42-t Mr. \V. Herapath's Experiments on Oil and Coal Gas. 



before the decomposition is effected. This circumstance has 

 hitherto prevented me from trying the cxj^erimcntum crvcis ,- 

 viz. coiletting the carbonic acid formed. When chlorate of 

 potash is used, it is necessary to repeat the operation several 

 times, as very little is decomposed each time. Kitre has still 

 less effect upon it. It is a good conductor of electricit}-. 



If this substance should turn out to be of the same compo- 

 sition as the diamond ; and the only difference between them 

 be, that the diamond has twice the number of atoms in the 

 same space, which is probable from its specific gravity being 

 S-5; it might throw some light upon the cause of transparency 

 and onacitv. We may learn something from the examination 

 of this substance; for as its formation is by thin layers, it is 

 evident that its source is not the coke but the gas ; and as it 

 is always deposited on the hottest part of the retort, it shows 

 that coal gas should not be exposed to a greater heat than 

 that at which it was produced; every portion of carbon so 

 deposited being lost both to the gas-maker and consumer, and 

 carbon is the only substance in gas which furnishes light, as 

 pure hydrogen gives out none. 



Yours, &c. 



Bristol, 5G 01(1 Market-street, WiLLlAM HerapaTH. 



May 19, 1823. 



LXXXVII. Experiments on Oil and Coal Gas. By Wiixiam 

 Herapath, Esq. 



''I ""HE following experiments were performed by Mr. Root- 

 sey and myself, for the purpose of discovering which of 

 the two gases was most fit for the purposes of ilhmiination, 

 and whether the}' were equally cheap to the consumer at the 

 prices of 1 5s. per thousand cubit feet for coal, and 50s. for oil 

 gas. As the results may affect generally as well as locally, I will 

 thank you to insert them in the Philosophical ^Magazine. 



Jamianj 30, 1823. — Cod Oil. 

 lb. oz. cr'j. 

 3 14 362 oil used. 

 Products. — Carbon found in various parts of the lb. 



apparatus (about ^th) 



And 44-. 2 cub. feet of gas, sp. gr. '876 2 



Water and aciil formed not noticed. 

 The retort was three feet long, having an internal iron tube 

 four inches in diameter and two feet three inches in length. 

 The oil was admitted in a very small stream, but little-faster 

 than dropping, 47 lbs of bricks having been introduced to in- 

 crease 



