saving  on  fuel 
except  when  the  heat  is  taken  from  a  source  of  waste,  it  follows 
that  a  live-steam  feedwater  heater  can  affect  the  fuel  con- 
sumption but  indirectly.  This  it  does  by  largely  preventing 
the  accumulation  of  scale  in  the  boiler  and  the  attendant  loss  in 
economy  due  to  the  lowering  of  the  rate  of  heat  transmission 
through  a  plate  heavily  covered  with  incrustation. 

Economy  of  Heating  Feedwater. — The  feedwater  furnished 
to  steam  boilers  must  of  necessity  be  raised  from  its  normal 
temperature  to  that  of  steam  before  evaporation  can  commence, 
and  if  not  otherwise  accomplished,  it  will  be  done  at  the  expense 
of  fuel  that  should  be  utilized  in  making  steam.  At  75 
Ib.  gauge  pressure  the  temperature  of  boiling  water  is  about 
320°  P.,  and  if  60°  is  taken  as  the  average  temperature  of  feed- 
water,  320- (50  =  200  B.  T.  U.  is  required  to  raise  1  Ib.  of  water 
from  60°  to  320°.  It  requires  1,151.5  B.  T.  U.  to  convert 
1  Ib.  of  water  at  60°  into  steam  at  75  Ib.  gauge  pressure,  so 
that  the  260  B.  T.  U.  required  for  heating  the  water  represents 


STEAM  BOILERS  139 

260-7-1,151.5  =  22.6%  of  the  total.  All  heat  taken  from  a 
source  of  waste,  therefore,  that  can  be  imparted  to  the  feed- 
water  before  it  enters  the  boilers  is  just  so  much  saved,  not 
only  in  cost  of  fuel  but  in  boiler  capacity. 

Types  of  Exhaust-Steam  Feedwater  Heaters. — The  impuri- 
ties contained  in  the  water  will  largely  determine  the  type  of 
exhaust-steam  heater  to  be  used  in  any  given  plant.  These 
heaters  are  divided  into  two  general  classes,  namely,  open 
heaters  and  closed  heaters. 

An  open  heater  is  one  in  which  the  water  space  is  open  to 
the  atmosphere.  In  a  direct-contact  open  heater,  the  exhaust 
steam  comes  in  contact  with  the  water,  which,  by  means  of 
some  one  of  a  number  of  suitable  devices,  is  broken  into  spray 
or  thin  sheets  so  that  it  will  readily  absorb  the  heat  of  the 
steam.  In  a  coil  heater,  the  exhaust  steam  passes  through 
coils  of  pipe  submerged  in  a  vessel  containing  the  water  to  be 
heated,  and  open  at  the  top. 

A  closed  heater  is  a  heater  in  which  the  feedwater  is  not 
exposed  to  the  atmosphere,  but  is  subjected  to  the  full  boiler 
pressure.  The  steam  does  not  come  in  contact  with  the  water; 
the  latter  is  heated  through  contact  with  metallic  surfaces, 
generally  those  of  tubes,  that  are  heated  by  the  exhaust  steam. 

Selection  of  Heater. — When  the  boiler  feedwater  is  free 
from  acids,  salts,  sulphates,  and  carbonates,  so  that  no  scale  is 
formed  at  a  high  temperature,  the  closed  feedwater  heater  will 
be  found  satisfactory.  Heaters  of  the  coil  type  may  be  used 
with  pure  water,  but  should  not  be  used  with  water  that 
will  precipitate  sediment  or  scale-forming  matter  of  any  kind. 
The  coil  heater  is  very  efficient  as  a  heater,  as  the  water  cir- 
culating through  the  coils  is  a  long  time  in  contact  with  the 
surface  surrounded  and  heated  by  the  exhaust  steam.  Heaters 
of  the  closed  type,  with  straight  tubes  and  sediment  chamber, 
can  be  cleaned  more  readily  than  those  having  curved  tubes, 
but  the  curved  tubes  allow  more  freedom  for  expansion  and 
contraction.  Heaters  of  the  tubular  type  should  have  ample 
sediment  chambers  and  may  be  used  with  water  that  contains 
organic  or  earthy  matter,  but  not  with  water  containing  scale- 
forming  ingredients.  Carbonate  of  lime  is  likely  to  combine 
with  earthy  matter  and  form  an  exceedingly  hard  scale. 


140  STEAM  BOILERS 

Heaters  of  the  open  exhaust-steam  type  have  the  advantage 
of  bringing  the  exhaust  steam  in  direct  contact  with  the  feed- 
water;  some  of  the  exhaust  steam  is  condensed,  thus  effecting 
a  saving  in  feedwater,  and  sediment  and  scale-forming  ingre- 
dients, except  sulphates  of  lime  and  magnesia,  are  precipitated 
or  will  settle  to  the  bottom  of  the  heater.  The  oil  in  the 
exhaust  steam  must  be  intercepted  by  special  oil  extractors, 
filters,  or  skimmers,  generally  combined  with  the  heater  and,  by 
automatic  regulation,  sufficient  fresh  feedwater  must  be  added 
to  make  up  the  total  quantity  required.  When  the  system  is 
properly  arranged,  all  live-steam  drips  and  discharges  from 
traps  are  led  to  the  heater. 


BOILER  TRIALS 

Purposes  of  Boiler  Trials. — A  boiler  trial,  or  boiler  test, 
as  it  is  often  called,  may  be  made  for  one  or  more  of  several 
purposes,  the  method  of  conducting  the  trial  depending  largely 
on  its  purpose.  The  boiler  trial  may  vary  from  the  simplest 
one,  in  which  the  only  observations  are  the  fuel  burned  and  the 
water  fed  to  the  boiler  in  a  stated  period  of  time,  to  the  elabo- 
rate standard  boiler  trial,  in  which  special  apparatus  and  sev- 
eral skilled  observers  are  essential.  The  object  of  a  boiler 
trial  may  be  to  determine  the  efficiency  of  the  boiler  under 
given  conditions;  the  comparative  value  of  different  boilers 
working  under  the  same  conditions;  the  comparative  value  of 
fuel;  or  the  evaporative  power,  or  horsepower,  of  the  boiler. 

Observations  During  Trial. — The  essential  operations  of  a 
boiler  trial  are  the  weighing  of  the  feedwater  and  fuel,  and 
the  observations  of  the  steam  pressure,  temperature  of  feed- 
water,  and  various  other  less  important  pressures  and  tempera- 
tures. In  conducting  a  boiler  trial,  the  various  observations 
of  temperatures,  pressures,  etc.  should  be  made  simultaneously 
at  intervals  of  about  15  min. 

Weighing  the  Coal. — The  coal  supplied  to  the  furnace  is 
weighed  out  in  lots  of  500  or  600  Ib.  It  is  a  convenient  plan 
to  have  a  box  with  one  side  open  placed  on  a  platform  scale. 
A  weight  is  then  placed  on  the  scale  beam  sufficient  to  balance 
the  box.  The  scale  may  then  be  set  at  500  or  600  Ib.,  the  coal 


STEAM  BOILERS  141 

shoveled  in  until  the  beam  rises,  and  then  fed  directly  from  the 
box  to  the  furnace.  After  the  test,  the  ashes  and  clinkers 
must  be  raked  from  the  ash-pit  and  grate  and  weighed.  This 
weight  subtracted  from  the  weight  of  the  coal  used  gives  the 
amount  of  combustible. 

Measurement  of  Feedwater.  —  The  amount  of  water  evap- 
orated in  a  test  for  comparative  fuel  values  may  be  taken  as 
equal  to  the  amount  of  feedwater  supplied  without  introducing 
any  serious  error.  The  most  reliable  method  of  measuring  the 
feedwater  delivered  to  the  boilers  is  to  weigh  it. 

Standard  of  Boiler  Horsepower.  —  When  making  a  horse- 
power or  an  efficiency  test,  a  more  elaborate  method  of  pro- 
cedure is  required  than  for  a  comparative  fuel-value  test. 
The  reason  for  this  is  that  different  boilers  generate  steam  at 
different  pressures,  different  feedwater  temperatures,  and  dif- 
*erent  degrees  of  dry  ness;  hence,  to  compare  the  performances 
of  boilers  so  as  to  determine  their  comparative  efficiencies,  it 
is  necessary  to  reduce  the  actual  evaporation  to  an  equivalent 
evaporation  from  and  at  212°  F.  per  pound  of  combustible. 

A  committee  of  the  American  Society  of  Mechanical  Engineers 
has  recommended  as  a  commercial  horsepower  an  evaporation 
of  80  Ib.  of  water  per  hour  from  a  feedwater  temperature  of  100° 
F.  into  steam  at  70  Ib.  gauge  pressure,  which  is  equivalent  to  34* 
units  of  evaporation;  that  is,  to  34  5  Ib.  of  water  evaporated 
from  a  feedwater  temperature  of  212°  F.  into  steam  at  the 
same  temperature. 

Since  965.8  B.  T.  U.  is  required  to  evaporate  a  pound  of 
water  from  and  at  212°,  a  boiler  horsepower  is  equal  to  965.8 
X  34|  =  33,320  B.  T.  U.  per  hr. 

Equivalent  Evaporation.  —  The  equivalent  evaporation  is 
readily  determined  by  means  of  the  formula 


965.8 

in  which  W  =  actual  evaporation,  in  pounds  of  water  per  hour; 
H  =  total  heat  of  steam  above  32°  F.  at  observed  pres- 

sure of  evaporation; 
t  =  observed  feedwater  temperature; 
Wi  =  equivalent  evaporation,  in  pounds  of  water  per 

hour,  from  and  at  212°  F. 
11 


142  STEAM  BOILERS 

EXAMPLE.  —  A  boiler  generates  2,200  Ib.  of  dry  steam  per  hour 
at  a  pressure  of  120  Ib.  gauge.  The  temperature  of  the  feed- 
water  being  70°  F.,  (a)  what  is  the  equivalent  evaporation? 
<6)  what  is  the  horsepower  of  the  boiler? 

SOLUTION.  —  (a)  According  to  the  Steam  Table,  the  total  heat 
H  corresponding  to  a  gauge  pressure  of  120  Ib.  is  1.188.6  B.T.U. 
Applying  the  formula, 


(b)     The  horsepower,  which  is  obtained  by  dividing  the  total 
equivalent  evaporation  by  34.5,  the  equivalent  of  1  H.  P.,  is, 
2,621  -=-34.5  =  76  H.  P.,  nearly 

TT  _  |     I     OQ 

Factor     of     Evaporation.  —  The     quantity     :  -     that 

96o.o 

changes  the  actual  evaporation  of  1  Ib.  of  water  to  equivalent 
evaporation  from  and  at  212°  F.  is  called  the  factor  of  evapora- 
tion. To  facilitate  the  calculating  of  equivalent  evaporation, 
the  accompanying  table  of  factors  of  evaporation  is  inserted. 
The  equivalent  evaporation  is  found  by  multiplying  the  actual 
evaporation  by  the  factor  of  evaporation  taken  from  the  table. 

EXAMPLE  1.  —  A  boiler  is  required  to  furnish  1,800  Ib.  of  steam 
per  hour  at  a  gauge  pressure  of  80  Ib.;  if  the  temperature  of  the 
feedwater  is  48°  F.,  what  will  be  the  rated  horsepower  of  the 
boiler? 

SOLUTION.  —  From  the  table,  the  factor  of  evaporation  for 
80-lb.  pressure  and  a  feedwater  temperature  of  40°  is  1.214, 
and  for  the  same  pressure  and  a  feedwater  temperature  of 
50°  it  is  1.203;  the  difference  is  1.214-  1.203  =  .  Oil.  The 
difference  of  temperature  is  50°  —  40°  =10°,  and  the  difference 
between  the  lower  temperature  and  the  required  temperature 
is  48°-  40°  =  8°.  Then,  10°:  8°  =  .  Oil  :  x,  or  x  =  .009;  1.214  —  .009 
=  1.205.  1,800X1.205  =  2,169  Ib.,  and  2,169  +  34.5  =  63  H.  P., 
nearly. 

EXAMPLE  2.  —  What  is  the  factor  of  evaporation  when  the 
feedwater  temperature  is  122°  F.  and  the  gauge  pressure  72? 

SOLUTION.  —  In  the  table,  under  the  column  headed  70  and 
opposite  120  in  the  left-hand  column  is  found  1.128;  in  column 
headed  80  and  opposite  120  is  found  1.131;  difference  is  .003. 


STEAM  BOILERS 


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144  STEAM  BOILERS 

In  the  same  vertical  columns  and  opposite  130  are  found  1.117 
and  1.120;  difference  is  .003;  same  as  above.  Hence,  for  an 
increase  of  10  Ib.  in  gauge  reading,  there  is  an  increase  of  .003 
in  the  factor  of  evaporation,  or  an  increase  of  .0003  for  1  Ib. 
and  of  .0003X2  =  .0006  for  2  Ib.  Therefore,  for  a  feedwater 
temperature  of  120°  and  72  Ib.  pressure,  the  factor  of  evap- 
oration is  1.128  +  .0006  =  1.1286.  The  difference  between  the 
numbers  opposite  120  and  130  in  the  two  columns  headed  70 
and  80,  respectively,  is  1.128-  1.117  =  .011,  and  1.131-1.120 
=  .011,  showing  that,  for  an  increase  of  temperature  in  the 
feedwater  of  10°,  there  is  a  decrease  in  the  factor  of  .011,  and 
for  1°  a  decrease  of  .0011,  or  for  2°  of  .0022.  Hence,  the  value 
of  the  factor  for  a  temperature  of  122°  and  a  gauge  pressure  of 
72  Ib.  is  1.1286-.  0022  =  1.126. 

Boiler  Efficiency.  —  The  efficiency  of  a  boiler  may  be  defined 
as  the  ratio  of  the  heat  utilized  in  evaporating  water  to  the 
total  heat  supplied  by  the  fuel.  The  efficiency  thus  calculated 
is  really  the  combined  efficiency  of  the  furnace  and  boiler,  as 
it  is  not  easily  possible  to  determine  separately  the  efficiency 
of  each. 

The  amount  of  heat  supplied  is  determined  by  first  accurately 
weighing  the  fuel  used  during  the  test  and  deducting  all  the 
ash  and  unconsumed  portions.  This  weight,  in  pounds,  is 
multiplied  by  the  total  heat  of  combustion  of  1  Ib.  of  the  fuel, 
as  determined  by  an  analysis,  the  product  being  the  total 
number  of  heat  units  supplied  during  the  test  under  the 
assumption  that  combustion  was  perfect.  The  heat  usefully 
expended  in  evaporating  water  is  obtained  by  first  weighing 
the  feedwater  and  correcting  this  weight  according  to  the 
quality  of  the  steam;  the  corrected  weight  is  then  multiplied 
by  the  number  of  heat  units  required  to  change  water  at  the 
temperature  of  the  feed  into  steam  at  the  observed  pressure. 
The  efficiency  of  a  boiler,  expressed  in  per  cent.,  may  be  found 
by  the  formula 


in  which  E  =  efficiency  of  boiler; 

A  =heat  utilized  in  evaporating  water; 
B  =  total  heat  supplied  by  fuel. 


STEAM  BOILERS  145 

EXAMPLE. — A  boiler  trial  shows  a  useful  expenditure  of 
186,429,030  B.  T.  U.  and  a  total  supply  of  270,187,000  B.  T.  U. 
What  is  the  efficiency  of  the  boiler? 

SOLUTION. — Applying  the  formula, 

186,429,030 

£=—  —  =  .69  =  69% 

270,187,000 

Standard  Code. — For  elaborate  boiler  trials,  the  standard 
code  recommended  by  the  American  Society  of  Mechanical 
Engineers  should  be  used. 


BOILER  MANAGEMENT 

FILLING  BOILERS 

Preparation  for  Filling  Boiler. — Before  starting  the  flow  of 
water  into  the  boiler,  the  manhole  plates  or  handhole  plates 
that  were  removed  preparatory  to  cleaning  and  overhauling 
must  be  replaced,  and  the  blow-off  valve  must  be  closed. 
The  gaskets,  and  also  the  surfaces  with  which  they  come  in 
contact,  should  be  examined  to  see  that  they  are  in  good  con- 
dition. It  is  customary  to  place  a  mixture  of  cylinder  oil  and 
graphite  on  the  outer  surface  of  each  gasket,  so  that  it  may  be 
removed  without  tearing.  It  is  important  that  the  manhole 
plates  and  handhole  plates  be  properly  replaced  and  secured 
in  order  to  prevent  leakage. 

Height  of  Water. — In  some  cases  the  water  can  flow  in  and 
fill  the  boiler  to  the  required  height  by  means  of  the  pressure 
that  exists  in  the  main  supply  pipe.  In  other  cases,  it  may  be 
necessary  to  use  a  hose  or  to  fill  the  boiler  with  a  steam  pump 
or  a  hand  pump.  The  boiler  should  be  filled  until  the  water 
shows  half  way  up  in  the  gauge  glass. 

Escape  of  Air. — While  filling  a  boiler  it  is  necessary  to  make 
provision  for  the  escape  of  the  contained  air,  since  otherwise 
the  pressure  caused  by  the  compression  of  the  air  may  prevent 
the  boiler  from  being  filled  to  the  proper  height.  Most  boilers 
have  some  valve  that  can  be  used  for  this  purpose;  a  gauge- 
cock  may  be  left  open  until  water  issues  therefrom,  when  it 
may  be  closed.  Sometimes  the  manhole  plate,  if  the  manhole 
is  on  top,  is  left  off  while  filling  a  boiler. 


146  STEAM  BOILERS 

MANAGEMENT  OF  FIRES  IN  STARTING 
Precautions  in  Starting. — After  the  boiler  has  been  filled  and 
before  starting  the  fire,  the  attendant  should  see  that  the  water 
column  and  connections  are  perfectly  clear  and  free,  that  is, 
that  the  valves  in  the  connections  and  the  gauge-glass  valves 
are  open  so  that  the  water  level  may  show  in  the  glass;  he 
should  also  see  that  the  gauge-cocks  are  in  good  working 
order  and  open  the  top  cock  or  the  safety  valve;  he  should 
take  care  that  the  stress  on  the  stop-valve  spindle  is  relieved 
by  just  unscrewing  the  valve  from  the  seat  without  actually 
opening  it.  He  should  make  sure  that  the  pump,  or  injector, 
or  whatever  device  is  used  to  feed  the  boiler,  is  in  good  working 
order,  and  ready  to  start  when  required. 

Starting  the  Fires. — It  is  customary  to  cover  the  grates  with 
a  layer  of  coal  first,  and  then  to  add  the  wood,  among  which 
may  be  thrown  oily  waste  or  other  combustible  material  that 
may  be  at  hand.  To  start  the  fire,  light  the  waste  or  other 
easily  ignited  material  and  open  the  damper  and  ashpit  doors 
to  produce  draft.  Then  close  the  furnace  door.  After  the 
wood  has  started  to  burn  well,  spread  it  evenly  over  the  grate 
and  add  a  fine  sprinkling  of  coal,  until  this  in  turn  begins  to 
glow,  when  more  coal  may  be  added  and  the  fire  occasionally 
leveled  until  the  proper  thickness  of  fire  has  been  obtained. 
It  sometimes  happens  that  the  chimney  refuses  to  draw;  the 
draft  can  be  generally  started,  however,  by  building  a  small 
fire  in  the  base  of  the  chimney. 

Value  of  Slow  Fires. — Wljen  getting  up  steam,  the  fire  should 
not  be  forced,  but,  instead,  should  be  allowed  to  burn  up 
gradually.  By  forcing  the  fire,  the  plates  or  tubes  that  are 
nearest  the  fire  suffer  extreme  expansion,  while  those  parts 
that  are  remote  from  the  fire  are  still  cold;  under  such  condi- 
tions the  seams  and  rivets,  and  also  the  tube  ends,  which  are 
expanded  into  the  tube  plates,  are  liable  to  be  severely  strained, 
and,  possibly,  permanently  injured.  It  is  not  desirable  to 
raise  steam  in  any  boiler,  except  in  steam  fire-engines,  in  less 
than  from  2  to  4  hr.,  according  to  the  size,  from  the  time  the 
fire  is  first  started.  When  steam  begins  to  issue  from  the 
opened  top  gauge-cock  or  the  raised  safety  valve,  as  the  case 
may  be,  the  cock  or  the  valve  may  be  closed  and  the  pressure 


STEAM  BOILERS  147 

still  allowed  to  rise  slowly  until  the  desired  pressure  has  been 
reached. 

Trying  the  Fittings. — After  the  pressure  at  which  the  boiler 
is  to  run  has  been  reached,  and  before  cutting  it  into  service, 
all  the  valves  and  cocks  should  be  tried.  The  safety  valve 
should  be  raised  and  its  action  noted;  the  water  column  should 
be  blown  out  and  the  gauge-cocks  tested;  the  feeding  apparatus 
should  be  tried;  and  it  should  be  noted  particularly  whether 
the  check-valves  seat  properly  and  the  valve  in  the  feedpipe 
is  open.  All  the  accessible  parts  should  be  examined  for  leaks. 

CONNECTING  BOILERS 

Cutting  Boiler  Into  Service. — Cutting  a  boiler  into  service 
is  accomplished  by  opening  the  stop-valve,  thus  permitting 
the  steam  to  flow  to  the  engine  or  other  destination.  The  stop- 
valve  should  be  opened  very  slowly  to  prevent  a  too  sudden 
change  in  the  temperature  and  consequent  expansion  of  the 
piping  through  which  the  steam  flows,  and  also  to  prevent 
water  hammer.  The  steam-pipe  drain  should  be  kept  open 
until  the  pipe  is  thoroughly  warmed  up.  In  large  plants  with 
many  boilers  and  long  steam  mains  it  takes  several  hours  to 
warm  these  pipes  thoroughly  by  a  slow  circulation  of  the 
steam,  but  not  until  then  should  the  main  stop-valve  be  fully 
opened. 

Connecting  Boilers  to  Main. — Before  connecting  the  differ- 
ent boilers  of  a  battery  to  the  same  steam  main,  the  precaution 
of  equalizing  the  pressures  in  the  different  boilers  must  be 
observed  in  order  to  prevent  a  sudden  rush  of  steam  from  one 
boiler  to  another.  All  the  pressures  should  be  equal  within  a 
variation  of  about  2  Ib.  before  an  attempt  is  made  to  connect 
the  boilers. 

Changing  Over. — In  plants  where  there  are  duplicate  sets  of 
boilers,  one  set  being  in  operation  while  the  other  is  under- 
going repairs,  overhauling,  and  cleaning,  the  method  of  chang- 
ing over,  or  connecting,  is  as  follows:  Start  the  fires  and  raise 
steam  in  the  boilers  that  are  to  be  cut  into  service.  Allow 
the  pressure  to  rise  in  all  to  within  5  Ib.  of  that  which  is  in  the 
boilers  in  operation.  All  arrangements  before  changing  over 
should  be  made  with  a  view  to  getting  all  the  heat  that  can  be 


148  STEAM  BOILERS 

obtained  from  the  fires  in  the  boilers  that  are  to  be  cut  out. 
This  can  be  accomplished  by  running  until  the  fires  have  given 
up  all  of  their  available  heat  for  making  steam,  as  indicated  by 
the  gradual  fall  in  pressure  when  the  dampers  are  wide  open, 
and  then  making  the  change.  While  the  fires  in  one  set  of 
boilers  are  burning  low  and  the  pressure  is  falling,  the  pressure 
in  the  boilers  to  be  cut  in  is  gradually  rising  and  meeting,  so 
to  speak,  the  falling  pressure  of  the  set  in  operation.  When 
the  difference  of  5  Ib.  is  reached,  change  over.  A  man  should 
be  stationed  at  each  stop-valve,  and  while  one  is  being  opened 
the  other  should  be  closed;  the  engine  will  continue  running 
uninterruptedly  while  the  change  is  being  made. 

EQUALIZING  THE  FEED 

When  the  boilers  of  a  battery  have  been  cut  into  service  and 
hence  are  all  connected  together  through  the  steam  main, 
the  regulation  and  equalization  of  the  feedwater  becomes  an 
important  factor.  Each  boiler  has  its  own  check-valve  and 
feed  stop- valve,  and  generally  all  the  boilers  are  supplied  from 
one  pump,  which  is  running  constantly.  The  quantity  of 
water  admitted  to  each  boiler  is  regulated  by  its  feed  stop- 
valve.  When  the  water  gets  low  in  any  boiler,  the  feed  stop- 
valve  should  be  opened  wider,  while  at  the  same  time  the  feed 
stop-valves  on  one  or  more  of  the  other  boilers  in  operation 
may  be  closed  partly  and  thus  divert  the  feedwater  to  the  one 
most  requiring  it.  Some  boiler  plants  have  check-valves  with 
an  adjustable  lift;  in  that  case  the  feed  is  equalized  by  adjust- 
ing the  lifts  of  the  check- valves,  the  stop- valves  being  left 
wide  open  while  running.  It  will  be  understood  from  the 
foregoing  that  the  object  in  view  is  the  maintaining  of  an  equal 
water  level  in  all  the  boilers  through  the  manipulation  of  the 
feed  stop-valves  or  check-valves.  A  boiler  that  is  not  doing 
its  legitimate  share  in  generating  steam  may  be  known  by  the 
fact  that  the  feed  stop-valve  or  check-valve  on  that  boiler 
will  be  nearly,  if  not  entirely,  closed  most  of  the  time. 

FIRING  WITH  SOLID  FUEL 

General  Remarks. — The  safe  and  economical  operation  of 
steam  boilers  calls  for  careful  and  intelligent  management. 
The  fires  should  be  kept  in  such  condition  as  to  maintain  the 


STEAM  BOILERS  149 

desired  pressure  and  to  burn  the  fuel  with  economy.  Different 
fuels  require  different  handling  and  hence  only  general  rules 
can  be  given;  much  will  depend  on  the  skill  and  judgment  of 
the  attendant,  who  must  himself  discover  in  each  case  by 
actual  trial  the  best  method  to  pursue.  The  fires  must  be 
cleaned  at  intervals;  the  time  and  method  of  cleaning  depend 
on  conditions  such  as  the  nature  of  the  fuel,  the  rapidity  with 
which  it  is  being  consumed,  the  style  of  grate  in  use,  and  the 
construction  of  the  furnace.  Here  much  is  left  to  the  choice 
and  judgment  of  the  attendant,  who  should  readily  discover 
what  is  best  to  be  done  in  any  particular  case. 

Cleaning  of  Fires. — There  are  two  methods  employed  in 
cleaning  the  fires:  first,  that  of  cleaning  the  front  half  and  then 
the  rear  half;  second,  that  of  cleaning  one  side  of  the  fire  and 
then  the  other  side.  In  the  first  method,  previous  to  cleaning, 
green  fuel  is  thrown  on  and  allowed  to  burn  partly  until  it 
glows  over  the  entire  surface.  The  new  and  glowing  fuel  is 
then  pushed  to  the  back  of  the  furnace  with  a  hoe,  leaving 
nothing  on  the  front  half  of  the  grate  but  the  ashes  and  clinkers, 
which  are  then  pulled  out,  leaving  the  front  end  of  the  grate 
entirely  bare.  The  new  fire  which  had  been  pushed  back  is 
now  drawn  forwards  and  spread  over  the  bare  half  of  the  grate. 
The  ashes  and  clinkers  that  are  on  the  rear  half  of  the  grate 
are  then  pulled  over  the  top  of  the  front  half  of  the  fire 
and  out  through  the  furnace  door;  this  leaves  the  rear  half 
of  the  grate  bare,  which  must  be  covered  by  pushing  back 
some  of  the  new  front  fire.  The  clean  fire  having  been 
spread  evenly,  some  new  fuel  must  be  spread  over  the  entire 
surface. 

The  second  method  referred  to  is  substantially  the  same  in 
principle  as  that  just  described,  with  the  difference  that  the 
fire  is  pushed  to  one  side  instead  of  to  one  end  of  the  furnace, 
as  in  the  first  method  described.  The  condition  of  the  fires 
themselves  and  the  nature  of  the  service  of  the  plant  will 
determine  just  how  often  and  at  what  time  the  cleaning  of 
fires  should  take  place.  In  general,  the  fires  in  stationary 
boilers  require  cleaning  at  intervals  of  from  8  to  12  hr.  Fires 
require  cleaning  more  often  when  fqrced  draft  is  used  than  when 
working  with  natural  draft. 


150  STEAM  BOILERS 

Rapidity  in  Cleaning  Fires. — Rapidity  in  cleaning  fires  is  of 
great  importance,  as  during  the  operation  a  large  volume  of 
cold  air  enters  the  furnace  and  chills  the  metallic  surfaces  with 
which  it  comes  in  contact;  consequently,  the  boiler  is  damaged, 
however  slightly.  It  is  the  greatest  advantage  of  shaking 
grates  that  they  allow  the  fire  to  be  cleaned  without  opening 
the  furnace  door;  the  inrush  of  cold  air  and  consequent  chilling 
of  the  plates,  etc.  is  thus  avoided. 

Before  starting  to  clean  fires,  the  steam  pressure  and  the 
water  level  should  be  run  up  as  high  as  is  safe  and  the  feed 
should  be  shut  off  in  order  to  reduce  the  loss  in  pressure  v/hile 
cleaning.  The  condition  of  the  fire  during  cleaning  and  the 
opening  of  the  furnace  doors  cause  the  pressure  to  drop  quite 
rapidly,  but  the  rapidity  and  the  amount  of  drop  will  be  reduced 
by  taking  the  precautions  mentioned  and  cleaning  quickly. 

Drop  of  Pressure  During  Cleaning. — The  amount  of  drop 
in  pressure  while  cleaning  fires  depends  on  several  conditions. 
For  example,  with  a  boiler  that  has  a  small  steam  space  and, 
in  addition,  is  too  small  for  the  work  required  of  it  without 
forcing,  it  is  to  be  expected  that  the  drop  in  pressure  will  be 
much  more  than  if  the  reverse  conditions  exist.  Furthermore, 
it  may  be  necessary  to  clean  fires  while  steam  is  being  drawn 
from  the  boiler,  instead  of  being  able  to  clean  at  a  time  when 
the  engine  is  stopped.  In  that  case  a  greater  drop  must  be 
expected  than  when  cleaning  while  no  steam  is  being  drawn 
from  the  boiler.  It  is  advisable  when  possible  to  do  the  clean- 
ing at  a  time  when  no  steam  is  being  drawn  from  the  boiler  or 
when  the  demand  for  steam  is  light. 

FIRING  WITH  LIQUID  FUEL 

Number  of  Oil  Burners  Required. — The  number  of  oil 
burners  to  be  installed  in  a  given  boiler  depends  on  the  type  of 
burner  to  be  used  and  .the  width  of  the  furnace.  The  object 
to  be  attained  is  a  uniform  distribution  of  heat  throughout  the 
furnace.  A  straight-shot  burner  will  produce  a  long,  compact 
flame,  whereas  a  fan-tailed  burner  will  produce  a  wide,  short 
flame;  hence,  one  burner  of  the  latter  class  may  be  sufficient  for 
a  furnace  that  would  require  two  burners  of  the  former  class. 
One  fan-tailed  burner  will  ordinarily  be  sufficient  for  a  furnace 


STEAM  BOILERS  151 

6  ft.  or  less  in  width;  two  such  burners  may  be  used  in  furnaces 
from  6  to  14  ft.  wide;  and  for  furnaces  over  14  ft.  in  width 
three  burners  should  be  installed.  If  narrow-flame  burners 
are  used,  their  number  will  have  to  be  greater. 

Location  of  Burners. — The  burners  may  be  installed  in  the 
centers  of  the  fire-doors,  if  desired,  and  this  practice  is  fre- 
quently followed.  In  case  only  one  burner  is  employed,  it 
may  be  placed  in  a  suitable  opening  in  the  boiler  front,  between 
the  fire-doors.  Another  method  that  has  been  used  is  to  insert 
the  burners  below  the  fire-doors.  So  far  as  combustion  is 
concerned,  the  location  of  the  burner  is  of  little  importance, 
provided  there  is  a  sufficient  air  supply  admitted  under  proper 
conditions;  but  the  heat  developed  may  be  utilized  to  better 
advantage  by  exercising  care  in  placing  the  burners.  The 
flames  should  not  be  directed  against  the  side  walls,  but  should 
be  approximately  parallel  thereto,  with  the  tip  of  the  burner 
about  6  or  8  in.  above  the  brick  covering  of  the  grate.  It  is 
the  usual  practice  to  direct  the  flame  from  the  front  to  the 
back  of  the  furnace;  but  in  some  installations  of  water-tube 
boilers  of  the  Stirling  and  Babcock  &  Wilcox  types,  the  burners 
have  been  placed  at  the  rear  of  the  furnace,  so  as  to  direct  the 
flames  toward  the  front.  This  was  found  to  be  advantageous, 
as  the  combustion  was  completed  in  the  portion  of  the  furnace 
having  the  greatest  cross -section,  where  the  rapid  expansion 
of  the  gases  due  to  the  heat  generated  could  be  accommodated 
most  readily. 

Necessity  for  Straining  of  Oil  Fuel. — The  crude  oils  used  for 
fuel  come  from  wells  drilled  in  the  earth,  and  as  a  result  they 
contain  varying  proportions  of  sand  and  dirt.  The  denser 
and  more  viscous  the  oil,  the  greater  is  the  tendency  for  it  to 
retain  impurities  in  suspension.  If  the  oil  is  stored  for  some 
time  in  tanks,  and  is  left  undisturbed,  some  of  the  heavier 
dirt  will  settle  to  the  bottom  and  thus  be  separated  from  the 
oil;  but  if  the  oil  is  taken  direct  from  the  wells  to  market, 
little  or  none  of  the  dirt  will  be  removed.  Even  fuel  oil, 
which  undergoes  a  preliminary  heat  treatment  to  separate 
the  more  volatile  hydrocarbons  from  it,  may  not  be  free  from 
foreign  matter.  It  may  be  assumed,  therefore,  that  all  oil 
fuel  contains  dirt  and  sand,  and  as  a  consequence  there  arises 


152  STEAM  BOILERS 

the  necessity  of  straining  the  oil  before  admitting  it  to  the 
oil-burning  system.  The  presence  of  sand  and  grit  in  the  oil 
supply  vri.ll  cause  wear  of  the  pump  and  erosion  of'the  burner 
nozzles  and  orifices,  and  may  result  in  the  clogging  of  small 
orifices. 

Oil  Pressure. — One  of  the  requirements  for  the  efficient 
operation  of  an  oil-burning  plant  is  uniformity  of  the  oil  sup- 
ply; for,  if  the  oil  supply  is  intermittent  or  varies  in  amount, 
the  combustion  will  be  irregular  and  incomplete.  To  obtain 
a  uniform  rate  of  feed  it  is  customary  to  supply  the  oil  at  a 
constant  pressure  by  means  of  an  ordinary  duplex  feed-pump. 
The  pressure  at  which  the  oil  is  delivered  to  the  burners  varies 
in  different  plants  and  under  different  conditions.  It  may 
range  from  1  or  2  Ib.  to  150  Ib.  per  sq.  in.,  although  the  pressure 
is  usually  between  10  and  40  Ib.  per  sq.  in.  The  type  of 
burner  employed  will  have  some  influence  on  the  pressure 
required;  also,  forcing  of  the  boiler  above  its  normal  rating  will 
necessitate  an  increase  in  the  oil  pressure,  to  produce  an 
increased  flow  of  oil. 

Objection  to  Gravity  Feeding  of  Oil. — When  a  standpipe  is 
used  as  a  pressure  regulator,  the  oil  flows  to  the  burners  by 
gravity.  Some  insurance  companies  refuse  to  insure  plants 
in  which  gravity  feeding  is  practiced,  on  the  ground  that,  if 
a  valve  is  left  open,  the  boiler  room  may  be  flooded  with  oil, 
thus  greatly  increasing  the  danger  from  fire.  To  overcome 
the  objection  to  having  a  considerable  amount  of  oil  held  in 
reserve  above  the  level  of  the  burners,  a  new  form  of  apparatus 
has  been  produced.  This  consists  of  a  pump  having  a  relief 
valve  between  the  suction  and  delivery  sides.  The  relief 
valve  is  set  at  the  desired  oil  pressure,  so  that,  if  that  pressure 
is  exceeded,  the  valve  will  lift  and  the  excess  of  oil  will  be 
returned  to  the  suction  side  of  the  pump.  When  a  standpipe 
is  used,  it  should  be  fitted  with  an  automatic  drain  valve  that 
will  open  and  drain  out  all  the  oil  when  the  steam  pressure  falls 
below  the  lowest  pressure  at  which  the  oil  can  be  atomized. 
The  flooding  of  the  burners,  with  the  attendant  danger  of 
explosion,  will  thus  be  averted. 

Heating  of  Oil  Fuel. — The  viscosity  of  certain  crude  oils 
at  ordinary  atmospheric  temperatures  is  very  great,  and  it 


STEAM  BOILERS  153 

increases  as  the  temperature  becomes  lower.  Below  40°  F.  the 
oil  is  so  sluggish  that  it  can  scarcely  be  forced  to  the  burners 
by  the  oil  pump.  Consequently,  in  all  localities  where  low 
temperatures  are  likely  to  occcur,  provision  must  be  made  for 
heating  oil  fuel,  so  that  it  may  flow  readily  through  the  pump 
and  the  pipes.  The  flow  of  oil  from  the  storage  tank  to  the 
pump  may  be  facilitated  by  surrounding  the  end  of  the  suc- 
tion pipe  with  a  coil  through  which  steam  is  led.  The  oil  in 
the  vicinity  of  the  pipe  is  thus  heated  and  made  more  fluid. 
Oftentimes,  the  oil  is  heated  after  leaving  the  pump,  to  aid  in 
obtaining  better  operation  of  the  burners.  In  any  case,  how- 
ever, the  heating  must  not  be  carried  to  a  temperature  suffi- 
cient to  cause  decomposition.  The  temperature  at  which  the 
decomposition  begins  depends  on  the  nature  and  source  of 
the  oil.  Ordinarily  the  oil  is  not  heated  beyond  a  tempera- 
ture of  about  140°  F. 

Construction  of  Oil  Tanks. — The  size  of  the  boiler  plant 
will  determine  the  character  of  the  oil-storage  tanks.  For 
plants  of  small  or  medium  size,  the  tanks  used  are  generally 
cylindrical  in  shape,  built  of  steel  plates,  and  coated  with  a 
protective  covering  of  tar.  For  large  plants,  rectangular  tanks 
made  of  reinforced  concrete  are  frequently  used.  The  penetra- 
tive properties  of  petroleum  necessitate  tight  joints,  and  conse- 
quently it  is  advisable  to  entrust  the  construction  of  a  steel 
tank  to  a  boilermaker.  The  rivet  holes  should  be  drilled  rather 
than  punched,  so  that  the  rivets  will  properly  fill  them,  and  the 
seams  should  be  calked.  There  should  be  no  openings  in  the 
bottom,  ends,  or  sides  of  the  tank;  all  inlets  and  outlets  should 
be  in  the  top.  The  manhole  opening  should  be  of  such  size 
as  to  permit  ready  entrance  to  the  tank  when  required,  and 
reinforcing  flanges  of  steel  or  wrought  iron  should  be  riveted 
to  the  tank  at  the  various  openings.  Concrete  tanks  are 
usually  made  with  partitions,  so  that  deposits  of  sediment  or 
of  viscous  matter  may  be  removed  at  intervals  without  inter- 
fering with  the  continuity  of  the  fuel  supply. 

Fittings  for  Oil  Tank. — Even  at  ordinary  temperatures,  oil 
undergoes  a  slow  process  of  evaporation,  during  which  gases 
are  evolved;  consequently,  every  oil-storage  tank  should  be 
fitted  with  a  ventilating  pipe  to  permit  the  escape  of  the  gases 


154  STEAM  BOILERS 

thus  set  free.  This  pipe  will  also  serve  to  lead  off  the  air  in 
the  upper  part  of  the  tank  during  the  operation  of  filling,  and 
will  thus  prevent  undue  pressure  from  accumulating.  The 
cross-sectional  area  of  the  ventilating  pipe  should  be  equal  to 
that  of  the  rilling  pipe.  Care  should  be  taken  in  locating  the 
ventilating  pipe  to  see  that  no  naked  light  can  approach  its 
upper  end;  moreover,  the  openings  in  this  end  should  be  pro- 
tected by  a  return  elbow  having  wire  gauze  firmly  fastened 
over  it.  The  gases  rising  from  the  oil,  when  mixed  with  air  in  the 
correct  ratio,  form  an  explosive  mixture,  and  could  be  ignited 
by  a  naked  flame.  This  flame,  however,  would  not  pass 
through  the  fine  meshes  of  the  gauze,  and  the  latter  therefore 
forms  a  safety  device;  also,  the  downward  curving  of  the  elbow 
prevents  any  sparks  from  dropping  into  the  opening.  In  addi- 
tion to  the  ventilating  pipe  there  should  be  a  telltale,  which  is 
a  device  for  indicating  the  amount  of  oil  in  the  tank  at  any 
specified  time. 

Installation  of  Oil  Tanks. — To  conform  with  the  require- 
ments of  underwriters  and  city  ordinances,  any  oil-storage 
tank  located  above  the  surface  of  the  ground  should  be  at  least 
200  ft.  from  inflammable  property.  Moreover,  the  top  of  the 
tank  should  be  at  a  lower  level  than  the  lowest  pipe  in  the  oil- 
burning  system,  so  that,  in  case  a  valve  is  inadvertently  left 
open,  the  plant  will  not  be  flooded  with  oil.  If  the  tank  is 
placed  underground,  as  is  usually  the  case,  its  top  should  be 
at  least  2  ft.  below  the  surface  of  the  ground,  and  it  should  be 
30  ft.  distant  from  the  nearest  building;  also,  the  top  of  the 
tank  should  not  be  at  a  higher  level  than  the  lowest  pipe  in  the 
oil  system.  These,  precautions  in  locating  the  tank  or  tanks 
are  necessary  because  of  the  highly  inflammable  nature  of  crude 
oil  and  fuel  oil. 

Separation  of  Water  From  Oil. — The  crude  oils  invariably 
contain  water  in  greater  or  less  proportions.  When  the  oil  is 
run  into  the  storage  tank,  the  water,  being  heavier,  sinks  to 
the  bottom  of  the  tank  and  gradually  accumulates.  If  the 
suction  pipe  extends  to  the  bottom  of  the  tank,  some  of  this 
water  will  be  drawn  to  the  pump  and  forced  to  the  burners, 
extinguishing  the  fires.  To  prevent  this  trouble,  provision 
should  be  made  for  the  removal  of  water  from  the  oil  tanks. 


STEAM  BOILERS  155 

There  is  no  practicable  device  that  can  be  used  to  separate  the 
water  from  the  oil.  The  best  thing  to  do  is  to  let  the  water 
settle  by  gravity  to  the  bottom  of  the  tank- and  then  to  pump 
it  out  at  intervals,  as  required.  The  oil  being  somewhat  lighter 
than  water,  will  float  on  top  of  the  latter,  and  by  watching  the 
discharge  of  the  pump  it  will  be  easy  to  discontinue  the  pump- 
ing as  soon  as  the  flow  of  water  ceases  and  oil  appears. 

Starting  an  Oil  Fire. — Assuming  that  the  oil  pump  has  been 
put  in  operation  and  that  the  desired  oil  pressure  has  been 
obtained,  the  first  step  in  starting  an  oil  fire  in  a  cold  boiler  is 
to  open  the  damper.  The  valve  in  the  oil  supply  pipe  leading 
to  the  burner  should  be  closed  tightly.  The  needle  valve,  or 
oil-regulating  valve,  on  the  burner  should  be  opened  one  turn, 
and  the  by-pass  valve  should  be  fully  open.  The  steam  valve 
is  now  opened,  admitting  steam  to  the  burner,  and  the  valve 
is  left  open  until  the  steam  blowing  through  appears  dry.  This 
operation  heats  up  the  burner,  cleans  the  oil  passages,  and 
removes  all  water  from  the  steam  passages  and  pipes.  The 
by-pass  valve  is  now'  closed  and  the  steam  is  almost,  but  not 
wholly,  shut  off.  A  bunch  of  oily  waste  is  next  lighted  and 
thrown  into  the  furnace,  and  the  fire-door  is  closed.  The  oil- 
regulating  valve  is  closed  slightly,  and  the  valve  in  the  oil- 
supply  pipe  is  opened  fully.  Steam  and  oil  then  pass  through 
the  burner  and  the  spray  is  ignited  by  the  burning  waste.  The 
condition  of  the  fire  is  regulated  by  adjusting  the  steam  valve 
and  the  oil-regulating  valve,  in  conjunction  with  the  ash-pit 
doors  and  the  damper.  The  fire  should  not  be  forced,  but 
should  be  increased  slowly,  so  as  to  permit  the  boiler  to  accom- 
modate itself  to  the  increasing  temperature. 

The  procedure  just  outlined  is  based  on  the  assumption  that 
a  supply  of  steam  for  atomizing  is  available  from  an  active 
boiler  in  the  battery,  or  else  from  a  small  auxiliary  boiler 
intended  solely  for  the  purpose.  In  case  there  is  but  a  single 
boiler  in  the  plant,  the  method  of  starting  a  fire  will  be  some- 
what different  from  that  just  described.  The  ash-pit  doors 
and  the  fire-doors  should  first  be  opened,  and  a  wood  fire  should 
be  built  in  the  furnace.  This  fire  should  be  kept  going  until 
the  gauge  on  the  boiler  shows  a  pressure  of  about  20  Ib.  Then 
the  steam  may  be  admitted  to  the  burner  and  the  latter  may 


156  STEAM  BOILERS 

be  started  in  the  manner  already  described,  using  the  wood  fire 
to  light  the  oil  spray.  The  wood  fire  should  be  built  on  the 
bottom  of  the  furnace;  or,  in  case  it  is  a  coal-burning  furnace 
converted  for  oil  burning,  the  fire  should  be  built  on  the  brick 
paving  covering  the  grates.  It  is  not  necessary  to  remove  the 
bricks,  nor  must  the  burner  be  taken  out  while  the  wood  fire 
is  burning,  Care  should  be  taken,  however,  to  keep  the  fire 
about  a  foot  from  the  burner,  to  prevent  overheating  of  the 
latter.  After  the  oil  burner  has  become  well  started,  the  wood 
fire  may  be  raked  out. 

Furnace  Conditions  With  Oil  Burning. — When  the  brick- 
work of  the  furnace  has  become  heated  and  the  burner  is  work- 
ing normally,  the  furnace  space  should  appear  to  be  filled  with 
flame.  In  every  properly  arranged  oil-burning  boiler  there 
should  be  peep-holes  at  different  points,  to  enable  the  fireman 
to  determine  the  conditions  of  combustion  in  the  furnace.  It 
is  also  advantageous  to  have  the  top  of  the  chimney  visible  to 
the  fireman,  as  the  conditions  at  that  point  serve  as  a  guide  in 
the  regulation  of  the  fire.  The  flame  in  the  furnace  should  be 
white  or  golden  white  in  color,  and  should  be  steady.  A  prop- 
erly adjusted  steam  burner  will  give  a  dazzling  flame,  whereas 
an  air  burner  will  produce  a  duller,  yellower  flame.  If  the 
burner  passages  are  not  kept  clean,  or  if  the  burner  is  improp- 
erly adjusted,  the  flame  will  become  irregular  and  smoke  will 
be  produced.  No  smoke  should  appear  at  the  top  of  the  chim- 
ney; instead,  there  should  be  a  light,  grayish  haze  when  the 
burner  is  properly  adjusted. 

Smoke  will  be  produced  if  there  is  too  great  a  supply  of  oil, 
or  too  little  air,  or  insufficient  steam  for  atomization.  The 
remedies  to  be  applied  to  rectify  these  faults  of  operation  are 
obvious.  If  the  burner  hisses  or  spits,  it  is  probable  that  the 
steam  used  for  atomizing  contains  moisture,  or  that  there  is 
water  in  the  oil  supplied  to  the  burner,  or  that  a  leak  has  devel- 
oped in  the  suction  pipe,  so  that  air  is  being  forced  into  the 
burner  with  the  oil.  As  a  rule,  oil  burning  in  steam-boiler 
furnaces  is  accompanied  by  a  roaring  noise  of  greater  or  less 
intensity,  and  firemen  experienced  in  the  burning  of  oil  fuel 
are  able  to  detect  changes  in  the  furnace  conditions  merely  by 
the  altered  roaring  of  the  burners.  An  excessive  supply  of 


STEAM  BOILERS  157 

cold  air  will  increase  the  noise  greatly  and  at  the  same  time 
will  cause  loss  of  heat;  hence,  as  a  general  rule,  it  is  safe  to 
assume  that,  the  quieter  the  fire,  the  more  nearly  perfect  is  the 
combustion.  This  is  further  corroborated  by  the  fact  that 
preheating  of  the  air,  which  is  conducive  to  better  combustion, 
reduces  the  roaring.  Sputtering  of  the  flame  from  the  burner 
may  be  due  to  the  heating  of  oil  to  such  a  point  as  to  cause  it 
to  be  vaporized. 

Draft  Required  for  Oil  Burning. — The  draft  of  the  chimney 
performs  the  function  of  drawing  air  into  the  furnace  and  of 
pushing  the  gaseous  products  of  combustion  through  the  boiler 
and  out  into  the  air.  When  solid  fuel  is  used,  a  large  part  of 
the  draft  pressure  is  required  to  force  the  air  through  the  layer 
of  fuel  on  the  grates,  the  remainder  serving  to  overcome  the 
resistance  to  the  flow  of  the  hot  gases  through  the  furnace, 
tubes,  flues,  and  chimney.  When  oil  is  used,  there  is  no  resist- 
ance due  to  a  fuel  bed  on  a  grate,  and  the  draft  pressure  sim- 
ply overcomes  the  resistance  due  to  the  flow  of  the  air  and  hot 
gases;  consequently,  the  draft  pressure  required  is  much  less 
than  for  solid  fuel.  It  follows,  then,  that  when  a  boiler  is 
changed  to  use  liquid  fuel  instead  of  solid  fuel,  the  chimney 
"that  was  satisfactory  for  the  latter  gives  too  strong  a  draft  for 
the  former,  and  care  must  be  exercised  to  prevent  the  admis- 
sion of  an  excess  of  air.  The  draft  pressure  necessary  for  the 
burning  of  oil  fuel  ranges  from  .1  to  .5  in.  of  water,  the  former 
corresponding  to  economical  firing  and  the  latter  to  firing  with 
a  large  excess  of  air.  If  the  boiler  is  overloaded,  the  draft 
must  be  increased  above  that  required  for  normal  working. 

Formation  of  Soot. — An  insufficient  supply  of  air  or  an  exces- 
sive feeding  of  oil  will  result  in  the  formation  of  soot,  which  will 
by  deposited  on  the  heating  surfaces  and  will  reduce  the  effi- 
ciency of  heat  transmission  from  the  hot  gases  to  the  water  in 
the  boiler,  and  may  result  in  the  overheating  of  some  parts. 
If  such  accumulations  occur,  they  must  be  cleaned  away,  to 
maintain  the  evaporative  efficiency  of  the  boiler.  With  care- 
ful management  of  fires,  boilers  burning  oil  have  been  run  at 
full  capacity  for  weeks  without  the  formation  of  a  troublesome 
amount  of  soot.  On  the  other  hand,  with  coal  as  a  fuel,  it 
would  have  been  necessary  to  clean  the  tubes  daily. 
12 


158  STEAM  BOILERS 

Shutting  Down  an  Oil  Burner. — To  shut  down  an  oil-burner 
that  is  in  active  operation  in  a  furnace,  the  oil  valve  in  the  sup- 
ply pipe  should  be  closed.  The  steam  valve  should  next  be 
nearly  closed,  so  that  only  a  small  amount  of  steam  passes. 
The  oil-regulating  valve  should  then  be  opened  a  full  turn,  and 
the  by-pass  valve  should  be  fully  opened,  after  which  steam 
should  be  turned  on  again  by  manipulating  the  steam  valve. 
Steam  will  thus  be  discharged  through  the  oil  passages  of  the 
burner,  and  all  oil  in  them  will  be  blown  out,  thus  preventing 
baking  or  carbonizing  of  the  oil  and  the  clogging  that  would 
otherwise  result.  When  the  burner  has  been  blown  out,  the 
by-pass  valve  should  be  closed,  and  finally  the  steam  should 
be  shut  off  completely.  The  burner  will  then  be  put  out  of 
action,  but  will  be  in  condition  to  be  started  again  at  short 
notice. 

Precautions  in  Relighting  Fires. — If  the  fire  should  go  out 
completely,  the  fireman  should  not  open  the  fire-door  to  look 
for  the  cause  of  the  trouble.  His  first  act  should  be  to  shut  off 
the  oil,  and  this  should  be  followed  by  shutting  off  of  the  steam. 
Then  the  furnace  door  may  be  opened,  a  piece  of  waste  may  be 
set  on  fire  and  thrown  in,  and  the  fire  may  be  restarted  in  the 
usual  way.  The  damper  should  be  wide  open  when  this  is 
being  done.  When  the  fire  goes  out  for  only  a  moment,  as  may 
happen  if  a  slug  of  water  comes  through  the  burner,  it  will 
generally  be  reignited  by  the  heat  of  the  incandescent  walls. 
It  is  dangerous  to  leave  the  steam  turned  on  and  to  increase 
the  amount  of  oil  fed,  in  order  to  restart  the  fire  in  an  incan- 
descent furnace;  for  the  explosion  at  the  instant  of  reignition 
may  blow  open  the  doors  of  the  furnace,  knock  down  the  brick- 
work, or  cause  other  damage.  The  safest  methed  is  to  relight 
the  fire  with  burning  waste. 

Accidental  Oil  Fires. — If  oil  should  escape  in  quantities 
from  the  system  and  should  become  ignited,  no  attempt  should 
be  made  to  put  out  the  fire  by  spraying  it  with  water,  as  this 
will  serve  merely  to  spread  the  blazing  oil  and  will  make  mat- 
ters worse.  Instead,  sand  or  loose  earth  should  be  thrown  on 
the  burning  oil,  to  smother  the  flames.  In  some  plants,  boxes 
of  sand  are  kept  at  convenient  points,  in  readiness  for  emergen- 
cies of  this  nature.  Also,  in  some  cases,  steam  pipes  are  run 


STEAM  BOILERS  159 

to  the  oil-storage  tanks,  so  that,. if  the  oil  in  the  tanks  should 
take  fire,  steam  could  quickly  be  run  in  to  smother  the  blaze. 

Thermal  Advantages  of  Oil. — The  calorific  value  of  a  pound 
of  oil  fuel  is  about  30%  higher  than  that  of  a  high-class  coal, 
so  that,  by  using  oil  instead  of  coal,  the  same  amount  of  heat 
may  be  obtained  with  a  smaller  weight  of  fuel.  As  has  already 
been  shown,  it  is  possible  to  obtain  more  nearly  perfect  com- 
bustion, using  less  excess  of  air,  with  oil  than  with  coal,  which 
increases  the  efficiency,  Again,  there  is  no  repeated  opening 
and  closing  of  the  fire  doors  when  oil  is  used,  and  this  prevents 
loss  of  heat  and  at  the  same  time  gives  a  better  distribution 
of  heat  in  the  combustion  chamber.  Also,  there  is  less  soot 
deposited  on  the  heating  surfaces,  in  consequence  of  which  the 
transfer  of  heat  is  rapid  and  there  is  less  heat  lost  up  the  chim- 
ney. The  capacity  of  the  boiler  may  therefore  be  increased 
from  one-third  to  one-half  by  changing  from  coal  to  oil,  while 
for  short  periods  the  capacity  may  be  doubled.  Owing  to  the 
uniformity  of  combustion  of  oil,  the  metal  of  the  boiler  is  not 
subjected  to  such  severe  conditions  as  when  solid  fuel  is  used. 

