Dr Fyfe on the Evaporative Paver of Coal. 277 



sists in throwing in small jets of steam at the front of the fur- 

 nace, immediately over the surface of the fuel, at the same 

 time admitting air, at the furnace-door or otherwise, also over 

 the fuel. It is not my intention to enter into a discussion as 

 to the merit of these processes for effecting the objects pro- 

 posed. I will, perhaps, at a future period make some re-- 

 marks regarding the latter, with which I have had many op- 

 portunities of operating, and with which I have obtained the 

 most unlooked-for, but, at'the same time, the most satisfactory 

 results. Keeping out of view these and other contrivances of 

 a similar nature, it is evident that the power of anthracite is 

 far beyond that of other kinds of fuel, more particularly when 

 it is of good quality, that is, rich in fixed carbon, simply be- 

 cause there being little, indeed in some kinds of it we may say 

 no, volatile inflammable matter, the whole of the combustible 

 substance is consumed, and the only loss of heat arises from 

 that which must pass up the chimney, and by which a draft is 

 secured, besides what is given off in the flues and otherwise by 

 communication, through the materials of the furnace. 



There is still another point to which I wish to advert. I 

 have already alluded to the great practical evaporative power 

 of those fuels containing much fixed carbon. On still farther 

 viewing the results of the experiments which have been de- 

 tailed, we find that not only does the evaporative power bear 

 a ratio to the proportion of this element in the different fuels, 

 but it would appear to be almost in the exact ratio of its quantity 

 in each. Thus the fixed carbon in the anthracite I employed 

 was 71.4 per cent. — now, taking that of pure carbon as 12.3 



as 100 : 12.3 : : 71.4 : 8.77, 

 the practical working of the fuel actually consumed was 8.73. 

 The fixed carbon in the Scotch coal was 50.5 per cent, and 



as 100 : 12.3 : : 50.5 : 6.21, 

 the practical working was 6.GG. In the anthracite used by 

 Dr Schafhaeutl, the fixed carbon was 92.42, 



and as 100 : 12.3 : : 92.42 : 10.36, 

 the practical working was 10.56. The evaporative power in 

 practice seems therefore to be^very nearly as the quantity of 

 fixed carbon in the fuel. I am strongly inclined to think that 

 this will be found to be the case with all fuels in their natural 



