284 Examination of a Coal from Ckerra JPunji. [No. 4. 



It would thus appear, so far as laboratory experiment can guide 

 us, that this coal is a first rate gas coal, but would not give a coke 

 applicable to any present known use, the coke being in fact a black 

 carbonaceous froth. 



As a steam coal, unless it be perhaps with tubular boilers, it would 

 not be found an economical one ; as though from its rapid flaming, 

 the steam would be quickly raised, yet from the large proportion of 

 gas, much of it would be unconsumed, and driven up the funnel or 

 chimney, and the proportion of carbon (coke) is too small to keep 

 up a long steady glowing heat, without a fresh supply of coal. If it is 

 used for steam in common furnaces, the most economical method of 

 using it, would probably be to burn two-thirds of Burdwan or other 

 inferior coal to one of this kind. 



On communication of these results to Messrs. Gilmore and 

 McKilligan, they shewed me a report from Mr. Ward of Messrs. 

 Jessop & Co. stating that they had found that the coal coked well ! 

 Supposing some error, I repeated my own experiment, and obtained 

 from Mr. Ward somo of their coal, and of its coke, which was very 

 fine and the coal evidently from the same seam ; but upon trying 

 some of it in the same (silver) crucible over a lamp furnace, it 

 produced only the puffy mass, like my former result. I called on 

 Messrs. Jessop to compare notes, and they informed me that from 

 2 maunds 35 seers of the coal, they had obtained but one maund of 

 coke, or rather less, since it was weighed when damp. This is very 

 nearly our proportion of 33 per cent of carbon and ash, for 100 : 

 33 : : 115 : 37,73, which was about the true weight of Messrs. Jes- 

 sop' s coke. 



The singular fact, however which it teaches us, i. e. that with 

 highly gaseous coal, the same result is not produced on a small scale 

 as on a large one, is highly interesting ; and thinking it might be 

 owing to the too sudden application of heat, from the lamp furnace 

 heating the silver crucible quickly to redness, I tried graduating 

 the heat very slowly but without success ; so that this is not the 

 cause of this extraordinary difference of results. 



