966 



IRON 



The calculations of the quantity of hoat capable of being realised In tho furnace by 

 the combustion of tho furnace-gases are founded on tho data on tho heat of combustion 

 given in the posthumous papers of Dulong, according to which 



1 kilogramme, OP 15,444 grains, of 



Carbon burning to CO, heats 1 5,444 grs, of water to 1499C 



CO', 7371 



Carbonic oxide . . . . . . 2502 



Hydrogen 34706 



Light carburetted hydrogen .... 13469 



Olefiantgas 12322 



Sulphuretted hydrogen - . . , . . 4476 



Ammonia . . . . . . . , 6060 



Using these numbers, it is found that by the combustion of 100 of the furnace-gases, 

 there are generated from the 



59'559 nitrogen 0000 



12765 carbonic acid 0000 



26*006 carbonic oxide 65067 



1-397 carburetted hydrogen .... 18826 



0-078 hydrogen 2704 



0-108 olefiant gas 1331 



0-053 sulphuretted hydrogen , 238 



0-034 ammonia 208 



88374 = 



units of heat generated, the unit being understood to mean the amount of heat neces- 

 sary to raise 1 kilogramme = 2-204 Ibs. = 15,444 grains of water from Centigrade to 

 1 cent. The amount of heat realized in the furnace is limited to that produced by 

 the expenditure of the oxygen, corresponding to 59*559 nitrogen in the production of 

 carbonic oxide ; this amounts to 20,001 units : hen<;e follows the remarkable conclusion, 

 that in the furnace which was the subject of .experiment not less than 81'54 per cent, 

 of the fuel is lost in the form of combustible matter still fit for use, and that only 

 18-46 per cent, of the whole fuel is realised in carrying out the processes in the furnaco. 



A more practical measure of the economy of fuel in the blast-furnace is that given 

 by Mr. Lowthian Bell. See p. 978. 



The temperature which should be produced by the flame of the furnace-gases when 

 burnt with air is found by dividing the units of heat, viz. 88374 arising from tho 

 combustion of 1 kilogramme of the gases by the number resulting when the quantity 

 of tho products of combustion is multiplied by their specific heat (1-9338 x 0'2696): 

 we thus get the number 3083 F. ; but this is below the truth, inasmuch as there is an 

 accession of combustible gases at the mouth of the furnace, arising from the decompo- 

 sition of the liquid products of the distillation of the coal in its passage over the red- 

 hot fuel. Making proper correction for this, and using numbers derived from actual 

 experiments, Messrs. Bunsen and Playfair calculated the temperature of the gases 



f >w^./~-^-~^v w /*"S 1 



1238 



when generated under favourable conditions at 3214 F., and oven this may bo in- 

 creased to 3632 F., a temperature far above that of cast iron, by the using a 1-l.ist 

 sufficiently heated. In utilising these waste gases, care must be taken not to remove 