Rapidity  of  Regulation. — Another  great  advantage  of  oil 
fuel  is  the  quickness  and  ease  with  which  the  intensity  of  com- 
bustion may  be  altered.  This  is  of  particular  importance  in  a 
plant  that  may  be  subjected  to  quick  increases  in  the  load. 
The  fire  in  the  furnace  of  an  oil-burning  boiler  may  be  brought 
very  quickly  from  a  moderate  heat  to  a  most  intense  heat,  to 
meet  a  sudden  demand  for  more  steam.  Also,  in  case  the  load 
falls  off  very  suddenly,  the  burners  may  be  adjusted  rapidly  to- 
produce  a  correspondingly  smaller  quantity  of  heat.  In  emer- 
gencies, the  fires  may  be  put  out  instantly,  and  may  be  almost 
as  quickly  relighted  when  the  danger  is  past.  The  closeness 
with  which  the  combustion  may  be  made  to  follow  the  demand 
for  steam  enables  an  almost  uniform  steam  pressure  to  be 
maintained  by  the  use  of  automatic  regulators  for  the  oil  pres- 
sure and  air  supply. 

Economy  of  Storage  and  Handling. — Oil  fuel  may  be  stored 
and  handled  with  less  labor  and  at  less  cost  than  is  possible 
with  coal.  The  volume  occupied  by  a  given  weight  of  oil  is 
less  than  the  volume  of  an  equal  weight  of  coal;  also,  because 
of  the  greater  calorific  value  of  oil,  it  is  possible  to  store  50% 


160  STEAM  BOILERS 

more  heating  value,  in  the  form  of  oil  fuel,  in  a  given  space, 
than  can  be  done  if  coal  is  the  fuel.  Oil  possesses  the  addi- 
tional advantage  that  it  does  not  deteriorate  or  lose  its  heating 
value  when  stored  for  some  time.  Coal,  on  the  other  hand, 
not  only  deteriorates  but  is  liable  to  spontaneous  combustion. 
The  cost  of  handling  oil  is  less  than  that  of  handling  coal,  for 
the  reason  that  oil  is  run  into  the  storage  tanks  by  gravity,  or 
else  is  pumped  into  and  out  of  storage. 

Saving  of  Labor  and  Equipment. — When  oil  is  employed  for 
fuel,  instead  of  coal,  there  is  no  necessity  for  cleaning  fires,  and 
consequently  the  boiler  can  be  operated  continuously  at  maxi- 
mum capacity.  There  is  a  lower  temperature  in  the  boiler  room, 
because  the  fire-doors  are  kept  shut.  There  is  less  wear  and 
tear  on  the  pumps  and  other  machinery  that  may  be  installed 
in  the  boiler  room,  inasmuch  as  the  absence  of  coal  dust  and 
ashes  enables  the  boiler  room  to  be  kept  clean.  The  expense 
of  removing  ashes  is  avoided,  and  there  is  a  great  saving  in 
labor,  as  fewer  firemen  and  attendants  are  necessary.  There 
is  no  formation  of  clinker  on  the  grates  or  side  walls,  and  no 
firing  tools  are  used,  so  that  the  damage  to  furnace  linings  by 
careless  handling  of  tools  is  obviated. 

Disadvantages  of  Oil  Fuel. — One  of  the  disadvantages  of 
oil  as  a  boiler  fuel  is  its  low  flash  point;  however,  if  oil  having  a 
flash  point  of  not  less  than  140°  F.  is  used  with  care  and  judg- 
ment by  firemen  of  ordinary  intelligence,  there  should  be  no 
serious  danger.  The  regulations  as  to  the  location  of  storage 
tanks  for  oil  fuel  may  be  found  irksome;  for,  in  the  case  of  a 
plant  situated  in  a  thickly  populated  district  in  a  city,  it  may 
be  wholly  impossible  to  place  the  storage  tanks  at  least  30  ft. 
from  the  nearest  building,  and  also  underground.  The  tem- 
perature of  the  fire  obtained  from  oil  fuel  is  greater  than  that 
of  a  coal  fire,  and  if  the  feedwater  used  contains  much  scale- 
forming  matter,  the  intense  heat  may  cause  more  rapid  deposit 
of  scale,  and  thus  increase  the  cost  of  tube  cleaning  and  repairs. 

UNIFORM   STEAM  PRESSURE 

Desirability  of  Uniform  Pressure. — The  attendant  should 
-aim  to  carry  the  pressure  in  the  boiler  as  uniform  as  possible. 
The  reason  why  a  steady  steam  pressure  and  a  steady  water 


STEAM  BOILERS  161 

level  are  conducive  to  economy  in  the  use  of  a  fuel  is  to  be  found 
in  the  fact  that  with  these  conditions  in  a  properly  designed 
plant  there  will  be  a  fairly  steady  temperature  in  the  furnace, 
which,  under  normal  conditions,  is  sufficiently  high  to  insure 
a  thorough  ignition  of  the  volatile  matter  in  the  coal.  Now, 
with  a  constant  demand  for  steam,  a  fluctuation  in  the  steam 
pressure  is  caused  by  a  change  in  the  furnace  temperature, 
assuming  the  feedwater  supply  to  be  constant,  and  whenever 
the  steam  pressure  is  down,  the  furnace  temperature  is  low  at 
the  same  time.  In  consequence  of  this,  large  quantities  of  the 
volatile  matter  in  the  coal  often  escape  unconsumed  and  cause 
a  serious  loss  of  heat.  Furthermore,  with  a  steady  steam  pres- 
sure the  stresses  on  the  boiler  are  constant,  and  herlce  the  life 
of  the  boiler  will  be  increased  and  repair  bills  will  be  smaller 
than  otherwise. 

Maintenance  of  Uniform  Pressure. — During  the  period  of 
time  between  the  cleaning  of  the  fires,  the  pressure  may  be  car- 
ried nearly  uniform  by  observing  the  following  instructions: 
Manipulate  the  feed  apparatus  so  that  just  the  necessary 
amount  of  water  constantly  enters  the  boiler  and  thus  main- 
tains a  constant  level.  Intermittent  feeding  is  practiced  under 
certain  local  conditions,  as,  for  example,  where  there  is  an  injec- 
tor or  a  pump  that  is  so  large  that  it  would  be  impossible  to  run 
it  continuously  without  increasing  the  height  of  the  water  level. 
In  such  a  case,  stop  feeding  just  before  firing;  that  is,  do  not 
feed  while  firing  nor  resume  feeding  until  the  new  fire  begins  to 
make  steam,  as  indicated  by  the  rise  of  pressure  on  the  gauge. 
If  the  pressure  tends  to  rise  above  the  standard  or  normal 
pressure,  partly  close  the  dampers  and  increase  the  quantity 
of  feed,  assuming  in  this  case  that  no  damper  regulator  is  fitted 
and  that  hence  the  damper  is  regulated  by  hand.  A  damper 
regulator,  systematic  firing,  and  proper  feeding  are  essential 
for  carrying  a  practically  uniform  pressure.  Should  the  pres- 
sure continue  to  rise,  throw  on  more  green  fuel,  close  the 
damper,  increase  the  feed,  and  only  as  a  last  resort  open 
the  furnace  door. 

A  uniform  steam  pressure  cannot  be  kept  without  proper 
firing.  To  maintain  such  a  pressure  the  following  directions 
should  be  observed:  Keep  the  fire  uniformly  thick;  allow  no 


162  STEAM  BOILERS 

air  holes  in  the  bed  of  fuel.  Fire  evenly  and  regularly;  be  care- 
ful not  to  fire  too  much  at  a  time.  Keep  the  fire  free 
from  ashes  and  clinkers,  and  do  not  neglect  the  sides  and  cor- 
ners while  keeping  the  center  clean.  Do  not,  however,  clean 
the  fires  oftener  than  is  necessary.  Keep  the  ash-pit  clear. 

Keeping  Water  Level  Constant. — In  connection  with  the 
maintenance  of  a  constant  water  level,  the  following  instruc- 
tions should  be  followed :  On  starting  to  work,  remember  that 
the  first  duty  of  the  fireman  is  to  examine  the  water  level.  Try 
the  gauge-cocks,  as  the  gauge  glass  is  not  always  reliable. 
If  there  is  a  battery  of  boilers,  try  the  gauge-cocks  on  each 
boiler. 

PRIMING  AND  FOAMING 

Priming. — The  phenomenon  called  priming  is  analogous  to 
boiling  over;  the  water  is  carried  into  the  steam  pipes  and 
thence  to  the  engine,  where  considerable  damage  is  liable  to 
take  place  if  the  priming  is  not  checked  in  time.  There  are 
several  causes  for  priming,  of  which  the  most  common  ones  are 
the  following:  Insufficient  boiler  power;  defective  design  of 
boiler;  water  level  carried  too  high;  irregular  firing;  and  sudden 
opening  of  stop-valves. 

When  the  boiler  power  is  insufficient,  the  best  remedy  is  to 
increase  the  boiler  plant;  the  next  best  thing  to  do  is  to  put  in 
a  separator,  which,  obviously,  will  only  prevent  the  entrained 
water  from  reaching  the  engine,  and  will  not  stop  the  priming. 

Defective  design  of  a  boiler  generally  consists  of  a  steam 
space  that  is  too  small  or  a  bad  arrangement  of  the  tubes, 
which  may  be  spaced  so  close  in  an  effort  to  obtain  a  large 
heating  surface  as  to  interfere  seriously  with  the  circulation. 
In  horizontal  return -tubular  boilers,  a  sufficiently  large  steam 
space  can  be  obtained  by  the  addition  of  a  steam  drum;  some- 
times the  top  row  of  tubes  can  be  taken  out  to  advantage, 
which  permits  a  lower  water  level.  Defective  circulation  in 
horizontal  fire-tube  boilers  is  difficult  to  detect  and  to  remedy; 
if  it  is  due  to  a  too  close  spacing  of  the  tubes,  a  marked  better- 
ment may  be  effected  by  the  removal  of  one  or  two  vertical 
rows  of  tubes.  The  remedy  for  a  water  level  that  is  too  high 
is  to  carry  the  water  at  a  lower  level. 


STEAM  BOILERS  163 

Evidences  of  Priming. — Priming  manifests  itself  first  by  a 
peculiar  clicking  sound  in  the  cylinder  of  the  engine,  due 
to  water  thrown  against  the  heads.  In  cases  of  very  violent 
priming,  the  water  will  suddenly  rise  several  inches  in  the  gauge 
glass,  thus  showing  more  water  in  the  boiler  than  there  really 
is.  When  priming  takes  place,  it  can  be  checked  temporarily 
as  follows:  Close  the  damper,  and  thereby  check  the  fires  until 
the  water  is  quiet ;  the  engine  stop-valve  should  also  be  partly 
closed  to  check  the  inrush  of  water.  Observe  whether  the 
water  drops  in  the  gauge  glass,  and  then,  if  more  feed  is  needed, 
increase  the  feed.  To  prevent  damage  to  the  engine,  open  the 
cylinder  drains.  Regular  and  even  firing  tends  to  prevent 
priming. 

Foaming. — The  phenomenon  called  foaming  is  not  the  same 
as  priming,  though  frequently  considered  so.  Foaming  is  the 
result  of  dirty  or  greasy  water  in  the  boiler;  the  water  foams 
and  froths  at  the  surface,  but  does  not  lift.  A  boiler  may  prime 
and  foam  simultaneously,  but  a  foaming  boiler  does  not  always 
prime.  Foaming  while  taking  place  is  visible  in  the  gauge 
glass  and  is  best  remedied  by  using  the  surface  blow-off.  If 
no  surface  blow-off  is  fitted,  the  bottom  blow-off  may  be  used 
in  order  to  get  rid  of  the  dirty  water.  Like  foaming,  priming, 
will  cause  a  wrong  level  to  be  shown,  and  hence  the  first  thing 
to  do  in  case  of  foaming  is  to  quiet  the  water  by  checking  the 
outrush  of  steam,  either  by  slowing  the  engine  down  or  by 
checking  the  fire,  or  by  both. 

SHUTTING  DOWN  AND  STARTING  UP 
Preparations  l:or  Shutting  Down. — Before  shutting  down  for 
the  night  it  is  advisable  to  fill  the  boiler  to  the  top  of  the  glass, 
so  as  to  be  sure  to  have  sufficient  water  to  start  with  in  the 
morning.  The  presence  of  possible  leaks  through  the  valves, 
tube  ends,  or  seams  necessitates  this  course  of  action.  Even 
if  no  leaks  exist,  it  is  good  practice  to  do  this,  if  for  no  other  rea- 
son than  to  admit  of  blowing  out  a  portion  before  raising  steem 
in  the  morning.  All  the  gauge  cocks  should  be  tried  and  the  water 
column  should  be  blown  out  to  insure  their  being  free  and  clear. 
Banking  of  Fires. — The  fires  may  be  banked  at  such  a  time 
that  there  will  be  about  enough  steam  to  finish  the  day's  run, 


164  STEAM  BOILERS 

thus  shutting  down  under  a  reduced  pressure  with  only  a  remote 
possibility  of  its  rising  again  through  the  night.  If  the  fires 
are  properly  banked  and  the  steam  worked  off  while  the  feed 
is  on,  it  will  be  remotely  possible  for  the  pressure  to  rise  during 
the  night  to  a  dangerous  extent.  To  bank  the  fires  they  should 
be  shoved  to  the  back  of  the  grate  and  well  covered  with 
green  fuel,  leaving  the  front  part  of  the  grate  bare,  thus  pre- 
venting any  possibility  that  the  banked  fire  will  burn  up  through 
the  night. 

Closing  Valves  and  Damper. — The  steam  stop-valve,  feed 
stop-valve,  whistle  valve,  and  other  steam  valves  should  be 
closed ;  the  valves  at  the  top  and  bottom  of  the  gauge  glass  also 
should  be  shut  off  to  prevent  loss  of  water,  etc.  in  case  the  glass 
should  break  during  the  night.  If  there  is  a  damper  regulator, 
it  should  be  so  arranged  that  the  damper  may  be  left  closed, 
but  not  quite  tight,  because  a  small  opening  must  be  left  to 
permit  the  collecting  gases  from  the  banked  fire  to  escape  up 
the  chimney;  otherwise  there  is  danger  that  the  accumulated 
gas  will  ignite  and  cause  an  explosion.  It  is  very  important 
to  take  this  precaution  and  also  to  make  a  mark  by  means  of 
which  the  distance  the  damper  is  open  can  be  ascertained  at  a 
glance.  In  fact,  a  damper  should  be  so  made  that  when  shut 
to  the  full  extent  of  its  travel  there  will  be  still  sufficient  space 
around  it  to  allow  the  gas  to  escape.  The  damper  regulator 
should  be  rendered  positively  inoperative  in  any  manner  per- 
mitted by  its  design  so  that  the  damper  when  closed  will  remain 
in  that  position  until  connected  properly  by  the  attendant 
in  the  morning. 

Starting  the  Fires. — On  entering  the  boiler  room  in  the  morn- 
ing, the  quantity  of  water  in  the  boiler  should  first  be  noted. 
The  gauge  glass  and  the  gauge-cocks  should  be  tried  and  the 
water  level  determined.  After  it  has  been  found  that  the 
water  is  not  too  low,  the  banked  fires  may  be  pulled  down  and 
spread  over  the  grates  and  allowed  to  burn  up  slowly,  the 
damper  regulator,  if  one  is  fitted,  in  the  meantime  having  been 
connected. 

Blowing  Down. — While  the  fires  are  burning  and  before  the 
pressure  begins  to  rise,  the  blow-off  cock  or  valve  should  be 
opened  and  the  boiler  blown  down;  that  is,  a  small  quantity  of 


STEAM  BOILERS  165 

the  water  should  be  blown  out.  This  should  be  done  every 
morning,  so  that  any  impurities  in  mechanical  suspension  in 
the  water  that  settled  during  the  night  may  be  blown  out. 
Great  care  should  be  exercised  while  blowing  down  that  too 
much  water  is  not  blown  out;  from  3  to  4  in.  as  shown  by  the 
gauge  glass,  is  sufficient.  Under  no  circumstances  should  the 
attendant  leave  the  blow-off  while  it  is  open.  Disaster  to  the 
boiler  is  liable  to  follow  a  disregard  of  this  injunction.  Next, 
all  the  valves,  except  the  stop-valve,  which  were  shut  the  night 
before  should  be  opened  and  tried  to  see  that  they  are  free  and 
in  good  working  order. 


BOILER  INSPECTION 

NATURE  OF  INSPECTION 

The  inspection  of  a  boiler  usually  consists  of  an  external 
examination  of  the  complete  structure,  and  of  the  setting  if 
the  boiler  is  externally  fired,  and  an  internal  inspection.  The 
examination  of  the  boiler  consists  of  an  ocular  inspection  for 
visible  defects,  and  a  hammer  test  or  sounding  for  hidden  defects 
of  plates,  stays,  braces,  and  other  boiler  parts.  The  hammer 
test  is  made  by  tapping  the  suspected  parts  with  a  light  ham- 
mer and  judging  the  existence  and  extent  of  defects  from  the 
sound  produced  by  the  hammer  blow.  If  the  examination 
discloses  marked  wear  and  tear,  a  series  of  calculations  is  often 
required  to  find  the  safe  pressure  that  may  be  allowed  on  the 
worn  parts,  using  such  formulas  or  rules  as  laws,  ordinances, 
and  regulations  may  prescribe  for  the  particular  official  inspec- 
tors. In  the  absence  of  officially  prescribed  formulas  and  rules, 
the  inspector  should  use  such  rules  as  he  deems  best  appli- 
cable or  in  best  accordance  with  good  practice.  The  inspec- 
tion is  usually,  but  not  always,  completed  by  a  so-called 
hydrostatic  test,  which  is  generally  prescribed  by  official 
regulations. 

EXTERNAL  INSPECTION 

Preparation. — Before  a  boiler  that  has  been  in  use  can  be 
inspected,  it  must  be  blown  out  and  must  be  allowed  to  cool  off. 


166  STEAM  BOILERS 

As  soon  as  the  water  has  been  removed,  the  manhole  covers, 
handhole  covers,  and  washout  plugs  should  be  taken  out  and 
all  loose  mud  and  scale  washed  out  with  a  hose.  If  the  boiler 
is  externally  fired,  the  tubes  must  be  swept  and  the  furnace, 
the  ash-pit,  the  smokebox,  and  the  space  back  of  the  bridge 
wall  must  be  cleaned  out.  Any  removable  insulating  cover- 
ing that  prevents  the  inspector  from  having  free  access  to  the 
exterior  of  the  boiler,  must  be  removed  to  the  extent  deemed 
necessary  by  him;  it  may  even  be  necessary  to  take  down  some 
of  the  bricks  of  the  setting. 

Inspection  of  Externally  Fired  Boilers. — In  the  inspection 
of  an  externally  fired  fire-tube  or  flue  boiler,  the  exterior  is  first 
examined.  The  seams  are  gone  over  inch  by  inch;  the  rivet 
heads  and  calking  edges  of  the  plates  are  carefully  scrutinized 
for  evidence  of  leaks;  and  possible  cracks  are  looked  for  between 
the  rivet  heads,  especially  in  the  girth  seams  and  on  the  under 
side  of  the  boiler.  The  plates  must  also  be  examined  for  cor- 
rosion, bulges,  blisters,  and  cracks.  The  heads  are  inspected 
for  cracks  between  the  tubes  or  flues,  cracks  in  the  flanges, 
leaky  tubes,  and  leaks  in  the  seams.  The  condition  of  the  fire- 
brick lining  of  the  furnace  and  bridge  and  the  top  of  the  rear 
combustion  chamber  is  noted  while  making  the  exterior  exami- 
nation of  the  under  side  of  the  boiler.  Every  defect  that  is  found 
should  be  clearly  marked.  Attention  must  also  be  paid  to  the 
condition  of  the  grate  bars  and  their  supports. 

Inspection  of  Internally  Fired  Boilers. — The  inspection  of 
the  shell  and  heads  must  be  followed  by  examination  of  the  fire- 
box or  furnace  tubes  or  flues,  and  of  the  combustion  chambers 
if  these  are  fitted  inside  the  boiler.  In  fireboxes,  special  atten- 
tion must  be  paid  to  the  crown  sheet.  The  ends  of  the  stay- 
bolts  require  close  examination;  if  such  ends  are  provided  with 
nuts,  these  must  be  examined,  as  they  are  liable  to  loosen  and 
are  also  liable  to  be  burned  off  in  time.  Each  stay  bolt  should 
be  tested  for  breakage,  which  is  done  by  holding  a  sledge  against 
the  outside  end  of  the  staybolt  and  striking  the  inner,  or  fire- 
box, end  with  a  light  hammer;  in  making  this  test  on  the  boilers 
of  locomotives  it  is  customary,  when  practical,  to  subject  the 
boiler  to  an  internal  air  pressure  of  from  40  to  50  Ib.  per  sq.  in. 
The  internal  pressure,  by  bulging  the  sheets,  separates  the  ends 


STEAM  BOILERS  167 

of  a  broken  staybolt,  which  renders  it  comparatively  easy  to 
find  them  by  the  hammer  test. 

Inspection  of  New  Boilers. — As  made  in  boiler  shops,  the 
external  inspection  of  new  boilers,  whether  fhey  are  internally 
or  externally  fired,  and  whether  they  are  of  the  water-tube  or 
the  fire-tube  type,  usually  consists  of  a  thorough  examination 
for  visible  defects  and  testing  under  water  pressure  to  locate 
leaks,  if  any.  If  a  new  boiler  subject  to  official  inspection  during 
construction  successfully  passes  such  a  hydrostatic  test  as  the 
regulations  prescribe,  it  will  usually  be  permitted  the  working 
pressure  it  was  designed  for,  the  design  having  been  approved 
officially  before  construction.  The  working  pressure  will  be 
reduced,  however,  if  the  inspection  discloses  poor  workmanship. 

In  the  external  inspection  of  water-tube  boilers  that  have 
been  in  use,  the  tubes  that  are  exposed  directly  to  the  heat  of 
the  fire  must  be  particularly  well  examined  for  evidence  of 
overheating.  The  plugs  or  handholes  placed  in  headers  to 
permit  the  insertion  of  the  tubes  and  the  cleaning  of  them  are 
inspected  for  leakage,  and  the  headers  are  inspected  for  cracks. 
Steam  drums  and  mud-drums  should  be  examined  as  carefully 
and  for  the  same  defects  as  the  shells  of  externally  fired  fire- 
tube  boilers.  The  firebrick  lining  of  the  furnace,  and  the 
interior  of  the  brick  setting  in  general,  as  well  as  the  baffle 
plates  controlling  the  direction  of  flow  of  the  gases  of  combus- 
tion, must  be  examined  for  cracks  and  any  other  defects.  The 
external  inspection  of  the  setting  can  usually  be  made  very 
rapidly,  as  everything  is  in  plain  sight. 

INTERNAL  INSPECTION 

Preparation. — Before  the  internal  inspection  is  begun  all 
loose  mud  should  be  washed  out  with  a  hose.  In  a  horizontal 
return-tubular  boiler  and  flue  boiler,  the  shell  plates  and  heads 
should  be  examined  for  corrosion  and  pitting;  if  the  boiler  has 
longitudinal  lap  seams,  these  should  be  inspected  at  the  inside 
calking  edge  for  incipient  grooving  and  cracks.  All  seams 
should  be  examined  for  cracks  between  the  rivet  holes.  Ob- 
viously, if  the  boiler  is  scaled  to  an  appreciable  degree,  the 
scale  must  be  removed  before  inspection.  The  tubes  or  flues 
should  be  examined  for  pitting,  as  well  as  for  uniform  corrosion. 


168  STEAM  BOILERS 

All  braces  should  be  inspected  by  sounding  them  with  a 
hammer,  and  if  they  are  attached  by  cotter  pins,  it  should 
be  seen  to  that  these  are  firmly  in  place.  All  defects  found 
should  be  marked1;  it  is  good  practice  to  make  a  memorandum 
of  them  as  well.  If  any  of  the  bracing  seems  to  have  worn 
considerably,'  it  should  be  measured  at  the  smallest  part  in 
order  that  the  safe  working  pressure  thereon  may  be  calculated 
afterwards.  To  determine  to  what  thickness  a  plate  attacked 
by  uniform  corrosion  has  been  reduced  the  inspector  will  have 
one  or  more  holes  drilled  through  the  plate  in  the  worn  part  to 
enable  him  to  measure  the  thickness.  These  holes  are  after- 
wards plugged,  generally  by  tapping  out  and  then  screwing  in 
a  plug. 

Inspection  of  Locomotive-Type  Boilers. — In  internally  fired 
boilers  of  the  firebox  and  locomotive  type,  particular  atten- 
tion must  be  paid  to  the  crown  bars,  crown  bolts,  and  sling 
stays,  and  in  boilers  having  the  crown  sheet  stayed  by  radial 
staybolts,  to  these.  As  a  general  rule  the  inspector  can  make 
only  an  ocular  inspection  of  most  of  them,  as  they  are  beyond 
his  reach;  where  the  outer  sheets  of  the  firebox  contain  inspec- 
tion or  washout  holes  above  the  level  of  the  crown  sheet,  a 
lighted  candle  tied  or  otherwise  fastened  to  a  stick  can  usually 
be  introduced  through  these  holes  from  the  outside  by  a  helper. 
In  inspecting  above  the  crown  sheet,  the  inspector  should  look 
for  mud  between  the  crown  sheet  and  crown  bars  and  sight 
over  the  top  of  the  bars  to  see  if  any  have  been  bent.  As  the 
inspector  can  reach  from  the  inside  of  the  boiler  only  a  few  of 
the  staybolts  staying  the  sides  of  the  firebox,  he  must  rely  on 
the  hammer  test  applied  from  the  inside  of  the  furnace  for 
finding  broken  staybolts. 

Flues  and  Combustion  Chambers. — In  boilers  having  cir- 
cular furnace  flues  and  internal  combustion  chambers  the  top 
of  the  furnace  flues  must  be  carefully  inspected  for  deposits  of 
grease  and  scale,  which  are  especially  liable  to  be  found  if  the 
feedwater  is  obtained  from  a  surface  condenser.  Even  a  light 
deposit  of  grease  on  the  furnace  flue  is  liable  to  lead  to  over- 
heating and  subsequent  collapse  of  the  top.  The  tops  of  the 
combustion  chambers,  together  with  their  supports,  are  usually 
easily  inspected,  there  being  ample  space  to  reach  every  part. 


STEAM  BOILERS  169 

Inspection  of  Vertical  Boilers. — Vertical  boilers  as  a  general 
rule,  except  in  the  largest  sizes,  have  no  manhole  to  admit  a 
person  to  the  inside,  and  such  internal  inspection  as  is  possible 
must  be  made  through  the  handholes.  Defects  to  be  looked 
for  are  pitting  and  uniform  corrosion  of  the  shell  and  tubes 
near  the  usual  water-line,  and  cracks  in  the  heads  between  the 
tubes,  the  lower  head  being  especially  liable  to  show  this  injury. 

HYDROSTATIC  TEST 

Value  of  Test. — While  a  hydrostatic  test  is  usually  demanded 
by  boiler  laws  and  official  rules  and  regulations,  it  does  not  at 
all  follow  that  a  boiler  that  has  successfully  stood  this  test  will 
be  safe.  The  chief  value  of  the  test  lies  in  showing  leaks. 
Under  no  consideration  should  the  test  pressure  be  such  as  to 
strain  the  parts  of  the  boiler  beyond  the  elastic  limit  of  the 
material. 

Care  in  Making  Test. — When  applying  the  hydrostatic  test, 
the  escape  of  air  from  the  boiler  while  filling  it  with  water 
should  be  provided  for,  as  by  raising  the  safety  valve.  After 
the  boiler  is  full,  all  outlets  must  be  tightly  closed  and  the 
safety  valve  so  blocked  that  it  cannot  open;  the  pressure  must 
then  be  pumped  up  very  slowly  and  carefully,  the  gauge  being 
watched  for  any  drop  of  pressure,  which  denotes  a  sudden 
yielding  of  some  part  of  the  boiler.  When  the  desired  test 
pressure  has  been  reached,  the  boiler  is  inspected  for  leaks,  and 
if  any  are  found  they  are  marked.  Before  calking  to  stop  a 
leak,  the  pressure  must  be  left  off  by  opening  some  convenient 
valve  or  cock.  In  cold  weather,  when  subjecting  the  boiler 
to  the  hydrostatic  test,  it  is  customary  to  heat  the  water  to  a 
lukewarm  temperature. 

Use  of  Blank  Flange. — If  the  boiler  to  be  tested  is  one  of  a 
battery,  and  the  others  are  to  be  in  use  while  this  one  is  being 
inspected  and  tested,  it  is  unwise  to  rely  on  a  closed  main  stop- 
valve  to  break  communication  with  the  other  boilers.  It  is 
good  practice  to  put  a  blank  flange  between  the  boiler  to  be 
tested  and  its  main  stop-valve. 

INSPECTION  OF  FITTINGS 

Inspection  of  Safety  Valve. — The  safety  valve  requires  very 
careful  inspection.  If  this  valve  is  known  to  leak,  it  should  be 


170  STEAM  BOILERS 

reseated  and  reground  before  the  hydrostatic  test  is  made. 
After  a  boiler  passes  the  hydrostatic  test,  the  clamp  locking  the 
safety  valve  is  removed,  and  by  running  the  pressure  up  once 
more,  the  point  at  which  the  safety  valve  opens  can  be  noted  by 
watching  the  steam  gauge,  which  is  supposed  to  have  been  tested 
and  corrected.  If  the  safety  valve  does  not  open  at  the  work- 
ing pressure  allowed  or  opens  too  soon,  it  is  readjusted.  If  the 
safety  valve  is  locked  by  a  seal,  as  is  often  required  by  official 
regulations,  the  seal  is  applied  after  adjustment  of  the  valve. 

Testing  of  Steam  Gauge. — The  steam  gauge  should  be  tested 
before  the  hydrostatic  test,  and  at  each  inspection,  with  a  so- 
called  boiler  inspector's  testing  outfit.  If  the  gauge  under  test 
is  more  than  5%  incorrect,  most  inspectors  will  condemn  it, 
although  some  will  condemn  gauges  showing  a  much  smaller 
error.  In  most  cases  the  gauge  can  be  repaired  at  small  expense 
by  the  makers. 

Inspection  of  Water  Gauge  and  Blow-Off. — The  connections 
of  water  columns  and  water-gauge  glasses  require  examina- 
tion in  order  to  see  that  they  are  clear  throughout  their  whole 
length.  The  blow-off  pipe  also  requires  examination  in  order 
to  see  that  it  is  clear. 

BOILER  EXPLOSIONS 

As  a  boiler  inspector  is  usually  called  on  to  investigate  the 
circumstances  of  a  boiler  explosion,  and  to  render  an  opinion 
concerning  it,  he  must  be  familiar  with  the  causes  of  such  explo- 
sions. Boiler  explosions  are  really  due  to  overpressure  of  steam. 
This  may  occur  because  the  boiler  is  not  strong  enough  to 
carry  safely  the  working  pressure  used,  or  because  the  pressure, 
through  some  cause,  such  as  sticking  or  overloading  of  the  safety 
valve,  has  been  allowed  to  rise  above  the  ultimate  strength 
of  the  boiler.  A  boiler  may  be  unfit  to  bear  its  working 
pressure,  for  any  of  the  following  reasons :  defective  design ; 
defects  in  workmanship  or  material;  corrosion,  and  wear  and 
tear  in  general;  and  mismanagement  in  operation. 

The  common  faults  in  design  that  have  led  to  boiler  explo- 
sions are:  insufficient  staying,  the  stays  being  too  small  or  too 
few  in  number;  the  cutting  away  of  the  shell  for  the  dome, 
manhole,  and  other  mountings,  without  reinforcing  the  edge 


STEAM  BOILERS  171 

of  the  plate  around  the  hole;  fixing  the  boiler  too  rigidly  in 
its  setting,  thus  causing  it  to  be  fractured  on  account  of  unequal 
expansion;  defective  water  circulation  in  a  boiler,  which  may 
lead  to  excessive  incrustation  and  thus  indirectly  to 'explosion; 
and  a  poorly  designed  feed  apparatus  or  safety  valve.  Defects 
in  workmanship  and  material  may  include  the  use  of  faulty 
material  containing  blisters,  lamination,  etc. ;  careless  punching 
and  shearing  of  plates;  burning  and  breaking  of  rivets;  burning 
or  otherwise  injuring  the  plates  in  flanging,  bending  or  weld- 
ing; scoring  of  the  plates  along  the  joints  by  sharp  calking 
tools;  and  injury  of  the  plates  by  the  use  of  the  drift  pin. 
Old  boilers  may,  while  being  patched  with  new  plates,  be  injured 
by  the  operation  of  removing  the  old  rivets  and  putting  in 
new  ones,  and  also  by  the  greater  expansion  and  contraction 
of  the  new  plate  as  compared  with  the  old  plate.  The  strength 
of  the  shell  may  be  weakened  by  corrosion,  pitting,  and  groov- 
ing. In  some  exploded  boilers,  the  plates  have  been  found  to 
have  wasted  to  little  more  than  the  thickness  of  wrapping 
paper.  Fractures  that  ultimately  end  in  explosion  may  be 
produced  by  letting  the  cold  feedwater  come  directly  into  con- 
tact with  the  hot  plates. 

If  a  boiler  fractures  while  undergoing  the  hydrostatic  test, 
the  water  escapes  through  the  rent  in  the  plate  and  no  explo- 
sion takes  place,  because  the  cold  water  has  little  or  no  stored 
energy.  But  when  a  boiler  filled  with  steam  and  water  at  a 
high  temperature  fractures,  a  violent  explosion  generally 
follows.  The  steam  escaping  through  the  opening  diminishes 
the  pressure,  and,  consequently,  a  new  body  of  steam  is  formed 
from  the  water,  which,  by  escaping,  lowers  the  pressure  still 
more,  allowing  the  formation  of  another  new  body  of  steam 
at  a  lower  pressure,  and  this  operation  is  continued  until  the 
pressure  reaches  that  of  the  atmosphere.  The  formation  of 
several  successive  large  bodies  of  steam  in  this  way,  which 
occurs  almost  instantaneously,  produces  a  'Disastrous  explosion. 
Generally  speaking,  the  larger  the  body  of  the  contained 
water,  the  more  disastrous  is  the  result.  For  this  reason 
water-tube  boilers,  which  contain  a  relatively  small  amount  of 
water,  are  generally  considered  to  be  much  safer  than  fire- 
tube  boilers. 


172 


STEAM  ENGINES 


STEAM    ENGINES 


INDICATING  OF  ENGINES 

Inside-Spring  Indicator. — The    indicator  is    an    instrument 
that  is  used  to  determine  the  action  of  the  steam  in  the  cylin- 


FIG.  1 

der  of  an  engine.  A  form  of  indicator  having  its  spring  inside 
the  barrel,  or  cylinder,  is  shown  in  Fig.  1.  The  instrument 
consists  essentially  of  a  cylinder  a  containing  a  piston  and  a 


STEAM  ENGINES  175 

helical  spring  for  measuring  the  steam  pressure,  a  lever  6  for 
transmitting  the  motion  of  the  piston  to  a  pencil  point  c,  and 
a  drum  d  that  carries  paper  on  which  this  motion  is  recorded. 
The  card  e  is  held  close  to  the  drum  by  clips  /,  so  that  the  pencil 
can  easily  trace  the  outline  of  the  diagram.  The  piston,  shown 
at  g,  must  work  in  the  cylinder  as  nearly  frictionless  as  possible, 
the  spring  h  being  the  only  resistance  to  the  upward  motion  of 
the  piston.  This  spring  is  calibrated;  that  is,  it  is  tested  so  as 
to  determine  the  pressures  required  to  move  the  pencil  to  vari- 
ous heights  against  the  resistance  of  the  spring.  Hence,  it  is 
possible  to  find  the  pressure  in  the  cylinder  by  the  position  of 
the  pencil  point.  By  turning  a  cock  in  the  small  pipe  con- 
necting the  indicator  with  the  engine  cylinder,  steam  may  be 
admitted  to,  or  shut  off  from,  the  cylinder  of  the  indicator  at 
pleasure.  When  steam  is  admitted  through  the  nipple  *',  its 
pressure  causes  the  piston  g  to  rise.  The  helical  spring  h  is 
compressed,  and  resists  the  upward  movement  of  the  piston. 
The  height  to  which  the  piston  rises  should  then  be  in  exact 
proportion  to  the  pressure  of  the  steam,  and  as  the  steam  pres- 
sure rises  and  falls  the  piston  must  rise  and  fall  accordingly. 

To  register  this  pressure,  a  pencil  might  simply  be  attached 
to  the  end  of  the  piston  rod,  the  point  of  the  pencil  being  made 
to  press  against  a  piece  of  paper.  It  is  desirable,  however,  to 
restrict  the  maximum  travel  of  the  piston  to  about  J  in.  while 
the  height  of  the  card  may  advantageously  be  2  in.  To  give 
a  long  range  to  the  pencil  while  keeping  the  travel  of  the  piston 
short,  the  pencil  is  attached  at  c  to  the  long  end  of  the  lever  b. 
The  fulcrum  of  the  lever  is  at  j,  and  the  piston  rod  is  connected 
to  it  at  k  through  the  link  /.  The  pencil  motion  is  thus  from 
four  to  six  times  the  piston  travel. 

The  indicator,  however,  not  only  must  register  pressures, 
but  it  must  register  them  in  relation  to  the  position  of  the  pis- 
ton. This  is  accomplished  by  means  of  the  cylindrical  drum 
shown  at  d.  This  drum  can  be  revolved  on  its  axis  by  pulling 
the  cord  m  that  is  coiled  around  it.  When  the  pull  is  released, 
a  spring  on  the  drum  spindle,  inside  the  drum,  turns  the  latter 
back  to  its  original  position.  If  the  cord  is  connected  with  some 
part  of  the  engine  that  has  a  motion  proportional  to  the  motion 
of  the  piston,  the  motion  of  the  drum  also  will  be  proportional 
13 


174  STEAM  ENGINES 

to  the  motion  of  the  piston.  The  outline  then  drawn  by  the 
pencil,  termed  an  indicator  diagram,  shows  the  pressure  on 
the  piston  at  every  point  of  the  stroke.  The  slip  of  paper 
on  which  the  diagram  is  drawn  is  called  an  indicator  card. 

Outside-Spring  Indicator. — The  spring  of  the  indicator 
shown  in  Fig.  1  is  subjected  to  the  heat  of  the  steam,  and, 
when  highly  superheated  steam  is  used  in  the  engine,  the  spring 
may  be  rendered  inaccurate  by  the  heating  due  to  the  steam. 


FIG.  2 

An  indicator  with  its  spring  located  outside  the  barrel  is  shown 
in  Fig.  2.  This  form  obviates  the  danger  of  heating  the  spring 
and  thus  introducing  eriors,  and  at  the  same  time  it  has  the 
advantage  of  allowing  the  spring  to  be  changed  for  a  heavier 
or  a  lighter  one,  with  less  trouble.  In  other  details  this  indica- 
tor is  similar  to  that  shown  in  Fig.  1. 

Indicator  Sptings. — The  height  to  which  the  piston  will  rise 
under  a  given  steam  pressure  depends  on  the  stiffness  of  the 
spring.  Indicators  are  usually  furnished  with  a  number  of 


STEAM  EXGIXES 


175 


springs  of  varying  degrees  of  stiffness,  which  are  distinguished 
by  the  numbers  20,  30,  40,  etc.  These  numbers  indicate  the 
pressure,  in  pounds  per  square  inch,  required  to  raise  the 
pencil  1  in.  Thus,  if  a  40  spring  is  used,  a  pressure  of  40  Ib.  per 
square  inch  raises  the  pencil  1  in.,  and  therefore,  the  vertical 
scale  of  the  diagram  is  40  Ib.  per  in.  That  is,  the  vertical 
distance,  in  inches,  of  any  point  on  the  diagram  from  the 
atmospheric  line,  multiplied  by  40,  gives  the  gauge  pressure 
per  square  inch  at  that  point.  The  scale  of  the  spring  chosen 
should  not  be  less  than  half  the  boiler  pressure,  because  it 
is  not  desirable  to  have  the  indicator  card  more  than  2  in.  in 
height. 

Attachment  of  Indicator. — To  attach  the  indicator  to  the 
engine,  a  hole  is  drilled  in  the  clearance  space  of  the  cylinder 


FIG.  3 

and  tapped  for  a  $-in.  nipple,  which  should  be  as  short  as 
possible.  The  nipple  has  an  elbow,  into  which  is  screwed  a 
cock.  The  indicator  may  then  be  attached  directly  to  the 
cock  by  the  nut  n.  Fig.  1,  the  conical  projection  i  of  the  indi- 
cator wedging  tightly  into  the  cock  to  prevent  the  leakage 
of  steam.  It  is  preferable  to  have  an  indicator  at  each  end 
of  the  cylinder,  but  if  that  is  not  convenient,  one  indicator 
may  be  connected  with  both  ends  of  the  cylinder  by  means 
of  a  three-way  cock,  as  shown  at  k,  Fig.  3.  This  construction 
is  undesirable,  however,  if  the  engine  has  a  long  stroke,  as  the 


176 


STEAM  ENGINES 


long  pipes  will  cause  considerable  resistance  to  the  flow  of  the 
steam.  The  pipe  connections  between  the  indicator  and  the 
engine  should  be  short  and  direct,  and  care  should  be  taken 
to  see  that  the  piston  at  the  end  of  the  stroke  does  not  cover 
the  hole  tapped  for  the  attachment  of  the  indicator  pipe. 
Before  attaching  the  indicator,  it  is  advisable  to  open  the  cock 
slightly,  to  blow  out  any  dirt  or  rust  that  may  have  accumu- 
lated in  the  pipe. 

Pendulum  Reducing  Motion. — The  motion  of  the  drum  cord 
is  usually  obtained  from  the  crosshead.     As  the  stroke  of  the 


FIG.  4 


FIG.  5 


engine  is  nearly  always  greater  than  the  circumference  of  the 
drum,  the  cord  cannot  be  attached  directly  to  the  crosshead, 
and  an  arrangement  called  a  reducing  motion  is  used.  A  pen- 
dulum reducing  motion  is  shown  in  Fig.  3.  The  upright  a  is 
fastened  to  the  engine  frame,  and  the  lever  b  is  pivoted  at  c 
to  the  upright.  Another  upright  d  is  fastened  to  the  cross- 
head  or  to  the  piston  rod  near  the  crosshead,  and  the  link  e 
is  connected  at  /  to  the  piece  d  and  at  g  to  the  lever  b.  The 
cord,  which  should  be  parallel  to  the  axis  of  the  cylinder,  is 
attached  to  the  point  h  on  the  lever  b,  which  point  must  be 
on  the  straight  line  connecting  c  and  g. 


STEAM  ENGINES 


177 


Slotted-Lever  Reducing  Motions. — A  form  of  reducing 
motion  consisting  of  a  swinging  slotted  lever  is  shown  in  Fig.  4. 
The  lever  a  is  pivoted  at  b  to  a  stationary  frame  or  girder  and 
is  slotted  at  c  so  as  to  fit  over  a  pin  d  fastened  to  the  crosshead 
e.  The  indicator  cord  /  is  attached  to  the  lever  at  g. 

Another  form  of  slotted-lever  reducing  motion  is  shown  in 
Fig.  5.  The  lever  a  is  pivoted  at  b  and  is  slotted  at  its  lower 
end  to  fit  over  the  pin  c  attached  to  the  crosshead.  The 
indicator  cord  d  is  fastened  to  a  bar  e  that  slides  in  the  guides  /. 


FIG.  6 


FIG.  7 


A  pin  g  fixed  in  the  bar  e  fits  in  a  short  slot  in  the  upper  end 
of  the  swinging  lever.  As  the  crosshead  moves  to  and  fro,  the 
bar  e ,  and  hence  the  indicator  cord  also,  copies  the  motion  of 
the  crosshead  to  a  reduced  scale. 

Pantograph  Reducing  Motion. — The  type  of  reducing 
motion  shown  in  Fig.  G  is  termed  a  pantograph.  It  consists  of 
four  straight  bars  a,  b,  c,  d  joined  together  with  pin  joints  to 
form  a  parallelogram.  One  of  the  end  bars  d  is  prolonged,  as 
shown,  and  is  pivoted  to  the  crosshead  of  the  engine  at  e. 


•  178 


STEAM  ENGINES 


The  uppermost  corner  of  the  parallelogram  is  pivoted  at  /  to 
a  stationary  support,  and  the  indicator  cord  g  is  attached  to 
the  bar  c  at  the  point  h,  which  lies  on  the  straight  line  joining 
the  points  e  and  /. 

Brumbo  Pulley. — A  familiar  form  of  reducing  motion  is 
that  shown  in  Fig.  7,  as  it  is  easy  to  construct.  The  lever  a  is 
connected  with  the  crosshead  b  by  the  bar  c,  pivoted  at  d  and  e. 
At  its  upper  end  the  lever  a  is  pivoted  on  a  stationary  pin  / 
and  has  firmly  fixed  to  it  the  sector  g.  The  indicator  cord  h 
is  fastened  to  the  sector  at  the  corner  *  and  lies  against  the 
curved  face  j  of  the  sector,  which  is  an  arc  of  a  circle  having 


its  center  at  /.     As  the  crosshead  moves  back  and  forth,  the 
cord  h  is  given  a  similar  but  reduced .  motion  by  the  sector. 

Reducing  Wheels. — Instead  of  a  reducing  motion  composed 
of  levers,  a  reducing  wheel  may  be  used.     Such  a  device  is 
illustrated  in  Fig.  8,  as  attached  to  the  engine  and  to  the 
indicator,  ready  for  use.     A  rigid  upright  is  firmly  fastened 
to  the  crosshead,  and  to  this  upright  is  tied  a  cord,  th< 
end  of  which  is  wound  on  the  wheel  a.     As  the  cr< 
moves  back  and  forth,  the  cord  rotates  the  wheel  a.     Evidently 
the  linear  movement  of  a  point  on  the  rim  of  this  wheel  in  any 
period  is  the  same  as  that  of  the  crosshead  in  that  period. 
Fixed  to  the  wheel  a  and  turning  with  it  on  the  same  shaft  is 


STEAM  ENGINES  179 

a  smaller  wheel  c,  on  which  is  wound  the  cord  leading  to  the 
indicator  b.  Hence,  as  the  wheel  a  turns,  the  drum  of  the 
indicator  is  given  a  rotary  motion  that  is  proportional  to 
the  motion  of  the  wheel  c,  and  hence  proportional  to  the 
crosshead  movement  also.  But  since  the  wheel  c  is  so  much 
smaller  than  wheel  a,  the  movement  of  a  point  on  the  drum 
surface  is  much  less  than  the  movement  of  the  crosshead. 
On  the  forward  stroke,  the  wheel  a  is  rotated  against  the 
resistance  of  a  spring  at  d;  but  on  the  return  stroke,  this 
spring  rotates  the  wheel  in  the  opposite  direction.  Both 
wheels  a  and  c  are  made  as  light  as  possible,  in  order  that  their 
inertia  may  not  affect  the  accuracy  of  the  reduction.  The 


FIG.  9 

cord  leading  from  the  wheel  a  to  the  upright  on  the  crosshead 
must  be  parallel  to  the  axis  of  the  cylinder,  but  the  cord  from 
the  wheel  c  to  the  indicator  may  incline  upwards  or  downwards. 
Reducing  wheels,  employing  gears,  are  often  made  of  alumi- 
num for  the  sake  of  lightness.  Such  a  wheel  is  shown  in  Fig.  9. 
It  really  consists  of  two  wheels;  on  the  larger  one,  shown  at  a, 
is  wound  the  string  that  is  attached  to  the  arm  on  the  cross - 
head,  and  from  the  smaller  one  b  runs  the  cord  to  the  indicator. 
A  spring  in  the  horizontal  case  c  takes  up  the  slack  in  the  string. 
Frequently,  the  reducing  wheel  is  attached  directly  to  the 
body  of  the  indicator,  as  shown  in  Fig.  2,  thus  avoiding  the 
necessity  of  fastening  it  to  the  engine  frame,  as  in  Fig.  8. 


180  STEAM  ENGINES 

Attachment  of  Indicator  Cord. — The  cord  leading  from  a 
reducing  motion  to  the  indicator  drum  should  be  in  two  pieces 
with  a  hook  on  one  of  the  free  ends,  preferably  the  end  next  to 
the  indicator,  and  a  loop  in  the  end  fastened  to  the  reducing 
motion.  This  makes  it  possible  to  disconnect  the  indicator 
from  the  reducing  motion  when  desired,  and  decreases  the  wear 
on  the  instrument.  The  length  of  the  string  should  be  care- 
fully adjusted  so  as  to  give  the  drum  the  correct  amount  of 
motion.  If  the  string  is  too  short,  it  will  be  broken;  and  if 
too  long,  there  will  be  lost  motion  and  the  card  will  not  repre- 
sent the  true  length  of  the  engine  stroke.  It  may  also  result 
in  damage  to  the  indicator. 

A  convenient  arrangement  is  shown  in  Fig.  10.  The  hook  a 
is  attached  to  the  indicator  cord,  and  the  cord  e  from  the 
reducing  motion  is  passed  through  a  plate  b,  as  shown.  By 


FIG.  10 

slackening  the  cord  at  the  point  d,  the  plate  may  be  slipped 
to  any  position  along  the  cord.  The  length  is  thus  easily 
adjusted.  When  the  indicator  is  in  operation,  the  hook  is 
hooked  into  the  loop.  By  unhooking  the  two  cords  the  indi- 
cator may  be  stopped  to  put  on  a  card. 

The  stretching  of  the  indicator  cord  may  introduce  serious 
errors  in  the  diagram.  Hence  it  is  better,  if  possible,  to  use 
a  wire  instead.  If  a  cord  is  used,  it  should  be  as  short  as 
convenient.  It  should  also  be  thoroughly  stretched  before 
being  used. 

Errors  of  Reducing  Motions. — The  forms  of  reducing  motions 
shown  in  Figs.  3,  4.  and  7  are  imperfect,  because  the  motion 
imparted  to  the  cord  is  not  exactly  proportional  to  the  move- 
ment of  the  crosshead.  The  only  forms  of  reducing  motion 
that  are  absolutely  accurate  are  those  in  which  the  distance 
from  the  pivot  to  the  point  of  attachment  of  the  cord  always 


STEAM  ENGINES  181 

bears  a  constant  ratio  to  the  distance  from  the  pivot  to  the 
point  where  the  lever  is  connected  to  the  crosshead.  This 
ratio  must  be  the  same  at  all  points  in  the  stroke,  or  at  every 
position  of  the  crosshead;  if  it  is  not,  the  reducing  motion  is 
not  exact.  In  the  reducing  motion  shown  in  Fig.  4,  for  instance, 
the  distance  from  the  pivot  b  to  the  center  of  the  pin  d  is 
variable,  depending  on  the  position  of  the  crosshead,  whereas 
the  distance  from  b  to  g,  where  the  cord  is  attached,  is  always 
the  same;  in  other  words,  the  length  of  the  long  arm  of  the 
lever  changes  while  the  length  of  the  short  arm  remains  con- 
stant. As  a  result,  the  motions  of  the  crosshead  and  the 
cord  differ  at  different  parts  of  the  stroke,  and  the  indicator 
diagram  is  correspondingly  distorted.  The  reducing  motions 
shown  in  Figs.  5  and  6,  and  the  reducing  wheels  shown  in  Figs. 
8  and  9,  are  accurate,  inasmuch  as  the  motion  of  the  cord  is  at 
all  times  proportional  to  the  motion  of  the  crosshead. 

Reduction  of  Errors. — For  ordinary  work  with  the  indicator, 
the  amount  of  error  caused  by  the  -  inexactness  of  reducing: 
motions  like  those  in  Figs.  3,  4,  and  7  is  not  serious  and  may 
be  ignored.  To  secure  a  minimum  of  distortion  of  the  diagram, 
the  long  lever  should  always  be  pivoted  in  such  a  position  that 
it  will  be  perpendicular  to  the  line  of  movement  of  the  cross- 
head  when  the  latter  is  at  the  middle  of  its  stroke.  The 
accuracy  of  the  motion  will,  in  general,  be  increased  by  increas- 
ing the  lengths  of  the  long  lever.  For  most  purposes  it  is 
sufficient  to  use  a  lever  whose  length  is  twice  the  stroke  of  the 
engine. 

Taking  the  Diagram. — After  the  instrument  is  properly 
attached,  a  blank  card  is  slipped  over  the  drum  so  as  to  fit 
smoothly,  as  in  Fig.  1.  The  hook  on  the  indicator  cord  is 
then  engaged  with  the  loop  on  the  cord  from  the  reducing 
motion,  and  the  drum  is  allowed  to  rotate  back  and  forth  several 
times,  to  see  that  it  works  properly  and  that  the  cord  is  adjusted 
correctly.  The  cock  is  then  opened  and  the  indicator  is  allowed 
to  work  freely  while  the  engine  makes  several  revolutions. 
This  warms  up  the  parts  to  the  working  temperature.  The 
pencil  is  then  pressed  lightly  against  the  card  during  a  single 
revolution.  Next,  the  cock  is  closed  and  the  pencil  is  again 
pressed  against  the  card,  recording  the  atmospheric  line. 


182  STEAM  ENGINES 

Finally,  the  cord  is  unhooked,  and  the  card  is  removed   from 
the  drum. 

If  but  one  indicator  and  a  three-way  cock  are  used,  as 
shown  in  Fig.  3,  the  cock  is  opened  to  admit  steam  from  one 
end  of  the  cylinder,  and  the  diagram  from  that  end  is  taken; 
then  the  cock  is  turned  to  admit  steam  from  the  other  end, 
and  another  diagram  is  taken;  finally,  the  steam  is  shut  off 
-entirely,  and  the  atmospheric  line  is  drawn. 


CLEARANCE  AND  CUT-OFF 

Clearance. — The  term  clearance  is  used  in  two  senses  in 
connection  with  the  steam  engine.  It  may  be  the  distance 
between  the  piston  and  the  cylinder  head  when  the  piston  is 
at  the  end  of  its  stroke,  or  it  may  represent  the  volume  between 
the  piston  and  the  valve  when  the  engine  is  on  dead  center. 
To  avoid  confusion,  the  former  is  called  piston  clearance,  and 
the  latter  is  termed  simply  clearance.  Piston  clearance  is 
always  a  measurement,  expressed  in  parts  of  an  inch.  Clear- 
ance, however,  is  a  volume. 

The  clearance  of  an  engine  may  be  found  by  putting  the 
engine  on  a  dead  center  and  pouring  in  water  until  the  space 
between  the  piston  and  the  cylinder  head,  and  the  steam  port 
leading  into  it,  is  filled.  The  volume  of  the  water  poured  it 
is  the  clearance.  The  clearance  may  be  expressed  in  cut 
feet  or  cubic  inches,  but  it  is  more  convenient  to  express  it 
as  a  percentage  of  the  volume  swept  through  by  the  piston. 
For  example,  suppose  that  the  clearance  volume  of  a  12"X18" 
is  found  to  be  128  cu.  in.  The  volume  swept  through 
by  the  piston  per  stroke  is  1 2-' X  .785-1X18  =  2,035.8  cu.  in. 
Then,  the  clearance  is  128 -=-2,035.8=  .063  =  6.3%.  The  cl 
ance  may  be  as  low  as  \%  in  Corliss  engines,  and  as  high 
It',  in  high-speed  engines. 

