On the Manufacture of Bar Iron in India. 43 



bined, and I have experimentally proved, that the pure ores 

 of India may be reduced in " reverberatory furnaces, bloom- 

 eries," without charcoal, wood, or coal : using any carbona- 

 ceous substance which is capable of being made to burn in 

 a blast furnace and of affording gas. This mode of making 

 11 gas-reduced iron," promises to be valuable in many parts 

 of India, where iron ore abounds, but fuel is scarce : but as 

 the subject of " gas furnaces" will afford matter for a se- 

 parate paper, I will not enlarge on this point at present. 

 January t 1845. 



On Gas Furnaces, By Captain J. Campbell, 2lst Regi- 

 ment, M. N. L 



1. The use of " gas furnaces" is an invention due to the 

 French, who have lately practically applied them on the 

 large scale in the arts, and have succeeded in producing 

 with them so high a temperature, as to answer the purpose 

 of heating reverberatory furnaces for the fusing and pud- 

 dling of cast iron, to reduce it to the malleable state. The 

 Germans appear also to have been in possession of the in- 

 vention prior to the French, but the principle was concealed 

 until the publication of it in France. 



2. In " gas furnaces" the carboniferous gases evolved 

 from the mouth of large blast furnaces, or from any sub- 

 stance capable of burning in a close furnace with a jet of air 

 from a blast pipe, are conducted through a range of heated 

 pipes, and forced out in jets from a series of nozzles in the 

 manner of a blowpipe ; while a jet of heated atmospheric 

 air is forced through the centre. Each jet therefore be- 

 comes a vast blowpipe blown with heated air, and by in- 

 creasing the number of jets and concentrating the action of 

 the flames, a very high degree of temperature is readily pro- 

 duced. 



3. The first application of gas furnaces, according to Peclet, 

 is dued to M. Aubertot, who in 1812 used the flame of a high 



