162 REPORT—1845. 
The heat lost in a furnace may be easily compared with that actually 
realized. The following numbers exhibit the quantities of heat (expressed 
by the unities which we formerly described) generated during the combustion 
of the gases, and they show at the same time the part played by each con- 
stituent in the development of the heat :— 
I. II. 
64135 Nitrogen yields . 2. . 2. sv» 00000 
33°758 Carbonic oxide yields . . . . . . 84463 
1°464 Light carburetted hydrogen yields . . 19719 
0°224 Carbonic acid yields oe @) rae | 00000 
0°154 Olefiant gas yields eile paves,  DB9S) 
0°114 Sulphuretted hydrogen yields . . . 510 
0°107 Hydrogen yields . net | 3713 
0:044 Ammonia yields . . . 1... 6s 267 
100:000 Furnace-gases yield . . . . « « « 110570 units of heat. 
The numbers (II.) representing the units of heat are calculated from the 
data on the heat of combustion found in the posthumous papers of Dulong. 
x «,, { Carbon burning to CO, heats 15444 grains of water to 1499°C. 
= ° ” ” CO,, bb} ” 7371° 
3. | Carbonic oxide i; ‘5 ‘8 2502° 
& & | Hydrogen ¥ mM 34:706° 
E a Light carburetted hydrogen Ri " 13469° 
2s Olefiant gas i i” 12329° 
uy 6 Sulphuretted hydrogen 9 iy 4476°% 
= Ammonia ss - 6060°* 
The quantity of heat actually generated in the furnace during the escape 
of the unused 110570 units of heat may be determined by the amount of 
nitrogen in the gases, which corresponds to the quantity of the air consumed 
during their escape. The amount of nitrogen found, viz. 64°126, corresponds 
to 83°29 of atmospheric air, which is able to effect the conversion of 14°367 
carbon into carbonic oxide gas. Proceeding on the experiments of Dulong, 
the quantity of heat thus liberated will be 21536°. Thus it follows that a 
furnace filled with Gasforth coal could realize in the most favourable condi- 
tions only 16°30 per cent. of its combustible material. The remainder, 83°70 
per cent., escapes as unused but useful combustible matter. The practical 
use of these gases does not depend merely upon the quantity of heat generated 
during their combustion, but involves another equally importaut considera- 
tion, viz. the temperature capable of being attained by their use as fuel. This 
may be determined without any new experiments, by founding the calculation 
on the composition of the gas, its combustible value, and the capacity for heat 
of the products generated during combustion. 
1 kil. of the gas gives, by its combustion, as we have already seen, 1105°7 
units of heat. The products of combustion weigh 271385 kil.; and if this 
last quantity + consisted of water, the heat liberated would raise it to a tem- 
sae Now as the capacity of heat of water is to that of the pro- 
ducts of combustion as 1 : 0°2665, and the elevation of temperature produced 
in different bodies of equal weight, by equal quantities of heat, is in inverse 
perature 
* The ammonia and sulphuretted hydrogen are calculated from their constituents. 
+ In this, and also in other similar calculations, the small quantity of sulphuretted hydrogen 
has been left out of the calculation, 