Effects  of  Clearance. — Theoretically,  there  should  be 
clearance,  since  the  steam  that  fills  the  clearance  space  does 
no  work  except  during  expansion;  it  is  exhausted  from  the 
cylinder  during  the  return  stroke,  and  represents  so  much  dead 
loss.  This  is  remedied,  to  some  extent,  by  compression.  If 


STEAM  ENGINES  183 

the  compression  were  carried  up  to  the  boiler  pressure,  there 
would  be  very  little,  if  any,  loss,  since  the  steam  would  then 
fill  the  entire  clearance  space  at  boiler  pressure,  and  the  amount 
of  fresh  steam  needed  would  be  the  volume  displaced  by  the 
piston  up  to  the  point  of  cut-off,  the  same  as  if  there  were 
no  clearance.  In  practice,  however,  the  compression  is  made 
only  sufficiently  great  to  cushion  the  reciprocating  parts  and 
bring  them  to  rest  quietly. 

It  is  not  practicable  to  build  an  engine  without  any  clear- 
ance, on  account  of  the  formation  of  water  in  the  cylinder  due 
to  the  condensation  of  steam,  particularly  when  starting  the 
engine.  Automatic  cut-off  high-speed  engines  of  the  best 
design,  with  shaft  governors,  usually  compress  to  about  half 
the  boiler  pressure,  and  have  a  clearance  of  from  7  to  14%. 
Corliss  engines  require  but  very  little  compression,  owing  to 
their  low  rotative  speeds;  they  also  have  very  little  clearance, 
since  the  ports  are  short  and  direct. 

Apparent  Cut-Off . — The  apparent  cut-off  is  the  ratio  between 
the  portion  of  the  stroke  completed  by  the  piston  at  the  point 
of  cut-off,  and  the  total  length  of  the  stroke.  For  example,  if 
the  length  of  stroke  is  48  in.,  and  the  steam  is  cut  off  from  the 
cylinder  just  as  the  piston  has  completed  15  in.  of  the  stroke, 
the  apparent  cut-off  is  if  =  tV 

Real  Cut-Off. — The  real  cut-off  is  the  ratio  between  the  volume 
of  steam  in  the  cylinder  at  the  point  of  cut-off  and  the  volume 
at  the  end  of  the  stroke,  both  volumes  including  the  clearance 
of  the  end  of  the  cylinder  in  question.  If  the  volume  of 
steam  in  the  cylinder,  including  the  clearance,  at  the  point  of 
cut-off  is  4  cu.  ft.,  and  the  volume,  including  the  clearance, 
at  the  end  of  the  stroke  is  6  cu.  ft.,  the  real  cut-off  is  $=?. 

Ratio  of  Expansion. — The  ratio  of  expansion,  also  called  the 
real  number  of  expansions,  is  the  ratio  between  the  volume  of 
steam,  including  the  steam  in  the  clearance  space,  at  the  end 
of  the  stroke,  and  the  volume,  including  the  clearance,  at  the 
point  of  cut-off.  It  is  the  reciprocal  of  the  real  cut-off.  For 
example,  if  the  volume  at  the  end  of  the  stroke  is  8  cu.  ft., 
and  the  cut-off  is  5  cu.  ft.,  the  ratio  of  expansion  is  8-4-5  =  1.6; 
in  other  words,  the  steam  would  be  said  to  have  one  and  six- 
tenths  expansions.  The  corresponding  real  cut-off  would  be  f . 


184  STEAM  ENGINES 

Let  e  =real  number  of  expansions; 

i  =  clearance,  expressed  as  a  per  cent,  of  the  stroke; 
k  =real  cut-off; 
^1  =  apparent  cut-off; 

r  =  apparent  number  of  expansions  =  —  . 

ki 

Then,  «--and*  =  -  (1) 

k  e 


EXAMPLE.  —  The  length  of  stroke  is  36  in.  ;  the  steam  is  cut  off 
•when  the  piston  has  completed  16  in.  of  the  stroke;  the  clear- 
ance is  4%.  Find  the  apparent  cut-off,  the  real  cut-off,  and 
the  real  number  of  expansions. 

SOLUTION.—  Apparent  cut-off  =  £f  =  |  =  .444. 

ki+i     .444  +  .04     .484 

Real  cut-off  =  k  =  -  =  -  =  -  =  .465. 
1+t        1  +  .04        1.04 

Real  number  of  expansions  =  e  =  -  =  —  -  =  2.15. 


MEAN  EFFECTIVE  PRESSURE 

Finding  the  Mean  Effective  Pressure. — In  order  to  find  the 
horsepower  of  an  engine,  it  is  necessary  to  know  the  mean 
effective  pressure,  abbreviated  M.  E.  P.,  which  is  defined  as 
the  average  pressure  urging  the  piston  forwards  during  its 
entire  stroke  in  one  direction,  less  the  pressure  that  resists 
its  progress.  The  mean  effective  pressure  is  usually  found 
from  the  indicator  diagram  in  one  of  two  ways. 

1.  The  area  of  the  diagram  in  square  inches  may  be  meas- 
ured by  an  instrument  called  a  planimeterj  the  M.  E.  P.  is 
then  found  by  dividing  the  area  of  the  diagram  in  square  inches 
by  the  length  of  the  diagram  in  inches,  and  multiplying  the 
quotient  by  the  scale  of  the  spring. 

2.  Where  a  planimeter  is  not  available,  the   M.  E.  P.  may 
be  found  with  a  fair  degree  of  accuracy  by  multiplying  the 
length  of  the  mean  ordinate  by  the  scale  of  the  spring. 


STEAM  ENGINES 


185 


Planimeter. — A  common  form  of  planimeter  is  shown  in 
Fig.  1.  It  consists  of  two  arms  hinged  together  by  a  pivot 
joint  at  j.  One  arm  carries  a  recording  wheel  d,  which  rolls 
on  the  surface  to  which  the  card  is  fastened,  while  the  outline 
of  the  diagram  is  being  traced  by  the  point  /.  The  needle 
point  p  is  fixed  in  the  paper  or  drawing  board,  and  remains 
stationary  during  the  operation. 

The  indicator  card  should  be  fastened  to  a  smooth  table  or 
a  drawing  board  that  has  previously  been  covered  with  a 
piece  of  heavy  unglazed  paper  or  cardboard.  The  point  p 
should  be  placed  far  enough  from  the  card  to  enable  the 
wheel  to  roll  on  the  unglazed  paper  without  touching  the  card, 
as  it  will  slip  if  rolled  over  a  smooth  surface.  Set  the  zero  of 


FIG.  1 

the  wheel  d  opposite  the  vernier  e;  then,  with  the  tracing 
point  /,  follow  the  line  of  the  diagram  carefully,  going  around 
the  diagram  in  the  direction  of  the  hands  of  a  watch,  and  stop 
exactly  at  the  starting  point. 

Reading  the  Vernier. — The'  area  is  read  from  the  recording 
wheel  and  vernier  as  follows:  The  circumference  of  the  wheel 
is  divided  into  10  equal  spaces  by  long  lines  that  are  consecu- 
tively numbered  from  0  to  9.  Each  of  these  spaces  represents 
an  area  of  1  sq.  in.  and  is  subdivided  into  10  equal  spaces, 
each  of  which  represents  an  area  of  .1  sq.  in.  Starting  with 
the  zero  line  of  the  wheel  opposite  the  zero  line  of  the  vernier 
and  moving  the  tracing  point  once  around  the  diagram,  the 
zero  of  the  vernier  will  be  opposite  some  point  on  the  wheel; 
if  it  happens  to  be  directly  opposite  one  of  the  division  lines 


STEAM  ENGINES 


on  the  wheel,  that  line  gives  the  exact  area  in  tenths  of  a  squ 
inch.  The  zero  of  the  vernier,  however,  will  probably  be 
between  two  of  the  division  lines  on  the  wheel,  in  which  case 
write  down  the  inches  and  tenths  that  are  to  the  left  of  the 
vernier  zero,  and  from  the  vernier  find  the  nearest  hundredth 
of  a  square  inch  as  follows:  Find  the  line  of  the  vernier  that  is 
exactly  opposite  one  of  the  lines  on  the  wheel.  The  number 
of  spaces  on  the  vernier  between  the  vernier  zero  and  this  line 
is  the  number  of  hundredths  of  a  square  inch  to  be  added  to 
the  inches  and  tenths  read  from  the  wheel.  An  example  is 
presented  in  Fig.  2,  where  the  0  of  the  vernier  lies  between 
the  lines  on  the  wheel  representing  4.7  and  4.8  sq.  in.,  respect- 
ively, showing  that  the  area  is  something  more  than  4.7  sq.  in. 
Looking  along  the  vernier  it  is  seen  that  there  are  three  spaces 
between  the  vernier  zero  and  the  line  of 
the  vernier  that  coincides  with  one  of  the 
lines  on  the  wheel;  this  shows  that  .03 
sq.  in.  is  to  be  added  to  the  4.7  sq.  in. 
read  from  the  wheel,  making  the  area 
4.73  sq.  in.,  to  the  nearest  hundredth  of  a 
square  inch.  The  reading  thus  taken  is 
the  area  of  the  diagram,  in  square  inches. 
The  M.  E.  P.  is  found  by  dividing  this 
area  by  the  length  of  the  diagram  on  a  line  parallel  with  the 
atmo spheric  line,  and  multiplying  by  the  scale  of  the  spring. 

EXAMPLE. — The  area  of  the  diagram  is  4.73  sq.  in.,  the  length 
is  3.5  in.,  and  a  40  spring  is  used;  find  the  M.  E.  P. 

4.73 

SOLUTION.— M.  E.  P.  =  -  -    X40  =  54  1  Ib.  per  sq.  in. 
3.o 

Hints  for  Use  of  Planimeter. — It  is  well  to  place  the  fixed 
point  p.  Fig.  1,  so  that,  as  the  tracing  point  moves  around  the 
diagram,  the  arms  will  swing  about  equally  on  each  side  of  a 
position  at  right  angles  with  each  other.  A  slight  dot  is  gen- 
erally made  with  the  tracing  point  to  mark  the  point  a' 
its  motion  around  the  diagram  begins;  when  the  tracing  point 
reaches  this  dot  in  the  paper,  the  operator  knows  that  the 
motion  around  the  diagram  has  been  completed.  The  Hirer - 
tion  of  motion  of  the  tracing  point  must  always  be  the 
same  as  that  of  the  hands  of  a  watch;  motion  in  the  opposite 


STEAM  ENGINES  187 

direction  will  move  the  wheel  in  the  wrong  direction  and  give  a 
negative  reading  for  the  area.  When  measuring  diagrams  with 
loops,  like  Fig.  3,  move  the  tracing  point  so  that  it  will  follow 
the  outline  of  the  loops  in  a  direction  opposite  to  the  direction 
of  motion  of  the  hands  of  a  watch,  as  is  indicated  by  the  arrow- 
heads on  the  diagram.  This  will  cause  the  instrument  auto- 
matically to  subtract  the  areas  of  the  loops  from  the  area  of  the 
main  part  of  the  diagram. 

An  excellent  check  on  the  work  is  to  start  with  the  recording 
wheel  at  zero  and  pass  the  tracing  wheel  around  the  diagram 
two  or  three  times,  noting  the  reading  of  the  wheel  each  time 
the  tracing  point  returns  to  the  point  of  starting.  Each  read- 
ing of  the  wheel  divided  by  the  number  of  times  the  outline 


FIG.  3 

of  the  diagram  has  been  traced  should  give,  very  nearly,  the 
value  of  the  first  reading;  if  there  is  considerable  difference 
between  the  first  reading  and  the  value  obtained  by  dividing 
the  second  reading  by  2  or  the  third  reading  by  3,  it  is  an  indi- 
cation that  an  error  has  been  made,  and  the  work  should  be 
repeated.  If  the  difference  is  small,  the  work  may  be  assumed 
to  be  satisfactory  and  the  value  to  be  used  for  the  area  or  the 
M.  E.  P.  may  be  taken  as  the  average  found  by  dividing  the 
last  reading  by  the  number  of  times  the  tracing  point  passed 
around  the  diagram. 

Finding  M.  E.  P.  by  Ordinates. — The  M.  E.  P.  may  be 
found  from  the  diagram  by  the  aid  of  two  triangles,  a  scale, 
and  a  hard  lead  pencil;  if  two  triangles  are  not  available,  a 


188 


STEAM  ENGINES 


single  triangle  and  a  straightedge  will  suffice.  Lines  perpen- 
dicular to  the  atmospheric  line  and  tangent  to  the  two  ends  of 
the  diagram  must  first  be  drawn.  The  perpendicular  distance 
between  these  tangents  will  be  the  length  of  the  diagram,  and 
this  length  must  be  divided  into  some  number  of  equal  parts; 
10  or  20  parts  are  the  most  convenient,  but  any  other  number 
may  be  used.  Midway  between  each  pair  of  points  of  dndsion 
draw  a  line  parallel  to  the  two  tangents;  the  part  of  this  line 
included  between  the  lines  of  the  diagram  is  the  middle  ordinate 
of  its  corresponding  space.  The  sum  of  the  lengths  of  all  of 
these  middle  ordinates  divided  by  the  number  of  ordinates  is 
the  mean  ordinate  and  gives,  approximately,  the  average 
height  of  the  diagram.  The  length  of  the  mean  ordinate 


FIG.  4 


should  agree  very  nearly  with  the  value  obtained  by  dividing 
the  area  of  the  diagram,  as  measured  by  a  planimeter,  by  the 
length  of  the  diagram.  The  M.  E.  P.  is  found  by  multiplying 
the  length  of  the  mean  ordinate  by  the  scale  of  the  spring 
with  which  the  diagram  was  taken.  A  diagram  thus  divided 
into  equal  parts,  with  the  lengths  of  the  ordinates  marked 
thereon,  is  shown  in  Fig.  4.  The  sum  of  the  lengths  of  the 
ordinates  is  9.06  in.  As  there  are  14  ordinates  the  length  of 

9  06 
the  mean  ordinate  is  — —  in.,  and  if  the  diagram  was  taken 


9.06 


with  an  80  spring,  the  M.  E.  P.  is X80 


51.77  Ib.  per  sq.  in. 
If  a  scale  graduated  to  correspond  with  the  scale  of  the 


STEAM  ENGINES  189 

spring  is  available,  the  M.  E.  P.  may  be  obtained  by  measuring 
the  ordinates  in  pounds  instead  of  in  inches;  the  sum  of  the 
lengths  of  the  ordinates  as  so  measured  divided  by  their  number 
gives  the  M.  E.  P.  of  the  diagram.  For  example,  let  the  scale 
of  the  spring  be  40;  then  each  -fo  in.  in  the  length  of  an  ordinate 
represents  a  pressure  of  1  Ib.  per  sq.  in.,  and  by  measuring  the 
length  of  an  ordinate  with  a  scale  graduated  in  fortieths  of  an 
inch,  the  number  of  pounds  of  pressure  represented  by  that 
ordinate  is  found. 

A  convenient  method  of  finding  the  sum  of  the  lengths  of 
the  ordinates  of  a  diagram,  and  one  that  is  especially  to  be 
recommended  when  a  decimal  scale  is  not  available,  is  the 
following:  Take  a  strip  of  paper  having  a  straight  edge  a  little 
longer  than  the  sum  of  the  lengths  of  the  ordinates.  Lay  this 
strip  along  the  first  ordinate.  From  the  point  on  the  strip 
representing  one  end  of  the  first  ordinate  lay  off  the  length  of 
the  next  ordinate.  In  the  same  way  lay  off  on  the  strip  the 
length  of  each  of  the  ordinates  in  succession.  The  length  of 
the  strip  included  between  the  extreme,  or  first  and  last,  points 
so  marked  will  be  equal  to  the  sum  of  the  lengths  of  the  ordi- 
nates, and  this  length  divided  by  the  number  of  ordinates  will 
give  the  length  of  the  mean  ordinate. 

Locating  the  Ordinates. — The  length  of  the  diagram  will 
seldom  be  divisible  into  equal  parts  that  can  readily  be  laid 
off  by  a  scale,  and  to  divide  the  length  into  equal  parts  by  a 
cut-and-try  process  will  be  found  very  tedious.  These  diffi- 
culties may,  however,  be  overcome  by  an  application  of  a 
simple  geometrical  principle,  in  the  manner  illustrated  in  Fig.  4. 
The  tangent  lines  at  the  ends  of  the  diagram  are  drawn  perpen- 
dicular to  the  atmospheric  line  AZ.  Suppose,  now,  that  it  is 
desired  to  have  fourteen  ordinates.  Draw  any  other  line  from 
A,  as  AB,  at  a  small  angle  to  AZ,  and  then  lay  off  any  con- 
venient distance  AC  fourteen  times  successively,  along  AB. 
Connect  the  last  point  B  with  Z,  and  from  the  other  points 
D,  E,  etc.  draw  lines  parallel  to  BZ  until  they  intersect  AZ. 
These  points  of  intersection  will  divide  the  line  AZ  into  four- 
teen equal  spaces.  The  middle  points  of  these  spaces  can 
then  be  located  by  direct  measurement  and  the  ordinates  may 
be  erected  at  these  middle  points. 
14 


190 


STEAM  ENGIXES 


Approximate  M.  E.  P.  —  If  an  indicator  is  not  available,  so 
that  diagrams  may  be  taken  in  order  to  determine  the  M.  E.  P. 
of  an  engine,  the  value  of  the  M.  E.  P.  may  be  estimated  by 
the  formula 


in  which   P  =  M.  E.  P.,  in  pounds  per  square  inch; 

C  =  constant   corresponding  to   cut-off,   taken   from 

accompanying  table; 
p  =  boiler  pressure,  in  pounds  per  square  inch,  gauge. 

The  foregoing  formula  applies  only  to  a  simple  non- 
condensing  engine.  If  the  engine  is  a  simple  condensing 
engine,  the  formula  should  be  altered  by  substituting  for  17 
the  pressure  existing  in  the  condenser,  in  pounds  per  square 
inch. 

CONSTANTS  USED  IN  CALCULATING  M.  E.  P. 


Cut-off 

Constant 

Cut-off 

Constant 

Cut-off 

Constant 

j 

.545 

1 

.773 

f 

.943 

i 

.590 

.4 

.794 

7 

.954 

* 

.650 
.705 

J 

.864 
.916 

J 

.970 
.981 

* 

.737 

; 

.927 

.993 

In  this  table,  the  fraction  indicating  the  point  of  cut-off  is 
obtained  by  dividing  the  distance  that  the  piston  has  traveled 
when  the  steam  is  cut  off  by  the  whole  length  of  the  stroke; 
that  is,  it  is  the  apparent  cut-off.  It  is  to  be  observed  that 
this  rule  cannot  be  applied  to  a  compound  engine  or  to  any 
other  engine  in  which  the  steam  is  expanded  in  successive 
stages  in  several  cylinders. 

EXAMPLE. — Find  the  approximate  M.  E.  P.  of  a  non-con- 
densing engine  cutting  off  at  $  stroke,  if  the  boiler  pressure  is 
80  lb.,  gauge. 

SOLUTION. — According  to  the  table,  the  constant  correspond- 
ing to  cut-off  at  J  stroke  is  C  =  .864.  Then,  applying  the  for- 
mula, P  =  .9[.864(80+ 14.7)  -17]  =  58.34  lb.  per  sq.  in. 


STEAM  ENGINES  191 

HORSEPOWER  AND  STEAM  CONSUMPTION 

Indicated  Hors'epower. — The  indicator  furnishes  the  most 
ready  method  of  measuring  the  pressures  on  the  piston  of  a 
steam  engine  and,  in  consequence,  of  determining  the  amount 
of  work  done  in  the  cylinder  and  the  corresponding  horsepower. 
The  power  measured  by  the  use  of  the  indicator  is  called  the 
indicated  horsepower.  It  is  the  total  power  developed  by  the 
action  of  the  net  pressures  of  the  steam  on  the  two  sides  of  the 
moving  piston.  The  indicated  horsepower  is  generally  repre- 
sented by  the  initials  I.  H.  P. 

Friction  Horsepower. — The  part  of  the  indicated  horsepower 
that  is  absorbed  in  overcoming  the  frictional  resistances  of 
the  moving  parts  of  the  engine  is  termed  the  friction  horse- 
power. If  the  engine  is  running  light,  or  with  no  load,  all  the 
power  developed  in  the  cylinder  is  absorbed  in  keeping  the 
engine  in  motion,  and  the  friction  'horsepower  is  equal  to 
the  indicated  horsepower.  This  principle  furnishes  a  simple 
approximate  method  of  finding  the  friction  horsepower  of  a 
given  engine;  as,  however,  the  friction  between  the  surfaces 
increases  with  the  pressure,  the  power  absorbed  in  over- 
coming the  engine  will  be  greater  as  the  load  on  the  engine  is 
increased. 

Net  Horsepower. — The  difference  between  the  indicated 
horsepower  and  the  friction  horsepower  is  the  net  horsepower. 
It  is  the  power  that  the  engine  delivers  through  the  flywheel 
or  shaft  to  the  belt  or  the  machine  driven  by  it,  and  is  sometimes 
called  the  delivered  horsepower.  Since  the  power  that  an  engine 
is  capable  of  delivering  when  working  under  certain  conditions 
is  often  measured  by  a  device  known  as  a  Prony  brake,  the  net 
horsepower  is  frequently  called  the  brake  horsepower,  abbrevi- 
ated B.  H.  P. 

Mechanical  Efficiency. — The  mechanical  efficiency  of  an 
engine  is  the  ratio  of  the  net  horsepower  to  the  indicated  horse- 
power; or  it  is  the  percentage  of  the  mechanical  energy  devel- 
oped in  the  cylinder  that  is  utilized  in  doing  useful  work.  To 
find  the  efficiency  of  an  engine,  when  the  indicated  and  net 
horsepowers  are  known,  divide  the  net  horsepower  by  the 
indicated  horsepower. 


192  STEAM  ENGINES 

General  Rule  for  Calculating  I.  H.  P.  —  Knowing  the  dimen- 
sions and  speed  of  the  engine  and  the  mean  effective  pressure 
on  the  piston,  all  the  data  for  finding  the  rate  of  work  done 
in  the  engine  cylinder  expressed  in  horsepower  are  at  hand. 
Let   H  —  indicated  horsepower  of  engine; 

P=  M.  E.  P.,  in  pounds  per  square  inch; 
A  =  area  of  piston,  in  square  inches; 
L  =  length  of  stroke,  in  feet; 
N  =  number  of  working  strokes  per  minute. 
PLAN 

Then-  H= 


In  a  double-acting  engine,  or  one  in  which  the  steam  acts 
alternately  on  both  sides  of  the  piston,  the  number  of  working 
strokes  per  minute  is  twice  the  number  of  revolutions  per 
minute.  For  example,  if  a  double-acting  engine  runs  at  a 
speed  of  210  R.  P.  M.  there  are  420  working  strokes  per  minute. 
A  few  types  of  engines,  however,  are  single-acting;  that  is, 
the  steam  acts  on  only  one  side  of  the  piston.  Such  are  the 
Westinghouse,  the  Willans,  and  others.  In  this  case,  only 
one  stroke  per  revolution  does  work,  and,  consequently,  the 
number  of  strokes  per  minute  to  be  used  in  the  foregoing 
formula  is  the  same  as  the  number  of  revolutions  per  minute. 
Unless  it  is  specifically  stated  that  an  engine  is  single-acting, 
it  is  always  understood,  when  the  dimensions  of  a  steam  engine 
are  given,  that  a  double-acting  engine  is  meant. 

Piston  Speed.  —  The  total  distance  traveled  by  the  piston 
in  1  min.  is  called  the  piston  speed.  It  is  customary  to  take 
the  stroke  in  inches.  Then,  to  find  the  piston  speed,  multiply 
the  stroke  in  inches  by  the  number  of  strokes  and  divide  by  12; 

or,  letting    5  represent  the  piston  speed,  S  =  rr^t  where  /  is 

the  stroke   in   inches.     But  N  =2  R,  where  R  represents  the 
number  of  revolutions  per  minute.     Hence, 

_M  _IX2JR     l_R 

~  12~~12~    "  6 

EXAMPLE.  —  An  engine  with  a  52-in.  stroke  runs  at  a  speed 
of  (id  R.  P.  M.  What  is  the  piston  speed? 

52X06 
SOLUTION.  —  By  the  formula,  5-  —         =572  ft.  per  rr.in. 


STEAM  ENGINES  193 

The  piston  speeds  used  in  modern  practice  are  about  as 


Small  stationary  engines  ......  ........  300  to     600 

Large  stationary  engines  ..............  600  to  1,000 

Corliss  engines  .......................  400  to     750    ' 

Marine  engines  .......................  200  to  1,200 

Allowance  for  Area  of  Piston  Rod.  —  It  is  generally  consid- 
ered sufficiently  accurate  to  take  the  total  area  of  one  side  of 
the  piston  as  the  area  to  be  used  in  calculating  the  horsepower 
of  an  engine.  The  effective  area  of  one  side  of  the  piston  is, 
however,  reduced  by  the  sectional  area  of  the  piston  rod,  and 
if  it  is  important  that  the  power  be  calculated  with  the  greatest 
practical  degree  of  accuracy,  an  allowance  for  the  area  of 
the  piston  rod  must  be  made.  This  is  done  by  taking  as  the 
piston  area  one-half  the  sum  of  the  areas  exposed  to  steam 
pressure  on  the  two  sides  of  the  piston.  Thus,  if  a  piston  is 
30  in.  in  diameter  with  a  6-in.  piston  rod,  the  average  area  is 

302  x  .7854  +  (302  X  .7854  -  62  X  .7854) 

-  -  —  —  =  692.72    sq.    in.     If   the 

piston  rod  is  continued  past  the  piston  so  as  to  pass  through  the 
head-end  cylinder  head,  that  is,  if  the  piston  has  a  tailrod, 
allowance  must  be  made  for  the  tailrod.  Thus,  with  a  piston 
30  in.  in  diameter,  a  piston  rod  6  in.  in  diameter,  and  a  tailrod 
5  in.  in  diameter,  the  average  area  is 

(302  x  .7854  -  52  X  .7854)  +  (3Q2  X  .7854  -  6*  X  .78.54) 

-  -  -     —  =682.9sq.in. 

Stating  Sizes  of  Engines.  —  The  size  of  a  simple  engine,  that 
is,  an  engine  having  but  one  cylinder,  is  commonly  stated  by 
giving  the  diameter  of  the  cylinder,  followed  by  the  length  of 
the  stroke,  both  in  inches.  Thus,  a  simple  engine  having  a 
cylinder  12  in.  in  diameter  and  a  stroke  of  24  in.  would  be 
referred  to  as  a  12"X24"  engine,  the  multiplication  sign  in 
this  case  serving  merely  to  separate  the  two  numbers.  The 
sizes  of  compound  and  multiple-expansion  engines  are  desig- 
nated in  a  similar  fashion.  Thus,  a  compound  engine  with  a 
high-pressure  cylinder  11  in.  in  diameter,  a  low-pressure 


194  STEAM  ENGINES 

cylinder  20  in.  in  diameter,  and  a  stroke  of  15  in.  would  be 
referred  to  as  an  11"  and  20"  XI 5"  compound  engine.  In 
the  same  way,  a  14",  22",  and  34"X18"  triple-expansion 
engine  would  be  one  in  which  the  diameters  of  the  cylinders 
are  14  in.,  22  in.,  and  34  in.,  and  the  stroke  is  18  in. 

Cylinder  Ratios. — The  cylinders  of  compound  and  multiple- 
expansion  engines  increase  in  diameter  from  the  high-pressure 
to  the  low-pressure  end,  and  it  is  customary  to  refer  to  their 
relative  sizes  by  means  of  cylinder  ratios.  As  all  the  cylinders 
have  the  same  length  of  stroke,  the  volumes  of  the  several 
cylinders  are  in  proportion  to  the  areas  of  the  cylinders,  and 
therefore  in  proportion  to  the  squares  of  the  diameters.  The 
area  of  the  high-pressure  cylinder  is  taken  as  unity,  and  the 
other  areas  are  referred  to  it,  and  the  ratios  of  these  areas,  or 
the  ratios  of  the  squares  of  the  diameters,  are  called  the 
cylinder  ratios.  For  example,  a  triple-expansion  engine  having 
cylinders  12  in.,  20  in.,  and  34  in.,  in  diameter  will  have  the  cyl- 
inder ratios  of  12*  :  20"  :  34=,  or  144  :400  :  1,156,  which  reduces 
to  1  :  2.78  :  8.03;  that  is,  the  intermediate  cylinder  is  2.78  times 
as  large  as  the  high-pressure  cylinder,  and  the  low-pressure 
cylinder  is  8.03  times  as  large  as  the  high-pressure  cylinder. 
If  there  are  two  cylinders  to  one  stage  of  expansion,  as,  for 
example,  two  low-pressure  cylinders,  the  sum  of  their  areas 
must  be  used  in  rinding  the  cylinder  ratios.  Thus,  if  there 
had  been  two  24-in.  low-pressure  cylinders  instead  of  one  34-in. 
cylinder,  in  the  foregoing  case,  the  cy Under  ratios  would  have 
been  12*  :2Q2 :  2X242,  or  144  :  400  :  1,152,  which  reduces  to 
1  :  2.78  : 8. 

Horsepower  of  Compound  Engines. — The  indicated  horse- 
power of  a  compound  or  triple-expansion  engine  may  be  cal- 
culated from  the  indicator  diagrams  in  exactly  the  same  manner 
as  with  any  simple  engine,  considering  each  cylinder  as  a  simple 
engine  and  adding  the  horsepowers  of  the  several  cylinders 
together.  In  taking  the  indicator  cards  from  a  compound 
engine,  the  precaution  of  taking  the  cards  simultaneously 
from  all  cylinders  must  be  observed,  especially  when  the  engine 
runs  under  a  variable  load,  because,  otherwise,  an  entirely 
wrong  distribution  of  power  may  be  shown,  and  there  may  also 
be  a  great  variation  between  the  indicated  horsepower  really 


STEAM  ENGINES  195 

existing  and  that  calculated  from  diagrams  taken  at  different 
times. 

Referred  Mean  Effective  Pressure. — The  indicated  horse- 
power of  compound  engines  is  sometimes  found  by  referring 
the  mean  effective  pressure  of  the  high-pressure  cylinder  to 
the  low-pressure  cylinder  and  calculating  the  horsepower  of 
the  engine  on  the  assumption  that  all  the  work  is  done  in  the 
low-pressure  cylinder.  To  do  this,  the  mean  effective  pressures 
of  the  two  cylinders  are  found  from  indicator  diagrams;  the 
mean  effective  pressure  of  the  high -pressure  cylinder  is  then 
divided  by  the  ratio  of  the  volume  of  the  low-pressure  cylinder 
to  that  of  the  high -pressure  cylinder;  and  the  quotient  is 
added  to  the  mean  effective  pressure  of  the  low-pressure  cyl- 
inder, the  sum  being  the  referred  mean  effective  pressure.  This 
sum  is  then  taken  as  the  mean  effective  pressure  of  the  engine, 
and  the  area  of  the  low-pressure  piston  as  the  piston  area; 
with  these  data,  the  length  of  stroke  and  the  number  of  strokes, 
the  horsepower  is  computed  as  for  any  simple  engine.  In  the 
case  of  a  triple-expansion  engine,  the  mean  effective  pressures 
of  the  high-pressure  and  intermediate  cylinders  are  referred 
to  the  low-pressure  cylinder  and  added  to  its  mean  effective 
pressure.  Thus,  suppose  that  in  a  12",  20",  -and  34"X30" 
engine  the  mean  effective  pressures  are  83.2  lb.,  27.8  lb.,  and 

83  2 
10.6  lb.,  respectively.     Then,  the  referred   M.  E.   P.  is  — 

8.03 

27  8     10.6 

— I =  10.4  +  10+10.6  =  31  lb.,  and  this  value  must  be 

2.78        1 

substituted  for  P  on  finding  the  horsepower  of  the  engine. 
While  this  method  shortens  the  labor  of  computing  the  horse- 
power, it  obviously  does  not  show  the  distribution  of  work 
between  the  cylinders. 

Dynamometers.— Dynamometers  are  instruments  for  meas- 
uring power.  They  are  divided  into  two  main  classes:  absorp- 
tion dynamometers  and  transmission  dynamometers.  The  most 
common  form  of  absorption  dynamometer  is  the  Prony  brake, 
which  consists  simply  of  a  friction  brake  designed  to  absorb 
in  friction  and  measure  the  work  done  by  a  motor,  or  the  power 
given  out  by  a  shaft.  A  transmission  dynamometer  is  used 


196 


STEAM  ENGINES 


to  measure  the  power  required  to  drive  a  machine  or  do  other 
work;  thus,  to  determine  the  power  required  to  run  the  shafting 
in  a  mill,  a  transmission  dynamometer  would  be  interposed 
between  the  shafting  and  the  source  of  power,  and  by  suitable 
belt  connections  the  shafting  would  be  driven  through  the 
dynamometer,  from  which  the  power  could  be  determined.  As 
transmission  dynamometers  do  not  enter  into  the  work  of  the 
steam  engineer,  they  will  not  be  treated  of  here. 

Prony  Brake. — The  brake  horsepower  of  steam  engines  is 
commonly  determined  by  means  of  some  form  of  friction 
brake.  One  construction  of  Prony  brake  is  shown  in  Fig.  1. 
It  consists  of  two  wooden  blocks  a  and  b  formed  so  as  to  fit 


FIG.  1 

the  face  of  the  iron  pulley  c  on  the  shaft  of  the  engine  to  be 
tested.  To  the  blocks  are  fixed  the  two  long  arms  d  and  e, 
and  the  whole  is  clamped  together  by  means  of  the  bolts  /  and  g 
and  the  nuts  h  and  «.  By  tightening  these  nuts  the  blocks 
a  and  b  may  be  pressed  more  tightly  against  the  face  of  the 
pulley,  thus  increasing  the  friction  at  the  surface  of  the 
pulley.  If  the  engine  rotates  so  as  to  turn  the  pulley  in  the 
direction  indicated  by  the  arrow,  the  friction  on  the  face  of 
the  pulley  will  tend  to  drag  the  blocks  around  in  the  same 
direction;  but  as  the  end  of  the  arm  d  carries  a  spring  balance  j 
attached  to  a  stationary  support  k,  the  tendency  to  turn  is 
indicated  by  a  pull  on  the  spring  balance.  The  tighter  the 


STEAM  ENGINES 


197 


nuts  h  and  i  are  screwed  up,  the  greater  will  be  the  pull  exerted 
on  the  spring  balance.  The  arm  e  is  extended  and  fits  between 
two  stops  I  and  n,  so  as  to  prevent  excessive  movement  of  the 
brake.  While  a  test  is  being  made,  the  arm  e  should  not 
touch  either  stop.  This  can  easily  be  attained  by  regulating 
the  tightness  of  the  nuts  h  and  i.  The  stops,  however,  should 
never  be  dispensed  with,  as  a  sudden  reversal  of  the  engine  or 
an  unexpected  gripping  of  the  pulley  by  the  wooden  blocks 
might  swing  the  brake  arms  around  and  injure  the  workmen. 
The  distance  n  from  the  center  of  the  pulley  c  to  a  plumb- 
line  suspended  from  the  center  of  the  bolt  o  should  be  measured 
very  accurately,  with  the  arm  d  in  a  level  position.  This 


FIG.  2 


distance  n  is  used  in  determining  the  brake  horsepower,  as  will 
be  explained  later. 

Another  form  of  friction  brake  is  illustrated  in  Fig.  2.  In 
this  type,  there  are  a  number  of  wooden  blocks  a  fastened  to  an 
iron  band  b  and  surrounding  the  pulley  c.  The  friction 
between  the  blocks  and  the  pulley  may  be  altered  by  loosening 
or  tightening  the  nut  d  on  the  bolt  e  that  joins  the  ends  of 
the  band  b.  To  the  bands  are  fastened  the  arms  /,  which  are 
bolted  together  at  their  outer  ends  and  rest  on  a  knife  edge  g 
fastened  to  a  block  h  resting  on  a  platform  scales  *.  When  the 
pulley  is  rotated  in  the  direction  indicated  by  the  arrow,  the 
outer  ends  of  the  arms  /  press  down  on  the  block  h  and 


198 


STEAM  ENGINES 


the  pressure  may  be  measured  by  the  scales.  The  distance 
between  the  center  of  the  shaft  to  which  the  pulley  is  keyed 
and  the  knife  edge  g  should  be  measured  carefully,  as  it  repre- 
sents the  effective  length  of  the  brake  arm. 

Rope  Brake. — A  form  of  brake  requiring  less  space  than  the 
Prony  brake  is  the  rope  brake,  shown  in  Fig.  3.  It  is  used  in 
determining  the  horsepower  of  engines  of  moderate  size.  The 
pulley  a  on  the  engine  shaft  is  encircled  by  a  double  rope  b  to 
which  are  fixed  blocks  c  that  bear  against  the  face  of  the 

pulley.  One  end  of  the 
rope  is  attached  to  a 
spring  balance  d  sus- 
pended from  a  beam  e, 
and  the  other  end  car- 
ries a  weight  /  that  may 
be  varied.  The  friction 
of  the  brake  on  the 
pulley  is  increased  by 
adding  to  the  weight  /. 
The  direction  of  rota- 
tion is  indicated  by  the 
arrow.  The  brake  arm 
in  this  type  of  brake  is 
the  distance  from  the 
center  of  the  pulley  to 
the  center  of  the  rope, 
and  this  distance  should 
be  measured  very  care- 
fully and  quite  accu- 


, 


FIG.  3 


rately,  as  it  is  required  in  calculating  the  horsepower. 

Cooling  of  Brake  Pulleys. — It  is  essential  that  the  pulleys  of 
brakes  should  be  well  lubricated  and  for  all  except  small  powers, 
means  must  be  provided  for  conducting  away  the  heat  generated 
by  friction.  If  there  are  internal  flanges  on  the  brake  wheel, 
water  can  be  run  on  the  inside  of  the  rim,  the  flanges  serving 
to  retain  the  water  at  the  sides  and  centrifugal  force  to  keep  it 
in  contact  with  the  rim.  A  funnel-shaped  scoop  can  be  used 
to  remove  the  water.  It  should  be  attached  to  a  pipe  and 
placed  so  as  to  scoop  out  the  water,  which  should  flow 


STEAM  ENGINES  199 

continuously.  An  arrangement  of  this  kind  is  shown  in  Fig.  2, 
in  which  water  is  led  into  the  rim  of  the  pulley  by  the  pipe  j 
and  is  scooped  out  and  led  away  by  the  pipe  k. 

Data  for  Brake  Horsepower. — It  is  necessary  to  know  three 
factors  in  order  to  determine  the  brake  horsepower.  These  are 

(1)  the  net  pull  or  pressure  exerted  at  the  end  of  the  brake  arm, 

(2)  the  length  of  the  brake  arm,  and  (3)  the  number  of  revo- 
lutions per  minute  of  the  brake  pulley.      The  work  done  by 
the  engine  is  converted  into  heat  by  the  friction  between  the 
wooden  blocks  and  the  face  of  the  pulley,  and  the  resistance 
offered  by  the  brake  to  the  rotation  of  the  pulley  is  a  meas- 
ure  of   the   work   done.     This   resistance   cannot    always   be 
measured  conveniently  at  the  surface  of  the  pulley,  but  it  can 
be  measured  at  the  end  of  the  brake  arm  by  the  scales  or  the 
spring  balance. 

Net  Pull  or  Pressure. — With  the  brake  shown  in  Fig.  1, 
there  will  be  a  pull  in  the  spring  balance  due  to  the  weight  of 
the  arm  d,  when  the  nuts  h  and  i  are  slacked  and  the  brake  is 
loose  on  the  pulley.  This  pull  should  be  observed  carefully, 
and  should  be  subtracted  from  the  pull  registered  by  the  spring 
balance  during  a  test.  The  difference  will  be  the  net  pull, 
from  which  the  brake  horsepower  is  calculated.  If  the  arm  d 
is  counterbalanced  accurately  by  adding  weights  to  the  arm  e, 
as  shown  dotted  at  p,  it  will  be  unnecessary  to  perform  this 
subtraction.  The  net  pull  will  then  be  indicated  directly  by 
the  reading  of  the  spring  balance. 

The  net  pressure  must  also  be  calculated  if  the  brake  shown 
in  Fig.  2  is  used.  The  nut  d  should  be  loosened,  and  the  arms  / 
should  be  worked  up  and  down,  to  make  sure  thnt  the  blocks 
are  loose  on  the  pulley.  The  ends  of  the  arms  should  then  be 
rested  on  the  knife  edge  g  and  the  reading  of  the  scale  beam 
should  be  observed.  This  weight  represents  the  pressure  due  to 
the  block  h  and  the  unbalanced  arms  /,  and  it  must  be  sub- 
tracted from  the  reading  of  the  scale  beam  observed  during  a 
test  in  order  to  determine  the  net  pressure. 

In  the  case  of  the  rope  brake  shown  in  Fig.  3,  the  net  pull 
is  easily  determined  by  subtracting  the  reading  indicated 
by  the  spring  balance  from  the  weight,  in  pounds,  applied 
at/. 


200  STEAM  ENGINES 

Calculation   of   Brake   Horsepower.  —  When   the   necessary 
data,  as  previously  noted,  have  been  determined,  the  brake 
horsepower  may  be  calculated  by  the  formula 
2,r  R  WN 

Hb 


in  which  /?&  =  brake  horsepower; 
7T  =  3.1416; 

R  =  length  of  brake  arm,  in  feet; 
W  =  net  pull  or  pressure,  in  pounds; 
N  =  number  of  revolutions  per  minute. 

EXAMPLE.  —  A  Prony  brake  with  an  arm  6  ft.  long  was  placed 
on  the  flywheel  of  an  engine  running  at  200  R.  P.  M.  What 
brake  horsepower  was  being  developed  when  the  net  pressure 
was  140  lb.? 

SOLUTION.  —  Applying  the  formula, 

2X3.1416X6X140X200 


33,000 


CONDENSERS 

Types  of  Condensers. — There  are  two  types  of  condensers 
in  general  use,  namely,  the  surface  condenser  and  the  jet  con- 
denser. In  the  former,  the  exhaust  steam  comes  in  contact 
with  a  large  area  of  metallic  surface  that  is  kept  cool  by  con- 
tact with  cold  water.  In  the  latter,  the  exhaust  steam,  on 
entering  the  condenser,  comes  in  contact  with  a  jet  of  cold  water. 
In  either  case,  the  entering  steam  is  condensed  to  water,  and 
in  consequence  a  partial  vacuum  is  formed.  If  enough  cold 
water  were  used,  the  steam  on  entering  would  instantly  con- 
dense and  a  practically  perfect  vacuum  would  be  obtained 
were  it  not  for  the  fact  that  the  feedwater  of  the  boiler  always 
contains  a  small  quantity  of  air,  which  passes  with  the  exhaust 
steam  into  the  condenser  and  therefore  partly  destroys  the 
vacuum.  To  get  rid  of  this  air,  the  condenser  is  fitted  with  an 
air  pump,  which  pumps  out  both  the  air  and  the  water  formed 
by  condensation. 

Surface  Condensers. — In  the  surface  condenser,  the  exhaust 
steam  and  the  injection  water  are  kept  separate  throughout 


STEAM  ENGINES  201 

their  course  through  the  condenser;  and  the  condensed  steam 
leaves  the  condenser  as  fresh  water,  free  from  the  Impurities 
contained  in  the  injection  water.  The  water  of  condensation 
from  a  surface  condenser  is  therefore  fit  to  be  used  as  boiler 
feed,  except  that  it  contains  oil  used  for  cylinder  lubrication, 
which  can  be  eliminated  by  means  of  an  oil  separator,  regardless 
of  the  quality  of  the  water  used  to  condense  it.  It  is  for  this 
reason  that  the  surface  condenser,  in  spite  of  its  greater  com- 
plication, cost,  size,  and  weight,  as  compared  with  the  jet 
condenser,  is  used  instead  of  the  latter  where  the  supply  of 
injection  water  is  unfit  for  use  as  boiler  feed.  Thus,  the 
surface  condenser  is  used  altogether  in  marine  work,  except 
for  vessels  navigating  clean  fresh  water  like  that  of  the  Great 
Lakes,  in  order  to  avoid  the  use  of  sea-water  in  the  boilers. 

In  the  surface  condenser  the  steam  may  be  outside  and  the 
water  inside  the  tubes,  or  the  reverse.  If  the  water  is  inside 
the  tubes,  it  should  enter  at  the  bottom  of  the  condenser  and 
be  discharged  at  the  top.  This  brings  the  coldest  v/ater  into 
contact  with  the  partly  condensed  steam,  and  the  warmest 
water  into  contact  with  the  hot  entering  steam.  When  the 
water  is  outside  the  tubes,  it  is  necessary  to  fit  baffle  plates 
on  the  water  side  to  force  the  water  into  a  defihite  and  regular 
circulation,  and  to  prevent  it  from  going  directly  from  inlet 
to  outlet  and  also  to  prevent  the  water  from  arranging  itself 
in  layers  according  to  temperature,  with  the  coldest  water  on 
the  bottom  and  the  hottest  water  on  top.  The  outlet  should 
be  well  above  the  top- row  of  tubes.  A  solid  body  of  water 
above  the  top  row  of  tubes  is  thus  assured,  and  the  accumula- 
tion of  a  stagnant  body  of  hot  water  in  the  top  of  the  condenser 
is  prevented  by  its  being  continually  drawn  off  by  the  circu- 
lating pump  and  replaced  by  cooler  water  from  beneath. 

Air  tends  to  accumulate  in  the  top  of  the  water  side  of  a 
surface  condenser.  This  is  particularly  inconvenient  where  the 
water  is  inside  the  tubes,  as  the  air  fills  the  top  rows  of  tubes  and 
excludes  the  water,  destroying  their  value  as  cooling  surfaces. 
To  prevent  this,  an  air  valve  must  be  provided ,  as  high  up  on 
the  water  side  as  possible,  in  all  surface  condensers,  by  which 
the  air  can  be  drawn  off  whenever  it  becomes  troublesome. 
Drain  valves  and  pipes  should  be  provided  at  the  bottom. 


202  STEAM  ENGINES 

As  the  condensed  steam  from  the  surface  condenser  is  gen- 
erally pumped  back  into  the  boiler  as  feedwater,  it  is  desirable 
to  have  it  as  hot  as  possible;  but  it  must  be  remembered  that 
it  is  impossible  to  get  the  feedwater  from  the  condenser  at  a 
higher  temperature  than  that  of  saturated  steam  at  the  abso- 
lute pressure  existing  in  the  condenser. 

It  will  be  considerably  cooler  than  this  if,  after  being  con- 
densed, it  is  allowed  to  lie  in  the  bottom  of  the  condenser 
and  give  up  its  heat  to  the  circulating  water.  The  heat 
thus  given  up  is  a  total  loss,  and  should  be  avoided  by  con- 
necting the  air-pump  suction  to  the  lowest  point  of  the  con- 
denser and  by  shaping  the  bottom  of  the  condenser  so  that  the 
water  will  drain  rapidly  into  the  air-pump  suction. 

Cooling  Water  for  Surface  Condenser. — The  amount  of 
cooling  water  required  in  the  case  of  a  surface  condenser  may 
be  found  by  the  formula 

H-  (/-32) 

t»-h       ' 
in  which  Q  =  number  of  pounds  of  cooling  water  required  to 

condense  1  Ib.  of  steam; 
H  =  total  heat  above  32°  of   1  Ib.  of  steam  at  pressure 

at  release; 
<— -  temperature    of    condensed    steam    on    leaving 

condenser; 

t\  =  temperature  of  cooling  water  on  entering  con- 
denser; 

*2  =  temperature  of  cooling  water  on  leaving  condenser. 
EXAMPLE. — Steam  exhausts  into  a  surface  condenser  from 
an  engine  cylinder  at  a  pressure  of  fi  Ib.,  absolute;  the  tempera- 
ture of  the  condensing  water  on  entering  is  55°  P.,  and  on  leaving 
it  is  100°  F. ;  the  temperature  of  the  condensed  steam  on  leaving 
the  condenser  is  125°  F.  How  many  pounds  of  cooling  water 
are  required  per  pound  of  steam? 

SOLUTION. — The  total  of  1  Ib.  of  steam  at  6  Ib.,  absolute, 
from  the  Steam  Table,  is  1,133.8  B.  T.  U.  Then,  substituting 
the  values  of  H,  t,  t\,  and  fj  in  the  formula, 

l.i:«..X-(125-32)       1.040.8 
'--•       ,«,,  "      45 


STEAM  ENGINES  203 

Injection  Water  for  Jet  Condenser. — The  quantity  of  injec- 
tion water  required  for  a  jet  condenser  may  be  found  by  the 
formula 

H-(t-32) 

t-h         ' 
in  which  Q  =  number  of  pounds  of  injection  water  required  to 

condense  1  Ib.  of  steam; 
H  =  total  heat  above  32°  of  1  Ib.  of  steam  at  pressure 

at  release; 
t  =  temperature  of  mixture  of  injection  water  and 

condensed  steam  on  leaving  the  condenser; 
ti  =  temperature  of  injection  water  on  entering  the 

condenser. 

EXAMPLE. — Steam  is  exhausted  into  a  jet  condenser  from 
an  engine  cylinder  at  a  pressure  of  10  Ib.,  absolute;  the  temper- 
ature of  the  injection  water  on  entering  is  60°  P.,  and  on  leaving 
140°  F.  How  much  injection  water  is  required  per  pound  of 
steam? 

SOLUTION. — The  total  heat  above  32°  of  1  Ib.  of  steam  at 
10  Ib.  absolute,  from  the  Steam  Table,  is  1,140.9  B.  T.  U. 
Then,  substituting  the  values  of  H,  t,  and  h  in  the  formula, 
1,140.9-(140-32)_1.032.9 
140-60  80 


ENGINE  MANAGEMENT 

STARTING  AND  STOPPING 

Warming  Up. — About  15  or  20  min.  before  starting  the 
engine,  the  stop-valves  should  be  raised  just  off  their  seats 
and  a  little  steam  should  be  allowed  to  flow  into  the  steam 
pipe.  The  drain  cock  on  the  steam  pipe  just  above  the  throttle 
should  be  opened.  When  the  steam  pipe  is  thoroughly  warmed 
up  and  steam  blows  through  the  drain  pipe,  the  drain  cock 
should  be  closed  and  the  throttle  opened  just  enough  to  let  a 
little  steam  flow  into  the  valve  chest  and  cylinder;  or  if  a 
by-pass  around  the  throttle  is  fitted,  it  may  be  used.  The 
cylinder  relief  valves,  or  drain  cocks,  and  also  the  drain  cocks 


204  STEAM  ENGINES 

on  the  valve  chest  and  the  exhaust  pipe  should  be  opened, 
if  the  engine  is  non-condensing.  If  the  cylinders  are  jacketed, 
steam  should  be  turned  into  the  jackets  and  the  jacket  drain 
cocks  should  be  opened.  While  the  engine  is  warming  up, 
the  oil  cups  and  the  sight-feed  lubricator  may  be  filled.  A 
little  oil  may  be  put  into  all  the  small  joints  and  journals  that 
are  not  fitted  with  oil  cups.  The  guides  should  be  wiped  off 
with  oily  waste  and  oiled.  By  this  time  the  engine  is  get- 
ting warm.  If  the  cylinder  is  fitted  with  by-pass  valves,  they 
should  be  used  to  admit  steam  to  both  ends  of  the  cylinder. 
In  general,  all  cylinders,  especially  if  they  are  large  and  intricate 
castings,  should  be  warmed  up  slowly,  as  sudden  and  violent 
heating  of  a  cylinder  of  this  character  is  very  liable  to  crack 
the  casting  by  unequal  expansion. 

An  excellent  and  economical  plan  for  warming  up  the  steam 
pipe  and  the  engine  is  to  open  the  stop-valves  and  throttle 
valve  at  the  time  or  soon  after  the  fires  are  lighted  in  the 
boilers,  permitting  the  heated  air  from  the  boilers  to  circulate 
through  the  engine,  thus  warming  it  up  gradually  and  avoiding 
the  accumulation  of  a  large  quantity  of  water  of  condensation 
in  the  steam  pipe  and  cylinder.  When  pressure  shows  on  the 
boiler  gauge  or  steam  at  the  drain  pipes  of  the  engine,  the  stop- 
valves  and  throttle  may  be  closed  temporarily,  but  not  hard 
down  on  their  seats.  When  this  method  of  warming  up  the 
engine  is  adopted,  the  safety  valves  should  not  be  opened 
while  steam  is  being  raised. 

Danger  of  Water  Hammer. — Stop-valves  and  throttle  valves 
should  never  be  opened  quickly  or  suddenly  and  thus  permit 
a  large  volume  of  steam  to  flow  into  a  cold  steam  pipe  or  cylin- 
der. If  this  is  done,  the  first  steam  that  enters  will  be  con- 
densed and  a  partial  vacuum  will  be  formed.  This  will  be 
closely  followed  by  another  rush  of  steam  with  similar  results, 
and  so  on  until  a  mass  of  water  will  collect,  \vhich  will  rush 
through  the  steam  pipe  and  strike  the  first  obstruction,  gener- 
ally the  bend  in  the  steam  pipe  near  the  cylinder,  with  great 
force,  and  in  all  probability  will  carry  it  away  and  cause 
a  disaster.  This  is  called  -water  hammer  and  has  caused  many 
serious  accidents.  Before  turning  steam  into  any  pipe  line  or 
into  a  cylinder,  all  drain  valves  should  be  opened. 


STEAM  ENGINES  205 

Easing  of  Throttle  Valve. — Another  precaution  that  should 
be  taken  is  the  easing  of  the  throttle  valve  on  its  seat  before 
steam  is  let  into  the  main  steam  pipe;  otherwise,  the  unequal 
expansion  of  the  valve  casing  may  cause  the  valve  to  stick 
fast  and  thereby  give  much  trouble.  Even  if  a  by-pass  pipe 
is  fitted  around  the  throttle,  it  would  be  better  not  to  depend 
on  it.  Considerable  space  has  been  devoted  to  the  subject 
of  warming  up  and  draining  the  water  out  of  the  steam  pipe 
and  engine  on  account  of  its  importance.  Water  being  non- 
compressible,  it  is  an  easy  matter  to  blow  off  a  cylinder  head 
or  break  a  piston  if  the  engine  is  started  when  there  is  a  quan- 
tity of  water  in  the  cylinder. 

Oil  and  Grease  Cups. — The  last  thing  for  the  engineer  to  do 
before  taking  his  place  at  the  throttle  preparatory  to  starting 
the  engine,  provided  he  has  no  oiler,  is  to  start  the  oil  and 
grease  cups  feeding.  It  is  well  to  feed  the  oil  liberally  at  first, 
but  not  to  the  extent  of  wasting  it;  finer  adjustment  of  the 
oiling  gear  can  be  made  after  the  engine  has  been  running  a 
short  time  and  the  journals  are  well  lubricated. 

Starting  Non-Condensing  Slide-Valve  Engine. — A  non- 
condensing  slide-valve  engine  is  started  by  simply  opening  the 
throttle;  this  should  be  done  quickly  in  order  to  jump  the 
crank  over  the  first  dead  center,  after  which  the  momentum 
of  the  flywheel  will  carry  it  over  the  other  centers.  The 
engine  should  be  run  slowly  at  first,  gradually  increasing  the 
revolutions  to  the  normal  speed.  When  the  engine  has 
reached  full  speed,  the  drain  pipes  should  be  examined;  if  dry 
steam  is  blowing  through  them,  the  drain  cocks  should  be 
closed.  If  water  is  being  delivered,  the  drain  cocks  should 
remain  open  until  steam'  blows  through  and  should  then  be 
closed. 

