Portable Agricultural Steam Engines at Newcastle. 711 
measures 12*387 cubic feet; hence at 70° or 530° absolute the 
volume of the whole of the air would be 
Cubic ft. 
(1 93 lbs. X 11 • 38 + 10 • 92 lbs. X G ' 08) 12 • 387 cu. ft. X 5 30° 
■ - = 301 J-1 
The coal and wood measured . . . . . . . . 2 ' 56 
Total volume at 70° 30196-56 
Oxygen combining with carbon, forms carbonic acid without 
change of volume of the oxygen, but in combining with hydro- 
gen its volume is doubled. Hence the volume of the products of 
combustion will be the volume of the air plus one volume of 
oxygen as regards that portion which was combined with the 
hydrogen. Now 'OSSS parts of hydrogen combined with '2664 
parts of oxygen, the volume of which = 
•2664 lb. X 11.204 c. ft. = 2-984 cubic feet 
the air measured 11 • 38 lbs. X 12 * 387 = 140 • 97 „ 
so that the total products of com- 1 ^^3.95^ ^^^.^ ^ 
bustion per 1 lb. 01 coal were) 
and for the total quantity of coal at 32° 
= 143 • 95 c. ft. X 193 lb. = 27,783 c. ft. 
For the wood the hydrogen available corresponding to '0672 
parts of oxygen = -0672 X 11-204 = -753 c. ft. and 6-08 lbs. 
of air required for perfect combustion give 6-08 X 12*387 = 
75- 314 c. ft., making per pound of dry wood 76*067, and 
76- 067 X 10-92 = 830-65. Adding this to the volume of 
products of the coal, we get a total of 28,614 c. ft. at 32°, or 
492° absolute, and consequently at 385% or 845° absolute, the 
volume will be = 28,614x^845° ^ ^g^^^^ ^ 
492 
In addition we have 8 • 15 lbs. of water in the wood and 
7-141 lbs. in the coal, making together 15-291 lbs. of steam. 
15-291 lbs. X 19 -913 eft, x 845° ^ ^23. 5 ^ 
492 ■ ' 
Cubic ft. 
Which, added to the previously obtained 49,144, gives ) ggg 
total volume of products at 385° .. .. .. j ' 
Less total volume of fuel (including air) at 70° .. 30,197 
Total increase of volume .. .. 19,471 
Now the work done is found by multiplying this increase of 
volume by the pressure of the atmosphere, which is 2117 lbs. 
