168 REPORT—1845. 
This result, contrasted with that obtained when the coal was distilled so 
as to prevent the products of distillation passing over the red-hot coal, 
enables us to see clearly the influence exerted upon the tar and steam by the 
glowing fuel. The liquid products of distillation and the coke are diminished 
in quantity, and in their place we find an increase of carbonic oxide, olefiant 
gas and hydrogen, arising from the carbon being oxidized at the expense of 
water, and from the decomposition of tar at an elevated temperature. Now 
if we calculate the composition of the furnace-gases from the principles now 
laid down, we obtain the following result :— 
I. Il. 
According to weight. According to volume. 
NittoPed wettest. se ee OAS 57°878 
Carbonicacilie "So Ph. oe Da 9°823 
Carbonic oxide... . . 23°956 24°042 
Light carburetted hydrogen . . . 1°555 2°743 
IPEVGrOuEN hie. ete? ees ates oe 4972 
Olefiant gas siege Fatttle Fie, coh ee + CUPGOG 0392 
Sulphuretted hydrogen. . . . . 0°043 0°035 
ANBAOHIA eke ts y's see, @ ODO 0115 
100000 100°000 
The proportion of the substances in this mixture of gases may be viewed 
as the limits to which the quantity of combustible constituents may increase, 
when formed under the conditions such as those existing in the Alfreton 
iron-works. We observe at the same time, that the increase of combustible 
materials effected by the reaction of the liquid products of distillation on the 
red-hot coal, principally depend upon the augmentation of hydrogen and ole- 
fiant gas. If we calculate from the above numbers, according to the princi- 
ples already laid down, the quantity of heat evolved in the furnace by the 
formation of 100 parts by weight of the gases, and compare it with the heat 
which might be derived by the combustion of these gases themselves, we 
obtain the proportion 98583 : 19550, a result showing that in the Alfreton 
furnaces, under favourable circumstances, only 16°55 per cent. of fuel is 
realized; while 83°45 per cent. is actually lost by escaping in the form of 
inflammable gases. 
1 kil. of the gas burnt with air gives 1-9290 kil. products of combustion, 
which consist of 
NGETOREN oon o),5 018. = ie peer oe 
Carbonic acid . .. . . 29°83 
Aqueous vapour... . 284 
100°00 
The specific heat of the products of combustion calculated from this com- 
position corresponds to 0°2740, from which it follows that the temperature of 
the flame of this gas burned with air would be 1768° C., or 3214° Fahr. 
Thus then the temperature of the gases of the Alfreton furnaces is 3214° 
Fahr., when generated under conditions approaching to the favourable cir- 
cumstances in the furnaces themselves. 
Theory of the Hot-Blast Furnaces. 
The previous inquiries have led us to a knowledge of the average compo- 
sition of the furnace-gases, as they are produced during the processes in 
operation in various parts of the furnace. We have endeavoured to point 