Stopping  Non-Condensing  Slide-Valve  Engine. — To  stop 
a  non-condensing  slide-valve  engine,  it  is  only  necessary  to 
shut  off  the  supply  of  steam  by  closing  the  throttle,  but  care 
should  be  taken  not  to  let  the  engine  stop  on  the  dead  center. 
After  the  engine  is  stopped,  the  oil  feed  should  be  shut  off  and 
the  main  stop-valve  closed.  The  valve  should  be  seated, 
but  without  being  jammed  hard  down  on  its  seat.  The 
drain  cocks  on  the  steam  pipe  and  engine  may  or  may  not 
15 


206  STEAM  ENGINES 

be  opened,  according  to  circumstances.  It  will  do  no  harm 
to  allow  the  steam  to  condense  inside  the  engine,  as  the  engine 
will  then  cool  down  more  gradually,  which  lessens  the  danger 
of  cracking  the  cylinder  casting  by  unequal  contraction.  All 
the  water  of  condensation  should  be  drained  from  the  engine 
before  steam  is  again  admitted  to  it. 

Starting  Condensing  Slide-Valve  Engine. — Before  the  main 
engine  is  started,  the  air  pump  and  circulating  pump  should 
be  put  into  operation  and  a  vacuum  formed  in  the  condenser; 
this  will  materially  assist  the  main  engine  in  starting  promptly. 
Prior  to  starting  the  air  and  circulating  pumps,  the  injection 
valve  should  be  opened  to  admit  the  condensing  water  into 
the  circulating  pump;  the  delivery  valve  should  also  be  opened 
at  this  time.  If  an  ordinary  jet  condenser  is  used,  no  circu- 
lating pump  is  required,  the  water  being  forced  into  the  con- 
denser by  the  pressure  of  the  atmosphere.  If  the  air  pump  is 
operated  by  the  main  engine,  a  vacuum  will  not  be  formed 
in  the  condenser  until  after  the  engine  is  started  and  at  least 
one  upward  stroke  of  the  air  pump  is  made.  In  this  case 
the  injection  valve  must  be  opened  at  the  same  moment  the 
engine  is  started;  otherwise  the  condenser  will  get  hot  and  a 
mixture  of  air  and  steam  accumulate  in  it  and  prevent  the 
injection  water  from  entering.  When  this  occurs,  it  is  neces- 
sary to  pump  cold  water  into  the  condenser  by  one  of  the 
auxiliary  pumps  through  a  pipe  usually  fitted  for  that  purpose; 
if  such  a  pipe  has  not  been  provided,  it  may  be  found  neces- 
sary to  cool  the  condenser  by  playing  cold  water  on  it  through 
a  hose. 

Stopping  Condensing  Slide-Valve  Engine. — The  operation 
of  stopping  a  slide-valve  surface-condensing  engine  is  precisely 
similar  to  that  of  stopping  a  non-condensing  engine  of  the  same 
type,  with  the  addition  that  after  the  main  engine  is  stopped 
the  air  and  circulating  pumps  are  also  stopped,  and  in  the 
same  way,  that  is,  by  closing  the  throttle,  after  which  the 
injection  valve  and  the  discharge  valve  should  be  closed  and 
the  drain  cocks  opened.  With  a  jet  condenser,  the  operation 
of  stopping  the  engine  is  the  same  as  the  above,  with  the 
exception  that  the  injection  valve  should  be  closed  at  the  same 
moment  that  the  engine  is  stopped. 


STEAM  ENGINES  207 

Starting  Simple  Corliss  Engine. — In  the  Corliss  engine,  the 
eccentric  rod  is  so  constructed  and  arranged  that  it  may 
be  hooked  on  or  unhooked  from  the  eccentric  pin  on  the  wrist- 
plate  at  the  will  of  the  engineer.  After  all  the  preliminary 
operations  have  been  attended  to,  the  starting  bar  is  shipped 
into  its  socket  in  the  wristplate  and  the  throttle  is  opened. 
The  starting  bar  is  then  vibrated  back  and  forth  by  hand, 
by  which  the  steam  and  exhaust  valves  are  operated 
through  the  wristplate  and  valve  rods;  as  soon  as  the  cylinder 
takes  steam,  the  engine  will  start.  After  working  the  starting 
bar  until  the  engine  has  made  several  revolutions  and  the 
flywheel  has  acquired  sufficient  momentum  to*  carry  the 
crank  over  the  dead  centers,  the  hook  of  the  eccentric  rod 
should  be  allowed  to  drop  upon  the  pin  on  the  wristplate. 
As  soon  as  the  hook  engages  with  the  pin,  the  starting  bar  is 
unshipped  and  placed  in  its  socket  in  the  floor.  The  way  to 
determine  in  which  direction  the  starting  bar  should  be  first 
moved  to  start  the  engine  ahead  is  to  note  the  position  of  the 
crank,  from  which  the  direction  in  which  the  piston  is  to  move 
may  be  learned.  This  will  indicate  which  steam  valve  to- 
open  first;  it  will  then  be  an  easy  matter  to  determine  in  which 
direction  the  starting  bar  should  be  moved.  If  the  engine  is 
of  the  condensing  type,  the  same  course  of  procedure  in  starting 
the  air  and  circulating  pumps  should  be  followed  as  with  the 
simple  condensing  slide-valve  engine. 

Stopping  Simple  Corliss  Engine. — A  Corliss  engine  is  stopped 
by  closing  the  throttle  ahd  unhooking  the  eccentric  rod  from 
the  pin  on  the  wristplate;  this  is  done  by  means  of  the  unhook- 
ing gear  provided  for  the  purpose.  As  soon  as  the  eccentric 
rod  is  unhooked  from  the  pin,  the  starting  bar  is  shipped  into 
its  socket  in  the  wristplate  and  the  engine  is  worked  by  hand 
to  any  point  in  the  revolution  of  the  crank  at  which  it  is  desired 
to  stop  the  engine.  The  procedure  is  then  the  same  as  for  the 
simple  slide-valve  engine.  After  stopping  a  Corliss  condensing 
engine,  the  same  course  should  be  followed  as  with  a  slide- 
valve  condensing  engine  in  regard  to  draining  cylinders,  closing 
stop-valves,  etc. 

Starting  Compound  Slide-Valve  Engine. — Before  starting 
a  compound  engine,  the  high-pressure  cylinder  is  warmed  up 


208  STEAM  ENGINES 

in  the  same  manner  as  a  simple  engine.  To  get  the  steam 
into  the  low-pressure  cylinder  is,  however,  an  operation  that 
will  depend  on  circumstances.  If  the  cylinders  are  provided 
with  pass-over  valves,  it  will  be  necessary  only  to  open  them 
to  admit  steam  into  the  receiver  and  from  thence  into  the 
low-pressure  cylinder.  If  the  cylinders  are  not  fitted  with 
pass-over  valves,  the  steam  can  usually  be  worked  into  the 
receiver  and  low-pressure  cylinder  by  operating  the  high- 
pressure  valves  by  hand.  Sometimes  compound  engines  are 
fitted  with  starting  valves,  which  greatly  facilitate  the  oper- 
ations of  warming  up  and  starting.  Usually  a  compound 
engine  will  start  upon  opening  the  throttle. 

If  the  high-pressure  crank  of  a  cross-compound  engine  is 
on  its  center  and  the  low-pressure  engine  will  not  pull  it  off, 
it  must  be  jacked  off.  If  the  pressure  of  steam  in  the  receiver 
is  too  high,  causing  too  much  back  pressure  in  the  high-pressure 
cylinder,  the  excess  of  pressure  must  be  blown  off  through  the 
receiver  safety  valve;  if  the  pressure  in  the  receiver  is  too 
low  to  start  the  low-pressure  piston,  more  steam  must  be 
admitted  into  the  receiver.  If  the  engine  is  stuck  fast  from 
gummy  oil  or  rusty  cylinders,  all  wearing  surfaces  must  be 
well  oiled  and  the  engine  jacked  over  at  least  one  entire  revolu- 
tion. If  the  cut-offs  are  run  up,  they  should  be  run  down, 
full  open.  If  there  is  water  in  the  cylinders,  it  should  be  blown 
out  through  the  cylinder  relief  or  drain  valves,  and  if  there 
is  any  obstruction  to  the  engine  turning,  it  should  be  removed. 

If  the  crank  of  a  tandem  compound  engine  is  on  the  center, 
it  must  be  pulled  or  jacked  off.  If  the  high-pressure  crank 
of  a  cross-compound  engine  is  on  the  center,  it  may  or  may 
not  be  possible  to  start  the  engine  by  the  aid  of  the  low-pressure 
cylinder,  depending  on  the  valve  gear  and  the  crank  arrange- 
ment. When  the  cranks  are  180°  apart,  which  is  a  very  rare 
arrangement,  the  crank  must  be  pulled  or  jacked  off  the  center. 
When  the  cranks  are  90°  apart  and  a  pass-over  valve  is  fitted, 
live  steam  may  be  admitted  into  the  receiver  and  thence  into 
the  low-pressure  cylinder,  in  order  to  start  the  engine.  When 
no  pass-over  is  fitted,  but  the  engine  has  a  link  motion,  suffi- 
cient steam  to  pull  the  high-pressure  crank  off  the  center  can 
generally  be  worked  into  the  low-pressure  cylinder  by  working 


STEAM  ENGINES  209 

the  links  back  and  forth.  When  no  pass-over  is  fitted,  but  the 
high-pressure  engine  can  have  its  valve  or  valves  worked  by 
hand,  steam  can  be  got  into  the  low-pressure  engine  by  work- 
ing the  high-pressure  valve  or  valves  back  and  forth  by  hand. 
If  no  way  exists  of  getting  steam  into  the  low-pressure  cylinder 
while  the  high-pressure  crank  is  on  a  dead  center,  it  must  be 
pulled  or  jacked  off. 

If  the  air  and  circulating  pumps  are  attached  to  and  operated 
by  the  main  engine,  a  vacuum  cannot  be  generated  in  the 
condenser  until  after  the  main  engine  has  been  started.  Con- 
sequently, in  this  case,  there  is  no  vacuum  to  help  start  the 
engine;  therefore,  if  it  is  tardy  or  refuses  to  start,  it  will  be 
necessary  to  resort  to  the  jacking  gear  and  jack  the  engine 
into  a  position  from  which  it  will  start.  A  vacuum  having 
been  generated  in  the  condenser  beforehand,  the  pressure  in 
the  receiver  acting  on  the  low-pressure  piston  causes  the  engine 
to  start  promptly,  even  though  the  high-pressure  crank  may 
be  on  its  center. 

Stopping  Compound  Slide-Valve  Engine. — Compound  slide- 
valve  engines,  whether  condensing  or  non-condensing,  are 
stopped  by  closing  the  throttle,  and,  if  a  reversing  engine,  throw- 
ing the  valve  gear  into  mid-position.  If  the  stop  is  a  permanent 
one,  the  usual  practice  of  draining  the  engine,  steam  chests,  and 
receiver,  closing  stop- valves,  stopping  the  oil  feed,  etc.  should  be 
followed.  If  the  engine  is  intended  to  run  in  both  directions  in 
answer  to  signals,  as  in  the  cases  of  hoisting,  rolling-mill,  and 
marine  engines,  the  operator,  after  stopping  the  engine  to  signal, 
should  immediately  open  the  throttle  very  slightly,  in  order  to 
keep  the  engine  warm,  and  stand  by  for  the  next  signal.  If 
the  engine  is  fitted  with  an  independent  or  adjustable  cut-off 
gear,  it  should  be  thrown  off,  that  is,  set  for  the  greatest 
cut-off,  for  the  reason  that  the  engine  may  have  stopped  in  a 
position  in  which  the  cut-off  valves  in  their  early  cut-off  posi- 
tions would  permit  little  or  no  steam  to  enter  the  cylinders, 
in  which  case  the  engine  will  not  start  promptly,  and  perhaps 
nut  at  all.  While  waiting  for  the  signal,  the  cylinder  drain 
valves  should  be  opened  and  any  water  that  may  be  in  the 
cylinders  should  be  blown  out.  When  dry  steam  blows  through 
the  drains,  the  cylinders  are  clear  of  water. 


210  STEAM  EXGIXES 

When  the  signal  to  start  the  engine  is  received,  it  is  only 
necessary  to  throw  the  valve  gear  into  the  go-ahead  or  backing 
position,  as  the  signal  requires,  and  to  operate  the  throttle 
according  to  the  necessities  of  the  case,  for  which  no  rule  can 
be  laid  down  beforehand,  as  the  position  of  the  throttle  will 
depend  on  the  load  on  the  engine  at  the  time. 

Starting  and  Stopping  Compound  Corliss  Engine. — The 
operation  of  starting  and  stopping  a  compound  Corliss  engine 
is  precisely  similar  to  that  of  starting  and  stopping  a  simple 
Corliss  engine.  The  high-pressure  valve  gear  only  is  worked 
by  hand  in  starting,  the  low-pressure  eccentric  hook  having 
been  hooked  on  previously.  The  low-pressure  valve  gear  is 
worked  by  hand  only  while  warming  up  the  low-pressure  cylin- 
der. The  directions  given  for  operating  the  simple  condensing 
engine  apply  to  the  condensing  Corliss  engine,  so  far  as  the 
treatment  of  the  air  pump,  circulating  pump,  and  condenser 
is  concerned. 

POUNDING  OF  ENGINES 

Loose  Brasses. — Loose  journal  brasses  are  the  most  frequent 
cajse  of  pounding  in  engines.  The  remedy  for  pounding  of 
this  nature  is  obvious.  The  engine  should  be  stopped  and 
the  brasses  set  up  gradually  until  the  pounding  ceases.  In  the 
case  of  shaft  journals,  they  may  be  set  up  without  stopping 
the  engine,  provided  the  engineer  can  reach  them  without 
danger  of  being  caught  in  the  machinery. 

Brass-Bound  Bearings. — It  may  so  happen  that  the  boxes 
or  brasses  are  worn  down  until  the  edges  of  the  upper  half 
and  those  of  the  lower  half  are  in  contact  and  cannot  be  set 
up  on  the  journal  any  farther;  they  are  then  said  to  be  brass 
and  brass,  or  brass-bound.  In  a  case  of  this  kind,  the  journal 
must  be  stripped,  as  it  is  called,  when  the  cap  and  brasses 
are  removed  from  a  journal.  The  edges  of  the  brasses  are 
then  chipped  or  filed  off,  in  order  to  allow  them  to  be  closed  in. 

Liners. — It  is  a  most  excellent  plan  in  practice  to  reduce 
the  halves  of  the  brasses  so  that  they  will  stand  off  from  each 
other  when  in  place  for  a  distance  of  J  to  A  in.  and  to  till  this 
space  with  hard  sheet-brass  liners  from  20  to  22  Birmingham 
wire  gauge  in  thickness,  or  even  thinner.  Should  the  journal 
become  brass-bound,  the  cap  may  be  slacked  off  and  a  pair 


STEAM  ENGINES  211 

of  the  liners  slipped  out  without  the  necessity  of  stripping  the 
journal. 

In  some  instances  journal-boxes  are  fitted  with  keepers,  or 
chipping  pieces,  as  they  are  sometimes  called.  These  usually 
consist  of  cast-brass  liners  from  i  to  |  in.  in  thickness, 
having  ribs  or  ridges  cast  on  one  side,  for  convenience  of 
chipping  and  filing.  These  keepers  are  sometimes  made  of 
hardwood  and  are  capable  of  being  compressed  slightly  by  the 
pressure  exerted  upon  them  during  the  setting-up  process. 
When  the  boxes  are  babbitted,  the  body  of  the  box  is  occasion- 
ally made  of  cast  iron,  in  which  case  iron  liners  and  keepers 
are  used  instead  of  brass  ones. 

Loose  Thrust  Block. — In  engines  fitted  with  some  types  of 
friction  couplings,  there  is  a  thrust  exerted  upon  the  shaft 
in  the  direction  of  its  length.  This  will  necessitate  having  a 
thrust  bearing,  or  thrust  block,  as  it  is  sometimes  called.  There 
are  a  number  of  types  of  thrust  bearings,  but  the  most  common 
is  the  collar  thrust,  which  consists  of  a  series  of  collars  on  the 
shaft  that  fit  in  corresponding  depressions  in  the  bearing. 
If  these  collars  do  not  fit  in  the  depressions  rather  snugly, 
the  shaft  will  have  end  play  and  there  probably  will  be  more 
or  less  pounding  or  backlash  at  every  change  of  load  on  the 
engine.  This  can  be  remedied  only  by  putting  in  a  new 
thrust  bearing  and  making  a  better  fit  with  the  shaft  collars, 
unless  the  rings  in  the  bearing  are  adjustable,  in  which  case 
the  end  play  may  be  taken  up  by  adjusting  the  rings. 

Water  in  Cylinders. — Pounding  often  occurs  in  the  cylinders 
and  is  frequently  caused  by  water  due  to  condensation  or 
carried  over  from  the  boilers.  This  may  be  a  warning  that 
priming  is  likely  to  occur  in  the  boilers  or  has  already  com- 
menced. If  the  cylinders  are  not  fitted  with  automatic  relief 
valves,  the  drain  cocks  should  be  opened  as  quickly  as  possible 
and  the  throttle  closed  a  little  to  check  the  priming. 

Loose  Piston. — Another  source  of  pounding  in  the  cylinder 
is  a  piston  loose  on  the  rod;  this  will  result  if  the  piston-rod 
nut  or  key  backs  off  or  the  riveting  becomes  loose,  permitting 
the  piston  to  play  back  and  forth  on  the  piston  rod.  If  due 
to  backing  off  of  the  nut,  the  engine  should  be  shut  down 
instantly.  There  is  generally  very  little  room  to  spare  between 


212  STEAM  ENGINES 

the  piston-rod  nut  and  the  cylinder  head;  therefore,  it  cannot 
back  off  very  far  before  it  will  strike  and  break  the  cylinder 
head.  After  the  engine  is  stopped  and  the  main  stop-valve 
is  closed,  the  cylinder  head  should  be  taken  off  and  the  piston 
nut  set  up  as  tightly  as  possible.  As  a  measure  of  safety, 
a  taper  split  pin  should  in  all  cases  be  fitted  through  the  piston 
rod  behind  the  nut  or  a  setscrew  should  be  fitted  through  the 
nut. 

Slack  Follower  Plate. — A  slack  follower  plate  or  junk  ring 
will  cause  pounding  in  the  cylinder.  It  seldom  happens,  how- 
ever, that  all  the  follower  bolts  back  out  at  one  time,  but 
it  is  not  an  infrequent  occurrence  that  one  of  the  follower 
bolts  works  itself  out  altogether.  This  is  a  very  dangerous 
condition  of  affairs,  especially  in  a  horizontal  engine.  If  the 
bolts  should  get  end  on  between  the  piston  and  cylinder 
head,  either  the  piston  or  the  cylinder  head  is  bound  to  be 
broken.  Therefore,  if  there  is  any  intimation  that  a  follower 
bolt  is  adrift  in  the  cylinder,  the  correct  procedure  is  to  shut 
down  the  engine  instantly,  take  off  the  cylinder  head,  remove 
the  old  bolt,  and  put  in  one  having  a  tighter  fit. 

Broken  Piston  Packing. — Broken  packing  rings  and  broken 
piston  springs  will  cause  noise  in  the  cylinder,  but  it  is  more  of 
a  rattling  than  a  pounding,  and  the  sound  will  easily  be  recog- 
nized by  the  practiced  ear.  There  is  not  so  much  danger  of 
a  breakdown  from  these  causes  as  may  be  supposed,  from 
the  fact  that  the  broken  pieces  are  confined  within  the  space 
between  the  follower  plate  and  the  piston  flange. 

Piston  Striking  Heads. — Pounding  in  the  cylinders  of  old 
engines  is  often  produced  by  the  striking  of  the  piston  against 
one  or  the  other  cylinder  head.  One  of  the  causes  of  this 
is  the  wearing  away  of  the  connecting-rod  brasses.  Keying 
up  the  brasses  from  time  to  time  has  the  effect  of  lengthening 
or  shortening  the  connecting-rod,  depending  on  the  design, 
and  this  change  in  length  destroys  the  clearance  at  one  end 
of  the  cylinder  by  an  equal  amount.  The  remedy  is  to  restore 
the  rod  to  its  original  length  by  placing  sheet-metal  liners 
behind  the  brasses;  this  obviously  will  move  the  piston  back 
or  ahead  and  restore  the  clearance.  A  rather  rare  case  of  the 
piston  striking  the  cylinder  head  is  due  to  unscrewing  of  the 


STEAM  ENGINES  213 

piston  rod  from  the  crosshead,  in  case  it  is  fastened  by  a  thread 
and  check-nut.  To  obviate  any  danger,  the  check-nut  should 
be  tried  frequently. 

Improper  Steam  Distribution. — The  primary  cause  of  another 
source  of  pounding  is  the  improper  setting  of  the  steam  valve, 
or  possibly  its  improper  design.  In  the  case  of  improper 
setting  of  the  valve,  insufficient  compression,  insufficient  lead, 
cut-off  too  early,  and  late  release  may  all  cause  pounding  on 
the  centers. 

Reversal  of  Pressure. — The  effect  of  a  reversal  of  pressure 
is  clearly  shown  in  the  accompanying  illustration.  With  the 
crankpin  at  a  and  the  engine  running  in  --^^ir-^ 

the  direction  indicated  by  the  arrow, 
the  connecting-rod  is  subjected  to  a 
pull,  but  after  the  crankpin  has  passed 
the  dead  center  c,  the  connecting-rod  is 
subjected  to  a  push,  in  which  case  the 
rear  brass,  as  shown  at  b,  bears  against 

the  crankpin,  while  in  the  former  case,  ^" *' 

as  shown  at  a,  the  front  brass  bears  against  the  crankpin. 
By  giving  a  sufficient  amount  of  compression,  the  lost  motion 
in  the  pins  and  journals  is  transferred  gently  from  one  side 
to  the  other  before  the  crankpin  reaches  the  dead  center.  If 
the  compression  is  insufficient,  there  will  be  pounding. 

Insufficient  Lead. —  Insufficient  lead  causes  an  engine  to 
pound  because  the  piston  has  then  little  or  no  cushion  to 
impinge  on  as  it  approaches  the  end  of  its  stroke,  and  it  is 
brought  to  rest  with  a  jerk.  A  similar  effect  will  be  produced 
by  a  late  release;  the  pressure  is  retained  too  long  on  the 
driving  side  of  the  piston.  The  ideal  condition  is  that  the 
pressures  shall  be  equal  on  both  sides  of  the  piston  at  a  point 
in  its  travel  just  in  advance  of  the  opening  of  the  steam  port. 
The  position  of  this  point  varies  Vvith  the  speed  of  the  piston 
and  other  conditions  that  only  the  indicator  card  can  reveal. 

Pounding  at  Crosshead. — The  crosshead  is  a  source  of 
pounding  from  various  causes,  of  which  the  loosening  of  the 
piston  rod  is  one  of  the  most  common.  There  are  several 
methods  of  attaching  the  piston  rod  to  the  crosshead.  The 
rod  may  pass  through  the  crosshead  with  a  shoulder  or  a 


L>1 5  STEAM  EXC.IXES 

taper,  or  both,  on  one  side  of  the  crosshead  and  a  nut  on  the 
other;  or  the  rod  may  be  secured  to  the  crosshead  by  a  cotter, 
instead  of  the  nut;  or  the  end  of  the  rod  may  be  threaded  and 
screwed  into  the  crosshead,  having  a  check-nut  to  hold  the  rod 
in  place.  In  the  case  first  mentioned,  the  nut  may  work 
loose,  which  would  cause  the  crosshead  to  receive  a  violent 
blow,  first,  by  the  nut  on  one  side  and  then  by  the  shoulder 
or  taper  on  the  other  at  each  change  of  motion  of  the  piston. 
The  remedy  is  to  set  up  the  nut.  A  similar  effect  will  be 
produced  if  the  cotter  should  work  loose  and  back  out.  In 
case  the  piston  rod  is  screwed  into  the  crosihead  and  the  rod 
slacks  back,  the  danger  is  that  the  piston  will  strike  the  rear 
cylinder  head.  The  check-nut  should  be  closely  watched. 
Pounding  at  the  crosshead  may  be  due  to  loose  wristpin  brasses, 
in  which  case  they  should  be  set  up,  but  not  too  tightly.  In 
case  a  crosshead  works  between  parallel  guides,  pounding  may 
be  caused  if  the  crosshead  is  too  loose  between  the  guides, 
and  the  crosshead  shoes  should  therefore  be  set  out. 

If  pounding  results  from  the  wearing  down  of  the  shoe  of 
a  slipper  crosshead,  a  liner  should  be  put  between  the  shoe  and 
the  foot  of  the  crosshead  or  the  shoe  should  be  set  out  by  the 
adjustment  provided. 

Pounding  in  Air  Pump. — Pounding  in  the  air  pump  is  gener- 
ally produced  by  the  slamming  of  the  valves,  caused  by  an 
undue  amount  of  water  in  the  pump,  which  will  usually  relieve 
itself  after  a  few  strokes.  The  pump  piston,  however,  may 
be  loose  on  the  piston  rod  or  the  piston  rod  may  be  loose  in 
the  crosshead.  A  broken  valve  may  also  cause  pounding  in 
the  air  pump,  all  of  which  must  be  repaired  as  soon  as  detected. 

Pounding  in  Circulating  Pump. — In  a  circulating  pump  of 
the  reciprocating  type,  pounding  may  be  caused  by  admitting 
too  little  injection  water,  and  the  pounding  n:ay  be  stopped 
by  adjusting  the  injection  valve  to  admit  just  the  right  quantity. 
It  may  so  happen,  however,  that  the  injection  water  is  very 
cold,  and  to  admit  enough  of  it  to  stop  the  pounding  in  the 
circulating  pump  will  make  the  feedwater  too  cold.  To 
meet  this  contingency,  an  air  check-valve  is  often  fitted  to  the 
circulating  pump  to  admit  air  into  the  barrel  of  the  pump  as 
a  cushion  for  the  piston;  this  check- valve  may  be  kept  closed 


STEAM  ENGINES  215 

when  not  needed  to  admit  air.  A  broken  valve,  a  piston  loose 
on  its  piston  rod,  and  a  piston  rod  loose  in  the  crosshead  will 
all  cause  pounding  in  the  circulating  pump;  they  should  be 
treated  in  the  same  manner  as  was  specified  for  similar  troubles 
in  the  air  pump. 

HOT  BEARINGS 

Mixtures  for  Reducing  Friction. — Should  any  of  the  bearings 
show  an  inclination  to  hsat  to  an  uncomfortable  point  when 
felt  by  the  hand,  the  oil  feed  should  be  increased.  If  the 
bearing  continues  to  get  hotter,  some  flake  graphite  should  be 
mixed  with  the  oil  and  the  mixture  should  be  fed  into  the 
bearing  through  the  oil  holes,  between  the  brasses,  or  wherever 
else  it  can  be  forced  in.  A  little  aqua  ammonia  introduced 
into  a  hot  bearing  will  sometimes  check  heating  by  converting 
the  oil  into  soap  by  saponification,  soap  being  an  excellent 
lubricant.  Mineral  oils  will  not  saponify. 

Danger  of  Increasing  Heating. — If,  after  trying  the  remedies 
just  mentioned,  the  bearing  continues  to  grow  hotter,  to  the 
extent,  for  instance,  of  scorching  the  hand  or  burning  the  oil, 
it  indicates  that  the  brasses  have  been  expanded  by  the  heat 
and  that  they  are  gripping  the  journal  harder  and  harder 
the  hotter  they  get.  At  this  stage,  if  the  engine  is  not  stopped 
or  if  the  heating  is  not  checked,  the  condition  of  the  bearing 
will  continue  to  grow  worse  as  long  as  the  engine  is  running, 
and  may  become  so  bad  as  to  slow  down  and  eventually  stop 
the  engine  by  excessive  friction.  By  this  time  the  brasses 
and  journal  will  be  badly  cut  and  in  bad  condition  generally, 
and  the  engine  must  be  laid  up  for  repairs. 

Remedies  for  Increasing  Heat. — The  state  of  affairs  just 
mentioned  should  not  be  permitted  to  be  reached.  After 
the  simple  remedies  previously  given  have  been  tried  and 
failed  to  produce  the  desired  results,  the  engine  should  be 
stopped  and  the  cap  or  key  of  the  hot  bearing  should  be  slacked 
back  and  the  engine  allowed  to  stand  until  the  bearing  has 
cooled  off.  If  necessity  requires  it,  the  cooling  may  be  hastened 
by  pouring  cold  water  oil  the  bearing,  though  this  is  objection- 
able, as  it  may  cause  the  brasses  to  warp  or  crack.  Putting 
water  on  a  very  hot  bearing  should  be  resorted  to  only  in  an 
emergency,  that  is,  when  an  engine  must  be  kept  running. 


216  STEAM  ENGINES 

Water  may  be,  used  on  a  moderately  hot  bearing  without  doing 
very  much  harm.  It  is  quite  common  in  practice,  when 
sprinklers  are  fitted  to  an  engine,  to  run  a  light  spray  of  water 
on  the  crankpins  when  they  show  a  tendency  to  heat,  with  very 
beneficial  results. 

Dangerous  Heating. — Should  a  bearing  become  so  hot  as 
to  scorch  the  hand  or  to  burn  oil  before  it  is  discovered  or 
because  of  the  necessity  of  keeping  the  engine  running  from 
some  cause,  it  is  imperative  that  the  engine  should  be  stopped, 
at  least  long  enough  to  loosen  up  the  brasses,  even  though  it 
is  necessary  to  start  up  again  immediately;  otherwise  the 
brasses  will  be  damaged  beyond  repair  and  deep  grooves 
will  be  cut  into  the  journals.  If  the  brasses  are  babbitted, 
the  white  metal  will  melt  out  of  the  bearing  at  this  stage. 
The  engine  will  then  be  disabled,  and  if  there  is  not  a  spare 
set  of  brasses  on  hand,  it  will  be  inoperative  until  the  old 
brasses  are  rebabbitted  or  until  a  new  set  is  made  and 
fitted. 

Running  Engine  With  Hot  Bearing. — If  it  is  absolutely 
necessary  in  an  emergency  to  keep  the  engine  running  while 
a  bearing  is  very  hot,  the  engineer  must  exercise  his  best 
judgment  as  to  how  he  shall  proceed.  After  slacking  off  the 
brasses,  about  the  best  he  can  do  is  deluge  the  inside  of  the 
bearing  with  a  mixture  of  oil  and  graphite,  sulphur,  soap- 
stone,  etc.,  and  the  outside  with  cold  water  from  buckets, 
sprinklers,  or  hose,  taking  the  chances  of  ruining  the  brasses 
and  cutting  the  journal. 

Refitting  Cut  Bearing. — The  wearing  surfaces  of  the  brasses 
and  journal  must  be  smoothed  off  as  well  as  circumstances 
will  permit;  but  if  the  grooves  are  very  deeply  cut,  it  will 
be  useless  to  attempt  to  work  them  out  entirely,  and  if  the 
brasses  are  very  much  warped  or  badly  cracked,  it  will  be  best 
to  put  in  spare  ones,  if  any  are  on  hand.  If  not,  the  old  ones 
must  be  refitted  and  used  until  a  new  set  can  be  procured. 
As  for  the  journal,  it  is  permanently  damaged.  Temporary 
repairs  can  be  made  by  smoothing  down  the  journal  and 
brasses;  but  at  the  first  opportunity  the  journal  should  be 
turned  in  a  lathe  and  the  brasses  properly  refitted  or  replaced 
with  new  ones. 


STEAM  ENGINES  217 

Newly  Fitted  Bearings. — The  bearings  of  new  engines  are 
particularly  liable  to  heat,  as  the  wearing  surfaces  of  the 
brasses  and  journal  have  just  been  machined  and  hence  are 
comparatively  rough.  The  conditions  just  mentioned  also 
exist  with  new  brasses  and  the  journals  of  an  old  engine.  If 
a  new  engine  or  one  with  new  brasses  is  run  moderately,  in 
regard  to  both  speed  and  load,  and  with  rather  loose  brasses, 
there  will  be  little  danger  of  hot  bearings,  provided  proper 
attention  is  given  to  adjustment  and  lubrication.  This  is 
what  is  familiarly  termed  wearing  dawn  the  bearings. 

Brasses  Too  Tight. — When  the  brasses  of  an  engine  bearing 
are  set  up  too  tight,  heating  is  inevitable.  It  is  often  the 
case  that  an  attempt  is  made  to  stop  a  pound  in  an  engine  by 
setting  up  the  brasses  when  the  thump  should  be  stopped  in 
some  other  way.  The  brasses  should  be  slacked  off  as  soon 
as  possible.  As  a  matter  of  fact,  hot  bearings  should  never 
occur  from  this  cause. 

Brasses  Too  Loose. — Bearings  may  heat  because  the  brasses 
are  too  loose.  The  heating  is  caused  by  the  hammering  of  the 
journal  against  the  brasses  when  the  crankpin  is  passing  the 
dead  centers.  The  derangement  is  easily  remedied,  however, 
by  setting  up  the  cap  nuts  or  the  key.  Most  engineers  have 
their  own  views  regarding  the  setting  up  of  bearings.  One 
method  is  to  set  up  the  cap  nuts  or  key  nearly  solid  and  then 
slack  them  back  half  way;  if  the  brasses  are  still  too  loose,  they 
are  set  up  again  and  slacked  back  less  than  before,  repeating 
this  operation  until  there  is  neither  thumping  nor  heating. 

Another  method  of  setting  up  journal  brasses  is  to  fill  up 
the  spaces  between  the  brasses  with  thin  metal  liners,  from 
18  to  22  Birmingham  wire  gauge  in  thickness,  and  a  few  paper 
liners  for  fine  adjustment.  Enough  of  these  should  be  put 
in  to  cause  the  brasses  to  set  rather  loosely  on  the  journal 
when  the  cap  nuts  or  keys  are  set  up  solid.  The  engine  should 
be  run  for  a  while  in  that  condition;  then  a  pair  of  the  liners 
should  be  removed  and  the  brasses  set  up  solid  again.  This 
operation  should  be  repeated  until  there  is  neither  thumping 
nor  heating.  It  may  require  a  week  or  more,  and  with  a  large 
engine  longer,  to  reach  the  desired  point.  If  this  system  is 
carefully  carried  out,  there  will  be  very  little  danger  of  heating. 


218  STEAM  ENGINES 


In  removing  the  liners,  great  care  should  be  exercised  not 
disturb  the  brasses  any  more  than  is  absolutely  necessary. 

Warped  and  Cracked  Brasses. — Warped  and  cracked  brasses 
will  cause  heating,  because  they  do  not  bear  evenly  on  the 
journal,  and  hence  the  friction  is  not  distributed  evenly  over 
the  entire  surface.  If  the  distortion  is  not  too  great,  the 
brasses  may  be  refitted  to  the  journal  by  chipping,  filing,  and 
scraping;  but  if  they  are  twisted  so  much  that  they  cannot, 
within  reasonable  limits,  be  refitted,  nothing  will  do  but  new 
brasses. 

Cut  Brasses  and  Journals. — Brasses  and  journals  that  have 
been  hot  enough  to  be  cut  and  grooved  are  liable  to  heat  up 
again  any  time  on  account  of  the  roughness  of  the  wearing 
surfaces.  As  long  as  the  grooves  in  the  journal  are  parallel 
and  match  the  grooves  in  the  brasses,  the  friction  is  not  greatly 
increased;  but  if  a  smooth  journal  is  placed  between  brasses 
that  ara  grooved  and  pressure  is  applied,  the  journal  crushes 
the  grooves  in  the  brasses  and  becomes  brazed  or  coated  with 
brass,  and  then  heating  results.  The  way  to  prevent  heating 
from  this  cause  is  to  work  the  grooves  out  of  the  journal  and 
brasses  by  filing  and  scraping  as  soon  as  possible  after  they 
occur. 

Imperfectly  Fitted  Brasses. — Faulty  workmanship  is  a  com- 
mon cause  of  the  heating  of  crankpins,  wristpins,  and  bear- 
ings. The  brasses  in  that  case  do  not  bear  fairly  and  squarely, 
even  though  they  appear  all  right  to  the  eye.  A  crankpin 
brass  must  fit  squarely  on  the  end  of  the  connecting-rod  and 
the  rod  itself  must  be  square.  If  the  key,  when  driven,  forces 
the  brasses  to  one  side  or  the  other  and  twists  the  strap  on  the 
rod,  it  will  draw  the  brasses  slantwise  on  the  pin  and  make 
them  bear  harder  on  one  side  than  on  the  other,  thus  reducing 
the  area  of  the  bearing  surfaces.  The  same  is  true  of  the  shaft 
bearings.  If  the  brasses  do  not  bed  fairly  on  the  bottom  of 
the  pillow-block  casting  or  do  not  go  down  evenly,  without 
springing  in  any  way,  heating  will  result. 

Edges  of  Brasses  Pinching  Journal. — Brasses,  when  first 
heated  by  abnormal  friction,  tend  to  expand  along  the  surface 
in  contact  with  the  journal;  this  would  open  the  brass  and 
make  the  bore  of  larger  diameter  were  it  not  prevented  by  the 


- 


STEAM  ENGINES  219 

cooler  part  near  the  outside  and  by  the  bedplate  itself.  If 
the  brass  has  become  hot  quickly  and  excessively,  the  resist- 
ance to  expansion  produces  a  permanent  set  on  the  layers  of 
metal  near  the  journal,  so  that  on  cooling,  the  brass  closes  and 
grips  the  journal.  This  is  why  some  bearings  always  run  a 
trifle  warm  and  will  not  work  cool.  A  continuance  of  heating 
and  cooling  will  set  up  a  bending  action  at  the  middle  of  the 
brass,  which  must  eventually  end  in  cracking  it.  Heating 
produced  in  this  way  may  be  prevented  by  chipping  off  the 
brasses  at  their  edges  parallel  to  the 
journal,  as  shown  at  a  in  the  accom- 
panying illustration,  in  which  b  is  -a 
section  of  the  journal  and  c  and  d 
represent  the  top  and  bottom  brasses, 
respectively. 

Stopped  Oil  Feed. — It  does  not  take 
long  for  a  bearing  to  get  very  hot  if  it 
is  deprived  of  oil.  The  two  principal 
causes  of  dry  bearings  are  an  oil  cup 
that  has  stopped  feeding,  either  by  reason  of  being  empty  or 
by  being  clogged  up  from  dirt  in  the  oil,  and  oil  holes  and 
oil  grooves  stopped  up  with  dirt  and  gum. 

Insufficient  Oil. — The  effect  produced  upon  a  bearing  by 
an  insufficient  oil  supply  is  similar  to  that  of  no  oil,  but  in  a 
less  degree.  Of  course,  it  will  take  longer  for  a  bearing  to  heat 
with  insufficient  oil  than  with  none  at  all,  and  the  engineer 
has  more  time  in  which  to  discover  and  remedy  the  difficulty. 

Dirty  and  Gritty  Oils. — Oils  that  contain  dirt  and  grit  are 
prolific  sources  of  hot  bearings.  There  is  a  great  deal  of  dirt 
in  lubricating  oils  of  the  average  quality;  therefore,  all  oil 
should  be  strained  through  a  cloth  or  filtered,  no  matter  how 
clear  it  looks.  All  oil  cups,  oil  cans,  and  oil  tubes  and  channels 
should  be  cleaned  out  frequently.  Oil  may  be  removed  from 
the  cups  by  means  of  an  oil  syringe,  and  all  oil  removed  from 
the  cups  and  cans  should  be  strained  or  filtered  before  being 
used. 

Oils  of  Poor  Quality. — There  are  on  the  market  many 
lubricating  oils  whose  quality  cannot  be  definitely  decided 
on  without  an  actual  trial,  and  it  is  a  difficult  matter  to  avoid 


220  STEAM  ENGINES 

getting  a  bad  lot  of  oil  sometimes.  About  the  only  safe  way 
to  meet  this  trouble  is  to  pay  a  fair  price  to  a  reputable  dealer 
for  oil  that  is  known  to  be  of  good  quality,  unless  the  purchaser 
is  expert  in  judging  oils. 

Oil  Squeezed  Out  of  Bearings. — Bearings  carrying  very 
heavy  shafts  sometimes  refuse  to  take  the  oil;  or,  if  they  do, 
it  is  squeezed  out  at  the  ends  of  the  brasses  or  through  the  oil 
holes,  and  then  the  journal  will  run  dry  and  heat.  Large 
journals  require  oil  of  a  high  degree  of  viscosity,  or  heavy  oil, 
as  it  is  popularly  called.  Oil  of  this  character  has  more  diffi- 
culty in  working  its  way  under  a  heavy  shaft  than  a  thin  oil 
has,  but  thin  oil  has  not  the  body  necessary  to  lubricate  a 
large  journal. 

This  difficulty  may  be  met  by  chipping  oil  grooves  or  channels 
in  the  brasses.  A  round-nosed  cape  chisel,  slightly  curved,  is 
generally  used  for  this  purpose;  care  should  be  taken  to  smooth 
off  the  burrs  made  by  the  chisel,  which  may  be  done  with  a 
steel  scraper  or  the  point  of  a  flat  file.  The  grooves  are  usually 
cut  into  the  brass  in  the  form  of  a  V  if  the  engine  is  required 
to  run  in  only  one  direction;  if  it  is  to  run  in  both  directions 
the  grooves  should  form  an  X.  In  the  first  instance,  care 
must  be  taken  that  the  V  opens  in  the  direction  of  rotation 
of  the  shaft;  that  is,  the  grooves  should  spread  out  from  their 
junction  in  the  same  direction  as  that  in  which  the  journal 
turns.  The  oil  grooves  may  be  about  J  in.  wide  and  J  in.  deep, 
and  semicircular  in  cross-section. 

Grit  in  Bearings. — Grit  is  an  ever-present  source  of  heating 
of  bearings,  and  only  by  persistent  effort  can  the  engineer 
keep  machinery  running  cool  in  a  dirty  atmosphere.  The 
machinery  of  coal  breakers,  stone  crushers,  and  kindred  indus- 
tries is  especially  liable  to  be  affected  in  this  way.  Work  done 
on  a  floor  over  an  engine  shakes  dirt  down  upon  it  at  some 
time  or  other;  hence,  all  floors  over  engines  should  be  made 
dust-proof  by  laying  paper  between  the  planks.  If  the  engine 
room  and  firerooms  communicate,  and  piles  of  red-hot  clinkers 
and  ashes  are  deluged  with  buckets  of  water,  the  water  is 
instantly  converted  into  a  large  volume  of  steam,  carrying 
with  it  small  particles  of  ashes  and  grit  that  penetrate  into 
every  nook  and  cranny,  and  these  will  find  their  way  intc  the 


STEAM  ENGINES  221 

bearings  sooner  or  later.  Hot  clinkers  and  ashes  should  be 
sprinkled,  and  the  fireroom  door  should  be  closed  while  the 
ashes  and  clinkers  are  being  hauled  or  wet  down  or  while  the 
fires  are  being  cleaned  or  hauled.  As  an  additional  precaution, 
all  open  oil  holes  should  be  plugged  with  wooden  plugs  or 
bits  of  clean  cotton  waste  as  soon  as  possible  after  the  engine 
is  stopped,  and  should  be  kept  closed  until  ready  to  oil  the 
engine  again  preparatory  to  starting  up.  Plaited  hemp  or 
cotton  gaskets  should  also  be  laid  over  the  crevices  between 
the  ends  of  the  brasses  and  the  collars  of  the  journals  of  every 
bearing  on  the  engine  and  kept  there  while  the  engine  is  stand- 
ing still. 

Overloading  of  Engine. — The  effect  produced  by  overloading 
an  engine  is  this:  the  pressure  on  the  brasses  is  increased  to- 
a  point  beyond  that  for  which  they  were  designed,  the  friction 
exceeds  the  practical  limit,  and  the  bearing  heats.  In  case 
an  engine  is  run  at  or  near  its  limit  of  endurance,  or  if  the 
journals  are  too  small,  it  would  be  a  wise  and  economical 
precaution  to  have  a  complete  set  of  spare  brasses  on  hand 
ready  to  slip  in  when  the  necessity  arises. 

Engine  Out  of  Line. — If  an  engine  is  not  in  line,  the  brasses 
do  not  bear  fairly  upon  the  journals.  This  will  reduce  the 
area  of  the  bearing  surfaces  in  contact  to  such  an  extent  as  to 
cause  heating.  If  the  engine  is  not  very  much  out  of  line, 
matters  may  be  considerably  improved  by  refitting  the  brasses 
by  filing  and  scraping  down  the  parts  of  those  which  bear 
most  heavily  on  the  journal.  If  this  does  not  answer,  the  heat- 
ing will  continue  until  the  engine  is  lined  up. 

The  crosshead  guides  of  an  engine  out  of  line  are  apt  to  heat, 
and  they  will  continue  to  give  trouble  until  the  defect  is  rem- 
edied. The  guides  may  also  heat  from  other  causes;  for  instance, 
the  gibs  may  be  set  up  too  much.  The  danger  of  hot  guides 
may  be  very  much  lessened  by  chipping  zigzag  oil  grooves 
in  their  wearing  surfaces  and  by  attaching  to  the  crosshead 
oil  wipers  made  of  cotton  lamp  wicking  arranged  so  as  to  dip 
into  oil  reservoirs  at  each  end  of  the  guides  if  they  are  hori- 
zontal, and  at  the  lower  end  if  they  are  vertical.  These 
wipers  will  spread  a  film  of  oil  over  the  guides  at  every  stroke 
of  the  crosshead. 
16 


222  STEAM  EXGINES 

Effect  of  External  Heat  on  Bearings. — Bearings  may  get  hot 
by  the  application  of  external  heat.  This  may  be  the  case 
if  the  engine  is  placed  too  near  furnaces  or  an  uncovered 
boiler,  or  in  an  atmosphere  heated  by  uncovered  steam  pipes 
or  other  means.  The  excessive  heat  of  the  atmosphere 
will  then  expand  the  brasses  until  they  nip  the  journals, 
which  will  generate  additional  heat  and  cause  further  expan- 
sion of  the  brasses,  and  so  on  until  a  hot  bearing  is  the 
result.  The  remedy  obviously  depends  upon  the  conditions 
of  each  case. 

Brasses  Too  Long. — If  the  brasses  are  too  long  and  bear 
against  the  collars  of  the  journal  when  cold,  they  will  mosjt 
surely  heat  after  the  engine  has  been  running  a  while.  It  is 
hardly  possible  to  run  bearings  stone  cold.  They  will  warm 
up  a  little  and  the  brasses  will  be  expanded  thereby,  which 
will  cause  them  to  bear  still  harder  against  the  collars.  This, 
in  turn,  will  induce  greater  friction  and  more  expansion  of  the 
brasses.  The  evil  may  be  obviated  by  chipping  or  filing  a  little 
off  each  end  of  the  brasses  until  they  cease  to  bear  against  the 
collars  while  running.  A  little  side  play  is  a  good  thing  for 
another  reason,  which  is  that  it  promotes  a  better  distribution 
of  the  oil  and  prevents  the  journal  and  brasses  from  wearing 
into  concentric  parallel  grooves. 

Springing  of  Bedplate. — If  the  bedplate  of  an  engine  is  not 
rigid  enough  to  resist  the  vibration  of  the  moving  parts,  or  if 
it  is  sprung  by  uneven  settling  or  the  instability  of  the  founda- 
tion, the  engine  will  be  thrown  out  of  line  either  intermittently 
or  permanently,  and  the  bearings  will  heat.  But  it  will  do  no 
good  to  refit  the  brasses  unless  the  engine  bed  is  stiffened  in 
some  way  and  leveled  up. 

Springing  or  Shifting  of  Pillow-Block. — The  effect  of  the 
springing  or  shifting  of  the  pedestal  or  pillow-block  is  similar 
to  the  springing  of  the  engine  bed;  that  is,  the  bearing  will 
be  thrown  out  of  line,  with  the  consequent  danger  of  heating. 
As  the  pedestal  is  usually  adjustable,  it  is  an  easy  matter  to 
readjust  it,  after  which  the  holding-down  bolts  should  be 
screwed  down  hard.  If  a  pedestal  is  not  stiff  enough  to  resist 
the  strains  upon  it  and  it  springs,  measures  should  be  taken  to 
stiffen  it. 


STEAM  TURBINES 


223 


STEAM  TURBINES 


ECONOMICAL  CONSIDERATIONS 

Steam  Consumption.— The  relation  between  the  brake 
horsepower  of  the  steam  turbine  at  full  load  and  the  steam 
consumption  is  shown  in  the  accompanying  table.  The  values 
in  this  table  are  taken  from  published  tests  of  steam  turbines 

STEAM  CONSUMPTION  PER  HOUR  OF  TURBINES 


Brake 
Horsepower 

Pounds  of 
Steam  Used 

Brake 
Horsepower 

Pounds  of 
Steam  Used 

100 
200 
300 
400 
500 

18.2 
17.5 
16.9 
16.3 
15.8 

600 
700 
800 
900 
1,000 

15.3 
14.8 
14.3 
13.7 
13.2 

that  have  attained  the  greatest  commercial  success.  The 
turbines  used  saturated  steam  of  from  115  to  140  Ib.  per 
sq.  in.,  gauge  pressure,  and  exhausted  into  a  vacuum  of  from 
26  to  28.5  in.  of  mercury.  Better  results  than  those  noted 
in  the  table  can  be  obtained  by  the  use  of  highly  superheated 
steam. 

Effect  of  Vacuum. — The  better  the  vacuum,  the  greater  is 
the  economy  in  the  use  of  steam,  both  in  the  steam  engine 
and  in  the  steam  turbine.  A  high  vacuum  is  of  greater  value 
to  the  turbine,  however,  because  the  turbine  can  take  advantage 
of  a  greater  range  of  expansion.  The  degree  of  vacuum  to  be 
carried  is  a  matter  of  dollars  and  cents;  that  is,  it  may  cost 
more  to  create  and  maintain  a  high  vacuum  than  may  be  saved 
in  steam  consximption.  In  a  comparative  test  of  a  turbine 
and  a  triple-expansion  engine  under  like  conditions,  it  was 
found  that,  in  the  case  of  the  reciprocating  engine,  little  or 
nothing  was  to  be  gained  by  carrying  a  greater  vacuum  than 


224  STEAM  TURBINES 


56    Of 


.about  26  in.;  but  the  economy  of  the  turbine  in  the  use 
steam  increased  rapidly  as  the  vacuum  was  increased  above 
26  in.     The  conclusion  is  that  high  degrees  of  vacuum  are  more 
desirable  for  turbines  than  for  engines. 

Advantages  of  Turbines. — The  steam  turbine  possesses  the 
following  advantages  over  the  reciprocating  engine: 

1.  The  ability  to  use  highly  superheated  steam,  resulting 
in  greater  economy. 

2.  Reduced  cost  per  unit  capacity  of  the  electric  genera- 
tor because  of  increased  speed  and  smaller  weight  per  horse- 
power. 

3.  Reduced  floor  space,  resulting  in  less  cost  for  land  and 
power-station  building. 

4.  Reduced  cost  of  lubrication,  as  no  cylinder  oil  is  needed 
and  less  oil  is  used  for  bearings. 

5.  Saving  in  labor,  as  no  oilers  are  required  and  one  engineer 
can  attend  to  more  output  than  on  reciprocating  engines. 

6.  Reduced  cost  of  foundations,  as  the  turbine  is  balanced 
-and  has  no  reciprocating  parts. 

7.  Good  steam  economy  over  a  wider  range  of  load  than 
the  reciprocating  engine.     This  is  particularly  advantageous 
in  power  stations,  where  the  load  is  variable;  thus,  a  turbine 
can  be  operated  at  one-fourth  or  one-half  load  with  smaller 
increase  of  steam  consumption  than  would  be  the  case  with 
a  reciprocating  engine  under  the  same  renditions.     Also,  the 
turbine  is  more  efficient  than  the  engine  under  overloads. 

The  foregoing  advantages  apply  mainly  to  turbines  used  on 
land.  The  steam  turbine,  however,  is  also  used  for  the  pro- 
pulsion of  ships.  Among  the  advantages  claimed  for  it  in  this 
class  of  service  are  the  following: 

1.  For  the  same  power,  the  turbine  plant  has  less  weight 
than  the  engine  installation. 

2.  There  is  less  danger  of  breakdowns,  because  of  the  smaller 
number  of  parts  in  a  turbine  installation. 

3.  The  balancing  obtained  almost  eliminates  vibration. 

4.  With   fast    vessels,   it   is    possible   to   obtain   a  higher 
speed   than    with    reciprocating    engines,  at  the  same    steam 
consumption. 

5.  Less  headroom  is  required  than  with  steam  engines. 


STEAM  TURBINES  225 

Comparison  of  Turbines  and  Engines. — If  the  matter  of 
steam  consumption  alone  is  considered,  the  average  condensing 
turbine  of  less  than  about  700  H.  P.  is  not  so  economical  as 
the  average  compound  or  triple-expansion  condensing  engine, 
although  the  turbine  may  be  preferred  to  the  engine  for  other 
reasons.  In  larger  sizes,  however,  and  particularly  in  very 
large  units,  the  economy  of  the  turbine  is  very  noticeable. 
The  turbine  possesses  the  ability  to  expand  the  steam  to  the 
lowest  available  condenser  pressure  without  difficulty;  bat 
to  do  this  in  a  reciprocating  engine  would  require  very  large 
valves,  and  ports  and  heavy  pistons,  because  of  the  great 
volume  of  steam  to  be  handled  at  very  low  pressures. 

Finding  Horsepower  of  Turbines. — There  is  no  way  of 
finding  the  indicated  horsepower  of  a  steam  turbine,  because 
no  form  of  indicator  applicable  to  the  turbine  has  been  invented. 
Nor  is  any  such  instrument  likely  to  be  developed,  owing  to 
the  very  great  difficulty  of  determining  the  energy  given  up 
to  the  blades  of  a  turbine  from  a  jet  of  steam.  The  usual 
way  of  finding  the  power  of  a  steam  turbine  is  to  use  a  brake 
or  a  dynamometer  and  thus  to  determine  the  brake  horse- 
power, or  else  to  connect  an  electric  generator  to  the  turbine 
and  measure  the  electrical  output  at  the  switchboard.  In 
case  the  latter  method  is  used,  the  efficiency  of  the  generator 
and  the  turbine  together  is  involved. 


TURBINE  TROUBLES 

Clearance  of  Blades. — To  obtain  free  running,  it  is  necessary 
to  allow  clearance  between  the  stationary  and  the  moving 
rows  of  blades,  as  well  as  between  the  ends  of  the  blades  and 
the  casing  or  the  rotor.  In  impulse  turbines,  such  as  the 
Curtis  and  the  Rateau,  the  clearance  between  the  rows  of  blades 
is  important;  however,  if  it  is  made  no  greater  than  is  neces- 
sary for  mechanical  reasons,  the  efficiency  will  not  be  affected 
seriously.  In  the  reaction  turbine,  such  as  the  Parsons,  the 
clearance  between  the  rows  is  of  small  consequence  as  com- 
pared with  the  clearance  between  the  ends  of  the  stationary 
blades  and  the  rotor  and  between  the  ends  of  the  moving 


226  STEAM  TURBINES 

blades  and  the  casing.  The  former  may  vary  from  J  to  1  in. 
or  more  from  the  high-pressure  to  the  low-pressure  stage; 
but  the  tip  clearance  must  be  kept  between  a  few  hundredths 
and  a  few  thousandths  of  an  inch. 

