708 Report of the Consulting Engineers on the Trials of 
The quantity of oxygen (41 '27) stated above, would make an 
union with 5 '16 of hydrogen. There was, as will be seen, a 
total 6*00 of hydrogen; deduct from this the 5 "16 needed for 
the oxygen, and there remains 0*84 of hydrogen available for 
fuel ; the rest of the hydrogen, with its oxygen, being in the 
form of water, or rather inchoate water, not capable of being 
expelled by drying. 
The foregoing observations will be found applicable to the 
question of oxygen and hydrogen in the coal. 
Having premised thus much, it will be well, by way of illus- 
tration, to calculate and draw up a Balance Sheet — say that of 
Davey, Paxman and Co.'s " Simple Engine," No. 3125. 
With respect to the wood for rekindling, it should be stated 
that immediately after the preliminary run, the fire-grate and 
ash-pan were cleared and 14 lbs. of wood were placed on the 
firebars, the heat of which rekindled it at once : coal was then 
added, and the trial run commenced. This operation occupied 
three minutes. 
The Debtor Side of the Account. 
Debtor to the units of heat produceable by the fuel. 
During the run, which lasted 263 minutes, 193 lbs. of coal 
were burnt. The temperature of the air was 70°, that of 
the products of combustion in the smoke-box 385°. Twenty-two 
per cent, of the wood, as already stated, were in the form of 
moisture, expellable by drying, equivalent on the 14 lbs. of 
wood to 3 '08 lbs. The heat developed by the remaining 
10*92 lbs. we calculate in the following manner. 
Units. 
Carbon 10-92 lbs. x -4995 x 14,544 u 79,331 
Hydrogen 10-92 lbs. x -0084 x 52,509 u 4,816 
84,147 
The heat developed by the coal we estimate as follows : — ■ 
Units. 
Carbon 193 lbs. X -884 x 14,544 u. .. 2,481,400 
Hydrogen 193 lbs. X -0333 X 52,509 u. ,. 337,475 
Sulphur 193 lbs. x 47 .. .. 9,071 
2,827,946 
Heat developed by the wood .. .. .. 84,147 
Total from wood and coal .. .. 2,912,093 