Stripping  of  Blades. — The  stripping  of  the  blades  is  one  of 
the  troubles  to  which  turbines  are  subject.  It  may  be  due 
to  the  interference  of  the  stationary  and  the  movable  blades, 
or  to  the  rubbing  of  the  blades  against  the  shell  or  the  rotor. 
In  either  of  these  cases  the  existing  clearances  are  reduced, 
by  wear  of  the  parts,  shifting  of  the  rotor,  or  unequal  expansion 
of  the  rotor  and  the  casing,  until  the  blades  touch  and  tear 
one  another  loose.  The  same  result  will  occur  if  some  foreign 
solid,  as  a  stray  nut  or  bolt,  is  carried  along  with  the  steam 
into  the  turbine.  If  a  turbine  is  started  too  quickly,  without 
being  properly  warmed  up,  the  sudden  unequal  expansion  set 
up  in  the  heavy  casing  and  the  lighter  rotor  may  cause  the 
blades  to  come  in  contact  and  be  stripped.  Stripping  is  claimed 
by  some  engineers  to  be  more  common  in  turbines  in  which  the 
blades  are  not  supported  at  their  outer  ends.  To  prevent  it, 
therefore,  shroud  rings  and  metal  lacings  are  applied  to  the 
blades  at  their  outer  ends,  by  some  manufacturers  of  steam 
turbines. 

Erosion  of  Blades. — As  there  are  no  valves,  pistons,  or  piston 
rings  in  the  turbine  to  be  maintained  free  from  leakage,  about 
the  only  thing  that  can  affect  the  steam  consumption  is  the 
condition  of  the  blades.  The  blades  of  steam  turbines  are 
subjected  to  the  cutting  action  of  steam  flowing  at  high  veloci- 
ties, and  often  carrying  water  particles  with  it.  This  cutting, 
or  erosion,  wears  away  the  edges  and  surfaces  of  the  blades. 
From  the  data  available,  it  appears  that  the  erosion  is  very 
slight  if  the  steam  is  dry  or  superheated,  no  matter  what 
velocities  are  used;  but  if  the  steam  is  wet,  erosion  will  take 
place,  and  it  will  be  greatly  increased  if  the  velocity  of  the 
steam  is  high.  The  horsepower  is  not  affected  to  any  great 
extent  by  blade  erosion,  according  to  the  results  of  experience. 
In  the  case  of  a  100-H.  P.  De  Laval  turbine,  the  steam  inlet 
edges  of  the  blades  were  worn  away  about  A  in-,  yet  the 
steam  consumption  was  only  about  5%  above  that  with  new 
blades. 


STEAM  TURBINES  227 

Slugs  of  Water. — If  the  boiler  supplying  steam  to  a  recipro- 
cating engine  primes  badly,  a  slug  of  water  may  be  carried 
over  into  the  cylinder,  resulting  in  a  cracked  piston  or  cylinder, 
a  buckled  piston  rod  or  connecting-rod,  or  a  wrecked  frame. 
In  case  a  steam  turbine  is  used,  however,  the  danger  is  greatly 
lessened.  In  turbines  in  which  the  blades  are  not  supported 
at  their  outer  ends,  the  \vater  may  cause  stripping  of  the  blades; 
but  this  is  not  very  likely,  as  the  blades  at  the  high-pressure 
end  of  the  turbine  are  short.  A  rush  of  water  from  the  boiler 
has  been  known  to  bring  a  turbine  almost  to  a  stop  without 
damaging  the  blades. 

Vibration. — On  account  of  the  high  speeds  attained  in  tur- 
bine practice,  the  rotors  are  balanced  accurately,  so  as  to  reduce 
vibration.  But  in  spite  of  this  careful  balancing,  vibration 
may  manifest  itself  during  ordinary  running.  It  may  be  caused 
in  any  one  of  several  ways,  but  the  fundamental  cause  is  lack 
of  balance.  If  the  rotor  is  warmed  up  too  rapidly,  the  shaft 
or  the  wheels  may  be  warped  by  unequal  expansion,  producing 
an  unbalanced  effect.  The  stripping  of  a  blade  or  two  will 
affect  the  balance  of  the  wheel  and  tend  to  produce  vibration. 
Even  water  carried  into  the  turbine  with  the  steam  will  bring 
about  an  unbalanced  condition  and  will  lead  to  vibration. 
When  vibration  is  observed,  it  is  well  to  reduce  the  speed  a 
little,  and  to  note  whether  this  causes  the  vibration  to  cease. 
If  it  does,  but  comes  back  again  as  soon  as  the  speed  is  increased, 
the  source  of  the  trouble  should  at  once  be  determined. 


OPERATION  OF  TURBINES 

Inspection.— If  the  steam  turbine  is  a  new  one,  or  if  it  has 
been  standing  idle  for  a  long  period,  it  should  not  be  started 
until  it,  together  with  its  auxiliary  apparatus,  has  been  thor- 
oughly inspected.  The  bearings  should  be  properly  adjusted 
and  free  from  dirt,  and  the  entire  lubricating  system  should 
be  clean  and  filled  with  clean  oil.  The  steam  pipe  from  the 
boilers  should  be  blown  through,  so  as  to  clear  it  of  any  foreign 
matter  that  could  be  carried  into  the  turbine  by  the  steam. 
The  governor  mechanism  should  be  examined,  to  see  that  it 


228  STEAM  TURBINES 

is  in  good  order;  the  oil  pump  should  be  looked  after,  to 
ascertain  whether  it  is  in  condition  to  maintain  a  continuous 
supply  of  oil;  and,  finally,  before  the  turbine  is  started,  the 
shaft  should  be  turned  over  by  hand,  to  insure  that  the  rotor 
will  turn  freely  in  the  casing. 

Starting. — A  steam  turbine  should  be  started  slowly,  and 
before  it  is  allowed  to  turn  over  under  steam  it  should  be 
warmed  up.  This  is  accomplished  by  opening  the  throttle 
valve  just  enough  to  let  steam  flow  into  the  turbine.  The 
drains  should  be  kept  open  until  the  turbine  is  well  started. 
The  length  of  time  required  for  warming  up  depends  on  the 
size  of  the  turbine,  a  large  unit  requiring  more  time  than  a 
small  one.  As  the  warming  up  proceeds,  the  throttle  may 
gradually  be  opened  more,  and  the  auxiliary  machinery  may 
be  started.  Once  it  has  been  started,  the  turbine  should  be 
brought  up  to  speed  slowly.  If  it  is  speeded  up  too  rapidly, 
vibration  will  result.  After  the  normal  running  speed  has 
been  reached,  the  load  may  be  thrown  on;  but  this,  also,  should 
be  done  gradually,  to  prevent  a  rush  of  water  from  the  boiler 
with  the  steam. 

If  superheated  steam  is  used,  extra  caution  must  be  employed 
in  starting,  for  during  the  warming  up,  with  the  throttle  valve 
only  slightly  opened,  the  passing  steam  will  be  cooled  consider- 
ably. But  when  the  valve  is  opened  wider,  the  greater  volume 
passing  will  not  lose  so  much  of  its  superheat,  and  if  care  is 
not  exercised  the  turbine  will  be  subjected  to  sudden  expan- 
sion because  of  the  higher  temperature  of  the  steam.  The 
main  point  in  starting  is  to  avoid  any  sudden  changes  of 
temperature  in  the  turbine.  If  a  turbine  must  be  ready  to 
be  put  in  operation  at  short  notice,  steam  may  be  allowed  to 
flow  through  it  continually,  by  means  of  a  by-pass  around 
the  throttle  valve.  It  will  always  be  warmed  up,  then,  and 
can  be  brought  up  to  speed  with  less  danger  and  more  rapidly. 
Lubrication  of  Bearings. — The  shaft  or  spindle  of  a  turbine 
rotates  at  high  speed,  and  therefore  the  bearings  should  be 
kept  well  lubricated;  for  if  the  oil  supply  fails,  or  if  a  bearing 
begins  to  heat  because  of  grit  carried  into  it,  the  resulting 
trouble  will  come  very  quickly.  The  presence  of  a  hot  bearing 
will  usually  be  evidenced  by  the  smell  of  burning  oil  or  by 


STEAM  TURBINES  229 

the  appearance  of  white  smoke.  When  these  signs  are  observed 
the  oil  supply  should  immediately  be  increased  to  the  greatest 
possible  amount.  If  this  does  not  reduce  the  temperature  of 
the  bearing  or  prevent  its  further  heating,  the  turbine  should 
be  shut  down.  To  continue  will  result  in  burning  out  the 
bearing,  and  it  is  better  to  stop  before  this  happens.  The  high 
speed  of  the  shaft  renders  it  impossible  to  nurse  a  hot  turbine 
bearing  along  as  is  done  frequently  in  the  funning  of  recipro- 
cating engines. 

Use  of  Superheated  Steam. — As  there  are  no  internal  rub- 
bing surfaces  in  the  steam  turbine,  superheated  steam  may  be 
employed  without  causing  any  of  the  lubrication  troubles 
attending  its  use  in  reciprocating  engines.  Because  of  the 
greater  amount  of  heat  contained  in  a  pound  of  superheated 
steam,  the  economy  of  a  turbine  working  with  superheated 
steam  is  greater  than  that  of  one  working  with  saturated 
steam;  also,  the  efficiency  is  increased  because  the  superheated 
steam  causes  less  frictional  resistance  to  the  motion  of  the 
blades.  To  show  the  value  of  superheated  steam  in  turbine 
work,  it  may  be  stated  that  50°  F.  of  superheat  reduces  the 
steam  consumption  about  6%;  100°  F.  of  superheat  reduces 
it  about  10%;  and  150°  F.  of  superheat  reduces  it  about  13f%. 
The  use  of  high  superheat,  however,  produces  expansion  of 
the  rotor  and  the  casing  and  may  cause  the  blades  to  interfere; 
as  a  result,  the  usual  degree  of  superheat  in  steam-turbine 
practice  is  100°  F.,  and  seldom  exceeds  150°  F. 

Exhaust-Steam  Turbine. — The  steam  turbine  shows  better 
economy  than  the  steam  engine  when  working  with  low-pressure 
steam  in  connection  with  a  high  vacuum;  but  when  working 
with  high-pressure  steam  and  a  vacuum  of  about  26  in.,  the 
engine  is  the  more  economical.  As  a  consequence,  a  combi- 
nation of  the  steam  engine  and  the  steam  turbine  has  been 
adopted.  The  engine  uses  the  high-pressure  steam  from  the 
boilers  and  expands  it  to  about  atmospheric  pressure.  This 
exhaust  steam  then  passes  into  the  turbine,  which  exhausts 
into  a  condenser  carrying  a  high  degree  of  vacuum,  and  the 
expansion  is  carried  to  the  extreme  practicable  limit.  The 
turbine  thus  used  in  connection  with  an  engine  is  termed  an 
exhaust-steam  turbine. 


230  STEAM  TURBINES 

Maintenance  of  Vacuum. — As  the  economy  of  the  steam 
turbine  is  dependent  so  largely  on  the  degree  of  vacuum  carried, 
it  is  necessary  for  the  engineer  to  watch  the  vacuum  gauge 
closely.  With  reciprocating  engines,  the  loss  of  1  or  2  in.  of 
vacuum  may  not  be  of  much  consequence;  but  in  a  turbine 
plant,  where  the  vacuum  is  from  27  to  28  in.,  a  loss  of  1  or 
2  in.  will  result  in  a  considerable  increase  in  the  steam  con- 
sumption. Because  of  the  high  vacuum  employed,  the  diffi- 
culty of  keeping  pipes,  valves,  and  glands  from  leaking  is 
greater  in  turbine  practice  than  in  engine  practice,  but  the 
greater  economy  obtained  by  keeping  everything  tight  over- 
balances the  increased  care  and  labor. 

Shutting  Down. — In  shutting  down  a  steam  turbine,  the 
throttle  valve  should  be  closed  partly  before  the  load  is  reduced, 
so  as  to  prevent  any  possibility  of  racing  when  the  load  is 
finally  taken  off.  The  load  may  then  be  used  as  a  brake  to 
bring  the  rotor  to  a  stop.  When  the  throttle  valve  has  been 
closed  and  the  steam  supply  has  been  shut  off  completely, 
the  auxiliary  machinery  may  be  stopped.  If  the  load  is  taken 
off  before  the  throttle  is  wholly  closed,  the  turbine  may  con- 
tinue to  rotate  for  half  an  hour,  as  the  rotor  is  then  running 
in  a  vacuum  and  under  no  load.  The  speed  may  be  reduced 
by  opening  the  drains  and  allowing  air  to  enter  the  casing. 
The  oil  supply  to  the  bearings  must  be  continued  until  the 
turbine  has  come  to  rest,  and  the  oil  pump  should  be  the  last 
auxiliary  to  be  stopped. 

Care  of  Gears  in  De  Laval  Turbines. — The  De  Laval  Steam 
Turbine  Company  in  their  directions  for  operating  their  tur- 
bines state  that  in  order  to  keep  the  gears  in  good  condition 
the  teeth  should  be  cleaned  occasionally  when  the  turbine  is 
not  in  service.  They  recommend  that  a  wire  brush  and 
kerosene  be  employed  for  this  purpose.  At  the  same  time  the 
gear-case  should  also  be  thoroughly  cleaned,  and  after  the 
cleaning  the  gears  should  be  well  lubricated. 

Should  an  engineer  for  any  reason  desire  to  take  the  gears 
out  of  the  case,  it  is  recommended  that  he  secure  special 
directions  relating  to  their  removal  from  the  manufacturers. 
The  same  statement  also  applies  to  the  adjustment  of  the 
gears,  which  need  to  be  kept  in  perfect  adjustment. 


PROPULSION  OF  VESSELS  231 


PROPULSION  OF  VESSELS 


SLIP 

True  Slip. — In  considering  the  speed  of  a  stream  projected 
by  a  propelling  instrument  from  a  ship  or  other  vessel  in 
motion,  it  must  be  borne  in  mind  that  while  the  stream  is 
propelled  astern  the  vessel  is  advancing.  Since  the  stream 
must  move  astern  faster  than  the  vessel  advances,  the  rear- 
ward speed  of  the  stream  in  relation  to  a  fixed  point  of  the 
water  some  distance  astern  of  the  ship,  as  a  floating  piece  of 
wood,  will  be  the  difference  between  the  speed  of  the  vessel 
in  relation  to  the  piece  of  wood  and  the  rearward  speed  of 
the  stream  in  relation  to  the  vessel.  When  the  propeller 
works  in  a  wake,  which  has  a  forward  motion,  the  speed  with 
which  water  is  fed  to  the  propelling  instrument  is  reduced 
thereby  and  it  becomes  equal  to  the  difference  between  the 
forward  speed  of  the  vessel  in  relation  to  a  fixed  point  of  the 
water  clear  of  the  wake  and  the  wake  velocity.  Thus,  if  the 
speed  of  the  ship  is  15  mi.  per  hr.  and  a  wake  that  has  a  forward 
velocity  of  3  mi.  per  hr.  collects  at  the  stern,  the  speed  with 
which  the  water  is  fed  to  a  screw  propeller  is  15  —  3  =  12  mi. 
per  hr.  The  difference  between  the  speed  with  which  water 
is  fed  to  the  propelling  instrument  and  the  speed  with  which 
it  is  projected  astern,  both  speeds  being  measured  in  relation 
to  the  vessel,  is  called  the  true  slip,  and  also  the  real  slip,  of 
the  stream. 

Apparent  Slip. — In  practice,  it  is  very  inconvenient  and 
exceedingly  difficult  to  measure  either  the  wake  velocity  or 
the  speed  of  the  ship  in  relation  to  the  wake,  but  it  is  a  very 
simple  matter  to  measure  the  speed  of  the  vessel  in  relation 
to  a  fixed  point  in  the  water  clear  of  the  wake  by  means  of 
an  instrument  called  a  log.  The  difference  between  the  speed 
of  the  stream  projected  by  the  propelling  instrument  and 
the  speed  of  the  ship  thus  found  is  taken  as  the  slip.  When 
calculated  in  this  manner  it  obviously  is  not  the  same  as  the 
true  slip;  it  is  called  the  apparent  slip. 


232  PROPULSION  OF  VESSELS 

Formulas  for  Slip.  —  It  is  customary  to  express  slip  in  per 
cent,  of  the  velocity  of  the  stream  projected  by  the  propelling 
instrument. 

Let  5t  =  true  slip  in  per  cent.,  expressed  decimally; 

Sa  =  apparent   slip   in  reference   to   the   ship's   motion 
through    the    water,    expressed    decimally    and 
in  per  cent.; 
V  —  velocity  of  stream  projected  by  propelling  instru- 

ment, in  relation  to  vessel; 

Vi  =  velocity  of  water  fed  to  propelling  instrument; 
that  is,  speed  of  vessel  in  relation  to  the  sur- 
rounding water  diminished  by  the  wake  velocity 
at  the  point  where  the  propelling  instrument 
is  located,  for  a  vessel  under  way. 
Vt  =  speed  of  vessel  in  relation  to  the  water,  as  shown 

by  the  log. 
Then,  the  true  slip  is  given  by  the  formula 


and  the  apparent  slip  by  the  formula 
V-Vt 

S^~T      (2) 

It  is  customary  among  writers  on  marine  propulsion  to 
refer  to  apparent  slip  simply  as  slip;  when  the  true  slip  is  meant, 
it  is  usually  called  distinctly  the  true  slip. 


SCREW  PROPELLERS 

Definitions. — If  a  point  is  caused  to  rotate  at  a  uniform  dis- 
tance from  and  about  an  axis,  and  if  the  point  at  the  same  time 
is  caused  to  advance  at  a  uniform  rate  in  the  direction  of  axis, 
its  path  will  be  a  helix.  If  the  point,  when  moving  away  from 
the  observer,  moves  in  the  direction  of  the  hands  of  a  watch, 
the  helix  will  be  right-handed;  if  in  an  opposite  direction,  left- 
handed.  The  distance  that  the  point  advances  in  one  complete 
revolution  is  known  as  the  pitch.  If  a  line  passing  through 
the  axis  is  caused  to  rotate  about  the  axis,  and  to  pass  along 


PROPULSION  OF  VESSELS  233 

the  path  of  the  point  mentioned  above,  its  path  will  be  the 
surface  of  a  true  screw,  provided  the  angle  that  the  line  makes 
with  the  axis  remains  constant.  From  this,  it  follows  that 
a  true  screw  is  one  in  which  the  advance  of  any  point,  in  the 
direction  of  the  axis,  at  any  distance  from  it,  for  any  part 
of  a  revolution,  but  the  same  in  each  case,  is  the  same.  By 
causing  lines  making  equal  angles  with  each  other  and  the 
axis  to  rotate  about  the  axis  in  a  helical  path,  a  multiple- 
threaded  true  screw  will  be  generated,  having  the  same  pitch 
as  a  single-threaded  true  screw  generated  by  a  line  following 
the  same  helical  path. 

Consider  a  four-threaded,  right-handed  screw,  generated 
by  the  lines  0  A ,  OB,  O  C,  and  O  D,  in  the  accompanying 
illustration.  These  lines  represent  the  intersections  of  the 
four  helical  surfaces  with  a 
plane  E  F  perpendicular  to  the 
axis.  Assume  the  helical  sur- 
faces to  be  cut  by  a  plane,  asGH, 
parallel  to  the  first  and  inter- 
secting the  axis  at  another  point.  i^^^-^it^^^  M  /*  \~°' 
Then,  O  A  A' O',  O  B  B' O',  D^  A  ^~IB'\D  W 

OCC'  O',  and  O  D  D' O'  will  be 

the  helical  surf  aces  of  the  blades  ^_^       .^.  .      . 

<5f  a  four-bladed.  right-handed  C^'    c  CJHC 

screw  propeller.  If  pieces  of 
metal  are  shaped  to  conform  to  these  helical  surfaces  and 
if  these  pieces  of  metal,  which  are  called  blades,  are  fas- 
tened to  a  hub,  which  in  turn  is  keyed  to  a  shaft  rotated 
by  an  engine,  the  screw  propeller  in  its  simplest  form  is 
obtained.  It  the  screw  propeller  is  revolving  in  the  direc- 
tion of  the  arrow,  the  portion  of  the  blade  that  strikes  the 
water  first,  which  will  be  near  the  plane  G  H,  is  known 
as  the  anterior  portion  of  the  blade;  and  the  portion  that 
is  near  the  plane  E  F,  as  the  posterior  portion.  That  part 
of  the  blade  that  is  near  the  periphery  A  A'  is  known  as 
the  tip.  In  practice,  screw  propellers  are  hardly  ever  made 
of  the  shape  shown.  Generally  the  anterior  portion  of  the 
blade  is  rounded  off  toward  the  tip,  as  shown  by  the  dotted 
line  on  the  blade  O  A  A'  O'.  The  posterior  portion  is  also 


234  PROPULSION  OF  VESSELS 

slightly  rounded.  Very  often  part  of  the  anterior  portion 
near  the  hub  is  also  cut  away. 

Radially  Expanded  Pitch. — Sometimes  the  surfaces  of  the 
blades  are  not  truly  helical;  as  usually  found,  the  pitch  near 
the  tip  is  greater  than  the  pitch  near  the  hub.  Such  a  propeller 
is  said  to  have  a  radially  expanded  pitch.  The  reason  for 
constructing  the  blade  in  this  manner  is  this:  Since  the  part  of 
the  blade  near  the  hub  strikes  the  water  at  nearly  a  right  angle, 
it  acts  chiefly  to  churn  the  water,  and  since  the  water  near  the 
periphery  is  thereby  disturbed,  the  tip  of  the  blade  acts  on 
water  in  motion.  By  increasing  the  pitch  at  the  tip,  it  is 
supposed  that  the  resistance  at  all  parts  of  the  blade  is  more 
nearly  equalized. 

Axially  Expanded  Pitch. — The  blades  are  sometimes  con- 
structed in  such  a  manner  that  the  anterior  portion  of  the  blade 
has  a  finer  pitch  than  the  posterior  portion.  Such  a  blade  is 
said  to  have  an  expanding  or  axially  expanded  pitch.  The 
object  to  be  attained  by  it  is  as  follows:  The  anterior  por- 
tion of  the  blade,  striking  on  water  at  rest  and  encountering 
the  resistance  due  to  a  solid  body  moving  through  water  at 
rest,  sets  the  water  in  motion,  driving  it  astern.  Therefore, 
the  posterior  portion  acts  on  water  in  motion.  By  expand- 
ing the  pitch  to  the  same  extent,  further  motion  is  given  to 
the  water  by  the  posterior  portion,  and  it  is  supposed  that  the 
resistance  at  all  parts  of  the  blade  is  thereby  equalized,  the 
same  as  with  radially  expanded  pitch  blades. 

Surface  Areas. — The  actual  area  of  the  surface  on  the 
driving  side  of  a  propeller  blade  is  known  by  various  names, 
as  the  developed  blade  area,  the  helicoidal  blade  area,  or  simply 
the  blade  area.  When  referring  to  the  total  blade  area,  it  is 
usually  spoken  of  as  the  developed  propeller  area,  the  helicoidal 
propeller  area,  or  simply,  the  propeller  area.  The  area  of  a 
blade  projected  on  a  plane  at  right  angles  to  the  propeller  shaft 
is  called  its  projected  area;  the  projected  area  of  all  the  blades 
is  the  projected  propeller  area.  The  area  of  the  circle  described 
by  the  tips  of  the  blades  is  the  disk  area  of  the  propeller.  The 
pitch  ratio  is  the  ratio  of  the  pitch  of  the  propeller  to  its  diameter. 

Measurement  of  Pitch.— In  practice,  the  pitch  of  a  pro- 
peller may  be  found  quite  closely  in  the  manner  shown  in  the 


PROPULSION  OF  VESSELS 


235 


illustration.  Take  a  piece  of  joist  or  lath  D,  which  should  be 
as  straight  as  possible  and  place  it  so  as  to  touch  one  of  the 
blades  at  any  distance,  as  b,  from  the  axis  A  B,  taking  care  to 
hold  it  parallel  to  the  axis.  Next  take  a  carpenter's  square, 
shown  at  E,  and  place  it  on  the  lath  and  against  the  blade,  so 
that  the  point  at  which  the  square  touches  the  blade  will  be 
the  same  distance  from  the  axis  as  is  the  lath.  Measure  the 
distances  a,  b,  and  c;  a  is  the  distance  from  the  square  to  the 
point  at  which  the  lath  touches  the  blade,  and  c  the  distance 
from  the  point  at  which  the  square  touches  the  blade  to  the 
lath.  The  distances  a  and  c  may  be  obtained  in  a  different 


manner,  if  considered  more  convenient,  thus:  Place  the  screw 
propeller  so  that  one  blade  is  horizontal.  To  a  piece  of  string 
about  10  ft.,  or  more,  in  length  tie  two  nuts;  place  the  string 
over  the  blade,  with  the  nuts  hanging  down,  at  the  distance 
from  the  shaft  axis  at  which  it  is  desired  to  find  the  pitch, 
taking  care  to  place  the  string  so  that  both  parts  hanging  down 
are  the  same  distance  from  the  axis.  The  distance  the  two 
parts  are  apart  is  the  distance  a.  To  find  c,  hold  a  lath  against 
the  blade  and  both  vertical  parts  of  the  string;  while  holding 
the  lath  parallel  to  the  shaft  axis  the  distance  c  can  be  measured. 
The  pitch  of  the  propeller  may  then  be  calculated  by  the 
6.2832  ba 


formula 


236  PROPULSION  OF  VESSELS 

in  which  P-  pitch  of  screw  propeller; 
a  =  depth  of  blade; 
b  =  distance  from  center  of  shaft  where  width  and 

depth  of  blade  is  measured; 
c  =  width  of  blade. 

The  distances  a,  b,  and  c  should  all  be  taken  in  inches,  and 
the  measurements  for  pitch  should  always  be  taken  on  the  side 
of  the  blade  that  strikes  the  water  when  propelling  the  vessel 
ahead. 

EXAMPLE. — If  a  screw  propeller  blade  6  ft.  from  the  center 
of  the  shaft  is  22  in.  deep  and  41  in.  in  width,  at  right  angles 
to  the  shaft,  what  is  the  pitch? 
SOLUTION. — Applying  the  formula, 

6.2832  X  12  X  6  X  22 
P  =  —  —  =  242.75  in.  =  20  ft.  2J  in. 

Determining  the  Kind  of  Pitch. — To  determine  whether  a 
screw  propeller  is  a  true  screw,  two  or  more  measurements 
of  the  pitch  should  be  taken  on  different  parts  of  the  blade  at 
the  same  distance  from  the  axis.  Another  set  of  measure- 
ments should  be  taken  at  some  other  distance  from  the  axis. 
If  the  pitches  calculated  from  these  measurements  agree  closely, 
the  propeller  is  a  true  screw. 

To  determine  whether  the  pitch  of  the  screw  is  radially 
expanded,  calculate  the  pitch  at  two  or  more  distances  from 
the  axis;  if  the  pitch  increases  toward  the  tip  of  the  blade, 
the  screw  propeller  is  of  radially  expanded"  pitch. 

To  determine  whether  the  screw  has  an  expanding  pitch, 
the  pitch  must  be  calculated  for  the  anterior  and  posterior 
portions  of  the  blade.  The  pitch  for  the  posterior  portion 
should  be  the  coarser;  and,  if  calculated  for  any  distance 
from  the  axis,  the  pitches  of  the  anterior  portion,  as  well 
as  those  of  the  posterior  portion  of  the  blade,  should  agree, 
provided  that  the  axial  measurements  arc  taken  in  the  same 
planes  passing  through  the  axis. 

Required  Pitch  of  Propeller. — The  pitch  required  for  a 
screw  propeller  may  be  found  by  the  formula 


PROPULSION  OF  VESSELS  237 

in  which  P  =  pitch,  in  feet; 

Fj  =  speed  of  ship,  in  feet  per  minute; 

Sa  =  apparent  slip,  in  per  cent.,  expressed  decimally; 

N  =  revolutions  per  minute; 

Required  Diameter  of  Propeller.  —  For  the  diameter  of  a 
screw  propeller,  Seaton  gives  the  formula: 


in  which  D  =  diameter  of  screw  propeller,  in  feet; 
H  =  indicated  horsepower; 
P  =  pitch  of  screw  propeller,  in  feet; 
N  =  revolutions  per  minute; 

C  =  a  constant  ranging  from  17,000  for  slow  freight 
steamers  to  25,000  for  fast-running  light 
steamers,  as  torpedo  boats  and  fast  steam 
launches. 

EXAMPLE.  —  Find  the  diameter  of  a  screw  propeller  for  a 
steam  launch  with  an  engine  of  10  H.  P.,  the  screw  having 
a  pitch  of  4  ft.  and  making  200  R.  P.  M. 
SOLUTION.  —  Applying  the  formula, 


25,000X-^  =  3.5  ft. 

When  the  rule  gives  a  diameter  that  is  impossible  for  the 
conditions,  either  P  or  N,  or  both,  must  be  varied.  Making 
either  or  both  of  these  values  larger  will  give  a  smaller  diameter 
of  screw;  conversely,  making  either  or  both  of  these  values 
smaller  gives  a  larger  diameter  of  screw.  The  rule  is  intended 
for  screw  propellers:  with  four  blades;  if  three  blades  are  to 
be  used,  the  diameter  should  be  increased  about  10%;  and  if 
two  blades  are  to  be  used,  about  20%.  The  pitch  ratio  varies 
in  practice  between  1.1  and  1.6. 

Blade  Area.  —  The  total  blade  area  of  four-bladed  propellers 
ranges  from  35  to  45%  of  the  disk  area;  in  three-bladed  pro- 
pellers, it  ranges  between  27  and  33%,  and  in  two-bladed 
propellers,  between  20  and  25%.  The  value  to  be  chosen 
should  vary  with  the  pitch  ratio,  using  a  low  total  blade  area 
for  a  low  pitch  ratio  and  increasing  the  value  as  the  pitch  ratio 
is  made  greater. 
17 


PROPULSION  OF  VESSELS 


SPEED  OF  VESSELS 

Powering  of  Vessels.  —  The  exact  power  required  to  propel 
a  vessel  at  a  given  speed  cannot  be  found  very  readily  by 
the  principles  of  mechanics.  Instead,  empirical  rules  based 
on  the  actual  performance  of  vessels  are  usually  relied  on. 
The  conditions  that  influence  the  relation  between  power 
and  speed  are  many,  but  only  a  few  of  the  more  important 
ones  will  be  enumerated  here.  For  instance,  the  area  of  the 
blades  of  the  screw  propeller  may  not  be  sufficient  for  high 
speed,  owing  to  a  churning  of  the  water  when  the  propeller 
is  revolved  beyond  a  certain  speed;  and,  although  the  power 
expended  in  revolving  the  propeller  faster  may  be  considerable, 
the  increase  of  the  speed  of  the  vessel  may  be  very  slight. 
A  similar  state  of  affairs  may  occur  if  the  area  of  the  buckets 
of  a  paddle  wheel  is  too  small.  It  may  be  amply  sufficient  for 
a  low  rate  of  speed,  and  still  be  entirely  too  small  for  a  higher 
rate,  thus  showing,  probably,  a  high  efficiency  of  the  propelling 
instrument  at  a  low  speed,  and  a  very  poor  one  at  a  higher 
rate.  Again,  the  efficiency  of  the  engine  may  vary  greatly 
for  different  powers  developed  by  the  same  engine.  There- 
fore, no  hard-and-fast  rule  that  will  express  the  relation 
between  power  and  speed  under  all  conditions  can  be  laid 
down. 

Admiralty  Rule.  —  The  PJ!C  most  frequently  used  in  the  pow- 
ering of  vessels  is  known  as  the  A  dmiralty  rule.  It  involves  the 
selection  of  a  proper  constant  based  on  actual  experience,  when 
this  constant,  a  number  of  which  are  given  in  the  accompany- 
ing table,  is  properly  selected,  the  results  of  the  rule  will  be 
found  to  agree  very  closely  with  the  actual  performance  of 
vessels  powered  by  the  rule,  at  least  under  ordinary  conditions 
and  for  ordinary  efficiencies  of  the  propelling  apparatus.  The 
formula  is 


in  which  H  =  indicated  horsepower; 

TV  =  displacement  of  vessel,  in  tons  of  2,240  lb.; 
k  =a  constant  taken  from  the  table; 
5  =  speed,  in  knots. 


PROPULSION  OF  VESSELS 


239 


Determining  Fineness  of  Vessel. — To  determine  whether 
a  vessel  is  fair  or  fine,  its  displacement,  in  cubic  feet,  is  usually 
compared  with  the  volume  of  a  rectangular  box  having  a  length 
equal  to  the  length  of  the  vessel  on  the  water-line,  a  width 
equal  to  the  beam,  and  a  depth  equal  to  the  mean  draft  of  the 
vessel  diminished  by  the  depth  of  the  keel.  If  the  displacement 
is  .55  of  the  volume  of  the  box,  or  less,  the  vessel  is  fine;  if 
above  .55  and  less  than  .70,  fair.  The  quotient  obtained  by 
dividing  the  displacement  by  the  contents  of  the  imaginary 
box  is  called  the  coefficient  of  fineness. 

VALUES  OF  *  IN  ADMIRALTY  RULE 


Description  of  Vessel 

Speed 
Knots 

ft 

Under  200  ft.,  fair.  . 
Under  200  ft    fine 

9  to  10 
9  to  10 
10  to  11 
11  to  12 
9  to  11 
9  to  11 
11  to  12 
9  to  11 
11  to  13 
9  to  11 
11  to  13 
13  to  15 
9  to  11 
11  to  13 
11  to  13 
13  to  15 
15  to  17 
15  to  17 

200 
230 
210 
200 
220 
240 
220 
250 
220 
260 
240 
200 
260 
240 
260 
240 
190 
240 

Under  200  ft.,  fine.. 

Under  200  ft.,  fine.. 
From  200  to  250  ft., 
From  200  to  250  ft., 

fair  

fine  

From  200  to  250  ft., 
From  250  to  300  ft., 
From  250  to  300  ft., 
From  250  to  300  ft., 
From  250  to  300  ft., 
From  250  to  300  ft., 
From  300  to  400  ft., 

fine 

fair  

fair 

fine  

fine  
fine 

fair  

From  300  to  400  ft., 
From  300  to  400  ft., 
From  300  to  400  ft., 
From  300  to  400  ft., 
Above  400  ft.,  fine.. 

fair  .    .. 

fine  

fine  

fine 

Selecting  Constant  in  Admiralty  Rule. — The  selection  of 
a  proper  value  of  k  calls  for  the  exercise  of  considerable  judg- 
ment, based  on  personal  knowledge  of  the  actual  performance 
of  similar  vessels.  Generally  speaking,  the  value  of  k  is  influ- 
enced by  the  length,  speed,  and  shape  of  the  vessel.  The 
value  of  k  should  be  greater  with  an  increased  length  of  the 
vessel  in  proportion  to  the  width,  and  also  with  a  finer  under- 
water body;  conversely,  its  value  should  be  less  as  the  ratio  of 
length  to  width  becomes  smaller,  and  as  the  form  becomes 


240  PROPULSION  OF  VESSELS 

fuller.  Furthermore,  the  value  of  k  should  be  smaller  for 
relatively  high  speeds  than  for  low  speeds,  for  vessels  of  the 
same  form  and  displacement.  Prof.  W.  F.  Durand  states  that 
-a  speed  may  be  considered  as  relatively  high  or  low  if  the 
speed  exceeds  the  numerical  value  of  the  square  root  of  the 
length  of  the  vessel  in  feet,  or  falls  below  it.  Thus,  if  a  vessel 
is  64  ft.  long,  V64  =  8,  a  speed  of  10  knots  would  be  considered 
as  relatively  high,  while  a  speed  of  5  knots  would  be  considered 
as  relatively  low.  For  small  boats,  if  the  speed  is  given  in 
statute  miles  per  hour,  the  values  of  k  range  between  150  and 
225,  and  for  speeds  given  in  knots,  between  100  and  150, 
according  to  Prof.  W.  F.  Durand. 

Relation  of  Horsepower  and  Revolutions.  —  The  speed  of  a 
ship  fully  under  way  is  about  directly  proportional  to  the 
number  of  revolutions  made  by  the  engine.  But  the  power 
required  to  turn  the  propelling  instrument  varies  as  the  cube 
of  the  number  of  revolutions,  or,  what  is  the  same  thing,  as 
the  cube  of  the  speed.  Hence,  it  is  possible  to  find,  approx- 
imately, the  power  developed  by  an  engine  for  any  given 
number  of  revolutions  per  minute,  any  other  horsepower  and 
the  corresponding  revolutions  per  minute  being  known  by  the 
use  of  the  formula 


in  which    Hi  =  required  indicated  horsepower; 

Ri  =  revolutions  per  minute  at  required  power; 

H  =  given  indicated  horsepower; 

R  =  revolutions  corresponding  to  the  horsepower  H. 
In  practice,  the  horsepower  calculated  by  this  formula  will 
not  always  correspond  to  that  actually  used,  as  found  by  the 
indicator  diagram.  This  is  due  to  the  fact  that  the  efficiency 
of  the  machinery  is  not  necessarily  the  same  at  all  speeds. 
As  a  general  rule,  the  engine  will  be  at  its  maximum  efficiency 
at  some  certain  speed,  and  will  have  a  lower  efficiency  at  a 
higher  or  lower  speed.  The  speed  at  which  the  engine  is  at 
its  best  efficiency  can  be  found  only  by  actual  trial. 

Reduction  of  Horsepower  When  Towing.  —  It  is  a  well-known 
fact  among  marine  engineers  that  an  engine  will  develop  a  lower 
horsepower  with  a  given  boiler  pressure,  throttle  position, 


PROPULSION  OF  VESSELS  241 

and  cut-off  when  towing  or  having  the  resistance  of  the  vessel 
increased  by  other  means,  than  will  be  developed  under  the 
same  engine  conditions  but  running  free.  The  reason  for  this 
is  explained  in  the  following  discussion,  in  which  for  the  sake 
of  simplicity  two  convenient  assumptions  have  been  made 
that  are  not  absolutely  correct  in  practice.  These  assumptions 
are  that  the  horsepower  of  an  engine  varies  directly  as  the 
number  of  revolutions,  the  mean  effective  pressure  remaining 
the  same,  and  that  the  speed  of  the  vessel  varies  directly  as" 
the  number  of  revolutions. 

Consider  a  paddle-wheel  steamer  running  free,  with  its 
engine  developing  its  greatest  horsepower  possible.  Since 
the  turning  effort  of  the  engine  depends  on  only  the  mean 
effective  pressure  in  the  cylinders,  it  is  independent  of  the 
revolution  so  long  as  the  throttle  position,  boiler  pressure, 
and  cut-off  remain  the  same.  This  turning  effort,  when 
exerted  at  the  circumference  of  the  effective  diameter  circle 
tangentially  to  the  same  parallel  to  the  surface  of  the  water, 
is  the  total  force  tending  to  propel  the  vessel  forwards,  and 
is  resisted  by  an  opposing  force,  which  is  the  resistance  of 
the  vessel.  Let  the  engine  be  started  and  assume  that  it  is 
making  its  greatest  turning  effort.  The  resistance  being  less 
than  the  forward  force,  the  vessel  moves  forwards  under  the 
influence  of  a  forward  accelerating  force  equal  to  the  differ- 
ence between  the  total  forward  force  and  the  resistance.  As 
the  vessel  gathers  headway,  the  resistance  increases;  this 
means  that  the  difference  between  the  forward  and  the  resist- 
ing force,  that  is,  the  accelerating  force,  decreases  until  the 
total  forward  force  and  total  resistance  have  become  equal, 
when  the  vessel  continues  at  a  uniform  speed.  Let  the  resist- 
ance be  increased  either  by  the  vessel  picking  up  a  tow,  by  a 
head-wind  or  head-sea,  by  encountering  an  adverse  current, 
or  by  a  combination  of  these  circumstances.  The  conditions 
remaining  the  same  as  before  at  the  engine,  the  turning  effort, 
that  is,  the  total  forward  force,  is  the  same;  but,  as  the  initial 
resistance  is  increased,  the  initial  difference  between  the  total 
forward  force  and  the  total  resistance  is  smaller  than  in  the  / 
first  case.  This  means  that  a  smaller  accelerating  force  is 
available  with  an  increased  resistance,  and  consequently  the 


242  PROPULSION  OF  VESSELS  . 

total  forward  force  and  total  resistance  become  equal  at  a 
lower  speed  of  the  vessel,  which  then  continues  under  way 
at  a  uniform,  but  lower  speed.  Now,  the  horsepower  of  an 
erigine  varies  (theoretically)  directly  as  the  number  of  revolu- 
tions, the  mean  effective  pressure  remaining  constant.  It  has 
been  shown  that  the  speed  of  the  vessel  has  been  lowered;  from 
this  it  follows  that  the  revolutions  and  consequently  the  horse- 
power must  be  less  when  the  resistance  has  been  increased. 
By  adding  to  the  resistance  of  the  vessel,  a  condition  is  finally 
reached  similar  to  that  of  a  vessel  moored  to  a  dock;  the 
forward  force  and  resistance  are  equal  and  the  vessel,  as  no 
accelerating  force  is  available,  remains  stationary.  In  this 
condition,  the  number  of  revolutions,  and,  hence,  the  horse- 
power, has  dropped  to  the  lowest  limit. 

Relation  of  Coal  Consumption  to  Speed. — The  fuel  con- 
sumption may  be  said  to  vary  directly  as  the  horsepower 
developed  (this  is  not  exactly  true,  but  only  approximately). 
The  horsepower  varies  about  directly  as  the  cube  of  the  speed, 
whence  it  follows  that  the  fuel  consumption  will  also  vary  as 
the  cube  of  the  speed,  approximately.  Hence,  to  find  the 
probable  coal  consumption  for  a  speed  different  from  a  known 
speed,  use  the  formula 

«-£    » 

in  which  c  =  coal  consumption,  in  tons,  at  the  new  speed; 
5  =  new  speed; 
5  =  known  speed; 

C  =  coal  consumption,  in  tons,  at  the  known  speed. 
To  find  approximately  the  speed  of  steaming  for  a  new  coal 
consumption,  use  may  be  made  of  the  formula 


c 

At  sea,  owing  to  an  accident,  it  is  often  desired  to  know  what 
speed  to  maintain  in  order  to  reach  a  given  port  with  the 
amount  of  coal  on  hand.  This  problem  is  readily  solved  by 
trial  and  by.  application  of  formula  1.  In  practice,  a  good 
margin  of  coal  should  be  shown  by  the  calculations  as  left 
over,  for  the  reason  that  the  actual  coal  consumption  at  the 


PROPULSION  OF  VESSELS  243 

reduced  speed  will,  as  a  general  rule,  be  in  excess  of  the  cal- 
culated consumption,  by  reason  of  the  decrease  in  economy  of 
the  engine  induced  by  reducing  the  developed  horsepower. 

EXAMPLE. — A  steamer  consumes  20  T.  of  coal  per  day  at 
a  normal  speed  of  10  knots;  the  distance  to  the  nearest  port 
where  coal  can  be  had  is  600  mi.,  and  the  estimated  quantity 
of  coal  in  the  bunkers  is  but  35  T.  Find  what  speed  should 
be  maintained  in  order  to  reach  the  coaling  station  with  the 
coal  supply  on  hand. 

SOLUTION. — The  best  way  to  proceed  in  a  case  of  this  kind 
is  to  assume  a  lower  speed,  as  8  knots,  and  calculate  the  new  coal 

consumption  for  that  speed;  thus,  c  = 3 — =  10.24  T.  per 

da.,  or  .43  T.  per  hr.  The  time  required  to  cover  a  distance 
of  600  mi.  at  a  speed  of  8  knots  is  600-^8  =  75  hr.,  and  at  a 
coal  consumption  of  .43  T.  per  hr.  the  total  quantity  of  coal 
required  at  that  speed  is  75 X. 43  =  32.25  T.  Hence,  if  a  speed 
of  8  knots  is  maintained,  the  supply  of  coal  on  hand,  or  35  T., 
will  suffice  to  reach  the  coaling  station  under  ordinary  weather 
conditions. 

Relation  Between  Engine  Speed  and  Ship's  Speed. — On 
taking  charge,  the  number  of  revolutions  to  produce  a  given 
speed  is  often  desired.  In  that  case  the  pitch  of  the  screw,  or 
the  effective  diameter  of  the  paddle  wheel  (taking  the  effective 
diameter  for  this  purpose  from  center  to  center  of  buckets) 
must  be  measured  and  a  fair  slip  value  assumed.  Then,  to 
find  the  revolutions  per  minute,  multiply  the  pitch  of  the 
screw  in  feet,  or  the  circumference  in  feet  of  the  effective 
diameter  circle  of  a  paddle  wheel,  by  60,  and  by  the  difference 
between  1  and  the  assumed  apparent  slip  expressed  decimally. 
Divide  the  speed  of  the  ship  in  feet  per  hour  by  this  product. 

EXAMPLE. — The  pitch  of  a  screw  propeller  is  16  ft.;  how 
many  revolutions  per  minute  must  it  make  to  drive  the  ship 
at  the  rate  of  10  knots,  the  apparent  slip  being  estimated 
at  10%? 

SOLUTION. — Applying  the  rule  and  taking  the  knot  at 
6,080ft.  10X6,080 


244  ENGINEERS'  LICENSE  LAWS 


ENGINEERS'  LICENSE  LAWS 


STATES    AND    CITIES    HAVING    LICENSE 
LAWS 

Engineers'  license  laws,  on  January  1,  1913,  are  in  force 
in  the  following  states  and  cities  in  the  United  States  of  America : 

States. — Massachusetts,  Minnesota,  Montana,  Ohio,  Penn- 
sylvania, and  Tennessee. 

Cities.— Alleghany,  Pa.;  Atlanta  (Pulton  County),  Ga.; 
Baltimore,  Md.;  Buffalo,  N.  Y.;  Chicago,  111.;  Denver,  Colo.; 
Detroit,  Mich.;  Elgin,  111.;  Goshen,  Ind.;  Hoboken,  N.  J.; 
Huntington,  W.  Va.;  Jersey  City,  N.  J.;  Kansas  City, 
Mo.;  Lincoln,  Neb.;  Los  Angeles,  Cal.;  Memphis,  Tenn.;  Mil- 
waukee, Wis.;  Mobile,  Ala.;  New  Haven,  Conn.;  New  York, 
N.  Y.;  Niagara  Falls,  N.  Y.;  Omaha,  Neb.;  Peoria,  111.;  Phila- 
delphia, Pa.;  Pittsburg,  Pa.;  Rochester,  N.  Y.;  Saginaw,  Mich.; 
Santa  Barbara,  Cal.;  St.  Joseph,  Mo.;  St.  Louis,  Mo. ;  Scranton, 
Pa.;  Sioux  City,  la.;  Spokane,  Wash.;  Tacoma,  Wash.;  Terre 
Haute,  Ind.;  Washington  (District  of  Columbia) ;  and  Yonkers, 
N.  Y.  

LICENSE  LAWS  FOR  STATIONARY 
ENGINEERS 

ABSTRACTS  OF  STATE  LAWS 

Following  are  abstracts  of  the  license  laws  and  ordinances 
of  the  different  states  and  most  of  the  cities  just  named. 
Abstracts  of  license  ordinances  of  some  cities  are  omitted 
because  copies  of  the  ordinances  of  these  places  were  not 
available  at  the  time  of  going  to  press. 

Massachusetts. — In  Massachusetts,  the  engineers'  and  fire- 
men's license  law  is  under  the  supervision  of  the  District 
Police,  Boiler-Inspection  Department,  State  House,  Boston. 

Section  78,  chapter  102,  of  the  revised  laws,  acts  of  1907, 
and  amendments,  which  took  effect  January  1,  1912,  reads: 


ENGINEERS'  LICENSE  LAWS       .  245 

"No  person  shall  have  charge  of  or  operate  a  steam  boiler 
or  engine  in  this  commonwealth,  except  boilers  and  engines 
upon  locomotives,  motor  road- vehicles,  boilers  in  private  resi- 
dences, boilers  in  apartment  houses  of  less  than  five  flats, 
boilers  under  the  jurisdiction  of  the  United  States,  boilers  for 
agricultural  purposes  exclusively,  boilers  of  less  than  9  H.  P., 
and  boilers  used  for  heating  purposes  exclusively,  which  are 
provided  with  a  device  approved  by  the  chief  of  the  district 
police  limiting  the  pressure  carried  to  15  Ib.  per  sq.  in.,  unless. 
he  holds  a  license  as  hereinafter  provided." 

A  steam  boiler  or  engine  may  not  be  operated  for  more  than 
1  wk.,  unless  the  person  in  charge  of  and  operating  it  is  duly 
licensed. 

"Section  80. — The  words  have  charge  or  in  charge,  used  in  the 
foregoing  section,  shall  designate  the  person  under  whose 
supervision  a  boiler  or  engine  is  operated.  The  person  oper- 
ating shall  be  understood  to  mean  any  and  all  persons  who 
are  actually  engaged  in  generating  steam  in  a  power  boiler." 
This  section  of  the  Massachusetts  laws  has  been  amended  so- 
as  to  include  a  designation  of  the  terms  operator,  operated,  or 
'operating,  where  used  in  the  law,  as  applying  to  any  person 
who,  under  the  supervision  of  the  licensed  person  in  charge,, 
operates  any  appurtenances  of  a  boiler  or  engine,  provided 
that  there  is  not  more  than  one  such  person  employed  for  every 
licensed  person,  and  that  any  such  operating  must  be  in  the 
presence  of  and  under  the  personal  supervision  of  the  latter 
person. 

Section  81  provides  that  whoever  desires  to  act  as  engineer 
or  fireman  shall  apply  for  a  license  therefor  to  the  state  inspc-c- 
tor  of  boilers  for  the  city  or  town  in  which  he  resides.  The 
application  blanks  are  to  be  obtained  from  the  boiler-inspection 
department  of  the  district  police. 

To  be  eligible  for  a  first-class  fireman's  license,  a  person 
must  have  been  employed  as  a  steam  engineer  or  fireman  in 
charge  of  or  operating  boilers  for  not  less  than  1  yr.,  or  he 
must  have  held  and  used  a  second-class  fireman's  license  for 
not  less  than  6  mo.  To  be  eligible  for  examination  for  a 
third-class  engineer's  license,  a  person  must  have  been  employed 
as  a  steam  engineer  or  fireman  in  charge  of  or  operating  boilers- 


246          .        ENGINEERS'  LICENSE  LAWS 

for  not  less  than  1J  yr.,  or  he  must  have  held  a  first-class 
fireman's  license  for  not  less  than  1  yr.  To  be  eligible  for 
examination  for  a  second-class  engineer's  license,  a  person  must 
have  been  employed  as  a  steam  engineer  in  charge  of  a  steam 
plant  or  plants  having  at  least  one  engine  of  over  50  H.  P., 
for  not  less  than  2  yr.;  or  he  must  have  held  and  used  a  third- 
class  engineer's  license  for  not  less  than  1  yr.,  or  have  held  and 
used  a  special  license  to  operate  a  first-class  plant  for  not  less 
than  2  yr.;  except  that  any  person  who  has  served  3  yr.  as 
apprentice  to  the  machinist  in  charge  or  boilermaking  trade 
in  stationary,  marine,  or  locomotive  engine  or  boiler  works, 
and  who  has  been  employed  for  1  yr.  in  connection  with  the 
operation  of  a  steam  plant,  or  any  person  graduated  as  a 
mechanical  engineer  from  a  duly  recognized  school  of  tech- 
nology, who  has  been  employed  for  1  yr.  in  connection  with 
the  operation  of  a  steam  plant,  shall  be  eligible  for  examination 
for  a  second-class  engineers'  license. 

To  be  eligible  for  examination  for  a  first-class  engineer's 
license,  a  person  must  have  been  employed  for  not  less  than 
3  yr.  as  a  steam  engineer  in  charge  of  a  steam  plant  or  plants 
having  at  least  one  engine  of  over  150  H.  P.,  or  he  must  have 
held  and  used  a  second-class  engineer's  license,  in  a  second- 
class  or  first-class  plant,  for  not  less  than  3J  yr.  The  appli- 
cant shall  make  oath  to  the  statements  contained  in  his 
application. 

Section  82  provides  that  licenses  shall  be  granted  according 
to  the  competence  of  the  applicant  and  shall  be  distributed 
in  the  following  classes: 

Engineers'  licenses:  First  class,  to  have  charge  of  and 
operate  any  steam  plant;  second  class,  to  have  charge  of  and 
operate  a  boiler  or  boilers,  and  to  have  charge  of  and  operate 
engines,  no  one  of  which  shall  exceed  150  H.  P.,  or  to  operate 
a  first-class  plant  under  the  engineer  in  direct  charge  of  the 
plant;  third  class,  to  have  charge  of  and  operate  a  boiler  or 
boilers  not  exceeding  in  the  aggregate  150  H.  P.,  and  an  engine 
not  exceeding  50  H.  P.,  or  to  operate  a  second-class  plant 
under  the  engineer  in  direct  charge  of  the  plant;  fourth  class, 
to  have  charge  of  and  operate  hoisting  and  portable  engines 
and  boilers. 


ENGINEERS'  LICENSE  LAWS  247 

Under  the  beading  of  classification  of  licenses,  two  new  classes 
have  recently  been  added,  namely,  a  portable  class  and  a 
steam  fire-engine  class.  The  former  applies  to  a  person  having 
charge  of  or  operating  portable  boilers  and  engines,  except 
hoisting  engines  and  steam  fire-engines,  and  the  latter  applies 
to  a  person  who  has  charge  of  or  operates  a  steam  fire-engine 
or  boiler. 

Minnesota. — The  engineers'  license  and  boiler-inspection 
laws  of  the  state  of  Minnesota  are  administered  by  a  board 
of  inspectors,  one  of  whom  shall  reside  in  each  senatorial  dis- 
trict. This  board  is  appointed  biennially  by  the  governor  of 
the  state.  It  also  has  jurisdiction  over  the  vessels  on  the  inland 
waters  of  the  state,  in  relation  to  masters  and  pilots,  as  well 
as  to  engineers  and  the  machinery  of  such  vessels. 

The  laws  state  that  engineers  shall  be  divided  into  four 
classes,  namely,  chief  engineers,  first-class  engineers,  second- 
class  engineers,  and  special  engineers. 

1.  No  license  shall   be  granted  to  any  person  under  21  yr. 
of  age,  except  to  special  engineers.     No  license  shall  be  granted 
to  any  person  to  perform  the  duties  of  chief  engineer  who  has 
not  taken  and  subscribed  an  oath  that  he  has  had  actual 
experience  of  at  least  5  yr.  in  operating  steam  boilers  and 
steam  machinery,  or  whose  knowledge,  experience,  and  habits 
of  life  are  not  such  as  to  justify  the  belief  that  he  is  compe- 
tent to   take  charge  of   all  classes  of  steam  boilers  and  steam 
machinery. 

2.  No  license  shall    be  granted  to    any  person  to  act  as 
first-class  engineer  who  has  not  had  actual  experience  of  at 
least  3  yr.  in  operating  steam  boilers  and  steam  machinery, 
and  whose  experience  and  habits  of  life  are  not  such  as  to 
warrant  the  belief  that  he  is  competent  to  take  charge  of  all 
classes  of  steam  boilers  and  steam  machinery  not  exceeding 
300  H.  P. 

3.  No  license    shall  be  granted  to  any  person    to  act  as 
second-class  engineer  who  has  not  had  at  least  1  yr.  of  actual 
experience  in  operating  steam  boilers  and  steam  machinery, 
or  whose  experience  and  habits  of  life  are  not  such  as  to  warrant 
the  belief  that  he  is  competent  to  take  charge  of  all  classes  of 
steam  boilers  and  steam  machinery  not  to  exceed  100  H.  P. 


248  ENGINEERS'  LICENSE  LAWS 

4.  No  license  shall  be  granted  to  any  person  to  act  as  special 
engineer  unless  he  is  found  on  examination  to  be  sufficiently 
acquainted  with  the  duties  of  an  engineer  to  warrant  the  belief 
that  he  can  be  safely  entrusted  with  steam  boilers  and  steam 
machinery  not  to  exceed  30  H.  P. 

The  fee  for  the  examination  of  an  applicant  for  an  engineer's 
license  shall  be  $1;  for  the  biennial  renewal  of  certificates  of 
license,  the  fee  shall  be  $1,  which  fee  shall  accompany  the  appli- 
cation. Applicants  must  subscribe  oath  as  to  their  experience 
period. 

Montana. — In  Montana,  the  license  laws  are  administered 
by  an  inspector  of  boilers,  who  is  appointed  by  the  governor 
of  the  state.  The  inspector  has  an  assistant,  and  they  must, 
as  often  as  is  convenient,  publish  in  some  suitable  newspaper 
a  notice  stating  on  what  days  they  will  be  in  certain  specified 
localities.  This  notice  must  also  state  that  they  will,  at  the 
time  and  place  specified  in  such  notice,  receive  applications  and 
make  examination  for  the  purpose  of  granting  engineers'  cer- 
tificates and  examine  boilers  subject  to  inspection. 

In  Montana,  engineers  entrusted  with  the  care  and  manage- 
ment of  steam  machinery  are  divided  into  three  classes,  namely, 
first-class  engineers,  second-class  engineers,  and  third-class 
engineers.  A  candidate  for  a  first-class  license  must  have  had 
.at  least  3  yr.  of  actual  experience  in  the  operation  of  steam 
boilers  and  steam  machinery,  or  his  knowledge  and  experience 
must  be  such  as  to  justify  the  belief  that  he  is  competent  to 
take  charge  of  all  classes  of  steam  boilers  and  steam  machinery. 
A  candidate  for  a  second-class  license  must  have  had  at  least 
2  yr.  of  experience  in  the  operation  of  steam  boilers  and  sceam 
machinery,  and  must  on  examination  be  found  competent  to 
take  charge  of  all  classes  of  steam  boilers  and  steam  machinery 
not  exceeding  100  H.  P.  A  candidate  for  a  third-class  license 
must  have  served  at  least  1  yr.  as  fireman  under  a  competent 
engineer,  and  must  be,  on  examination,  found  competent  to 
be  entrusted  with  the  duties  pertaining  to  the  operation  of 
steam  boilers  and  steam  machinery  not  exceeding  20  H.  P. 

All  firemen  who  have  charge  of  steam  boilers,  as  to  the  regu- 
lation of  feed  water  and  fuel,  where  the  boilers  are  so  situated 
as  not  at  all  times  to  be  under  the  eye  of  the  engineer  in  charge. 


ENGINEERS'  LICENSE  LAWS  249 

are  required  to  pass  a  third-class  engineer's  examination  and 
procure  the  same  kind  of  license.  Engineers  holding  licenses 
of  any  of  the  preceding  classes,  and  who  are  entrusted  with 
the  care  and  management  of  traction  engines,  or  engines  or 
boilers  on  wheels,  other  than  locomotives,  are  required  to  pass 
an  examination  as  to  their  competency  to  operate  such  class  of 
machinery,  and  to  procure  a  license  known  as  a  traction  license. 
Such  traction  license  shall  not  entitle  the  holder  thereof  to 
operate  any  other  class  of  machinery. 

All  certificates  of  license  to  engineers  of  all  classes  shall  be 
renewed  yearly.  The  fee  for  renewal  is  $1  in  all  cases.  The 
fee  for  the  examination  of  applicants  for  engineers'  license? 
is  $7.50  for  first-class  engineers,  $5  for  second-class  engineers, 
$3  for  third-class  engineers,  and  $3  for  traction  engineers. 
Fees  must  be  paid  at  the  time  of  application  for  license.  In 
case  of  the  failure  of  any  applicant  co  pass  a  successful  exami- 
nation, 90  da.  must  elapse  before  he  can  again  be  examined 
as  an  applicant  for  license  in  the  class  for  which  he  was  exam- 
ined. *But  the  inspector  may  grant  to  the  applicant  a  lower 
grade  of  license  than  applied  for  on  such  examination. 

Ohio. — In  the  state  of  Ohio,  the  license  laws  are  administered 
by  the  chief  examiner  of  steam  engineers  and  a  number  of 
district  examiners.  The  chief  examiner  is  appointed  by  the 
governor  of  the  state,  and  the  district  examiners  are  appointed 
by  the  chief  examiner,  with  the  approval  of  the  governor. 

The  laws  state  that  any  person  who  desires  to  act  as  a 
steam  engineer  shall  make  application  to  the  district  examiner 
of  steam  engineers  for  a  license  so  to  act,  on  a  blank  furnished 
by  the  examiner,  and  shall  successfully  pass  an  examination 
on  the  construction  and  operation  of  steam  boilers,  steam 
engines,  and  steam  pumps,  and  also  hydraulics,  under  such 
rules  and  regulations  as  may  be  adopted  by  the  chief  examiner, 
which  rules  and  regulations  and  standards  of  examination, 
however,  shall  be  uniform  throughout  the  state.  If,  on  such 
examination,  the  applicant  is  found  to  be  proficient  in  the 
prescribed  subjects,  a  license  shall  be  granted  him  to  have 
charge  of  and  operate  stationary  steam  boilers  and  engines. 
It  shall  be  unlawful  for  any  person  to  operate  a  stationary 
steam  boiler  or  engine  of  more  than  30  H.  P.  without  having 


250  ENGINEERS'  LICENSE  LAWS 


been  licensed  to  do  so.  Boilers  and  engines  under  the  jurisdic- 
tion of  the  United  States  and  locomotive  boilers  and  engines 
are  excepted. 

Licenses  continue  in  force  for  1  yr.  from  the  date  of  their 
issue,  unless  something  occurs  to  render  the  holder  unfit  to 
discharge  the  duties  of  steam  engineer,  in  which  case  the  license 
may  be  revoked.  Renewals  of  licenses  are  granted  on  appli- 
cation at  the  expiration  of  1  yr.  from  the  date  of  issue.  The 
fee  for  examination  of  applicants  for  license  is  $2,  which  must 
be  paid  at  the  time  of  application  for  examination;  each  renewal 
of  license  costs  $2. 

Pennsylvania. — In  the  state  of  Pennsylvania  there  are  license 
laws  relating  to  steam  engineers  and  the  inspection  of  steam 
boilers  in  cities  of  the  second  and  third  classes.  The  adminis- 
tration of  these  laws  is  in  the  hands  of  the  boiler  inspector?  of 
the  several  cities  involved.  The  councils  of  the  cities  provide 
for  the  creation  of  the  office  of  boiler  inspector.  No  steam 
boiler  or  steam  engine  of  over  10  H.  P.  may  be  operated  by 
any  person  who  is  not  over  21  yr.  of  age  and  who  does  not 
hold  a  license,  except  in  the  following  cases:  locomotive  boilers 
used  in  transportation  and  steam  boilers  and  engines  carrying 
pressures  of  less  than  15  Ib.  per  sq.  in. 

Every  person  desiring  authority  to  perform  the  duties  of 
an  engineer  shall  apply  to  the  boiler  inspector  of  such  cities, 
who  shall  examine  the  applicant  as  to  to  his  knowledge  of  steam 
machinery  and  his  experience  in  operating  it,  and  also  the 
proofs  he  produces  in  support  of  his  claim.  If  the  inspector 
is  satisfied  that  the  applicant's  character,  habits  of  life,  knowl- 
edge and  experience  in  the  duties  of  an  engineer  are  such  as  to 
authorize  the  belief  that  he  is  a  suitable  and  safe  person  to  be 
entrusted  with  the  powers  and  duties  of  such  station,  he  shall 
be  granted  a  license  on  the  payment  of  $3.  Licenses  are  to 
be  renewed  annually  on  the  payment  of  $1  and  within  10  da. 
after  the  expiration  of  date  of  such  license. 

Licenses  arc  of  two  classes,  namely,  those  entitling  the  holders 
to  have  charge  of  or  to  operate  stationary  steam  boilers  and 
steam  engines  only,  and  those  entitling  the  holders  to  have 
charge  of  or  to  operate  portable  steam  boilers  and  steam 
engines  only.  Transferring  from  one  grade  to  the  other  can 


6 

nes 


ENGINEERS'  LICENSE  LAWS  251 

be  done  only  through  a  reexamination,  but  without  cost  to  the 
licensee. 

No  person  shall  be  eligible  to  examination  for  license  unless 
he  furnishes  proof  that  he  has  been  employed  about  a  steam 
boiler  or  a  steam  engine  for  a  period  of  not  less  than  2  yr., 
prior  to  the  date  of  application,  which  proof  must  be  certified 
by  at  least  one  employer  and  two  licensed  engineers.  It  shall 
be  the  duty  of  every  licensed  engineer  when  he  vacates  a  posi- 
tion as  engineer  to  notify  the  boiler  inspector  of  such  fact. 
Failure  to  do  so  is  punishable  by  suspension  of  license  for  such 
a  period  of  time  as  the  boiler  inspector  may  determine. 

Tennessee. — In  Tennessee,  the  license  laws  are  administered 
by  a  board  of  inspectors  appointed  by  the  mayor  or  the  presi- 
dent of  cities  having  a  population  of  30,000  or  over.  The 
duties  of  the  board  are  to  examine  into  the  qualifications  of 
applicants  for  license  to  act  as  engineers  of  steam  plants,  The 
board  holds  sessions  at  least  twice  each  month  for  the  purpose 
of  receiving  applications  for  license.  The  laws  state  that  the 
board  shall  grant  certificates  of  license  for  1  yr.,  to  all  appli- 
cants who,  on  examination,  shall  have  the  skill,  experience, 
and  habits  of  sobriety  requisite  to  perform  the  duties  of  an 
engineer.  Any  owner  or  user  of  steam  boilers  of  a  capacity 
of  not  over  75  sq.  ft.  of  heating  surface  and  a  pressure  of  not 
over  25  Ib.  per  sq.  in.,  and  of  all  boilers  of  a  pressure  less  than 
15  Ib.  per  sq.  in.  used  for  heating  purposes  only,  may  obtain 
a  permit  from  the  board  to  employ  a  careful  and  trustworthy 
person  instead  of  a  licensed  engineer,  such  person  to  be  recom- 
mended by  two  citizens,  one  of  whom  shall  be  a  steam  user  or 
a  licensed  engineer.  When  boilers  are  used  for  engines  run  day 
and  night,  the  owner  or  user  of  them  may  employ  some  trust- 
worthy person  in  place  of  a  licensed  engineer,  not  exceeding 
12  hr.  at  a  time,  under  the  instructions  of  a  licensed  engineer- 
in-charge. 

In  case  an  owner  may  be  deprived  of  the  services  of  a 
licensed  engineer,  he  may  put  a  careful  and  trustworthy  per- 
son in  charge  for  a  time  not  exceeding  6  da.  In  places  where 
there  are  steam  boilers  or  steam-generating  apparatus  of  over 
10  H.  P.,  and  when  such  apparatus  is  in  use,  there  must  b«> 
employed  at  least  one  licensed  engineer. 


252  ENGINEERS'  LICENSE  LAWS 

Applicants  for  engineer's  license  must  make  application  on 
a  blank  furnished  by  the  board  for  that  purpose.  Applicants 
must  have  experience  of  at  least  2  yr.  at  mechanical  or  steam 
engineering,  and  must  state  their  experience  on  the  blanks. 
All  applications  must  be  signed  by  two  citizens,  one  of  whom 
must  be  a  steam  user  or  a  licensed  engineer,  who  shall  go  before 
the  board  and  make  oath  that  the  statements  set  forth  in  the 
application  are  true.  In  taking  charge  of  a  plant,  and  when 
leaving  a  plant  to  assume  charge  of  another,  engineers  must 
notify  the  board  immediately  in  the  first  instance  and  10  da. 
previous  in  the  second  instance.  The  fee  for  each  license  or 
renewal  is  $5. 

ABSTRACTS  OF  CITY  ENGINEERS'  LICENSE 
ORDINANCES 

Allegheny,  Pa. — See  Pennsylvania  state  law,  on  page  250. 

Atlanta,  Fulton  County,  Ga. — The  license  laws  for  Atlanta, 
which  is  in  Fulton  County,  Ga.,  are,  in  part,  as  follows: 

Any  person  desiring  to  be  examined  for  a  license  to  run  and 
operate  steam  boilers  and  stationary  engines  in  Fulton  County 
shall  make  application 'in  writing  to  the  Board  of  Examiners 
of  Engineers  of  Fulton  County.  Such  application  must  be 
indorsed  by  three  reputable  citizens  of  this  county,  one  of 
whom  shall  be  a  licensed  engineer.  The  three  citizens  must 
certify  to  the  good  character  and  sober  habits  of  the  appli- 
cant and  that  he  has  had  experience  of  not  less  than  1  yr. 
as  an  engineer,  or  experience  of  1  yr.  as  an  apprentice  under  a 
licensed  engineer.  No  license  shall  be  issued  by  the  board  of 
examiners  to  any  one  until  after  a  full  compliance  with  this 
rule. 

A  license  shall  be  granted  to  only  such  engineers  as,  after 
a  careful  examination,  the  board  of  examiners  shall  be  satisfied 
are  competent  to  have  full  charge  of  the  class  of  engines  and 
boilers  covered  by  the  license  issued  to  them. 

The  board  of  examiners  shall  classify  all  licenses  in  accord- 
ance with  the  character  of  the  engines  run  by  stationary 
engineers,  from  the  plain  slide-valve  engine  to  that  employing 
the  most  difficult  and  complicated  machinery.  The  license 
must  show  on  its  face  the  character  or  class  of  same. 


ENGINEERS'  LICENSE  LAWS  253 

The  board  of  examiners  shall  have  the  authority  to  issue 
licenses  to  assistant  engineers,  classifying  them  as  above  pro- 
vided, and  issue  to  the  same  only  such  license  as  may  cover 
the  character  of  the  engine,  which  in  their  judgment  such 
assistant  engineer  is  competent  to  have  charge  of,  and  then 
only  when  the  chief  engineer  in  charge  of  the  same  engine  has 
a  full  license  covering  the  class  to  which  it  belongs. 

Whenever  any  engineer  or  assistant  engineer  has  received 
a  license  of  one  class,  and  desires  to  be  licensed  in  a  higher 
class,  or,  in  the  case  of  an  assistant  engineer,  to  be  licensed  as 
chief  engineer,  he  may  make  application  to  the  board  of  exam- 
iners for  that  purpose.  After  a  reexamination  the  engineer 
or  the  assistant  engineer  may  be  granted  such  higher  license 
if,  in  the  opinion  of  said  board  of  examiners,  he  is  competent 
to  take  charge  of  such  engine  as  may  be  covered  thereby. 

When  any  person  shall,  after  written  notification  from  the 
board  of  examiners,  continue  to  run  or  operate  any  stationary 
engine  or  boiler  in  Fulton  County  without  a  license  from 
them  covering  the  class  of  engine  that  he  has  in  charge,  or  when- 
ever any  person  shall  knowingly  employ  or  cause  to  be  employed 
any  person  to  run  or  operate  a  stationary  engine  or  boiler  in 
Fulton  County  who  has  not  been  licensed  by  the  board  of 
examiners,  such  person  shall  be  prosecuted  by  the  board  of 
examiners  under  the  criminal  laws  of  this  state. 

Each  license  issued  by  the  board  is  issued  and  accepted 
subject  to  the  rules  of  examiners. 

The  board  of  examiners  shall  receive  a  fee  from  each  person 
examined  for  a  license  as  either  engineer  or  assistant  engineer 
of  $5  in  each  case,  which  fee  shall  be  required  to  be  paid  prior 
to  the  examination  of  the  applicant  and  whether  the  license 
is  issued  to  him  or  not. 

Baltimore,  Md. — In  the  city  of  Baltimore  there  is  a  board 
of  examining  engineers  appointed  biennially  by  the  governor 
of  the  state.  The  law  states  that  this  board  shall  have  general 
supervision  of  all  stationary  engineers  within  the  state  of 
Maryland,  except  as  hereinafter  provided.  It  shall  be  the 
duty  of  the  board  to  examine  all  engineers  of  the  age  of  21  yr. 
and  upwards  who  shall  apply  to  them  for  examination.  Those 
who  pass  the  examination  and  receive  a  certificate  shall  pay 
18 


254  ENGINEERS'  LICENSE  LAWS 

the  board  the  sum  of  $3  for  each  certificate  so  issued,  and  tor 
all  renewals  of  all  grades  the  sum  of  $1.50. 

The  certificates  shall  be  of  three  grades.  A  certificate  of  the 
first  grade  will  permit  the  holder  to  take  charge  of  any  plant 
of  machinery;  one  of  the  second  grade,  to  take  charge  of  any 
plant  of  machinery  from  1  to  500  H.  P.;  and  one  of  the  third 
grade,  to  take  charge  of  any  plant  of  machinery  from  1  to 
30  H.  P.  The  said  certificate  shall  run  for  the  term  of  1  yr. 
and  shall  be  renewed  annually. 

All  persons  desiring  to  fill  a  position  as  a  stationary  engineer 
must  make  application  to  the  board  of  examining  engineers, 
with  the  following  exceptions:  Persons  who  are  running 
•engines  and  boilers  in  sparsely  settled  country  places,  where 
not  more  than  twenty  persons  are  engaged  in  work  about  such 
engines  and  boilers;  engineers  running  country  saw  mills  and 
grist  mills,  threshing  machines,  and  other  machinery  of  a 
similar  character;  marine  engineers  engaged  in  steamboats  or 
any  vessel  run  by  steam;  and  persons  engaged  as  locomotive 
engineers  of  any  steam  railway  company. 

The  law  also  states  that  the  headquarters  of  the  board  shall 
be  in  Baltimore  and  that  it  shall  meet  at  least  once  in  every 
-week,  and  at  a  specified  hour  and  day  shall  sit  until  all  applicants 
shall  be  examined.  If  there  are  too  many  applicants  to  examine 
on  the  regular  day  for  the  purpose,  the  board  shall  continue 
its  sessions  until  all  applicants  have  been  examined. 

Buffalo,  N.  Y. -Every  person  within  the  city  limits  of  the 
city  of  Buffalo  in  charge  of  or  operating  any  steam  engine  or 
steam  boiler  (excepting  persons  operating  locomotive  steam 
engines  or  marine  engines,  or  persons  licensed  as  engineers  by 
the  authorities  of  the  United  States,  or  persons  in  charge  of 
any  steam  engine  or  boiler  in  any  of  the  public-school  build- 
ings, or  any  engineer  while  in  the  employ  of  the  fire  depart- 
ment of  the  city)  shall  appear  in  person  before  the  examiner 
of  stationary  engineers  for  examination  as  to  his  qualifications 
as  a  stationary  engineer,  and  if  found  qualified,  shall  be  duly 
licensed,  as  the  ordinance  provides.  But  such  persons  who 
have  charge  of  any  steam  boiler  or  steam  engine  in  public- 
school  buildings  of  the  city  shall  be  examined  as  to  their 
qualifications  to  have  charge  of  same. 


ENGINEERS'  LICENSE  LAWS  255 

No  person  shall  be  granted  a  license  unless  he  be  an  actual 
resident  of  the  city  of  Buffalo,  and  shall  be  a  citizen,  or  shall, 
have  declared  his  intention  to  become  a  citizen,  of  the  United 
States.  All  licenses  must  be  renewed  annually,  and  no  person, 
shall  have  charge  of  or  operate  more  than  one  steam  plant. 
A  fee  of  $3  shall  be  collected  by  the  examiner  upon  issuing  a 
license,  and  $2  for  each  annual  renewal. 

The  classification  and  grades  are  as  follows:  Chief  engineer f 
first-class  engineer,  second-class  engineer,  and  special  engineer. 
The  grades  are  according  to  the  capacity  and  horsepower  of  a 
steam  engine,  steam  boiler,  or  steam  plant  of  which  such 
engineers  are  found  competent  to  take  charge.  Chief  engineers 
are  qualified  to  take  charge  of  and  operate  any  size  of  steam 
plant;  first-class  engineers,  to  take  charge  of  any  steam  plant 
not  exceeding  150  H.  P.;  second-class  engineers,  to  take  charge 
of  and  operate  any  size  plant  not  exceeding  75  H.  P. ;  and  special 
engineers,  to  take  charge  of  only  a  certain  steam  engine  or  boiler 
to  be  stated  in  the  license,  such  steam  engine  or  boiler  not  to- 
exceed  10  H.  P.  and  such  license  not  to  be  used  for  a  longer 
term  than  1  yr. 

Chicago,  111. — In  Chicago  a  board  of  examiners  deals  with 
the  licensing  of  engineers.  This  board  holds  in  quarters  pro- 
vided by  the  commissioner  of  Public  Works,  daily  sessions  for 
the  purpose  of  examining  and  determining  the  qualifications  of 
applicants  for  licenses  for  engineers.  Every  application  for  a. 
license  must  be  made  on  printed  blanks  furnished  by  the  board 
of  examiners;  that  for  an  engineer  must  be  accompanied  by  a 
fee  of  $2,  and  that  for  a  boiler  or  water  tender  must  be  accom- 
panied by  a  fee  of  $1. 

An  applicant  for  an  engineer's  license  must  be  a  machinist 
or  an  engineer  having  a  practice  of  at  least  2  yr.  in  the  man- 
agement, operation,  or  construction  of  steam  boilers  and  engines 
An  applicant  for  a  boiler  tender's  license  must  be  a  person  who 
has  a  thorough  knowledge  of  the  construction  and  manage- 
ment, and  operation  of  steam  boilers.  Each  applicant  must  state 
upon  the  blank  the  extent  of  his  experience;  must  be  at  least 
21  yr.  of  age,  a  citizen  of  the  United  States,  or  have  declared 
his  intention  to  become  such;  and  must  be  of  good  character; 
all  of  which  must  be  vouched  for  in  writing  by  at  least 


256  ENGINEERS'  LICENSE  LA  ITS' 

two  citizens  of  Chicago,  or  may  be  verified  under  oath  by  the 
applicant  when  required  by  the  board  of  examiners. 

It  shall  be  the  duty  of  the  board  to  see  that  each  boiler  plant 
in  the  city  of  Chi  ,ago  shall  have  a  licensed  engineer,  or  boiler 
or  water  tender,  or  both  as  the  case  may  be,  in  charge  at  all 
times  when  working  under  pressure;  certificates  must  be  dis- 
played in  a  conspicuous  place  in  the  engine  or  boiler  room. 
Each  engine  and  boiler  tender  shall  devote  his  entire  time, 
while  boilers  are  working  under  pressure,  to  the  duties  of  the 
plant  under  his  charge,  Any  person  having  charge  of  a  steam 
boiler  whose  duty  it  is  to  keep  up  the  water  in  such  boiler 
shall  be  deemed  a  boiler  or  water  tender  within  the  meaning 
of  the  ordinance,  but  the  provisions  for  the  examination,  licen- 
sing, and  regulation  of  boiler  or  water  tenders  shall  apply  only 
to  boiler  or  water  tenders  who  ~re  in  charge  of  a  steam  boiler 
or  boilers,  that  are  detached  from  the  engine  room  or  so  far 
removed  therefrom  or  otherwise  located  as  to  render  it  difficult 
for  the  engineer  in  charge  of  the  plant  to  give  it  or  them  his 
personal  attention  and  supervision. 

The  following  are  exempt  from  the  provisions  of  the  ordi- 
nance: engineers  in  charge  of  locomotives  and  all  boilers  used 
for  heating  private  dwellings,  hothouses,  conservatories,  and 
other  boilers  carrying  a  pressure  of  not  more  than  10  Ib.  per 
sq.  in.  and  the  persons  operating  them. 

Denver,  Colo. — In  Denver  the  mayor  appoints  a  board  of 
examiners  consisting  of  the  city  boiler  inspector  and  two 
practical  engineers,  whose  duty  it  is  to  examine  applicants  for 
licenses  as  engineers  and  boiler  or  water  tenders,  in  accordance 
with  the  rules  and  regulations  of  the  ordinance,  and  to  issue  cer- 
tificates of  qualification.  The  law  states  that  each  certificate 
issued  by  the  board  shall  expire  1  yr.  from  the  date  of  issue, 
and  that  the  board  shall  hold  weekly  sessions  of  such  duration 
as  may  be  deemed  requisite  for  the  purpose  of  examining  and 
•determining  the  qualifications  of  applicants  for  licenses  as 
engineers  or  as  boiler  or  water  tenders. 

Every  application  for  a  license  must  be  made  on  printed 
blanks  furnished  by  the  board  of  examiners,  and  must  set  forth 
the  name,  age,  and  citizenship  of  the  applicant  and  the  extent 
of  his  experience.  An  application  for  an  engineer's  license 


ENGINEERS'  LICENSE  LAWS  257 

must  be  accompanied  by  a  fee  of  $2,  and  that  for  a  boiler  or 
water  tender's  license,  by  a  fee  of  $1. 

According  to  the  ordinance,  an  applicant  for  an  engineer's 
license  shall  be  a  machinist  or  engineer,  having  a  practice  of 
at  least  2  yr.  in  the  management,  operation,  or  construction 
of  steam  engines  and  boilers,  and  an  applicant  for  a  boiler  ten- 
der's license  shall  be  a  person  who  has  a  thorough  "knowledge 
of  the  construction,  management,  and  operation  of  steam 
boilers.  Each  engineer  and  boiler  or  water  tender  so  to  be 
licensed  shall  be  at  least  21  yr.  of  age  and  of  good  character, 
all  of  which  shall  be  vouched  for  in  writing  by  at  least  two 
citizens  of  Denver,  or  shall  be  verified  under  oath  by  the  appli- 
cant when  required  by  the  board  of  examiners. 

All  such  licenses  may  be  renewed  from  year  to  year  upon 
payment  of  the  license  fee  before  specified  and  without  further 
examination,  unless  the  applicant  applies  for  a  different  class 
or  grade  of  license. 

Engineers  in  charge  of  locomotives  and  engineers  or  boiler 
or  water  tenders  in  charge  of  boilers  carrying  a  steam  presssure 
of  not  more  than  10  Ib.  per  sq.  in.  are  exempt  from  the  pro- 
visions of  the  ordinance. 

Detroit,  Mich. — In  Detroit  the  city  boiler  inspector  examines 
candidates  as  to  their  fitness  to  perform  the  duties  of  the 
stationary  engineer.  Any  person  claiming  to  be  qualified  to 
operate  a  boiler  must  apply  in  writing  on  blanks  provided  for 
the  purpose  for  a  license.  The  inspector  shall  examine  him 
and  consider  the  proof  offered  in  support  of  his  claims.  If  the 
inspector  is  satisfied  that  the  applicant's  knowledge,  experience, 
and  character  render  him  competent  to  handle  boilers  with 
safety,  he  shall  issue  a  license  certificate  to  that  effect,  design- 
ating the  class  in  which  the  engineer  is  authorized  to  operate. 

There  shall  be  three  grades  of  engineers'  license.  First- 
class  engineers'  licenses  shall  be  unlimited  as  to  the  number 
of  boilers  and  pressure,  and  shall  be  granted  to  any  citizen 
having  an  experience  of  5  yr.  in  the  care  of  steam  boilers,  pro- 
vided he  can  pass  a  satisfactory  examination.  Second-class 
licenses  shall  be  limited  to  75  H.  P.  and  shall  be  granted  to 
any  citizen  having  an  experience  of  3  yr.  in  the  care  of  steam 
boilers,  provided  he  can  pass  a  satisfactory  examination. 


258  ENGINEERS'  LICENSE  LAWS 

Third  class  licenses  shall  be  limited  to  25  H.  P.  and  shall  be 
granted  to  any  citizen  having  experience  in  firing  steam  boilers 
for  2  yr.,  provided  he  can  pass  a  satisfactory  examination. 

If  any  person  makes  application  for  a  certain  class  of  license 
and  fails  to  procure  it  for  any  cause,  the  inspector  can  assign 
him  to  the  class  to  which  his  examination  entitles  him,  and  he 
cannot  make  application  again  for  a  period  of  less  than  3  mo. 
Any  person  having  a  second-class  or  a  third-class  license  can 
act  as  assistant  to  a  first-class  engineer. 

The  fee  for  licenses  shall  be  $1,  payable  before  examination, 
but  one-half  of  the  amount  paid  shall  be  refunded  if  the  license 
is  refused.  The  provisions  of  the  ordinance  do  not  apply  to 
locomotive  boilers  used  on  railroads,  boilers  under  the  jurisdic- 
tion of  the  United  States,  boilers  in  the  fire  department  of  the 
city,  and  boilers  used  in  private  residences  for  heating  purposes. 

Elgin,  111. — The  engineers'  license  laws  for  Elgin,  111.,  are, 
in  part,  as  follows: 

There  shall  be  and  there  is  hereby  authorized  to  be  appointed 
by  the  mayor,  by  and  with  the  consent  of  the  city  council,  a 
board  of  examining  engineers.  The  said  board  shall  consist 
of  three  practical  engineers.  The  duties  of  the  board  shall  be 
to  examine  into  the  qualifications  of  applicants  for  engineer's 
license;  to  license  those  found  qualified,  and,  for  cause,  to 
suspend  or  revoke  the  same. 

The  examination  may  be  written  or  oral  and  shall  be  entirely 
practical.  Applications  for  license  shall  be  made  on  a  printed 
blank  furnished  by  a  board  of  examiners  and  shall  set  lorth 
the  name,  age,  citizenship,  residence,  experience,  etc.,  of  the 
applicant,  together  with  the  location  of  the  plant  for  which  a 
license  is  desired.  Each  application  for  license  shall  be  accom- 
panied with  $1,  which  fee  shall  be  returned  in  case  of  failure 
to  secure  a  license. 

The  board  of  examiners  may  suspend  the  license  of  any 
engineer  for  carelessly  permitting  the  water  to  get  too  low  and 
burning  the  boiler;  for  carrying  the  steam  pressure  higher  than 
allowed  by  law;  for  absence  from  his  post  of  duty;  for  neg- 
lect, incapacity,  or  intoxication  while  on  duty;  provided  that 
no  license  be  suspended  or  revoked  without  first  giving  the 
accused  person  an  opportunity  to  be  heard  in  his  own  defense. 


ENGINEERS'  LICENSE  LAWS  259 

The  license  will  be  suspended  not  to  exceed  30  da.  for  the  first 
offense,  not  to  exceed  90  da.  for  the  second  offense,  and  not  to 
exceed  6  mo.  for  an  offense  after  that. 

Engineers'  licenses  will  be  good  for  1  yr.  from  date  of  issue 
and  must  be  renewed  annually.  Engineers  who  change  from 
one  plant  to  another  must  secure  permission  from  the  board 
of  examiners,  who  will  either  authorize  the  change  or  reexamine 
the  applicant,  at  their  discretion,  without  additional  cost  to 
applicant.  Engineers'  licenses  must  be  framed  under  glass 
and  kept  in  a  conspicuous  place  in  engine  room  or  boiler  room. 

All  applicants  for  an  engineer's  license  shall  have  a  practi- 
cal experience  of  at  least  1  yr.  in  the  management  of  steam 
engines  and  boilers.  Each  applicant  shall  be  at  least  20  yr.  of 
age  (except  that  by  unanimous  consent  of  the  board  a  younger 
man  may  be  licensed)  and  must  be  of  temperate  habits  and 
good  character,  all  of  which  must  be  vouched  for  in  writing 
by  two  freeholders  of  Elgin,  or  verified  under  oath  by  the 
applicant  when  required  by  the  examiners. 

It  shall  be  unlawful  for  any  unlicensed  person  to  take  charge 
of  or  operate  any  steam  power  or  boiler  plant  within  the  city 
of  Elgin,  excepting  engineers  in  charge  of  locomotives,  steam- 
road  carriages,  and  those  in  charge  of  boilers  carrying  a  steam 
pressure  of  less  than  15  Ib.  per  sq.  in.  Any  person  who  shall 
take  charge  of  or  operate  any  steam  power  or  boiler  plant  for 
a  longer  time  than  to  the  next  meeting  of  the  board  of  examiners, 
shall  be  guilty  of  a  misdeameanor  and  subject  to  a  fine  of 
not  more  than  $20  nor  less  than  $5.  Any  person,  company, 
or  corporation  controlling  any  steam  power  or  boiler  plant 
who  shall  authorize  or  permit  any  person,  without  proper  and 
valid  license,  to  take  charge  of  or  operate  the  same  for  a  longer 
period  than  above  stated,  shall  be  guilty  of  a  misdemeanor 
and  subject  to  a  fine  of  not  more  than  $50,  nor  less  than  $20, 
for  each  offense,  and  each  day's  violation  of  this  ordinance 
shall  constitute  a  separate  offense. 

Any  engineer  whose  license  has  expired  for  a  period  of  10  da. 
must  give  satisfactory  explanation  to  the  board  of  examining 
engineers  why  such  a  condition  exists,  and  any  engineer  whose 
license  has  expired  for  a  period  of  1  yr.  or  more  shall  be  sub- 
jected to  a  reexamination. 


2CO  ENGINEERS'  LICENSE  LAWS 

Any  engineer  or  water  tender  changing  his  position  from 
one  plant  to  another  shall  within  5  da.  have  his  license  trans- 
ferred to  the  plant  he  is  to  operate. 

Goshen,  Ind. — In  the  city  of  Goshen,  Ind.,  there  is  appointed 
by  the  mayor,  with  the  consent  of  the  common  council,  an 
examining  engineer  who  has  charge  of  matters  pertaining  to 
the  licensing  of  stationary  engineers. 

Any  person  desiring  to  act  as  an  engineer  shall  make  appli- 
cation to  the  examiner,  upon  blanks  furnished  by  the  examiner, 
and  if,  upon  examination,  the  applicant  is  found  to  be  trust- 
worthy and  competent,  a  license  shall  be  granted  to  said 
applicant;  such  license  shall  continue  in  force  for  1  yr.,  unless 
for  cause  it  may  be  revoked. 

License  shall  be  granted  according  to  competency  of  the 
applicant,  and  shall  be  divided  into  classes  as  follows:  Class  1, 
the  engineer's  license  for  which  shall  be  unlimited  as  to  horse- 
power; class  2,  the  license  for  which  shall  be  limited  to  150  H.  P.; 
and  class  3,  the  license  for  which  shall  be  limited  to  50  H.  P. 
Engineers  holding  second-  or  third-class  licenses  may  act  as 
assistant  engineers  in  a  plant  of  any  capacity,  provided  the 
man  in  charge  holds  a  first-class  license. 

The  fee  for  examination  of  applicants  shall  be  $1,  to  be  paid 
at  the  time  of  the  application  for  examination,  and  $1  for 
each  renewal  of  license.  Locomotive  boilers  and  engines, 
boilers  of  private  residences,  or  boilers  of  less  than  8  H.  P. 
do  not  require  a  licensed  engineer  to  operate  them. 

Hoboken,  N.  J. — License  laws  in  Hoboken,  N.  J.  are  admin- 

and   enforced   by   a   board   of   examining    engineers, 

consisting  of  five  members  appointed  by  the  council.      The 

mayor  and  the  council  of  the  city  of  Hoboken  do  ordain  as 

follows: 

No  person  shall  be  the  engineer  of,  or  shall  have  charge  of, 
or  operate  any  steam  boiler,  or  steam  engine  in  the  city  of 
Hoboken,  for  a  period  exceeding  2  da.,  who  shall  not  have  a 
license  certificate  or  shall  have  made  application  for  the  same 
authorizing  him  to  have  charge  of,  or  to  operate  such  engine, 
or  boiler,  from  the  board  of  examining  engineers,  and  no  such 
license  shall  be  granted  unless  the  applicant  therefor  be  a 
citizen  of  the  United  States. 


ENGINEERS'  LICENSE  LAWS  2G1 

Before  any  person  shall  be  employed  as  an  engineer  of  any 
such  steam  boiler  or  engine,  or  shall  have  charge  of  or  operate 
any  such  boiler  or  engine,  he  shall  make  a  written  application 
on  blanks  furnished  by  the  city  to  said  board  of  examining 
engineers,  for  the  license  heretofore  mentioned,  which  appli- 
cation shall  be  accompanied  by  references  as  to  the  character 
and  ability  of  the  applicant,  and  the  filing  of  such  references 
with  said  board  shall  be  considered  as  a  compliance  with  the 
provisions  of  this  ordinance  for  30  da.  thereafter  or  until  the 
said  application  shall  have  been  passed  upon  by  said  board, 
and  said  applicant  after  the  riling  of  said  reference  shall  have  the 
right  to  operate  and  have  charge  of  any  such  engine,  boiler 
or  plant  until  his  application  shall  have  been  passed  upon  by 
said  board. 

Every  person  who  shall  satisfy  said  board  of  examining 
engineers  that  he  is  a  safe  and  competent  person  to  operate 
and  have  charge  of  such  steam  boiler,  engine  or  plant  specified 
in  his  application,  shall,  upon  payment  of  $2  to  the  city  clerk 
as  his  fee,  receive  a  license  permitting  him  to  operate  the  same 
for  1  yr.,  unless  such  license  shall  be  sooner  revoked.  For  an 
annual  renewal  of  such  license  the  licensee  shall  pay  to  the 
city  clerk  as  his  fee  the  sum  of  $1  therefor;  additional  hearing 
shall  not  be  required,  unless  in  the  judgment  of  the  said  board 
the  same  may  be  necessary.  Such  licenses  must  be  framed  and 
hung  in  a  conspicuous  place  in  the  plant,  or  upon,  or  near  the 
engine  or  boiler,  in  charge  of  such  licensee. 

Said  board  may  at  any  time  after  proper  hearing  revoke 
any  license  issued  on  account  of  inebriety,  incompetency,  or 
negligence  of  the  holder  of  any  such  license,  or  for  any  other 
good  cause,  and  no  license  shall  be  issued  to  any  licensee 
whose  license  shall  have  been  revoked  for  a  period  of  6  mo., 
after  which  the  license  revoked  may  be  renewed,  if  in  the 
judgment  of  the  board  the  cause  of  its  revocation  no  longer 
exists. 

If  said  board  shall  refuse  to  grant  to  any  applicant  a  license, 
no  license  shall  be  issued  to  him  for  the  next  6  mo.  following 
the  refusal  of  said  application,  but  after  said  period  said  appli- 
cant may  make  another  application,  and,  if  qualified,  may  be 
granted  a  license. 


262  ENGINEERS'  LICENSE  LAWS 


This  ordinance  shall  not  apply  to  locomotive  engineers  or 
to  engineers  on  steam  vessels  coming  under  the  jurisdiction 
of  the  United  States  Board  of  Supervising  Inspectors,  nor  shall 
it  apply  to  boilers  in  private  residences  for  heating  purposes, 
unless,  in  the  opinion  of  said  board,  such  boiler  is  so  equipped 
and  run  as  to  endanger  public  safety  unless  operated  by  a 
licensed  engineer. 

Any  engineer  in  charge  of  any  steam  engine  or  boiler  who 
shall  abandon  it  while  in  operation  without  leaving  a  person 
in  charge  of  same,  who  shall,  in  the  opinion  of  the  board  of 
examining  engineers,  be  competent  to  take  charge  of  same, 
shall  be  fined  the  sum  of  $10. 

Huntington,  W.  Va. — License  laws  in  the  city  of  Huntington, 
W.  Va.,  are  administered  and  enforced  by  a  board  of  engineers 
consisting  of  four  members.  Candidates  for  examination  must 
have  had  at  least  1  yr.  of  experience  in  operating  steam  engines 
and  boilers.  The  law  states  that  it  shall  be  the  duty  of  the 
board  of  engineers,  upon  the  payment  of  $3  by  the  applicant, 
to  examine  persons  touching  their  qualifications  as  engineers, 
who  desire  to  act  as  engineers  and  take  charge  of  steam  boilers, 
engines,  and  pumps.  If  the  applicant  passes  a  satisfactory 
examination,  the  board  shall  grant  and  issue  to  him  a  certi- 
ficate of  qualification.  If  the  applicant  fails  to  pass  a  satis- 
factory examination,  he  shall  not  be  allowed  to  apply  again 
for  certificate  for  2  mo.  thereafter.  All  certificates  granted 
shall  be  in  force  for  1  yr,  from  the  date  thereof  and  no  longer, 
and  any  person  holding  a  certificate  from  the  board  may  have 
the  same  renewed  at  its  expiration  for  a  period  of  1  yr.  by  the 
applicant  for  such  renewal  paying  the  sum  of  $2,  provided, 
however,  that  the  person  applying  for  such  renewal  is  entitled 
thereto,  and  such  application  for  renewal  is  made  on  or  before  the 
last  regular  meeting  of  the  board  before  the  expiration  of  the 
applicant's  certificate.  Unless  the  above  provision  is  complied 
with,  the  board  may,  at  its  discretion,  order  a  new  examination. 

The  board  shall  have  the  right  to  adopt  rules  and  regulations 
as  they  deem  necessary  and  proper,  not  inconsistent  with  this 
ordinance.  The  full  board,  by  an  unanimous  vote,  shall  have 
power  and  may  revoke  any  engineer's  certificate  upon  cau.se 
being  shown  therefor. 


ENGINEERS'  LICENSE  LAWS  263 

It  shall  be  the  duty  of  each  engineer  holding  a  certificate 
from  the  board  to  display  the  same  in  some  prominent  place 
near  the  boiler  or  boilers  in  his  charge.  The  board  may  revoke 
the  certificate  of  any  engineer  who  shall  fail  or  refuse  to  comply 
with  this  section. 

It  shall  be  unlawful  for  any  person  to  operate  or  cause  to  be 
operated  any  steam  boiler  used  to  furnish  steam  at  a  pressure 
to  exceed  25  Ib.  per  sq.  in.,  unless  there  be  in  charge  of  such 
boiler  an  experienced  person  having  a  certificate  from  the  board 
of  engineers,  and  any  person  found  in  charge  and  operating 
a  boiler  not  having  a  certificate  from  the  board  of  engineers 
shall  be  deemed  guilty  of  a  misdemeanor  and,  upon  conviction 
thereof,  shall  be  fined  in  the  sum  of  not  less  than  $5,  nor  more 
than  $50  for  each  offense;  provided,  however,  that  any  owner 
or  user  of  any  boiler  in  use  which  shall  for  any  cause  be  deprived 
of  the  service  of  a  person  holding  such  certificate  may  procure 
an  experienced  and  careful  person  to  take  charge  of  such  boiler 
for  a  period  not  to  exceed  10  da. 

Jersey  City,  N.  J. — Engineers*  license  laws  are  administered 
by  a  board  of  examiners  in  Jersey  City,  N.  J.  The  laws,  in 
part,  are  as  follows: 

No  person  shall  be  the  engineer  of,  or  shall  have  charge  of 
or  operate  any  steam  boiler  or  steam  engine,  in  the  city  of 
Jersey  City,  for  a  period  exceeding  1  wk.,  who  shall  not  have  a 
license  certificate  authorizing  him  to  have  charge  of  or  operate 
such  engine  or  boiler,  from  the  board  of  examiners. 

Before  any  person  shall  be  employed  as  an  engineer  of  any  such 
steam  boiler  or  engine,  or  shall  have  charge  of  or  operate  any 
such  boiler  or  engine,  he  shall  make  a  written  application  to 
the  board  of  examiners  for  the  license,  and  shall  specify  in  such 
application  the  particular  engine,  boiler,  or  plant  that  he 
desires  to  operate,  or  have  charge  of,  which  application  shall 
be  accompanied  by  references  as  to  his  character  and  ability, 
and  the  filing  of  such  reference  with  such  said  board  shall  be 
considered  as  a  compliance  with  the  provisions  of  this  ordinance 
for  30  da.  thereafter,  or  until  his  said  application  shall  have  been 
passed  upon  by  said  board,  and  said  applicant,  after  the  filing 
of  said  references,  shall  have  the  right  to  operate  until  his 
application  shall  have  been  passed  upon  by  said  board. 


264  ENGINEERS'  LICENSE  LAWS 

Every  person  who  shall  satisfy  said  board  of  examiners  that 
he  is  a  safe  and  competent  person  to  operate  and  have  charge 
of  the  steam  plant,  boiler,  or  engine  specified  in  his  application, 
shall,  on  payment  of  $1  to  the  city  clerk,  for  the  benefit  of  the 
city,  receive  a  license  permitting  him  to  operate  the  same  for 
1  yr.,  unless  sooner  revoked.  Said  license  shall  apply  only  to  the 
plant,  boiler,  or  engine  for  which  it  is  issued,  and  before  taking 
charge  of  another  plant  the  licensee  shall  apply  for  another 
license  for  such  other  plant,  for  which  other  license,  if  the 
application  be  made  within  a  year,  no  charge  shall  be  made. 
For  annual  renewals  of  such  licenses  a  fee  of  $1  shall  be 
paid.  For  the  renewals  above  mentioned,  no  additional  hear- 
ing shall  be  required,  unless  in  the  judgment  of  said  board 
it  shall  be  necessary.  Said  licenses  must  be  framed  and 
hung  in  a  conspicuous  place  in  the  plant,  or  upon  or  near  the 
engine  for  which  is  is  issued. 

If  the  board  shall  refuse  to  grant  to  any  applicant  a  license, 
oo  license  shall  be  issued  to  him  for  the  next  6  mo.  following 
the  refusal  of  his  application,  but  after  said  period  said  appli- 
cant may  make  another  application,  and  if  found  qualified, 
may  be  granted  a  license. 

Whenever  said  board  shall  refuse  to  grant  any  application, 
or  shall  revoke  any  license,  they  shall  give  immediate  notice 
of  such  refusal  or  revocation  to  the  applicant  or  licensee,  and 
such  applicant  or  licensee  may  appeal  from  the  decision  of  such 
board  to  the  board  of  aldermen,  in  which  case  said  applicant 
or  licensee  shall  file  his  appeal  with  the  board  of  aldermen 
within  10  da.  after  receiving  notice  of  the  decision  of  said 
board,  and  the  board  of  aldermen  may  confirm  or  reverse  the 
decision  of  said  board,  and  issue  such  license. 

The  ordinance  shall  not  apply  to  railway  locomotives,  nor 
to  engineers  employed  thereon,  nor  to  steam  vessels  coming 
under  the  jurisdiction  of  the  United  States  Board  of  Super- 
vising Inspectors,  when  employed  upon  the  vessel  to  which 
said  license  applies.  Nor  shall  it  apply  to  boilers  in  private 
residences  or  buildings  for  heating  purposes,  unless,  in  the 
opinion  of  said  board,  such  boiler  is  so  equipped  and  run 
aj>  to  endanger  public  safety  unless  operated  by  a  licensed 


ENGINEERS'  LICENSE  LAWS  265 

Kansas  City,  Mo. — In  Kansas  City,  Mo.,  a  board  of  engineers 
appointed  by  the  mayor,  with  the  consent  of  the  council, 
administers  the  license  laws.  The  board  convenes  for  business 
once  each  month,  to  examine  into  the  qualifications  of  appli- 
cants for  engineers'  licenses.  According  to  the  laws,  the  board 
shall  grant  certificates  of  license,  charging  $5  to  each  applicant 
for  the  first  certificate,  $3  of  which  is  to  be  deposited  at  once. 
Each  applicant  is  to  be  allowed  three  trials,  and  if  he  then  fails 
to  pass  a  satisfactory  examination,  the  applicant  shall  forfeit 
the  money  deposited  (namely,  $3)  with  the  clerk  of  the  board. 
But  if  the  applicant  has  the  capacity,  skill,  experience,  and 
habits  of  sobriety  requisite  to  perform  the  duties  of  an  engineer, 
and  shall  pass  the  examination,  the  board  shall  grant  him  a 
license  for  the  term  of  1  yr.  upon  the  payment  of  an  additional 
$2.  Any  person  so  qualified  shall  not  be  refused  a  license. 

Renewal  of  license  will  be  granted  to  applicants,  upon 
payment  of  $2.50,  if  renewed  on  or  before  the  next  regular 
meeting  of  the  board  of  engineers  after  its  expiration.  All 
engineers,  engines,  and  boilers  of  the  fire  department  of  Kansas 
City,  the  locomotive  boilers  used  on  railroads,  and  steam 
boilers  supplied  with  water  automatically,  when  used  only  for 
heating  dwelling  houses  and  not  carrying  a  pressure  over 
10  lb-  per  sq.  in.,  are  exempt  from  the  provisions  of  this 
ordinance. 

Every  applicant  for  a  license  who  fails  to  pass  the  exami- 
nation of  the  board  is  required  to  wait  4  wk.  before  again 
making  application  for  license,  and  the  board  shall  then  give 
him  another  examination.  Applicants  failing  to  pass  the 
examination  after  the  third  trial  shall  not  be  permitted  to 
appear  again  before  the  board  for  6  mo. 

Every  engineer  licensed  by  the  board  and  under  control 
of  the  board  is  required  to  notify  the  boiler  inspector — who  is 
a  member  of  the  examining  board  referred  to — when  he  accepts 
employment,  and  within  3  da.  thereafter,  the  name  of  his 
employer,  and  the  location  of  the  boilers  in  his  charge.  Any 
engineer  who  shall  neglect  or  refuse  to  comply  with  this  rule 
shall  be  deemed  guilty  of  a  misdemeanor.  Engineers  shall 
report  semiannually  to  the  boiler  inspector,  during  the  first 
3  da.  of  the  months  of  January  and  July,  the  condition  of  the 


266  ENGINEERS'  LICENSE  LAWS 

boilers,  pumps,   and  connections  under  their  charge.     Failure 
to  comply  with  the  rule  shall  be  deemed  a  misdemeanor. 

Lincoln,  Neb. — License  laws  in  Lincoln,  Neb.,  are  adminis- 
tered by  a  board  of  engineers,  which  consists  of  three  members 
appointed  by  the  mayor  with  the  consent  of  the  city  council. 

The  law  states  that  it  shall  be  the  duty  of  the  board  of 
engineers,  on  the  payment  of  $3  by  the  applicant,  to  examine 
persons,  touching  their  qualifications  as  engineers,  who  desire 
to  act  as  engineers  and  take  charge  of  steam  boilers.  All 
certificates  granted  shall  be  in  force  for  1  yr.  from  the  date 
thereof  and  no  longer;  and  at  the  end  of  1  yr.  certificates  may 
be  renewed  for  another  year  by  the  applicant  paying  the 
sum  of  $2,  provided  the  person  applying  for  such  renewal 
is  entitled  thereto  and  such  application  is  made  on  or  before  the 
last  regular  meeting  of  the  board,  before  the  expiration  of  the 
applicant's  certificate. 

It  shall  be  the  duty  of  every  person  holding  a  certificate 
from  the  board  to  make  a  semiannual  report  to  the  board,  during 
the  months  of  January  and  July  of  each  year,  of  the  condition 
of  every  boiler,  pump,  and  connection  under  his  charge. 
Failure  to  make  such  report  is  sufficient  cause  for  the  board 
to  revoke  the  certificate  of  the  person  involved.  Heating 
apparatus  in  private  dwellings  are  exempt  from  inspection, 
as  provided  by  the  ordinance  in  this  city,  also  those  boilers 
kept  insured  in  any  reputable  and  legitimate  insurance  com- 
pany requiring  inspection. 

Four  grades  of  certificates,  namely,  first-,  second-,  and 
third-grade  certificates  and  a  certificate  specified  low  pressure, 
are  issued  by  the  board.  First-grade  certificates  are  granted 
to  applicants  who,  on  examination,  are  found  qualified  to  take 
charge  of  and  operate  any  steam  plant;  second-grade  certificates 
are  granted  to  applicants  who,  on  examination,  are  found  qual- 
ified to  take  charge  of  and  operate  any  steam  plant  up  to 
75  H.  P.  only;  and  third-grade  certificates  are  granted. to 
applicants  who,  on  examination,  are  found  qualified  to  take 
charge  of  and  operate  any  steam  plant  up  to  25  H.  P.  only. 
Certificates  specified  low  pressure  are  granted  to  applicants 
who,  on  examination,  are  found  qualified  only  to  take  charge  of 
and  operate  low-pressure  boilers  for  heating  purposes. 


ENGINEERS'  LICENSE  LAWS  267 

Los  Angeles,  Cal. — The  license  laws  in  Los  Angeles  are  admin- 
istered by  the  city  boiler  inspector  and  an  assistant  inspector 
appointed  by  the  city  council,  together  with  a  board  of  examin- 
ing engineers,  of  which  there  are  three  in  number. 

The  board,  so  the  law  states,  shall  hold  one  meeting  on  the 
first  and  third  Wednesday  in  each  month  for  the  purpose  of 
examining  applicants  for  engineer's  license,  and  shall  hold  the 
meeting  on  the  second  and  fourth  Tuesday  of  each  month  for 
the  purpose  of  examining  applicants  for  elevator  license.  The 
board  shall  make  a  careful  and  thorough  examination  as  to  the 
qualifications  of  all  applicants  for  engineer's  license,  and  shall 
grant  certificates  of  license  to  all  persons  found  qualified;  it 
shall  charge  and  collect  from  each  applicant  for  a  chief,  or  first- 
class,  license,  the  sum  of  $5,  and  from  each  applicant  for  a 
second  or  a  third-class  license,  the  sum  of  $3.  Such  licenses  are 
good  for  the  term  of  1  yr.,  unless  revoked  for  cause. 

In  case  any  owner  or  user  of  any  boiler  shall  for  any  cause  be 
deprived  of  the  services  of  a  licensed  engineer,  he  muct  notify 
the  boiler  inspector  at  once,  and  may  place  an  experienced  per- 
son in  charge,  for  a  time  not  beyond  the  date  of  the  next  regular 
meeting  of  the  board  of  engineers.  When  boilers  are  used  and 
engines  run  night  and  day,  the  owner  or  user  of  them  must 
employ  at  least  two  licensed  engineers,  who  shall  stand  watch 
alternately.  No  person  shall  use  or  operate  any  steam  boiler 
or  steam-generating  apparatus  in  the  city  of  Los  Angeles  with- 
out obtaining  a  certificate  of  license  as  provided  for;  this  applies 
to  apparatus  of  over  5  H.  P. 

Applicants  for  license  who  fail  to  pass  the  examination  of  the 
board  of  engineers,  shall  be  required  to  wait  for  4  wk.  before 
making  another  application.  Applicants  who  fail  to  pass  after 
a  third  trial  shall  not  be  permitted  to  again  appear  before 
the  board  for  6  mo.  An  engineer  must  notify  the  boiler 
inspector  of  any  employment  that  he  may  enter  into  as  an  engi- 
neer, and  within  3  da.  after,  the  name  of  his  employer  and  the 
location  of  the  plant  in  his  charge.  Engineers  must  also  report 
semiannually  to  the  boiler  inspector,  during  the  first  3  da.  of 
the  months  of  January  and  July  of  each  year,  the  condition  of 
the  boiler  or  other  apparatus  and  their  connections  under  or 
in  his  charge. 


268  ENGINEERS'  LICENSE  LAWS 

Applicants  for  renewal  of  licenses  shall  pay  to  the  board  of 
engineers  the  sum  of  $1  for  each  yearly  renewal. 

Any  person  violating  any  of  the  provisions  of  this  ordinance 
shall  be  deemed  guilty  of  a  misdemeanor,  and  upon  conviction 
shall  be  punished. 

Memphis,  Tenn. — In  the  city  of  Memphis,  Tenn.,  there  is 
a  board  of  examiners  appointed  by  the  legislative  council.  This 
board  consists  of  the  city  boiler  inspector  and  four  practical 
steam  engineers,  and  is  created  for  the  purpose  of  examining 
and  licensing  engineers  having  charge  of  or  operating  boilers 
and  steam  engines  in  the  city  of  Memphis. 

The  Jaws  of  this  city  state  that  the  board  of  examiners  shall 
hold  at  least  two  sessions  each  month,  on  the  first  and  third 
Mondays,  for  the  purpose  of  receiving  and  acting  on  applica- 
tions for  license.  The  board  shall  grant  certificates  of  license 
for  1  yr.  to  applicants  who,  on  examination,  shall  have  the 
skill,  experience,  and  habits  requisite  to  perform  the  duties 
of  an  engineer.  Licenses  shall  be  renewed  without  examination 
upon  payment  of  the  required  fee.  Applicants  for  license  must 
not  be  less  than  21  yr.  of  age,  and  must  be  citizens  of  the  United 
States  or  have  declared  their  intention  to  become  citizens.  Appli- 
cations must  be  made  upon  blanks  furnished  by  the  board  for 
such  purpose.  Applicant?  must  have  an  experience  of  at  least 
3  yr.  at  mechanical  or  steam  engineering,  and  so  state  it  on  the 
blanks.  All  applications  must  be  signed  by  two  citizens  of  the 
United  States,  one  of  whom  must  be  an  engineer  or  steam  user, 
and  both  of  whom  must  make  affidavit  before  an  officer,  quali- 
fied to  administer  an  oath,  that  the  statements  set  forth  in 
such  applications  are  true.  When  an  applicant  fails  to  pass  an 
examination  three  times,  he  will  not  be  eligible  to  take  another 
examination  until  60  da.  has  passed  from  the  time  of  his  last 
appearance  before  the  board. 

Licenses  shall  be  of  three  grades,  namely,  first,  second,  and 
third.  A  first-grade  license  shall  entitle  its  rightful  holder  to 
operate  or  to  have  charge  of  steam  plants  of  unlimited  capacity 
as  to  horsepower  of  boilers.  A  second-grade  license  shall 
entitle  its  rightful  holder  to  assist  a  first-grade-license  engineer 
in  any  steam  plant  where  such  services  are  required  under  the 
instructions  of  first-grade  engineer  in  charge  of  steam  plant; 


ENGINEERS'  LICENSE  LAWS  269 

or  he  may  have  charge  of  and  operate  steam  plants  limited  to 
75  H.  P.  of  boilers.  A  third-grade  license  shall  entitle  its  right- 
ful holder  to  assist  first-  or  second-grade  engineers  where  such 
services  are  required,  under  the  instructions  of  engineer  in 
charge  of  steam  plant;  or  he  may  have  charge  of  or  operate 
steam  plants  limited  to  25  H.  P.  of  boiler. 

The  fee  for  each  license  or  yearly  renewal  shall  be  $2. 
The  provisions  of  this  ordinance  shall  apply  to  all  steam  plants  or 
boilers  operated  within  the  city  limits,  except  locomotive  boilers 
used  on  railroads.  If  any  owner  or  user  of  any  boiler  or  boilers 
or  steam-generating  apparatus  is  deprived  of  the  services  of  the 
licensed  engineer  or  engineers  employed  by  him,  for  any  reason 
over  which  he  has  not  control,  he  may  employ  an  unlicensed 
engineer  for  30  da.,  in  which  time  he  must  secure  a  licensed 
engineer. 

No  person  shall  receive  a  license  who  is  not  able  to  determine 
the  weight  necessary  to  be  placed  on  the  lever  of  a  safety  valve 
(the  various  data  to  work  the  problem  being  given)  to  with- 
stand any  given  pressure  of  steam  in  the  boiler.  Applicants 
must  also  be  able  to  figure  and  determine  the  strain  brought  on 
the  braces  of  a  boiler  with  a  given  pressure  of  steam,  the  position 
and  distance  apart  being  known.  They  must  be  able  to  figure 
and  determine  the  safe  working  pressure  of  a  boiler,  such 
knowledge  to  be  determined  by  an  examination  in  writing. 
No  license,  except  third  grade,  shall  be  granted  to  any  engineer 
who  does  not  possess  the  foregoing  qualifications.  No  license 
shall  be  granted  to  any  engineer  who  cannot  read  and  write 
and  does  not  understand  the  plain  rules  of  arithmetic.  The 
examination  questions  asked  an  applicant  for  license  shall  be 
practical  ones  pertaining  to  boiler  and  engine  care  and 
management;  correct  answers  to  80%  of  such  questions  shall 
qualify  the  applicant  to  receive  his  license. 

Milwaukee,  Wis. — The  engineers'  license  laws  in  the  city  of 
Milwaukee  are  administered  and  enforced  by  a  board  of  exam- 
ining engineers,  consisting  of  two  persons. 

No  person  may  operate  or  have  control  of  any  stationary  or 
portable  steam  boiler,  engine,  or  any  portion  of  a  steam  plant, 
over  10  H.  P.,  when  working  under  pressure,  except  a  duly 
licensed  engineer. 
19 


270  ENGINEERS'  LICENSE  LAWS 

The  board  of  examiners  shall  hold  daily  sessions  for  the  pur- 
pose of  examining  and  determining  the  qualifications  of  appli- 
cants for  licenses  for  engineers  and  for  persons  having  charge 
of  steam  boilers  or  engines,  as  provided  in  the  ordinance. 

All  persons  desiring  to  perform  the  duties  of  a  stationary  or 
portable-boiler  engineer  shall  make  application  therefor  to  the 
board  of  examiners,  and  shall  present  therewith  a  receipt  from 
the  city  treasurer  for  a  fee  of  $3.  The  board  shall  have  the 
power  to  examine  applicants,  to  grant  licenses,  and  to  revoke 
or  suspend  the  same  for  cause.  Applications  must  be  made  on 
printed  blanks  furnished  by  the  board. 

Licenses  shall  be  in  force  for  1  yr.  from  date  of  issuance,  and 
at  the  expiration  of  1  yr.  and  on  the  payment  of  $1  licenses  may 
be  renewed  without  further  examination.  An  applicant  for 
engineer's  license  must  be  a  machinist,  engineer,  oiler,  or  fire- 
man having  an  experience  of  at  least  2  yr.  in  the  management, 
operation,  or  construction  of  steam  boilers  and  engines.  Each 
applicant  must  state  the  extent  of  his  experience,  be  at  least 
21  yr.  of  age,  and  of  good  character,  all  of  which  must  be 
vouched  for  in  writing  by  at  least  two  citizens  of  the  city  of 
Milwaukee. 

If  the  applicant,  on  examination,  be  found  qualified  as  an 
engineer  of  a  stationary  or  a  portable  steam  boiler  or  engine, 
he  shall  be  granted  a  license  according  to  class,  as  provided  for. 
Licenses  so  granted  shall  be  graded  into  three  classes:  (1)  Per- 
sons holding  first-class  licenses  may  take  charge  of  and  operate 
any  steam-  or  motive-power  plant;  (2)  persons  holding  second- 
class  licenses  may  take  charge  of  and  operate  any  steam-  or 
motive  power  plant  not  exceeding  300  H.  P.;  (3)  persons  hold 
ing  third-class  licenses  may  take  charge  of  and  operate  ar 
steam-  or  motive-power  plant  not  exceeding  75  H.  P.  Twelv*. 
sq.  ft.  of  boiler  heating  surface  shall  be  equivalent  to  1  H.  P. 

The  holder  of  a  second-class  license  may  act  as  an  assistant 
engineer  to  an  engineer  in  charge  of  a  plant  under  a  first-class 
license;  and  the  holder  of  a  third-class  license  may  act  as  an 
assistant  engineer  to  an  engineer  in  charge  of  a  plant  under  a 
second-class  license. 

It  shall  be  unlawful  to  carry  a  higher  pressure  of  steam  than 
that  fixed  by  the  board.  Engineers'  licenses  must  be  displayed 


ENGINEERS'  LICENSE  LAWS  271 

under  glass,  in  a  conspicuous  place  in  the  boiler  or  engine  room. 
It  shall  be  the  duty  of  every  licensed  engineer  to  report  to  the 
board  of  examiners  any  defects  in  any  steam  boiler,  engine,  or 
appurtenance  belonging  thereto  under  his  charge. 

This  ordinance  does  not  apply  to  engineers  in  charge  of  loco- 
motives or  to  those  in  charge  of  engines  or  steam-boiler  machin- 
ery under  the  civil  service  of  the  city,  county,  state,  or  federal 
government,  or  to  engines  or  steam  boilers  used  for  heating 
private  dwellings,  and  other  engines  or  steam-boilers  carrying 
a  pressure  of  less  than  15  Ib.  per  sq.  in. 

Mobile,  Ala. — A  board  of  examiners  of  engineers,  consisting 
of  three  members  and  elected  by  the  general  council,  admin- 
isters the  license  laws  in  the  city  of  Mobile.  The  board  must 
meet  at  least  twice  each  month  for  the  despatch  of  such  business 
as  may  come  before  it. 

According  to  the  laws  of  this  city,  no  person  shall  be  entrusted 
with,  or  have  charge  of,  the  management  or  operation  of  any 
steam  boiler  having  more  than  200  sq.  ft.  of  heo.ting  surface,  or 
carrying  a  pressure  greater  than  20  Ib.  per  sq.  in.,  until  such 
person  has  been  duly  examined  by  the  board  of  examining 
engineers. 

Whenever  any  person  makes  application,  or  is  called  before 
the  board  for  examination,  he  shall  be  thoroughly  examined  as 
to  his  competency  to  manage  and  operate  steam  boilers,  feed 
pumps,  and  injectors.  If  the  applicant  is  found  competent  by 
the  board,  a  license  certificate  shall  be  issued  to  him.  Such 
license  shall  be  in  force  for  1  yr.  from  the  date  of  issuance. 
A  new  license  may  be  issued  to  the  said  holder  at  the  expiration 
of  each  year  thereafter  without  further  examination,  as  long 
as  the  holder  continues  in  operating  steam-engineering  occupa- 
tion. Should  an  engineer  abandon  his  occupation  as  an  operator 
for  more  than  1  yr.,  his  license  certificate  shall  become  null  and 
void,  and  it  shall  be  necessary  for  said  person  to  be  reexamined 
by  the  board  to  obtain  a  new  license  certificate,  before  again 
undertaking  to  manage  and  operate  steam  boilers,  feed  pumps, 
and  injectors. 

Engineers  are  required  to  report  in  writing  to  the  board  of 
examining  engineers,  during  the  months  of  January  and  June 
of  each  year,  the  condition  of  the  boiler  or  boilers  under  their 


272  ENGINEERS'  LICENSE  LAW'S 

charge;  this  also  applies  to  those  engineers  who  have  charge  of 
elevators.  All  reports  mtist  contain  full  detailed  and  accurate 
information,  and  must  be  made  on  blank  forms  to  be  obtained 
from  the  board. 

For  each  original  certificate  of  license  issued  by  the  board, 
a  sum  of  $2  shall  be  paid  by  the  person  to  whom  the  license  is 
issued;  and  for  each  renewal  of  license  the  sum  of  SI  shall  be 
paid.  These  fee  shall  be  collected  by  the  board  of  examining 
engineers. 

New  Haven,  Conn. — A  board  of  examiners,  appointed  by 
the  mayor  and  consisting  of  three  members,  administers  the 
license  laws  in  the  city  of  New  Haven. 

No  person  shall  be  engineer  of,  or  shall  have  charge  of,  or 
operate  any  steam  boiler  or  steam  engine  in  the  city  of  New 
Haven,  for  a  period  exceeding  1  wk.  who  shall  not  have  a  license 
certificate  from  the  board  of  examiners,  authorizing  him  to 
have  charge  of  and  operate  such  boiler  or  engine.  This  ordi- 
nance shall  not  apply  to  railway  locomotives  nor  engineers 
employed  thereon,  nor  to  steam  vessels  coming  under  the  juris- 
diction of  the  United  States  inspectors,  nor  to  boilers  in  private 
residences  or  buildings  for  heating  purposes,  unless,  in  the 
opinion  of  the  board,  such  boiler  is  so  equipped  and  run  as  to 
•endanger  public  safety,  unless  operated  by  a  licensed  engineer. 

Before  any  person  shall  be  employed  as  an  engineer  of  any 
steam  boiler  or  engine  he  shall  make  written  application  to 
the  board  for  a  license.  He  shall  specify  in  the  application 
the  particular  engine,  boiler,  or  plant  that  he  desires  to  operate 
or  have  charge  of,  and  the  application  shall  be  accompanied 
by  references  as  to  his  character  and  ability.  After  filing 
such  references,  he  may  operate  a  plant  for  30  da.  thereafter 
or  until  his  application  shall  have  been  passed  upon  by  the 
board. 

Every  person  who  shall  satisfy  the  board  of  examiners  that 
he  is  a  safe  and  competent  person  to  operate  and  have  charge 
of  the  steam  plant,  boiler,  or  engine  specified  in  his  applica- 
tion, shall  on  the  payment  of  $1  receive  a  license  permitting 
him  to  operate  the  same  for  1  yr.  unless  sooner  revoked  for  cause. 
Said  license  shall  apply  only  to  the  plant  for  which  it  is  issued. 
Before  taking  charge  of  another  plant,  the  licensee  shall  apply 


ENGINEERS'  LICENSE  LAWS  273 

for  another  license  for  such  other  plant,  for  which  other  license 
if  application  be  made  within  a  year,  no  charge  shall  be 
made.  For  annual  renewals  of  such  licenses,  a  fee  of  $1  shall 
be  paid. 

The  board  may  at  any  time  revoke  any  license  for  cause, 
such  as  incompetency,  neglect,  or  inebriety.  In  case  a  license 
is  revoked,  application  may  be  made  for  a  new  license  6  mo. 
after,  and  on  examination,  provided  the  applicant  is  found 
qualified,  the  board  may  grant  a  license  to  him. 

New  York,  N.  Y.  — The  engineer's  license  laws  for  the  city 
of  New  York  are,  in  part,  as  follows: 

No  owner,  or  agent  of  such  owner,  or  lessee  of  any  steam 
boiler  to  generate  steam  shall  employ  any  person  as  engineer 
or  to  operate  such  boiler  unless  such  person  shall  first  obtain 
a  certificate  as  to  qualification  therefor  from  a  board  of  prac- 
tical engineers  detailed  as  such  by  the  police  department,  such 
certificate  to  be  countersigned  by  the  officer  in  command  of 
the  sanitary  company  of  the  police  department  of  the  city  of 
New  York.  In  order  to  be  qualified  to  be  examined  for  and 
to  receive  such  certificate  of  qualification  as  an  engineer,  a 
person  must  comply,  to  the  satisfaction  of  said  board,  with  the 
f ol  lowing  requirements : 

1.  He  must  be  a  citizen  of  the   United  States  and  over  21 
yr.  of  age. 

2.  He  must,  on    his  first  application  for    examination,  fill 
out,  in  his  own  handwriting,  a  blank  application  to  be  prepared 
and  supplied  by  the  said  board  of  examiners,  and  which  shall 
contain  the  name,  age,  and  place  of  residence  of  the  applicant, 
the  place   or  places  where  employed  and  the  nature  of  his 
employment  for  5  yr.  prior  to  the  date  of  his  application,  and 
a  statement  that  he  is  a  citizen  of  the  United  States.  »The  appli- 
cation shall  be  verified  by  him,  and  shall,  after  the  verification, 
contain  a  certificate  signed  by  three  engineers,  employed  in 
New  York  City  and  registered  on  the  books  of  said  board  of 
examiners  as  engineers  working  at  their  trade,  certifying  that 
the  statements  contained  in  such  application  are  true.     Such 
application  shall  be  filed  with  said  board. 

3.  The  following  persons,  who  have  first  complied  with  the 
provisions  of  subdivisions  one  and  two  of  this  section,  and  no 


274  ENGINEERS'  LICENSE  LAWS 

other  persons  may  make  application  to  be  examined  for  a 
license  to  act  as  engineer: 

(a)  Any  person  who  has  been  employed  as  a  fireman,  as 
an  oiler,  or  a  as  general  assistant  under  the  instructions  of  a 
licensed  engineer  in  any  building  or  buildings  in  the  city  of 
New  York,  for  a  period  of  not  less  than  5  yr. 

(&)  Any  person  who  has  served  as  a  fireman,  oiler,  or  gen- 
eral assistant  t.o  the  engineer  on  any  steamship,  steamboat, 
or  on  any  locomotive  engine  for  the  period  of  5  yr.  and  shall 
have  been  employed  for  2  yr.  under  a  licensed  engineer  in  a 
building  in  the  city  of  New  York. 

(c)  Any  person  who    has  learned    the  trade  of  machinist, 
or  boilermaker,  or  steam  fitter  and  worked  at  such  trade  for 
3  yr.  exclusive  of  time  served  as  apprentice,  or  while  learning 
such   trade,  and   also  any  person   who   has   graduated   as  a 
mechanical  engineer  from  a  duly  established  school  of  tech- 
nology, after  such  person  has  had  an  experience  of  2  yr.  in  the 
engineering  department  of  any  building  or  buildings  in  charge 
of  a  licensed  engineer,  in  the  city  of  New  York. 

(d)  Any  person  who   holds  a  certificate  as   engineer  issued 
to  him  by  any  duly  qualified  board  of  examining  engineers  exist- 
ing pursuant  to  law  in  any  state  or  territory  of  the  United 
States  and  who  shall  file  with  his  application  a  copy  of  such  cer- 
tificate and  an  affidavit  that  he  is  the  identical  person  to  whom 
said  certificate  was  issued.     If  the  board  of  examiners  of  engi- 
neers shall  determine  the  applicant  has  complied  with  the 
requirements  of  this  section,  he  shall    be  examined  as  to  his 
qualifications  to  have  charge  of,  and  operate  steam  boilers  and 
steam  engines  in  the  city  of  New  York,  and  if  found  qualified 
said  board  shall  issue  to  him  a  certificate  of    the   third  class. 
After  the  applicant  has  worked  for  a  period  of  2  yr.  under  his 
certificate  of  the  third  class,  he  may  be  again  examined  by 
said  board  for  a  certificate  of  the  second  class,  and  if  found 
worthy  the  said  board  may  issue  to  him  such  certificate  of  the 
second  class.     After  he  has  worked  for  a  period  of  1  yr.  under 
said  certificate  of  the  second  class  he  may  be  examined  for  a 
certificate  of  the  first  class,  and  when  it  shall  be  made  to  appear 
to  the  satisfaction  of  said  board  of  examiners  that  the  appli- 
cant for  either  of  said  grades  lacks  mechanical  skill,  is  a  person 


ENGINEERS'  LICENSE  LAWS  275 

of  bad  habits,  or  is  addicted  to  the  use  of  intoxicating  beverages, 
he  shall  not  be  entitled  to  receive  such  grades  of  license  and  shall 
not  be  reexamined  for  the  same  until  after  the  expiration  of  1  yr. 

Every  owner  or  lessee,  or  the  agent  of  the  owner  or  lessee, 
of  any  steam  boiler,  steam  generator,  or  steam  engine  afore- 
said, and  every  person  acting  for  such  owner  or  agent  is  hereby 
forbidden  to  delegate  or  transfer  to  any  person  or  persons 
other  than  the  licensed  engineer  the  responsibility  and  liabil- 
ity of  keeping  and  maintaining  in  good  order  and  condition 
any  such  steam  boiler,  steam  generator,  or  steam  engine,  nor 
shall  any  such  owner,  lessee,  or  agent  enter  into  a  contract  for 
the  operation  or  management  of  a  steam  boiler,  steam  gen- 
erator, or  steam  engine,  whereby  said  owner,  lessee,  or  agent 
shall  be  relieved  of  the  responsibility  or  liability  for  injury 
tbat  may  be  caused  to  person  or  property  by  such  steam  boiler, 
steam  generator,  or  steam  engine.  Every  engineer  holding  a 
certificate  of  qualification  from  said  board  of  examiners  shall 
be  responsible  to  the  owner,  lessee,  or  agent  employing  him 
for  the  good  care,  repair,  good  order  and  management  of  the 
steam  boiler,  steam  generator,  or  steam  engine  in  charge  of, 
or  run,  or  operated  by  such  engineer. 

Niagara  Falls,  N.  Y. — A  board  of  examiners  of  stationary 
engineers,  consisting  of  three  members,  administers  the  license 
laws  in  the  city  of  Niagara  Falls.  Any  person  desiring  a  license 
to  act  as  a  stationary  engineer  or  fireman  in  this  city,  may  file 
with  the  city  clerk  an  application,  together  with  the  required 
fee  for  a  license,  provided  one  is  granted,  which  fee  is  returned 
to  the  applicant  in  case  a  license  is  not  granted  to  him.  The 
application  is  to  be  submitted  to  the  board  of  examiners  by 
the  city  clerk,  when  such  board  shall  examine  the  applicant  at 
a  time  and  place  named  by  the  board. 

It  shall  be  unlawful  for  any  person  to  have  charge  of  or  oper- 
ate any  steam  plant,  steam  engine,  or  steam  boiler  within  this 
city,  excepting  locomotive  steam  engines,  or  marine  engines, 
or  engines  used  by  the  fire  department  of  the  city  of  Niagara 
Falls,  without  having  procured  a  license  from  the  board  of 
examiners. 

The  board  of  examiners  shall  issue  licenses  of  the  following 
classes : 


276  ENGINEERS'  LICENSE  LAWS 

(a)  A  license  as  chief  engineer  to  any  person  found  quali- 
fied to  take  charge  of  and  operate  any  steam  plant. 

(&)  A  license  as  first-class  engineer  to  any  person  found 
qualified  to  take  charge  of  a  steam  plant  or  engine  not  exceed- 
ing 300  H.  P. 

(c)  A  license    as  first-class    fireman  to    any  person    found 
qualified  to  take  charge  of  a  steam  boiler  not  to  exceed  300 
H.  P. 

(d)  A  license  as  second-class  engineer  to  any  person  found 
qualified  to  take  charge  of  and  operate  any  steam  plant  or 
engine  not  exceeding  75  H.  P. 

(e)  A  license   as  second-class  fireman  to  any  person  found 
qualified  to  take  charge  of  and  operate  any  steam  boiler  not 
exceeding  75  H.  P. 

(/)  A  license  as  special  engineer  or  fireman  to  any  person 
found  qualified  to  take  charge  of  and  operate  a  certain  steam 
engine  or  steam  boiler  of  a  certain  horsepower  capacity,  to  be 
designated  in  the  license. 

(g)  A  license  to  the  owner  of  a  steam  engine  or  boiler 
using  not  to  exceed  10  H.  P.,  and  used  by  him  in  his  own 
business. 

Licenses  are  granted  for  1  yr.  and  the  fees  for  them  are  as 
follows:  For  any  license,  save  the  license  provided  for  in 
subdivision  (g),  $3.  For  a  license  issued  under  subdivision 
(g),  $1.  Licenses  are  to  be  renewed  annually  and  the  fee  for 
each  renewal  is  $2. 

It  shall  be  unlawful  for  any  person  to  take  charge  of  a 
steam  engine,  a  steam  boiler,  or  a  steam  plant  of  greater 
capacity  and  horsepower  than  that  authorized  by  his  license; 
and  it  shall  also  be  unlawful  tor  any  person  to  have  charge 
of  or  operate  more  than  one  plant  at  the  same  time.  It 
shall  be  unlawful  for  any  engineer  or  fireman  to  be  absent 
from  the  steam  boiler  or  the  steam  engine  operated  by  him 
for  more  than  20  min.  nor  to  be  farther  distant  from  such 
plant  than  100  ft.,  while  wo^ng  under  pressure. 

It  shall  not  be  necessary  to  psocure  a  license  to  take  charge 
of  or  to  operate  a  steam  boiler  used  in  private  residences  in 
cases  where  the  water  returns  automatically  to  the  boiler  and 
the  pressure  does  not  exceed  10  Ib.  per  sq.  in. 


ENGINEERS'  LICENSE  LAWS  277 

Omaha,  Neb. — In  the  city  of  Omaha  a  board  of  engineers 
administers  and  enforces  the  engineers'  license  laws.  This 
board  consists  of  the  city  boiler  inspector  and  two  practical 
and  mechanical  engineers,  all  of  whom,  are  appointed  by  the 
mayor,  with  the  consent  of  the  city  council.  The  board  con- 
venes once  in  each  month  to  examine  into  the  qualifications 
of  applicants  for  engineers'  certificates. 

Every  applicant  for  a  certificate  who  fails  to  pass  the  exam- 
ination of  the  board  is  required  to  wait  3  mo.  before  again 
making  application  for  a  certificate.  At  the  expiration  of  that 
time,  the  board  will  give  him  another  examination.  Appli- 
cants for  examination  will  be  furnished  with  a  blank  for  the 
purpose  by  the  board.  Applicants  must  have  an  experience 
of  at  least  2  yr.  at  mechanical  or  steam  engineering,  and  must 
write  and  state  their  experience  in  the  blank.  All  applica- 
tions must  be  signed  by  two  citizens,  one  of  whom  must  be  a 
steam  user  or  engineer.  Each  applicant  is  required  to  make 
oath  before  the  board  as  to  the  truth  of  the  statements  in  the 
blank.  Engineers  holding  certificates  granted  by  the  board  are 
required  to  notify  the  board  when  accepting  or  leaving  employ- 
ment; also  to  state  the  name  of  the  new  employer  and  the 
location  of  the  boiler  in  their  charge.  This  must  be  done 
immediately. 

Engineers  holding  certificates  granted  by  the  board  are 
required  to  make  out  a  report  as  to  the  condition  of  all  boilers 
and  apparatus  under  their  charge  and  to  send  it  to  the  board; 
this  must  be  done  during  the  first  10  da.  of  January  and  July 
of  each  year. 

The  board  shall  issue  three  grades  of  certificates,  as  follows: — 
First-grade  certificates  shall  entitle  tha  holder  to  take  charge 
of  and  run  any  plant;  second-grade  certificates  shall  entitle  the 
holder  to  take  charge  of  and  run  any  steam  plant  under  100 
H.  P.,  and  third-grade  certificates  shall  entitle  the  holder  to 
take  charge  of  and  run  any  steam  plant  under  50  H.  P.  The 
board  of  engineers  may  grant  to  persons  operating  low- 
pressure,  gravity  steam-heating  plants,  carrying  a  pressure 
not  to  exceed  20  Ib.  per  sq.  in.,  a  special  third-grade  certifi- 
cate to  be  valid  for  one  particular  specified  plant  and  no 
other. 


278  ENGINEERS'  LICENSE  LAWS 

A  fee  of  $5  shall  be  charged  for  each  examination  of  an 
engineer  for  license  by  the  board.  Applicants  must  be  at  least 
21  yr.  of  age.  Certificates  are  valid  for  1  yr.  and  no  longer, 
but  may  be  renewed  each  year  upon  the  payment  of  $1  to  the 
city  treasurer  and  then  presenting  his  receipt  for  the  same  to 
the  city  boiler  inspector;  where  boilers  are  used  and  engines  run 
night  and  day,  the  owners  or  users  of  steam  power  must  employ 
two  certified  engineers,  who  may  stand  watch  alternately. 

Peoria,  111. — A  board  of  engineers  consisting  of  three  mem- 
bers, including  the  city  boiler  inspector,  appointed  by  the 
Mayor  and  approved  by  the  council  administers  and  enforces 
the  license  laws  in  the  city  of  Peoria. 

According  to  the  laws,  the  board  shall  hold  sessions  twice 
each  month  for  the  purpose  of  examining  and  determining  the 
qualifications  of  applicants  for  engineers'  licenses.  The  certi- 
ficates of  license  shall  be  of  two  grades — first  and  second — and 
the  requirements  for  each  grade  shall  be  determined  by  the 
board  of  examiners. 

Every  application  for  a  license  must  be  made  on  the  printed 
blank  furnished  by  the  board  for  that  purpose;  that  for  an 
engineer  must  be  accompanied  by  a  fee  of  $5,  and  that  for  a 
boiler  or  a  water  tender  must  be  accompanied  by  a  fee  of  $2. 
Licenses  are  in  force  for  1  yr.  only  from  date  of  issue.  Reissues 
are  made  upon  the  payment  of  a  fee  of  $2  for  an  engineer's 
license  and  a  fee  of  $1  for  a  boiler  tender's  license. 

An  applicant  for  license  must  have  had  a  practice  of  at  least 
3  yr.  under  the  supervision  of  a  practical  engineer.  An  appli- 
cant for  a  boiler  tender's  license  must  be  a  person  who  has 
a  thorough  knowledge  of  the  construction,  management,  and 
operation  of  steam  boilers.  Each  applicant  must  state  upon 
the  blank  the  extent  of  his  experience,  he  must  be  at  least  21  yr. 
of  age  and  a  citizen  of  the  United  States,  or  have  declared  his 
intention  to  become  such,  and  he  must  be  of  good  character. 
All  of  this  information  must  be  vouched  for  in  writing  by  at 
least  three  first-class  engineers  of  Peoria,  or  it  may  be  verified 
under  oath  by  an  applicant  when  required  by  the  board. 

It  shall  be  the  duty  of  the  board  of  examiners  to  see  that  each 
boiler  plant  in  the  city  shall  have  a  licensed  engineer  or  boiler 
or  water  tender,  or  both,  in  charge  at  all  times  when  working 


ENGINEERS'  LICENSE  LAWS  279 

under  pressure.  Any  person  who  has  charge  of  a  steam  boiler, 
whose  duty  it  is  to  keep  up  the  water  in  such  boiler,  shall  be 
deemed  a  boiler  or  water  tender  within  the  meaning  of  this 
ordinance,  but  the  provisions  for  the  examining  and  licensing 
of  a  boiler  or  water  tender  shall  apply  only  to  boiler  or  water 
tenders  who  are  in  charge  of  a  steam  boiler  or  boilers  that  are 
detached  from  the  engine  room  or  so  far  removed  therefrom  as 
to  render  it  difficult  for  the  engineer  in  charge  of  the  plant  to- 
give  it  or  them  his  personal  attention  or  supervision. 

Every  engineer  licensed  under  this  ordinance  shall  within 
the  first  10  da.  of  January  and  July,  respectively,  of  each  year, 
make  a  written  report  to  the  board  of  examiners  of  the  condition 
of  the  engine,  boilers,  and  steam  apparatus  under  his  charge, 
and  every  boiler  or  water  tender  shall  at  the  same  time  make  a 
similar  report  of  the  condition  of  the  boiler  or  boilers  under 
his  charge. 

Engineers  in  charge  of  locomotives  are  exempt  from  the 
provisions  of  this  ordinance,  as  are  also  all  boilers  used  for 
heating  private  dwellings  and  hothouses  and  other  boilers 
carrying  a  pressure  of  not  more  than  10  Ib.  per  sq.  in.,  and  the 
persons  operating  them. 

Philadelphia,  Pa. — It  is  unlawful  for  any  person  or  persons 
to  have  charge  of  or  to  operate  a  steam  boiler  or  steam  .engine 
over  10  H.  P.  in  cities  of  the  first  class  of  the  commonwealth 
of  Pennsylvania,  except  locomotive  boilers  used  in  transporta- 
tion and  steam  engines  and  steam  boilers  carrying  a  pressure 
of  less  than  15  Ib.  per  sq.  in.,  unless  said  person  or  persons  are 
upward  of  21  yr.  of  age  and  hold  a  license  as  provided  for  by 
the  laws. 

The  laws  state  that  all  persons  desiring  authority  to  perform 
the  duties  of  an  engineer  shall  apply  to  the  boiler  inspector  of 
such  cities,  who  shall  examine  the  applicant  as  to  his  knowledge 
of  steam  machinery  and  his  experience  in  operating  the  same, 
also  the  proofs  he  produces  in  support  of  his  claim;  and  if  the 
inspector  is  satisfied  that  the  applicant's  character,  knowledge, 
and  experience  in  the  duties  of  an  engineer  are  such  as  to 
authorize  the  belief  that  he  is  a  suitable  person  to  be  entrusted 
with  the  powers  and  duties  of  such  station,  he  shall  grant  him 
a  license,  on  the  payment  of  $3,  authorizing  him  to  be  employed 


280  ENGINEERS'  LICENSE  LAWS 

in  such  duties  for  the  term  of  1  yr.,  and  such  license  shall  be 
annually  renewed,  without  examination,  upon  the  payment 
of  $1,  provided  it  is  presented  for  renewal  within  10  da.  after 
its  expiration. 

Licenses  so  granted  shall  be  graded  into  two  classes,  one  of 
which  shall  entitle  the  licensee  to  have  charge  of  or  to  operate 
stationary  steam  boilers  and  steam  engines  only,  and  the  other 
of  which  shall  entitle  the  licensee  to  have  charge  of  or  to  operate 
portable  steam  boilers  and  steam  engines  only.  Such  licenses 
shall  not  be  transferred  from  one  grade  to  the  other  without  a 
reexamination,  said  reexamination  to  be  conducted  without 
cost  to  the  licensee. 

No  person  shall  be  eligible  for  examination  for  license  unless 
he  furnishes  proof  that  he  has  been  employed  about  a  steam 
boiler  or  steam  engine  for  a  period  of  not  less  than  2  yr.  prior 
to  the  date  of  application,  which  must  be  certified  to  by  at 
least  one  employer  and  two  licensed  engineers. 

The  inspector  shall  have  authority  to  suspend  or  revoke 
licenses  upon  proof  of  negligence  or  incompetency  of  the  holders 
of  licenses.  Licenses  must  be  framed  under  glass  and  placed 
in  a  conspicuous  place  about  the  engine  or  boiler  rooms.  When 
a  licensed  engineer  vacates  a  position,  he  must  notify  the  boiler 
inspector  of  that  fact. 

Pittsburg,  Pa. — See  Pennsylvania  state  laws,  on  page  250. 

Rochester,  N.  Y. — The  ordinance  governing  the  granting  of 
engineers'  licenses  in  Rochester,  N.  Y.,  is  in  part  as  follows: 
No  person  shall  operate  any  boiler  to  generate  steam  within 
the  city  of  Rochester,  except  for  railroad  locomotive  engines 
and  for  heating  purposes  in  private  dwellings,  unless  he  be  21  yr. 
of  age  and  shall  have  been  duly  examined  and  licensed  for  that 
purpose  as  required  by  the  terms  of  this  ordinance. 

The  common  council  of  the  city  shall  appoint  a  committee 
of  three  competent  persons  to  examine  all  applicants  for  license 
to  operate  steam  boilers  and  to  issue  licenses  to  such  applicants 
as  shall  be  found  qualified. 

Applications  for  examinations  shall  be  made  in  writing  to 
the  city  clerk,  and  must  state  the  location  and  capacity  of  the 
boiler  plant  that  the  applicant  intends  to  operate.  Every  appli- 
cation must  be  accompanied  by  a  certificate  of  two  reputable 


ENGINEERS'  LICENSE  LAWS  281 

persons  to  the  effect  that  the  applicant  is  of  good  character. 

The  examining  committee  shall  hold  meetings  at  least  twice 
each  month  for  the  transaction  of  business  and  the  conduct  of 
examinations  of  engineers.  In  case  an  applicant  upon  his  first 
examination  shall  fail  to  satisfy  the  committee  of  his  ability  to 
operate  the  boiler  plant  mentioned  in  his  application,  a  tem- 
porary permit  may  be  granted  to  him  to  operate  the  plant  for 
a  period  not  exceeding  20  da.,  at  which  time  the  applicant 
must  again  present  himself  for  examination.  Such  temporary 
permit  shall  not  be  granted  more  than  once  to  the  same  person. 

Every  person  found  qualified  by  the  committee  to  operate 
a  steam  boiler  shall  be  entitled  to  receive  a  license  for  that 
purpose.  The  fee  for  such  license  is  $2,  to  be  paid  to  the  city 
treasurer.  Licenses  expire  at  the  end  of  the  year  from  the  date 
of  issuance,  and  may  be  renewed  for  a  term  of  1  yr.  on  the  pay- 
ment to  the  city  treasurer  of  $1.  In  case  of  a  change  of  position, 
licensed  engineers,  under  this  act,  shall  notify  the  city  clerk 
within  1  wk.  of  such  change  and  present  themselves  for  exami- 
nation for  the  new  position.  If  found  qualified  for  the  new  posi- 
tion, a  license  to  operate  the  new  plant  for  the  unexpired  part 
of  the  year  covered  by  the  original  license  shall  be  issued  with- 
out further  fee. 

The  common  council  of  the  city  of  Rochester  has  the  power 
to  suspend  or  revoke  a  license  at  any  time  upon  proof  of  negli- 
gence or  incompetency. 

Santa  Barbara,  Cal. — A  board  of  examining  engineers,  con- 
sisting of  three  members  appointed  by  the  mayor,  administers 
and  enforces  the  license  laws  in  the  city  of  Santa  Barbara,  Cal. 
It  is  the  duty  of  the  board  to  examine  all  applicants  for  engi- 
neer's license.  The  board  shall  hold  one  meeting  a  month — 
on  the  second  Tuesday — for  the  purpose  of  examining  appli- 
cants for  license. 

Licenses  are  granted  for  a  term  of  1  yr.  upon  a  payment  of  $3 
from  each  applicant.  They  may  be  revoked  by  the  board  upon 
proof  of  incompetency  or  neglect  on  the  part  of  the  licensee. 
Where  boilers  are  used  and  engines  are  run  night  and  day,  the 
owner  or  the  us'er  must  employ  at  least  two  licensed  engineers, 
who  may  stand  watch  alternately.  Boilers  or  steam -generating 
apparatus  of  5  H.  P.  or  over  must  be  operated  by  a  competent 


282  ENGINEERS'  LICENSE  LAWS 

engineer  who  has  secured  a  license.  Automobiles  are  exempt 
from  the  provisions  of  this  ordinance,  as  are  also  all  engines 
and  boilers  of  locomotives  used  on  railroads. 

Every  applicant  for  a  license  who  fails  to  pass  the  examina- 
tion of  the  board  shall  be  required  to  wait  4  wk.  before  making 
another  application.  Any  applicant  who  fails  to  pass  after  the 
third  trial  shall  not  be  permitted  to  appear  again  before  the 
board  for  4  mo. 

Engineers  shall  notify  the  boiler  inspector  when  they  enter 
any  employment  as  an  engineer,  and  within  3  da.  after  give  the 
name  of  the  employer  and  the  location  of  the  boiler  or  other 
apparatus  in  charge.  They  also  shall  report  the  condition  of 
the  apparatus  under  their  charge  semiannually,  during  the 
first  3  da.  of  January  and  July  of  each  year.  Licenses  must 
be  framed  under  glass  and  placed  in  a  conspicuous  place  near 
the  boilers  or  engines. 

St.  Joseph,  Mo. — A  board  of  engineers  consisting  of  the  city 
boiler  inspector  and  two  mechanical  engineers,  all  of  whom  are 
appointed  by  the  mayor,  with  the  consent  of  the  common  coun- 
cil, administers  and  enforces  the  license  laws  in  St.  Joseph,  Mo. 

The  board  convenes  for  business  twice  each  month  to  examine 
into  the  qualifications  of  applicants  for  engineer's  license.  The 
law  states  that  the  board  shall  grant  licenses,  charging  each 
applicant  the  sum  of  $10  for  engineer's  license,  $3  to  be  depos- 
ited with  the  clerk  of  the  board  when  application  is  made. 
Each  applicant  is  to  be  allowed  three  trials.  If  he  then  fails  to 
pass  a  satisfactory  examination,  the  applicant  shall  then  forfeit 
the  money  deposited  with  the  clerk  of  the  board;  but  if  the 
applicant  successfully  passes  the  examination,  the  board  shall 
grant  him  a  license  for  the  term  of  1  yr.  upon  the  paymert  of 
an  additional  $7.  The  fee  for  each  annual  renewal  of  license 
shall  be  $2.50. 

Any  person  taking  charge  of  a  steam  boiler  or  steam  boilers, 
for  heating  purposes  only,  shall  be  examined  by  the  board  of 
engineers,  and  if  found  qualified  the  board  shall  grant  him  a 
license  to  that  effect  on  the  payment  of  $5,  said  license  to  be  in 
force  for  1  yr.  from  the  date  of  issue.  Such  licenses  may  be 
reissued  upon  the  payment  of  a  fee  of  $2.  The  board  has  the 
power  to  revoke  licenses  upon  proof  of  incompetency  or  neglect. 


ENGINEERS'  LICENSE  LAWS  283 

When  boilers  are  used  and  engines  run  night  and  day,  two 
licensed  engineers  must  be  employed  and  must  stand  watch 
alternately. 

All  engineers,  engines,  and  boilers  of  the  fire  department  of 
St.  Joseph  and  all  steam  rollers,  steam  automobiles,  and  portable 
boilers  used  on  the  streets  of  the  city  are  subject  to  the  provi- 
sions of  this  ordinance,  except  that  there  shall  be  no  fee  charged 
for  the  inspection  of  boilers  of  fire  engines;  but  all  locomotive 
boilers  used  on  railroads  and  steam  boilers  supplied  with  water 
automatically,  when  used  for  heating  dwellings  and  not  carrying 
a  pressure  of  over  10  Ib.  per  sq.  in.,  are  exempt  from  the  provi- 
sions of  this  ordinance. 

Every  applicant  for  license  who  fails  to  pass  the  examination 
is  required  to  wait  2  wk.  before  again  making  application  for 
license.  If  applicants  fail  to  pass  after  the  third  trial,  they  may 
not  make  application  again  for  6  mo. 

Engineers  must  notify  the  boiler  inspector  upon  accepting 
employment  as  an  engineer;  and,  within  3  da.  after,  he  must 
give  the  name  of  his  employer  and  the  location  of  the  boiler  or 
boilers  under  his  care.  Renewals  for  license  shall  be  made  not 
later  than  the  first  regular  meeting  of  the  board  next  following 
the  expiration  of  the  license.  Unless  this  provision  is  complied 
with,  it  shall  be  necessary  for  the  applicant  to  be  reexamined, 
to  take  out  a  new  license,  and  to  pay  the  regular  fee  before 
referred  to. 

St.  Louis,  Mo. — In  the  city  of  St.  Louis  the  engineers'  license 
laws  are  administered  and  enforced  by  a  board  of  engineers 
consisting  of  the  city  inspector  of  boilers  and  elevators  and  two 
other  members,  all  of  whom  are  appointed  by  the  mayor,  with 
the  consent  of  the  council.  This  board  convenes  for  business 
once  in  each  week  to  examine  applicants  for  engineers'  license. 

According  to  the  laws,  the  board  shall  giant  certificates  of 
license  for  1  yr.  from  the  date  thereof  to  all  applicants  who  pass 
the  required  examination  and  satisfy  the  board  as  to  their 
fitness.  Each  applicant  for  license  shall  at  the  time  of  filing 
his  application,  pay  to  the  inspector  of  boilers  and  elevators 
a  fee  of  $2,  for  each  examination,  but  no  charge  is  made  for 
renewals.  Licenses  may  be  revoked  by  the  board,  upon  proof 
of  incompetency  or  neglect  on  the  part  of  the  licensee. 


284  ENGINEERS'  LICENSE  LAWS 

The  owners  or  users  of  steam  boilers  or  engines  of  a  capacity 
of  not  over  75  sq.  ft.  of  heating  surface,  and  a  steam  pressure 
of  not  over  25  Ib.  per  sq.  in.,  used  for  power  only,  and  all  boilers 
under  a  pressure  of  15  Ib.  per  sq.  in.  used  for  heating  purposes 
only,  shall  apply  for  a  permit  to  employ  a  competent,  careful, 
and  trustworthy  person,  instead  of  a  licensed  engineer;  such 
person  to  be  recommended  by  two  citizens,  one  of  whom  shall 
be  a  steam  user  or  a  licensed  engineer,  and  if  found  competent 
by  the  inspector  of  boilers  and  elevators,  said  permit  shall  be 
granted.  The  inspector  of  boilers  and  elevators  may  revoke 
such  permit  for  cause. 

At  all  times  when  boilers  are  in  use  and  engines  run  there 
shall  be  in  charge  an  engineer  having  a  certificate  of  license 
from  the  board  of  engineers,  such  certificate  to  be  displayed 
in  some  prominent  place  where  the  boilers  or  engines  are  in 
use. 

The  engineers,  engines,  and  boilers  of  the  fire  department, 
locomotive  boilers  used  on  railroads,  and  steam  boilers  sup- 
plied with  water  automatically,  and  having  no  pumps  or  injec- 
tors and  used  only  for  heating  dwellings,  not  carrying  a  steam 
pressure  of  more  than  8  Ib.  per  sq.  in.,  are  exempt  from  the  pro- 
visions of  this  ordinance. 

Every  applicant  for  license  who  fails  to  pass  the  examina- 
tion of  the  board  is  required  to  wait  4  wk.  before  again  making 
application  for  license.  Applications  for  license  must  be  made 
upon  blanks  furnished  by  the  inspector  of  boilers  and  eleva- 
tors. The  applicant  must  have  had  an  experience  of  at  least 
2  yr.  at  mechanical  or  steam  engineering,  and  must  write  and 
state  his  experience  on  said  blank.  He  shall  go  before  the 
inspector  of  boilers  and  elevators  and  make  oath  that  his 
statements  are  true. 

Licensed  engineers  must  give  to  the  inspector  of  boilers  and 
elevators  notice  of  changes  of  employment  when  he  accepts 
or  leaves  his  position,  and  within  24  hr.  thereafter  he  must 
give  the  name  of  his  employer  and  the  location  of  the  boilers 
in  his  charge.  Licensed  engineers  must  make  semiannual 
reports  of  the  condition  of  all  apparatus  under  their  charge  to 
the  inspector  of  boilers  and  elevators  during  the  first  10  da. 
of  January  and  July. 


ENGINEERS'  LICENSE  LAWS  285- 

Scranton,  Pa. — See  Pennsylvania  state  laws,  on  page  250. 

Sioux  City,  la. — A  board  of  examining  engineers  consisting 
of  three  persons,  all  of  whom  are  appointed  by  the  mayor, 
with  the  consent  of  the  city  council,  administers  and  enforces 
the  license  laws  in  Sioux  City,  la. 

It  is  the  duty  of  the  board  of  examining  engineers  to  grant 
licenses  of  the  first,  second,  and  third  grade  to  persons  examined 
and  found  qualified.  A  first-class  license  qualifies  the  holder 
to  take  charge  of  boilers  of  125  H.  P.  or  over;  a  second-class 
license,  to  take  charge  of  boilers  of  25  H.  P.  or  over,  up  to  125 
H.  P.:  and  a  third-class  license,  to  take  charge  of  all  boilers 
of  less  than  25  H.  P.,  12  sq.  ft.  of  heating  surface  to  constitute 
1  H.  P.  The  certificates  so  granted  shall  run  for  1  yr.,  at  which 
time  they  shall  be  renewed.  The  board  of  examiners  has  the 
power  to  revoke  licenses  upon  proof  of  incompetency  or  negli- 
gence on  the  part  of  licensees. 

Steam  boilers  or  engines  of  a  capacity  of  not  over  75  sq.  ft. 
of  heating  surface  with  a  pressure  of  not  over  25  Ib.  per 
sq.  in.,  and  all  boilers  not  exceeding  75  sq.  ft.  of  heating 
surface  under  a  pressure  of  15  Ib.  per  sq.  in.  used  for  heating 
only,  require  a  person  with  a  permit  only,  instead  of  an  engi- 
neer holding  a  license.  Such  person  must  be  recommended 
by  two  citizens  of  Sioux  City,  one  of  whom  shall  be  an  engi- 
neer holding  a  license  from  the  board  of  engineers.  Permits 
are  granted  by  the  board  to  the  proper  persons. 

When  any  boiler  or  engine  requiring  the  services  of  an 
engineer  holding  a  first-class  license  is  run  day  and  night,  the 
owner  or  user  may  employ  an  engineer  holding  a  second-class 
license,  not  exceeding  12  hr.  at  a  time,  under  the  instructions 
of  an  engineer  in  charge,  holding  a  first-class  license. 

Applications  for  license  must  be  made  on  blanks  furnished 
by  the  board  of  examining  engineers.  Licensed  engineers 
must  notify  the  board  when  they  accept  or  leave  employment, 
and  within  10  da.  after,  the  name  of  employer  and  the  location 
of  the  boilers  must  be  given.  Applications  for  renewals  of 
license  or  permits  shall  be  made  not  later  than  the  third  week 
preceding  their  expiration. 

In  case  of  the  failure  of  any  applicant  for  a  license  to  pass- 
the  examination,  he  may  within  10  da.  after  receiving  notice 
20 


286  ENGINEERS'  LICENSE  LAWS 

of  such  failure  make  written  application  to  the  mayor  of  the 
city  and  also  to  the  board  of  examining  engineers  for  a  second 
examination,  which  shall  be  granted  by  the  board  within  10 
da.  after  such  application  is  made.  Failure  to  comply  with 
the  foregoing  requirements  as  to  a  second  examination  neces- 
sitates the  applicant  waiting  the  pleasure  of  the  board  as  to 
when  he  may  be  again  examined,  such  time,  however,  must 
not  exceed  G  mo. 

No  person  shall  be  granted  a  first-class  license  until  he  gives 
satisfactory  proof  that  he  has  had  an  experience  of  5  yr.  in 
steam  engineering.  No  person  shall  be  granted  a  second-class 
license  until  he  gives  satisfactory  proof  that  he  has  had  an 
experience  of  3  yr.  in  steam  engineering.  No  person  shall  be 
granted  a  third-class  license  until  he  gives  satisfactory  proof 
that  he  has  had  an  experience  of  2  yr,  in  steam  engineering. 
For  all  the  grades  of  licenses,  the  sum  of  $3  each  shall  be  charged 
and  for  each  annual  renewal  of  licenses  the  sum  of  $1  shall 
be  charged  by  the  board  of  examining  engineers.  The  provi- 
sions of  this  ordinance  shall  not  apply,  and  shall  not  be  con- 
strued to  be  applicable  to,  boilers  or  steam  generators  of  any 
kind  used  for  heating  private  residences  only,  nor  to  persons 
in  charge  of  them. 

Spokane,  Wash. — The  board  of  public  works  administers 
and  enforces  the  license  laws  in  the  city  of  Spokane. 

Every  engineer  must  appear  before  the  examiner  appointed 
by  the  board  of  public  works  for  examination  as  to  qualifi- 
cations to  act  as  engineer  in  the  city  of  Spokane.  Applicants 
for  examination  as  engineer  shall  pay  the  examiner  a  fee  of 
50c.  Every  person  receiving  a  permit  from  the  board  of 
public  works  to  run  or  operate  a  steam  engine  or  boiler,  before 
acting  as  such,  shall  pay  to  the  city  treasurer  a  semiannual 
license  fee  of  $1,  and  no  license  shall  be  granted  for  a  shorter 
period.  Upon  presenting  the  treasurer's  receipt  for  the  fee 
and  the  permit  from  the  board  of  public  works  to  the  comp- 
troller, that  officer  shall  issue  a  license  for  a  period  of  6  mo. 

All  engineers  shall  instruct  all  night  watchmen,  or  other 
persons  whose  duty  it  may  be  to  get  up  steam,  as  to  their  duty 
and  the  practical  mode  of  procedure,  but  no  night  watchmen 
or  other  person  not  a  licensed  engineer  shall  be  permitted  by 


ENGINEERS'  LICENSE  LAWS  287 

reason  of  this  clause  to  operate  continuously  any  steam  engine 
or  boiler  to  which  this  ordinance  applies.  Applications  for 
license  must  be  made  in  writing  to  the  board  of  public  works. 
Nothing  in  this  ordinance  shall  apply  to  locomotive  engines 
or  boilers. 

Tacoma,  Wash. — In  the  city  ot  Tacoma  a  board  of  examiners 
consisting  of  the  city  boiler  inspector  and  two  other  persons 
all  of  whom  are  appointed  by  the  mayor,  administers  and 
enforces  the  engineers'  license  laws. 

Any  person  desiring  to  procure  a  license  as  a  stationary 
engineer  may  apply  for  it  to  the  boiler  inspector  upon  an  appli- 
tion  blank  furnished  by  the  inspector.  He  shall  then  be  exam- 
ined as  to  his  qualifications  as  a  stationary  engineer  by  the 
examiners.  At  the  conclusion  of  the  examination,  the  board 
of  examiners  shall  transmit  to  the  city  council  all  papers  used 
in  the  examination,  including  all  questions  and  answers  given, 
together  with  the  recommendation  of  the  board  as  to  its  find- 
ings. The  city  council  decides  as  to  whether  or  not  a  license 
shall  be  granted  the  applicant. 

Licenses  are  for  a  period  of  1  yr.  and  the  fee  for  a  license 
is  $2,  payable  to  the  city  treasurer.  Upon  the  expiration  of 
a  license  and  upon  the  payment  of  a  fee  of  $1  to  the  city  treas- 
urer, the  board  of  examiners  may  recommend  a  renewal  of 
the  same,  without  further  examination  of  the  applicant,  for  a 
period  of  1  yr. 

The  licenses  granted  are  classified  as  follows:  First-class 
or  chief  engineer's  license  which  entitles  the  holder  to  take 
charge  of  and  control  the  operation  of  any  steam  plant  in  the 
city  of  Tacoma;  second-class,  or  assistant  engineer's  license, 
which  entitles  the  holder  to  take  charge  of  and  control  the 
operation  of  any  steam  plant  in  the  city  not  exceeding  150  boiler 
H.  P.,  or  to  act  as  assistant  engineer  to  the  chief  engineer  of 
any  steam  plant  in  the  city;  third-class  engineer's  license, 
which  entitles  the  holder  to  take  charge  of  and  control  the 
operation  of  any  steam  plant  in  the  city  not  exceeding  50  boiler 
H.  P.,  or  to  act  as  ar  assistant  engineer  to  an  engineer  of  the 
second  class  or  as  a  second  assistant  engineer  to  an  engineer  of 
the  first  class;  fourth-class,  or  special-engineer's  license,  which 
entitles  the  holder  to  take  entire  charge  and  control  of  a 


288  ENGINEERS'  LICENSE  LAWS 

particular  steam  plant  for  which  the  same  license  is  granted, 
as  stated  upon  its  face. 

This  ordinance  does  not  apply  to  locomotive  or  marine 
engineers,  nor  to  persons  having  charge  of  steam  boilers,  or 
apparatus  used  in  private  dwellings  for  heating  purposes  only, 
in  which  the  steam  pressure  does  not  exceed  10  Ib.  per  sq.  in. 
while  in  operation. 

Terre  Haute,  Ind. — A  board  of  examining  engineers  con- 
sisting of  three  members  appointed  by  the  mayor,  subject  to 
confirmation  by  the  common  council,  administers  and  enforces 
the  license  laws  in  the  city  of  Terre  Haute. 

Any  person  desiring  to  operate  or  to  have  charge  of  any 
steam  boiler  or  steam-generating  apparatus  under  steam  pres- 
sure within  the  meaning  of  this  act  shall  make  a  verified  appli- 
cation to  the  board  of  examiners  for  a  license  to  do  so.  The 
application  shall  be  in  writing,  giving  particulars  as  to  expe- 
rience, and  attached  thereto  shall  be  a  certificate  of  at  least 
two  freeholders  or  householders  to  the  effect  that  the  appli- 
cant for  license  is  known  to  be  a  fit  person  to  have  charge  of 
steam-generating  apparatus.  The  applicant  must  pay  $3 
to  the  board  of  examiners  before  the  examination  is  entered 
upon.  If  the  applicant  is  found  qualified,  a  license  is  issued 
to  him. 

Applicants  must  be  American  citizens  at  least  21  yr.  of  age 
and  must  have  had  at  least  2  yr.  experience  in  firing  stationary 
steam  boilers  or  steam-generating  apparatus,  or  must  have  an 
actual  experience  of  at  least  1  yr.  in  the  operation,  management, 
and  control  of  steam  engines  or  boilers  or  steam-generating 
apparatus. 

Examinations  shall  be  made  in  writing,  except  by  agreement 
between  the  applicant  and  the  board.  All  grading  of  such 
examinations  shall  be  upon  the  percentage  basis.  Three 
grades  of  licenses — namely,  first-class,  second-class,  and  third- 
class — are  issued.  Third-class  licenses  authorize  the  holder 
only  to  operate  a  steam  engine,  engines,  or  other  steam-gen- 
erating apparatus  under  the  direct  supervision  of  a  person 
•or  persons  holding  a  first-class  or  a  second-class  license. 

An  applicant  who  has  had  5  yr.  or  more  of  actual  experi- 
ence as  an  engineer,  and  who  is  otherwise  qualified,  and  who, 


ENGINEERS'  LICENSE  LAWS  289 

on  examination,  makes  a  grade  of  90%  or  more,  shall  be 
entitled  to  a  first-class  license.  An  applicant  who  is  ocher- 
wise  qualified,  and  who  makes  75%  or  more,  and  less  than 
90%,  shall  be  entitled  to  a  second-class  license.  An  applicant 
who  is  otherwise  qualified,  and  who  makes  60%  or  more,  and 
less  than  75%,  shall  be  entitled  to  a  third-class  license.  The 
board  has  the  power  to  suspend  or  revoke  licenses  upon  proof 
of  incompetency  or  neglect. 

All  licenses  must  be  renewed  1  yr.  from  date  of  issue,  and 
the  fee  for  such  renewal  is  $2.  If  any  licenses  are  not  renewed, 
within  10  da.  after  the  expiration  of  such,  the  fee  for  renewal 
shall  be  $3. 

Engineers  in  charge  of  locomotives  are  exempt  from  the 
provisions  of  this  ordinance,  as  are  also  persons  who  operate 
boilers  used  for  heating  purposes  only,  not  carrying  more  than 
15  Ib.  of  steam  pressure  per  square  inch. 

Washington  and  District  of  Columbia. — In  the  District  of 
Columbia,  which  includes  the  city  of  Washington,  all  persons 
applying  for  a  steam  engineer's  license  shall  be  examined  by  a 
board  of  examiners  composed  of  the  boiler  inspector  of  the 
District  of  Columbia  and  two  practical  engineers,  to  be 
appointed  by  the  district  commissioner. 

Applicants  for  license  must  be  at  least  21  yr.  of  age  and  of 
good  character,  and  certified  to  by  at  least  three  citizens  of  the 
District  of  Columbia,  themselves  of  good  character.  Applica- 
tion must  be  made  in  writing.  The  fee  for  a  license  as  steam 
engineer  is  $3.  Licenses  may  be  revoked  upon  proof  of  negli- 
gence on  the  part  of  licensee. 

It  is  unlawful  for  any  person  to  act  as  a  steam  engineer  who 
is  not  regularly  licensed  to  do  so  by  the  commissioners  of  the 
District  of  Columbia.  Boilers,  and  operators  of  same  used  for 
heating  purposes,  where  the  water  returns  to  the  boiler  without 
the  use  of  a  pump,  injector,  or  inspirator,  are  exempt  from  the 
provisions  of  this  act.  Engineers  licensed  by  the  United  States 
government  are  also  exempt. 

Yonkers,  N.  Y. — In  the  city  of  Yonkers,  N.  Y.,  a  board  of 
examiners  consisting  of  three  members  appointed  by  the  mayor, 
with  the  consent  of  the  common  council,  administers  and 
enforces  the  license  laws. 


290  ENGINEERS'  LICENSE  LAWS 

According  to  the  law,  it  shall  be  the  duty  of  the  board  of 
examiners  to  examine  all  persons  proposing  to  operate,  manage, 
or  run  steam  boilers  or  engines,  and  to  certify  the  qualifications 
of  such  as  are  found  competent  as  either  first-  or  second-class 
engineers.  Persons  desiring  examination  shall  apply  to  that 
member  of  the  board  officially  known  as  the  inspector  of  engi- 
neers and  of  steam  boilers  in  the  city  of  Yonkers.  Application 
must  be  in  writing,  specifying  in  full  the  experience  of  the  appli- 
cant and  stating  where,  how  and  by  whom  employed;  also,  the 
application  must  contain  the  names  of  at  least  three  residents 
of  the  city  who  can  vouch  for  the  good  character  of  the  appli- 
cant. Upon  receiving  such  application,  the  inspector  notifies 
the  board  of  examiners,  who  in  turn  notifies  the  applicant  as 
to  the  time  and  place  of  examination. 

There  shall  be  two  classes  of  licenses  issued  — one  to  first- 
class  engineers  and  one  to  second-class  engineers. 

A  license  for  a  second-class  engineer  shall  authorize  the 
person  to  whom  it  is  issued  to  have  charge  of  a  steam  boiler 
only  when  not  connected  with  any  engine,  or  when  the  engine 
connected  therewith  shall  not  be  running  or  in  operation.  All 
licenses  shall  be  for  1  yr.  from  the  date  of  issue.  Licenses 
may  be  renewed  by  the  board  for  a  period  of  1  yr. 

No  license  will  be  issued  by  the  board  to  any  person  who 
lacks  ability,  knowledge  or  experience,  and  who  has  not  a  good 
character. 

Licenses  may  be  revoked  by  the  board  upon  proof  of  neglect 
or  incompetency. 

For  the  examination  of  engineers,  the  sum  of  $2  must  be 
paid  by  each  applicant,  and  for  each  renewal  of  same,  50c. 

This  ordinance  does  not  apply  to  railroad  locomotives  used 
as  such,  nor  to  boilers  actually  used  for  propelling  steam  vessels 
navigating  the  Hudson  River,  when  the  same  shall  have  been 
inspected  and  licensed  according  to  the  United  States  laws; 
nor  does  it  apply  to  steam  boilers  used  solely  for  heating  pur- 
poses, or  the  persons  operating  them. 


ENGINEERS'  LICENSE  LAWS  291 

EXTRACTS  FROM  UNITED  STATES  LAWS 

Following  is  a  true  copy  of  certain  sections  from  the  United 
States  Marine  Laws,  the  sections  relating  to  the  licensing  of 
marine  engineers: 

''1.  Before  an  original  license  is  issued  to  any  person  to 
act  as  a  master,  pilot,  or  engineer,  he  must  personally  appear 
before  some  local  board  or  a  supervising  inspector  for  examina- 
tion; but  upon  the  renewal  of  such  license,  when  the  distance 
from  any  local  board  or  supervising  inspector  is  such  as  to  put 
the  person  holding  the  same  to  great  inconvenience  and  expense 
to  appear  in  person,  he  may,  upon  taking  oath  of  office  before 
any  person  authorized  to  administer  oaths,  and  forwarding 
the  same,  together  with  the  license  to  be  renewed,  to  the  local 
board  or  supervising  inspector  of  the  district  in  which  he 
resides  or  is  employed,  have  the  same  renewed  by  the  said 
inspectors,  if  no  valid  reason  to  the  contrary  be  known  to  them; 
and  they  shall  attach  such  oath  to  the  stub  end  of  the  license 
which  is  to  be  retained  on  file  in  their  office:  Provided,  how- 
ever, That  any  officer  holding  a  license,  and  who  is  engaged 
in  a  service  which  necessitates  his  continuous  absence  from 
the  United  States,  may  make  application  in  writing  for  one 
renewal  and  transmit  the  same  to  the  board  of  local  inspect- 
ors with  a  statement  of  the  applicant,  verified  before  a  consul 
or  other  officer  of  the  United  States  authorized  to  administer 
an  oath,  setting  forth  the  reasons  for  not  appearing  in  person, 
and  upon  receiving  the  same  the  board  of  local  inspectors 
that  originally  issued  such  license  shall  renew  the  same  for 
one  additional  term  of  such  license,  and  shall  notify  the 
applicant  of  such  renewal. 

"  The  first  license  issued  to  any  person  by  a  United  States 
inspector  shall  be  considered  an  original  license,  where  the 
United  States  records  shows  no  previous  issue  to  such  appli- 
cant." 

''  No  original  license  shall  be  issued  to  any  naturalized 
citizen  on  less  experience  in  any  grade  than  would  have  been 
required  of  an  American  by  birth. 

"  2.  All  licenses  hereafter  issued  to  masters,  mates,  pilots, 
and  engineers  shall  be  filled  out  on  the  face  with  pen  and  ink 


292  ENGINEERS'  LICENSE  LAWS 

instead  of  typewritten.  Inspectors  are  directed,  when  licenses 
are  completed,  to  draw  a  broad  pen  and  black  ink  mark 
through  all  unused  spaces  in  the  body  thereof,  so  as  to  prevent 
as  far  as  possible,  illegal  interpolation  after  issue. 

"3.  Licensed  officers  serving  under  5  yr.  license,  entitled  by 
license  and  service  to  raise  of  grade,  shall  have  issued  to  them 
new  licenses  for  the  grade  for  which  they  are  qualified,  the 
local  inspectors  to  forward  to  the  Supervising  Inspector-General 
the  old  license  when  surrendered,  with  the  report  of  the  cir- 
cumstances of  the  case. 

"But  the  grade  of  no  license  shall  be  raised,  except  as  herein- 
after provided,  unless  the  applicant  can  show  1  yr.  actual 
experience  in  the  capacity  for  which  he  has  been  licensed. 

"4.  In  case  of  loss  of  license,  of  any  class,  from  any  cause, 
the  inspectors,  upon  receiving  satisfactory  evidence  of  such  loss, 
shall  issue  a  certificate  to  the  owner  thereof,  which  shall  have 
the  authority  of  the  lost  license  for  the  unexpired  term,  unless 
in  the  meantime  the  holder  thereof  shall  have  the  grade  of  his 
license  raised  after  due  examination;  in  which  case  a  license 
in  due  form  for  such  grade  may  be  issued. 

"5.  Inspectors  shall,  before  granting  an  original  license  to 
any  person  to  act  as  an  officer  of  a  vessel,  require  the  applicant 
to  make  his  written  application  upon  the  blank  form  author- 
ized by  the  Board  of  Supervising  Inspectors,  which  application 
shall  be  filed  in  the  records  of  the  Inspectors'  office.  Inspectors 
shall  also,  when  practicable,  require  applicants  for  pilot's 
license  to  have  the  written  indorsement  of  the  master  and  engi- 
neer of  a  vessel  upon  which  he  has  served,  and  of  one  licensed 
pilot,  as  to  his  qualifications.  In  case  of  applicants  for  original 
engineer's  license,  they  shall  also,  when  practicable,  have  the 
indorsement  of  the  master  and  engineer  of  a  vessel  on  which 
they  have  served,  together  with  one  other  licensed  engineer. 

''6.  No  original  master's,  mate's,  pilot's,  or  engineer's 
license  shall  be  issued  hereafter  or  grade  increased  except  upon 
written  examination,  which  written  examination  shall  be 
placed  on  file  as  records  of  the  office  of  the  inspectors  issuing 
said  license;  and,  before  granting  or  renewing  a  license,  inspec- 
tors shall  satisfy  themselves  that  the  applicants  can  properly 
hear  the  bell  and  whistle  signals. 


ENGINEERS'  LICENSE  LAWS  293 

"7.  Any  applicant  for  license  who  has  been  duly  examined 
and  refused  may  come  before  any  local  board  for  reexamination 
after  1  yr.  has  expired. 

"8.  When  any  person  makes  application  for  license  it  shall 
be  the  duty  of  the  local  inspectors  to  give  the  applicant  the 
required  examination  as  soon  as  practicable. 

"9.  Any  person  who  has  served  at  least  1  yr.  as  master, 
commander,  pilot,  or  engineer  of  any  steam  vessel  of  the  United 
States  in  any  service  in  which  a  license  as  master,  mate,  pilot, 
or  engineer  was  not  required  at  the  time  of  such  service,  shall 
be  entitled  to  license  as  master,  mate,  pilot,  or  engineer,  if  the 
inspectors,  upon  written  examination,  as  required  for  appli- 
cants for  original  license,  may  find  him  qualified:  Provided, 
That  the  experience  of  any  such  applicant  within  3  yr.  of  making 
application  has  been  such  as  to  qualify  him  to  serve  in  the 
capacity  for  which  he  makes  application  to  be  licensed. 

"Any  officer  of  the  Naval  Militia  who  is  an  applicant  for 
license  as  chief  engineer  or  assistant  engineer  of  steam  vessels 
of  the  Naval  Militia  may  be  examined  by  inspectors  and 
granted  a  special  license  as  such,  and  for  no  other  purpose,  if, 
in  the  judgment  of  the  inspectors,  he  is  qualified.  And  the 
inspectors  shall  state  on  the  license  the  name  of  the  vessel  on 
which  such  master,  mate,  pilot,  or  engineer  is  authorized  to  act 
in  the  capacity  for  which  he  is  licensed. 

"All  licenses  issued  to  officers  of  the  Naval  Militia  provided 
for  in  the  preceding  paragraph  of  this  section  shall  be  surren- 
dered upon  the  party  holding  it  becoming  disconnected  from  the 
Naval  Militia  by  resignation  or  dismissal  from  such  service; 
and  no  license  shall  be  issued  as  above  except  upon  the  official 
recommendation  of  the  chief  officer  in  command  of  the  Naval 
Militia  station  of  the  State  in  which  the  applicant  is  serving. 

"10.  No  person  holding  special  license  (Form  878)  shall  be 
eligible  for  examination  for  a  higher  grade  of  license  until  such- 
person  has  actually  served  two  full  seasons  under  the  authority 
of  his  license  and  one  additional  full  season  in  a  subordinate 
capacity  upon  steamers  requiring  regularly  licensed  officers. 

"11.  Whenever  an  officer  shall  apply  for  a  renewal  of  his 
license  for  the  same  grade  the  presentation  of  the  old  certificate 
shall  be  considered  sufficient  evidence  of  his  litle  to  renewal, 


294  ENGINEERS'  LICENSE  LAWS 

which  certificate  shall  be  retained  by  the  inspectors  upon  their 
official  files  as  the  evidence  upon  which  the  license  was  renewed: 
Provided,  That  it  is  presented  within  12  mo.  after  the  date  of 
its  expiration,  unless  such  title  has  been  forfeited  or  facts  shall 
have  come  to  the  knowledge  of  the  inspectors  which  would 
render  a  renewal  improper;  nor  shall  any  license  be  renewed 
in  advance  of  the  date  of  the  expiration  thereof,  unless  there  are 
extraordinary  circumstances  that  shall  justify  a  renewal  before- 
hand, in  which  case  the  reasons  therefor  must  appear  in  detail 
upon  the  records  of  the  inspectors  renewing  the  license. 

"12.  When  the  license  of  any  master,  mate,  pilot,  or  engineer 
is  revoked  such  license  expires  with  such  revocation,  and  any 
license  subsequently  granted  to  such  person  shall  be  considered 
in  the  light  of  an  original  license.  And  upon  the  revocation  or 
suspension  of  the  license  of  any  such  officer  said  license  shall  be 
surrendered  to  the  local  inspectors  ordering  such  suspension  or 
revocation. 

"13.  The  suspension  or  revocation  of  a  joint  license  shall 
debar  the  person  holding  the  same  from  the  exercise  of  any  of 
the  privileges  therein  granted,  so  long  as  such  suspension  or 
revocation  shall  remain  in  force. 

"14.  When  the  license  of  any  master,  mate,  pilot,  or  engineer 
is  suspended,  the  inspectors  making  such  suspension  shall 
determine  the  term  of  its  duration,  except  that  such  suspension 
cannot  extend  beyond  the  time  for  which  the  license  was  issued. 

CLASSIFICATION  OF  ENGINEERS 

"20.     Chief  engineer  of  ocean  steamers. 

"Chief  engineer  of  condensing  lake,  bay,  and  sound  steamers. 

"Chief  engineer  of  non-condensing  lake,  bay,  and  sound 
steamers. 

"Chief  engineer  of  condensing  river  steamers. 

"Chief  engineer  of  non-condensing  river  steamers. 

"Any  person  holding  chief  engineer's  license  shall  be  per- 
mitted to  act  as  first  assistant  on  any  steamer  of  double  the 
tonnage  of  same  class  named  in  said  chief's  license. 

"Engineers  of  all  classifications  may  be  allowed  to  pursue 
their  profession  upon  all  waters  of  the  United  States  in  the 
class  for  which  they  are  licensed. 


ENGINEERS'  LICENSE  LAWS  295 

FIRST  ASSISTANT 

"First  assistant  engineer  of  ocean  steamers. 

"First  assistant  engineer  of  condensing  lake,  bay,  and  sound 
steamers. 

"First  assistant  engineer  of  non-condensing  lake,  bay,  and 
sound  steamers. 

"First  assistant  engineer  of  condensing  river  steamers. 

"First  assistant  engineer  of  non-condensing  river  steamers. 

"  Engineers  of  lake,  bay,  and  sound  steamers,  who  have  actu- 
ally performed  the  duties  of  engineer  for  a  period  of  3  yr.,  shall 
be  entitled  to  examination  for  engineer  of  ocean  steamers,  appli- 
cant to  be  examined  in  the  use  of  salt  water,  method  employed 
in  regulating  the  density  of  the  water  in  boilers,  the  application 
of  the  hydrometer  in  determining  the  density  of  sea  water,  and 
the  principle  of  constructing  the  instrument;  and  shall  be 
granted  such  grade  as  the  inspectors  having  jurisdiction  on  the 
Great  Lakes  and  seaboard  may  find  him  competent  to  fill. 

"Any  assistant  engineer  of  ocean  steamers  of  1,500  gr.  T. 
and  over,  having  had  actual  service  in  that  position  for  1  yr. 
may,  if  the  local  inspectors,  in  their  judgment,  deem  it  advis- 
able, have  his  license  indorsed  to  act  as  chief  engineer  on  lake, 
bay,  sound  or  river  steamers  of  750  gr.  T.  or  under. 

"Any  person  having  had  a  first  assistant  engineer's  license 
for  2  yr.  and  having  had  2  yr.  experience  as  second  assistant 
engineer,  shall  be  eligible  for  examination  for  chief  engineer's 
license. 

SECOND  ASSISTANT 

"Second  assistant  engineer  of  ocean  steamers. 

"Second  assistant  engineer  of  condensing  lake,  bay,  and 
sound  steamers. 

"Second  assistant  engineer  of  non-condensing  lake,  bay,  and 
sound  steamers. 

"Second  assistant  engineer  of  condensing  river  steamers. 

"Any  person  having  had  a  second  assistant  engineer's 
license  for  2  yr.,  and  having  had  2  yr.  experience  as  third 
assistant  engineer,  shall  be  eligible  for  examination  for  first 
assistant  engineer's  license. 

THIRD  ASSISTANT 

"Third  assistant  engineer  of  ocean  steamers. 


296  ENGINEERS'  LICENSE  LAWS 

"Third  assistant  engineer  of  condensing  lake,  bay,  and  sound 
steamers. 

"First,  second,  and  third  assistant  engineers  may  act  as  such 
on  any  steamer  of  the  grade  of  which  they  hold  license,  or  as 
such  assistant  engineer  on  any  steamer  of  a  lower  grade  than 
those  to  which  they  hold  a  license. 

"Any  person  having  a  third  assistant  engineer's  license  for 
2  yr.,  and  having  had  2  yr.  experience  as  oiler  or  water  tender 
since  receiving  said  license,  shall  be  eligible  for  examination  for 
second  assistant  engineer's  license. 

"Inspectors  may  designate  upon  the  certificate  of  any  chief 
or  assistant  engineer  the  tonnage  of  the  vessel  on  which  he  may 
act. 

"Any  assistant  engineer  may  act  as  engineer  in  charge  on 
steamers  of  100  T.  and  under.  In  all  cases  where  an  assistant 
engineer  is  permitted  to  act  as  engineer  in  charge,  the  inspectors 
shall  so  state  on  the  face  of  his  certificate  of  license  without 
further  examination. 

"21.  It  shall  be  the  duty  of  an  engineer  when  he  assumes 
charge  of  the  boilers  and  machinery  of  a  steamer  to  forthwith 
thoroughly  examine  the  same,  and  if  he  finds  any  part  thereof 
in  bad  condition,  caused  by  neglect  or  inattention  on  the  part 
of  his  predecessor,  he  shall  immediately  report  the  facts  to  the 
master,  owner,  or  agent,  and  to  the  local  inspectors  of  the  dis- 
trict, who  shall  thereupon  investigate  the  matter,  and  if  the 
former  engineer  has  been  culpably  derelict  of  his  duty,  they 
shall  suspend  or  revoke  his  license. 

"22.  Before  making  general  repairs  to  a  boiler  of  a  steam 
vessel  the  engineer  in  charge  of  such  steamer  shall  report,  in 
writing,  the  nature  of  such  repairs  to  the  local  inspector  of  the 
district  wherein  such  repairs  are  to  be  made. 

"And  it  shall  be  the  duty  of  all  engineers  when  an  accident 
occurs  to  the  boilers  or  machinery  in  their  charge  tending  to 
render  the  further  use  of  such  boilers  or  machinery  unsafe  until 
repairs  are  made,  or  when,  by  reason  of  ordinary  wear,  such 
boilers  or  machinery  have  become  unsafe,  to  report  the  same  to 
the  local  inspectors  immediately  upon  the  arrival  of  the  vessel 
at  the  first  port  reached  subsequent  to  the  accident,  or  after  the 
discovery  of  such  unsafe  condition  by  said  engineer. 


ENGINEERS'  LICENSE  LAWS  297 

"23.  Whenever  a  steamer  meets  with  an  accident  involving 
loss  of  life  or  damage  to  property  it  shall  be  the  duty  of  the 
licensed  officers  of  any  such  steamer  to  report  the  same  in 
writing  and  in  person  without  delay  to  the  nearest  board. 
Provided,  That  when  from  distance  it  may  be  inconvenient 
to  report  in  person  it  may  be  done  in  writing  only  and  the  report 
sworn  to  before  any  person  authorized  to  administer  oaths. 

"24.  No  person  shall  receive  an  original  license  as  engineer 
or  assistant  engineer  (except  for  special  license  on  small  pleasure 
steamers  and  ferryboats  of  10  T.  and  under,  sawmill  boats, 
pile  drivers,  boats  exclusively  engaged  as  fishing  boats,  and 
other  similar  small  vessels),  who  has  not  served  at  least  3  yr. 
in  the  engineer's  department  of  a  steam  vessel,  a  portion  of 
which  experience  must  have  been  obtained  within  the  3  yr. 
next  preceding  the  application. 

"Provided,  That  any  person  who  has  served  3  yr.  as  appren- 
tice to  the  machinist  trade  in  a  marine,  stationary,  or  locomotive 
engine  works,  and  any  person  who  has  served  for  a  period  of  not 
less  than  3  yr.  as  a  locomotive  or  stationary  engineer,  and  any 
person  graduated  as  a  mechanical  engineer  from  a  duly  recog- 
nized school  of  technology,  may  be  licensed  to  serve  as  an 
engineer  of  steam  vessels  after  having  had  not  less  than  1  yr. 
experience  in  the  engine  department  of  steam  vessels,  a  portion 
of  which  experience  must  have  been  obtained  within  the  3  yr. 
preceding  his  application;  which  fact  must  be  verified  by  the 
certificate  in  writing,  of  the  licensed  engineer  or  master  under 
whom  the  applicant  has  served,  said  certificate  to  be  filed  with 
the  application  of  the  candidate;  and  no  person  shall  receive 
license  as  above,  except  for  special  license,  who  is  not  able  to 
determine  the  weight  necessary  to  be  placed' on  the  lever  of  a 
safety  valve  (the  diameter  of  valve,  length  of  lever,  distance 
from  center  of  valve  to  fulcrum,  weight  of  lever,  and  weight  of 
valve  and  stem  being  known) ,  to  withstand  any  given  pressure 
of  steam  in  a  boiler,  or  who  is  not  able  to  figure  and  determine 
the  strain  brought  on  the  braces  of  a  boiler  with  a  given  pressure 
of  steam,  the  position  and  distance  apart  of  braces  being  known, 
such  knowledge  to  be  determined  by  an  examination  in  writing, 
and  the  report  of  examination  filed  with  the  application  in 
the  office  of  the  local  inspectors,  and  no  engineer  or  assistant 


298  ENGINEERS'  LICENSE  LAWS 

engineer  holding  a  license  shall  have  the  grade  of  the  same 
raised  without  possessing  the  above  qualifications.  No  original 
license  shall  be  granted  any  engineer  or  assistant  engineer  who 
cannot  read  and  write  and  does  not  understand  the  plain  rules 
of  arithmetic. 

"25.  Any  person  may  be  licensed  as  engineer  (on  Form 
2130J)  (New  Form  880)  on  vessels  propelled  by  gas,  fluid, 
naphtha,  or  electric  motors,  of  15  gr.  T.  or  over,  engaged  in 
commerce,  if  in  the  judgment  of  the  inspectors,  after  due 
examination  in  writing,  he  be  found  duly  qualified  to  take  charge 
of  the  machinery  of  vessels  so  propelled. 

"Any  person  holding  a  license  as  engineer  of  steam  vessels, 
desiring  to  act  as  engineer  of  motor  vessels,  must  appear  before 
a  board  of  local  inspectors  for  examination  as  to  his  knowledge 
of  the  machinery  of  such  motor  vessels,  and  if  found  qualified 
shall  be  licensed  as  engineer  of  motor  vessels.  Form  878, 
special  license  to  engineers,  shall  be  issued  only  to  engineers  in 
charge  of  vessels  of  10  T.  and  under.  All  other  licenses  to 
engineers  shall  be  issued  on  Forms  876  and  877,  according  to 
grades  specified  in  this  section." 


MEMORANDA 


MEMORANDA 


Promotion 
Advancement  in  Salary 

and 

Business  Success 


Secured 
Through  the 


STEAM 


Steam-Electric 

Engine  Running 

Stationary  Firemen's 

Engine  and  Dynamo  Running 

Locomotive  Running 

COURSES  OF  INSTRUCTION 
OF  THE 

International 
Correspondence  Schools 

International  Textbook 
Company,    Proprietors 

SCRANTON,  PA.,  U.  S.  A. 

^-^"  SEE  FOLLOWING  PAGES  ^S^ 

21 


Salary  Increased  450 
Per  Cent. 

For  several  years  I  had  charge  of  small  steam 
plants  which  paid  me  about  $20  a  month. 
An  I.  C.  S.  Representative  put  the  correspond- 
ence school  question  up  to  me  in  such  a  way 
I  felt  it  plainly  marked  "Opportunity."  I 
subscribed  for  the  Engine  Running  Course,  and 
began  studying  in  my  spare  moments.  Night 
after  night,  when  the  little  ones  were  in  dream- 
land, I  was  digging  into  the  technicalities  of 
steam  engineering. 

My  reward  is  being  gathered  each  week  as  I 
receive  my  pay  envelope,  increased-  by  450  per 
cent,  over  what  it  was  when  I  bought  the  Course. 

I  now  have  charge  of  a  new  steam-electric 
plant  of  about  850  horsepower,  having  from 
five  to  eight  men  in  my  department.  The 
position  I  fill  was  won  only  by  the  preparation 
the  I.  C.  S.  gave  me.  I  know  of  no  other  way 
I  could  have  prepared  myself  for  this  position. 
I  have  my  diploma  from  the  I.  C.  S.,  and  I  prize 
it  more  highly  than  any  mark  of  honor  I  have 
received. 

To  all  ambitious  men  I  say,  "To  succeed  you 
need  only  pluck,  push,  perseverance,  and  a 
Course  in  the  I.  C.  S." 

J.  EDGAR  WILLIAMS, 
315  Cable  St.,  Indianapolis,  Ind. 


IGNORANCE  HINDERS;  THE  I.  C.  S.  HELPS 

S.  T.  RICHARDSON,  Grosse  lie,  Mich.,  found  himself  stuck 
fast  in  a  night  engineer's  position,  unable  to  advance  because 
of  a  defective  education.  Knowing  nothing  of  fractions,  nor 
even  of  division,  he  took  up  our  Complete  Steam  Engineering 
Course.  By  so  doing  he  fitted  himself  for  the  position  which 
he  now  holds  as  chief  engineer  at  a  salary  of  $125  a  month. 

150  PER  CENT.  INCREASE 

That  it  pays  an  engineer  to  acquire  a  first-class  knowledge  of 
everything  connected  with  his  work  is  proved  by  the  case  of 
C.  W.  FELLOWS,  First  National  Bank  Building,  Houston,  Tex. 
He  was  earning  $70  a  month  when  he  enrolled  for  the  Station- 
ary Engineers'  Course.  He  is  now  general  superintendent  of 
a  large  office  building,  having  20  men  at  work  under  his  direc- 
tion. His  salary  has  increased  150  per  cent. 

CHOSEN  AHEAD  OF  MANY  OTHERS 

ELVIN  THOMPSON,  Afount  Vernon,  Ohio,  had  only  a  little 
education  and  was  working  as  a  fireman  when  he  enrolled  for 
the  Stationary  Engineers'  Course.  After  graduating  from  the 
Course,  he  made  application  for  the  position  of  engineer  in  the 
State  Sanitarium.  Although  there  were  hundreds  of  appli- 
cants, he  was  chosen.  He  is  now  considered  an  authority  on 
steam  engineering  and  his  salary  is  200  per  cent,  larger  than 
when  he  enrolled. 

ONE  THOUSAND  DOLLARS  A  YEAR  LARGER 

W.  A.  BERGER,  Hotel  Rome,  Omaha,  Neb.,  was  working  in 
a  factory  when  he  enrolled  for  the  Stationary  Engineers'  Course. 
He  praises  the  I.C.S.  because  they  have  advanced  him  to  the 
position  of  chief  engineer  of  the  Hotel  Rome  and  Hotel  Millard, 
increasing  his  salary  about  one  thousand  dollars  a  year. 

EARNS  $150  A  MONTH 

•  CLARENCE  GRETTUM,  Innisfail,  Alberta,  Can.,  had  obtained 
so  little  education  that  he  could  barely  read  and  write  when  he 
enrolled  for  the  Complete  Steam  Engineers'  Course.  At  the 
time  he  was  earning  $60  a  month  working  twelve  hours  a  day 
as  a  fireman.  He  has  now  taken  charge  of  the  Municipal 
Electric  Light  Plant  of  his  city  at  a  salary  of  $150  a  month. 

500  PER  CENT.  LARGER 

When  ARNOLD  W.  RIDLEY,  3256  Madison  St.,  Denver,  Colo., 
enrolled  with  the  I.C.S.  for  the  Steam  Engineering  Course  he 
was  employed  as  a  helper.  He  declares  that  a  fireman's 
practical  experience  combined  with  the  I.C.S.  training  will  make 
an  efficient  engineer.  He  is  now  plant  superintendent  for  the 
Denver  Gas  &  Electric  Co.  His  salary  has  increased  about 
500  per  cent. 


300  Per  Cent.  Increase 

Because  of  the  death  of  his  father,  leaving 
his  mother  on  her  own  resources,  R.  J.  BISSETT, 
814-16  Columbia  Building,  Cleveland,  Ohio, 
was  obliged  to  leave  school  and  compelled  to  go 
to  work  at  the  age  of  13.  While  he  was  earn- 
ing $2.75  a  day  as  an  engineer  at  the  age  of  34, 
he  enrolled  with  the  I.  C.  S.  for  the  Stationary 
Engineers'  Course.  One  year  later  he  was 
made  superintendent  of  the  Chamberlain  & 
Target  Company,  and  his  salary  increased. 
This  position  he  held  for  about  10  years.  For 
the  past  8  years  he  has  been  the  president  of 
the  R.  J.  Bissett  Company,  handling  steam 
appliances,  having  now  20  agents  under  his 
direct  supervision.  His  income  has  increased 
300  per  cent.,  and  sometimes  rises  even  higher. 


PRAISES  THE  SCHOOLS 

C.  S.  COUPLAND,  Box  -17,  Maricopa,  Calif.,  says  that  he  can- 
not praise  the  Schools  too  highly,  since  his  Steam-Electric 
Course  has  advanced  him  from  a  position  as  steamfitter's 
apprentice  to  the  position  of  chief  engineer,  increasing  his  sal- 
ary from  $50  to  $125  a  month. 


SALARY  INCREASED  266  PER  CENT. 

P.  J.  GRACE,  602  Atlantic  St.,  Bridgeport,  Conn.,  was  a  fire- 
man working  12  hours  a  day  in  an  electric  light  works  when  he 
enrolled  with  the  I.C.S.  for  the  Stationary  Engineers'  Course. 
He  is  now  the  chief  engineer  of  the  plant  of  the  Locomobile 
Company,  having  22  men  under  his  charge.  His  salary  has 
increased  260  per  cent. 


EARNS  $1,800  A  YEAR 

C.  M.  IRWIN,  429  Walnut  St.,  San  Francisco,  Calif.,  is  now 
chief  engineer  of  the  Head  Building.  Before  he  had  a  tech- 
nical knowledge  of  engineering  he  was  a  machinist  at  $3  a  day. 
His  I.C.S.  Course  has  raised  his  salary  to  $150  a  month. 


GRADUATE  BECOMES  CHIEF  ENGINEER 

ED.  BURROW,  Box  175,  San  Angelo,  Tex.,  is  proud  of  his 
diploma,  because  it  has  taken  him  from  a  position  in  the  engine 
room  where  he  worked  all  night  for  $24  a  month  to  the  place 
of  chief  engineer  at  a  salary  of  $150  a  month.  He  says:  "I 
cannot  see  how  a  boy  with  ambition  can  keep  from  enrolling." 


145  PER  CENT.  LARGER 

E.  E.  HUNTER,  1520  N.  Broadway,  Oklahoma  City,  Okla., 
was  earning  $85  a  month  at  the  time  of  his  enrolment  for  the 
Steam-Electric  Course.  He  declares  that  this  Course  was 
largely  instrumental  in  securing  his  advancement  to  the  posi- 
ti9n  of  chief  engineer  at  the  Oklahoma  Gas  &  Electric  Company, 
with  an  increase  in  salary  of  145  per  cent. 


NOW  CHIEF  ENGINEER 

GEO.  W.  DRENNON,  879  Mead  Ave.,  Oakland,  Calif.,  declares 
that  he  has  derived  much  benefit  from  his  Marine  Engineers' 
Course  for  which  he  enrolled  with  the  I.C.S.  When  he  began 
to  study  he  was  employed  as  an  assistant  engineer.  He  is  now 
chief  engineer  on  the  steamer  "Frances"  for  the  A.,  T.  &  S.  F. 
R.  R.  He  holds  an  engineer's  license  for  ocean  steamers  of  any 
tonnage  as  the  result  of  spare-time  study. 


800  Per  Cent.  Increase 

At  the  time  of  enrolling  in  the  I.  C.  S.  for  the 
Stationary  Engineers'  Course  I  had  received 
very  little  schooling — anything  beyond  long 
division  was  a  mystery  to  me.  When  I  sub- 
scribed I  sold  my  watch  to  make  the  first  two 
payments.  My  wages  at  that  time  were  $8.75 
a  week.  I  am  now  engineer  and  selling  agent 
for  the  Westinghouse  Company  at  an  increase 
in  salary  of  800  per  cent.  There  is  not  the 
slightest  doubt  that  the  I.  C.  S.  Course  was  the 
tidal  wave  that  carried  my  little  boat  into  a 
port  not  dreamed  of  in  the  beginning.  All 
men  have  not  the  same  kind  of  a  boat,  but  they 
have  some  kind  of  boat,  nevertheless.  It  is 
up  to  each  individual  which  chart  to  use. 

JOHN  M.  NICHOLSON, 
165  Broadway,  New  York,  N.  Y. 


DOUBLED  HIS  PAY 

CLARK  DULEY,  Allenswqrth,  Tulare  County,  Calif.,  was 
earning  $GO  a  month  at  the  time  of  his  enrolment  for  the  Steam- 
Electric  Course.  Although  he  had  never  seen  a  dynamo,  at 
the  time  he  took  charge  of  the  electric  lighting  plant  of  Bandcn, 
Ore.,  he  was  able  to  make  a  record  of  keeping  the  lights  burn- 
ing for  3  months  with  only  10  seconds'  trouble.  His  salary  has 
been  increased  to  $130  a  month. 

ONCE  A  LABORER 

IRA  G.  WHIFFLE,  1801  Kentucky  St.,  Lawrence,  Kans.,  was 
a  laborer  27  years  old  when  he  enrolled  for  the  Steam-Electric 
Course.  He  says  that  his  work  with  the  Schools  helped  him 
to  get  his  present  position  as  assistant  engineer  at  the  Kansas 
State  University. 

NOW  CHIEF  ENGINEER 

JOHN  M.  MORRISON,  Glace  Bay,  N.  S.,  Canada,  was  run- 
ning an  air  compressor  for  the  Dominion  Coal  Company  when 
he  enrolled  with  the  I.C.S.  for  the  Steam-Electric  Course. 
He  recommends  our  system  of  teaching  wh'ch  enabled  him  to 
become  chief  engineer  for  the  No.  4  Colliery,  one  of  the  lead- 
ing collieries  of  the  company,  with  an  increase  in  salary  of 
25  per  cent. 

SALARY  NEARLY  DOUBLED 

When  H.  L.  FULLER,  Rossford,  Ohio,  enrolled  for  the  Steam- 
Electric  Course,  he  was  working  as  general  utility  man  around 
a  plate  glass  works.  Today  he  is  first  assistant  engineer  for 
the  Edward  Ford  Plate  Glass  Company,  in  charge  of  a  modern 
turbine  plant  at  a  salary  of  $100  a  month. 

FROM  $660  TO  $1,500  A  YEAR 

GARRETT  BURGESS,  269  Stanford  Ave.,  Detroit,  Mich.,  was 
working  as  a  helper,  earning  $660  a  year  at  the  time  he  enrolled 
for  the  Engine  Running  Course.  Since  obtaining  his  diploma 
he  has  been  advanced  to  the  position  of  assistant  chief  engi- 
neer for  the  Morgan  &  Wright  Rubber  Company  at  a  salary 
of  $1,500  a  year. 

300  PER  CENT.  LARGER 

EARNEST  LEWIS,  5  Mott  Ave.,  Burlington,  N.  J.,  was  em- 
ployed as  a  fireman  by  the  Thomas  Devlin  Mfg.  Company  at 
the  time  of  his  enrolment  for  the  Complete  Steam  Engineering 
Course.  Sixteen  months  later,  through  faithful  study  of  his 
Course,  he  was  advanced  to  the  position  of  chief  engineer,  with 
an  increase  in  salary  of  300  per  cent.  He  declares  positively 
that  he  could  never  hold  his  present  position  if  it  had  not  been 
for  the  I.C.S. 


Salary  Quadrupled 

When  I  enrolled  with  the  I.  C.  S.  for  the 
Stationary  Engineers'  Course,  I  was  a  machin- 
ist earning  $13  a  week.  When  a  boy  at  school 
I  could  see  no  need  of  an  education,  and  quit 
as  soon  as  the  law  allowed,  having  learned  very 
little  while  I  did  attend  school.  For  a  few 
years  I  was  satisfied,  and  then  I  began  to  wish 
that  I  had  something  better,  but  soon  found  out 
that  I  was  not  qualified  for  advancement,  as 
I  had  wasted  my  time  in  school.  I  then  got 
out  the  old  arithmetic,  but  could  not  get  any 
satisfaction  out  of  it,  so  I  threw  it  up  and  de- 
cided that  I  was  a  hopeless  case.  Some  time 
afterward,  one  of  my  shop  mates  told  me  that 
he  had  taken  out  the  Stationary  Engineers' 
Course  with  the  I.  C.  S.  and  invited  me  to  his 
home  to  see  his  books.  I  then  enrol. ed,  and, 
although  I  have  not  made  any  very  wonderful 
strides,  I  have  gained  steadily  until  on  May  1, 
1910,  I  was  appointed  chief  engineer  of  the 
Springfield  Street  Railway  Power  Station  at  a 
salary  four  times  what  I  earned  in  the  iron 
works.  My  enrolment  with  the  Schools  was 
the  best  move  I  ever  made. 

\V.  C.  TRACY. 
791  Main  St..  Springfield,  Mass. 


SALARY  MORE  THAN  DOUBLED 

R.  F.  SHANK,  22  Florence  Ave.,  Rosedale,  Kans.,  was  work- 
ing as  an  oiler  for  $50  a  month  when  he  enrolled  for  our  Steam- 
Electric  Course.  He  had  only  obtained  a  fifth  grade  common 
school  education,  and  was  obliged  to  work  12  hours  a  day. 
Largely  through  the  study  of  the  Bound  Volumes,  he  advanced 
himself  to  the  position  of  chief  engineer  for  the  Kimball  Cereal 
Company,  of  Kansas  City,  Mo.,  at  a  salary  of  $21  a  week. 

250  PER  CENT.  INCREASE 

When  C.  F.  RASMUSSEN,  Clay  Center,  Kans.,  enrolled  with 
the  I.  C.  S.  for  the  Stationary  Engineers'  Course,  he  was  work- 
ing in  a  creamery  at  $30  a  month.  Having  graduated  from 
our  Stationary  Engineers'  Course,  and  also  from  our  Steam- 
Electric  Course,  he  has  been  able  to  command  a  better  position, 
and  hence  has  been  advanced  from  time  to  time  until  he  now 
draws  250  per  cent,  larger  salary,  as  superintendent  of  the  City 
Light  and  Water  Works  plant. 

NOW  CHIEF  ENGINEER 

J.  G.  BLYTHEWOOD,  Voth,  Tex.,  was  trying  to  learn  the  engi- 
neer's profession  when  he  enrolled  for  our  Stationary  Engi- 
neers' Course.  At  that  time  he  was  working  wherever  he 
could,  earning  $1  a  day.  He  says  that  our  system  is  the  best 
way  for  a  laboring  man  to  acquire  an  education,  since  it  has 
promoted  him  to  the  position  of  chief  engineer  for  the  Beau- 
mont Irrigating  Company  at  a  salary  of  $150  a  month. 

GRADUATE  GAINS  150  PER  CENT. 

JOHN  W.  HILFRANK,  White  Plains,  N.  Y.,  is  now  chief  engi- 
neer at  the  New  York  Orthopaedic  Dispensary  and  Hospital. 
When  he  enrolled  for  our  Stationary  Engineers'  Course,  he 
was  working  for  $12  a  week.  He  recommends  the  Cpurse, 
from  which  he  has  graduated,  because  it  has  increased  his  sal- 
ary 150  per  cent. 

NOW  FOREMAN 

GEORGE  KORNEGOE,  Van  Meter,  Iowa,  had  only  a  common 
school  education  when  he  enrolled  for  our  Steam-JElectric 
Course.  He  is  now  foreman  for  the  Platt  Company,  brick  and 
tile  manufacturers,  drawing  $100  a  month. 

NOW  EARNS  $196  A  MONTH 

ARCHIE  F.  HUBBARD,  Rich  Grove,  Tulare  County,  Cal.t 
was  running  a  harvester  when  he  began  to  study  our  Engine 
Running  Course.  He  now  runs  a  130-horsepower  traction 
engine,  earning  $196  a  month  and  board  during  the  harvesting 
months,  and  $130  a  month  during  the  plowing  months. 

9 


Now  Superintendent 

When  I  enrolled  with  the  International 
Correspondence  Schools  for  the  Complete 
Steam  Engineering  Course  I  was  working  on  a 
farm  earning  $20  a  month.  I  had  had  a  public 
school  education,  and  not  being  able  to  go  to 
the  high  school,  decided  to  try  the  I.  C.  S. 
method.  After  completing  my  Course  with 
very  little  difficulty,  I  became  interested  in  the 
mines.  I  am  now  superintendent  of  the  Peter- 
son Lake  Mining  Company  at  a  salary  of  about 
$160  a  month.  I  am  now  working  on  your 
Metal  Mining  Course.  The  large  increase  in 
my  earning  capacity  is  due  almost  entirely  to 
your  splendid  Courses,  which  are  worth  their 
cost  10  times  over. 

HENRY  SANKEY, 
Cobalt,  Ontario,  Canada 


10 


WORKING  AGAINST  ODDS 

CARL  SIMPSON,  Newark,  Ohio,  had  only  a  little  education 
and  was  working  13  hours  a  day  7  days  in  a  week,  trying  to 
support  his  family  when  he  enrolled  for  our  Engine  Running 
Course.  Although  his  own  people  thought  that  he  was  spend- 
ing his  time  and  money  for  nothing,  he  struggled  on  alone  until 
he  obtained  his  diploma.  He  is  now  chief  engineer  at  the 
Municipal  Water  Works  for  the  city  of  Newark  at  a  salary  of 
$100  a  month,  nearly  double  what  he  received  at  the  time  of 
enrolment. 

INCREASED  HIS  SALARY  100  PER  CENT. 

C.  W.  SINGER  was  earning  $12  a  week  when  he  subscribed  for 
pur  Advanced  Engine  Running  Course.  He  is  now  super- 
intendent of  the  Optimo  Mining  Company's  mines  at  Linden, 
Wis.,  having  35  men  at  work  for  him,  and  earning  $25  a  week. ' 

HAD  NO  EDUCATION 

JOHN  G.  SCHAFNITZKY,  206  State  St.,  Hudson,  N.  Y.,  had 
never  seen  the  inside  of  an  American  school  house,  and  had 
only  been  to  a  German  school  for  3  years.  After  picking  up  a 
little  English  from  his  younger  sisters,  who  were  sent  to  school, 
he  became  ambitious  to  learn  and  enrolled  for  our  Engine 
Running  Course.  At  that  time  he  was  earning  $1.30  for  12 
hours'  work.  He  is  now  master  mechanic  for  the  James 
Stewart  Construction  Company  at  a  salary  of  $25  a  week 
straight  time. 

NOW  SUPERINTENDENT 

M.  C.  REYNOLDS,  Box  48,  Carey,  Ohio,  was  working  as  a 
fireman  in  a  small  pumping  station,  earning  $35  a  month  when 
he  telephoned  our  Representative  to  come  to  the  works  to 
enroll  him  for  the  Engine  Running  Course.  Today  he  is 
superintendent  of  the  electric  lighting  and  water  works  plant 
of  Carey,  Ohio,  making  three  times  his  former  salary. 

SALARY  NEARLY  DOUBLED 

Forced  to  leave  school  at  an  early  age  to  go  to  work  in  the 
mines,  JOHN  PARKS,  319  Highland  Ave.,  Lexington,  Mo., 
found  himself  at  the  age  of  IS  with  a  knowledge  of  only  simple 

Eroblems  in  addition.     While  working  as  a  fireman,  he  enrolled 
ar  the  Engine  Running  Course.     He  is  now  engineer  at  a 
salary  90  per  cent,  greater  than  he  received  at  the  time  of  his 
enrolment. 

HIS  COURSE  WORTH  $50  A  MONTH  MORE  TO  HIM 

MAYNARD  JOSEPH,  Collinsville,  111.,  was  earning  $50  a  month 
as  a  fireman  when  he  took  out  our  Engine  Running  Course. 
This  enabled  him  to  pass  the  state  examination  and  to  obtain 
a  first-grade  certificate  of  competency  as  a  hoisting  engineer. 
He  now  has  charge  of  the  plant  of  the  Donk  Brothers  Coal 
Company,  a  plant  having  a  capacity  of  3,000  tons  of  coal  a 
day,  and  his  salary  has  increased  $50  a  month. 

11 


Salary  Increased  500 
Per  Cent. 

I  was  employed  as  a  farm  hand  at  $15  a 
month  when  I  enrolled  with  the  Schools  for 
the  Stationary  Engineers'  Course.  This  en- 
abled me  to  become  an  engineer  for  the  Booth- 
Kelly  Lumber  Company,  increasing  my  salary 
$50  a  month.  I  studied  your  volumes  on  elec- 
tricity, of  which  I  had  no  previous  knowledge, 
and  they  enabled  me  to  erect  about  75  miles 
of  telephone  lines  and  to  install  a  central  office. 
I  am  now  doing  construction  work  for  the 
Oregon  Power  Company  of  this  place,  at  a 
salary  500  per  cent,  larger  than  what  I  re<  ^ 
at  the  time  of  enrolment. 

PHILIP  A.  JOHNSON, 

Springfield,  Ore. 


12 


NOW  GENERAL  MANAGER 

JOHN  J.  PRICE,  Cement  City,  Mich.,  had  only  a  common 
school  education  before  he  enrolled  with  the  International 
Correspondence  Schools  for  the  Stationary  Engineers'  Course. 
He  did  his  studying  at  night,  running  an  engine  during  the  day. 
After  working  for  the  Peninsular  Portland  Cement  Company  in 
a  subordinate  position,  he  was  given  charge  of  their  power  house, 
and  then  of  their  dredges,  until  he  was  made  general  manager 
of  the  entire  works  at  a  salary  of  $2,000  a  year,  the  works 
employing  150  men.  Mr.  Price  earned  $50  a  month  when  he 
enrolled. 

NOW  CHIEF  ENGINEER 

D.  S.  KENNEDY,  19  Wetmore  St.,  Warren,  Pa.,  was  earning 
$65  a  month  as  an  electrician  when  he  began  to  study  our 
Stationary  Engineers'  Course.  He  recommends  this  Course 
to  young  men  because  it  has  enabled  him  to  become  chief  engi- 
neer of  the  Warren  Electrical  Company  with  an  increase  of 
50  per  cent,  in  salary. 

NO  LONGER  BLUNDERS  ALONG 

CHARLES  H.  WAINNER,  Itox  353,  Pratt,  Kans.,  had  no  reg- 
ular position,  and  was  working  wherever  he  could  at  $1.25  a 
day  when  he  enrolled  for  our  Stationary  Engineers'  Course. 
Until  he  had  mastered  this,  no  one  wanted  to  have  him  blunder- 
ing around  an  engine  room.  He  is  now  a  successful  engineer 
in  charge  of  the  power  plant  for  the  Pratt  Milling  Company, 
at  a  salary  150  per  cent,  larger  than  when  he  first  enrolled. 

NOW  PROPRIETOR 

OTIS  MORRIS,  Warren,  Idaho,  was  making  $1.25  a  day  when 
he  enrolfed  with  the  I.  C.  S.  for  the  Stationary  Engineers' 
C9urse.  He  is  now  in  business  for  himself,  leasing  several 
mines,  and  taking  charge  of  all  machinery. 

NOW  GENERAL  MANAGER 

JOHN  HARRIS,  Lilly,  Pa.,  was  firing  boilers  at  night  when 
,he  enrolled  for  our  Engine  Running  Course.     This,  he  says, 
proved  a  great  help  to  him,  enabling  him  to  become  the  gen- 
eral manager  of  the  James  Harris  &  Sons  Bituminous  Coal 
Mines. 

233  PER  CENT.  INCREASE 

Gus  LUNDGREN,  Cherokee,  Iowa,  was  a  fireman  in  a  small 
electric  lighting  plant  earning  but  $30  a  month  when  he  enrolled 
with  the  I.  C.  S.  for  the  Stationary  Engineers'  Course.  With- 
out this,  he  says,  he  could  never  have  reached  his  present  posi- 
tion as  manager  of  the  Cherokee  Electric  Company.  His 
income  has  increased  233  per  cent. 

13 


Now  Foreman  of  Engines 

I  had  been  working  for  the  Chesapeake  & 
Ohio  Railroad  Company  as  an  engineman 
for  several  years,  and  had  always  been  con- 
sidered an  A  No.  1  engineer,  which  made  me 
a  little  conceited.  I  imagined  that  I  needed 
no  further  training,  but  since  completing  my 
Locomotive  Running  Course  with  the  I.  C.  S., 
I  am  forced  to  change  my  mind,  and  must  now 
admit  that  my  former  knowledge  was  very 
limited  and  ordinary.  I  would  not  exchange 
the  benefits  I  have  received  from  the  Course 
for  $1,000  in  cash.  On  October  1,  1911,  I  was 
promoted  to  the  position  of  road  foreman  of 
engines,  which  position  I  now  hold,  with  head- 
quarters at  Covington,  Ky. 

D.  F.  EVANS, 
1220  Madison  St., 

Covington,  Ky. 


14 


THREE  TIMES  HIS  FORMER  SALARY 

J.  C.  WHITTEN,  t6  Danforth  St.,  Providence,  R.  I.,  while 
working  as  a  fireman  for  $12  a  week,  enrolled  for  our  Loco- 
motive Running  Course.  Having  been  a  poor  boy,  he  had  no 
chance  for  an  education,  needing  a  dictionary  to  define  common 
words.  His  Course  enabled  him  to  secure  promotion  at  his 
first  examination.  He  is  now  an  engineer,  earning  three  times 
what  he  received  at  the  time  of  enrolment. 

GRADUATE  WORKS  FOR  THE  GOVERNMENT 

HUGH  L.  RUSSELL,  Keams  Canon,  Ariz.,  was  earning  $12 
a  week  in  a  roller  mills  when  he  subscribed  for  our  Complete 
Steam  Engineering  Course  9  years  ago.  Since-  graduating, 
he  was  able  to  pass  the  Civil  Service  examination  with  a  grade 
of  98.3,  receiving  immediate  appointment.  He  has  since 
enrolled  for  the  Complete  Electrical  Engineering  Course. 
He  is  now  a  steam  and  electrical  engineer  in  the  service  of  the 
government,  Interior  Department,  with  a  salary  which  has 
increased  about  300  per  cent. 

GRADUATE  RECEIVES  PROMOTION 

M.  J.  McKiNNEY,  916  S.  Fell  Ave.,  Normal.  111.,  finished 
our  Locomotive  Running  Course  and  was  able  to  pass  the 
State  examination,  receiving  immediate  promotion.  He  now 
holds  a  profitable  place  as  engineer  on  the  Chicago  &  Alton 
Railroad. 

SALARY  MORE  THAN  DOUBLED 

HANS  C.  BROWN,  14  E.  Linden  St.,  Wilkes-Barre,  Pa.,  was 
a  railroad  fireman,  earning  $2.20  a  day  when  he  enrolled  for 
our  Complete  Locomotive  Running  Course.  Although  he  had 
received  only  a  common  school  education  in  his  native  land, 
Denmark,  he  was  able  to  pass  an  examination  and  receive 
promotion  as  engineer  for  the  Lehigh  Valley  Railroad  Company, 
where  he  now  earns  more  than  double  his  former  salary. 

SALARY  INCREASED  $95  A  MONTH 
When  NICHOLAS  COLILAR,  R.  F.  D.  31,  Costello,  Potter 
County,  Pa.,  enrolled  for  the  Complete  Locomotive  Running 
Course,  he  was  earning  $45  a  month  as  a  fireman.  His  Course 
has  helped  him  beyond  his  expectation.  He  is  now  a  loco- 
motive engineer,  for  the  Emporium  Lumber  Company,  earn- 
ing $95  a  month  more  than  when  he  enrolled. 

OFTEN  EARNS  $150  A  WEEK 

W.  R.  HAY,  Gulfport,  Miss.,  was  straw  boss  of  a  ditch  gang 
repairing  streets,  earning  $12.25  a  week,  when  he  enrolled  with 
the  I.  C.  S.  for  the  Complete  Steam  Engineering  Course. 
He  also  studied  our  Marine  Engineering  Course  and  Mechan- 
ical Drawing.  He  is  now  chief  engineer  and  manager  of  the 
tug  "Beaver,"  earning  from  $90  to  $150  a  week. 

15 


Bettered  His  Position 

When  I  enrolled  with  the  I.  C.  S.  for  the 
Complete  Locomotive  Running  Course,  I  was 
employed  as  an  engine  wiper  at  a  salary  of 
$54  a  month.  Since  then  I  have  become  fire- 
man, and  was  later  promoted  to  the  position 
of  engineer.  I  believe  that  my  work  with  the 
Schools  on  the  above  course  helped  me  a  great 
deal  in  my  examinations  enabling  me  to  pass 
with  great  success.  I  am  now  employed  by  the 
Northwestern  Pacific  Railway  Co.  as  an  engi- 
neer, averaging  from  $125  to  $160  a  month. 
G.  F.  BRADLEY,  Jr., 
310  3rd  St., 

San  Rafael,  Cal. 


10 


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