42 Remarks on auArlidc tiUUled " A few Facts 



One cubic foot of oil gas go as far as four of coal gas ! ! In 

 what a most extraordinary point of view must the writer of the 

 above have been contemplating his favourite oil gas! However, 

 we must look to him for the proof, as well as to explain the fol- 

 lowing discrepance, That " Mr. DeVille of the Strand, who has 

 made many important experiments upon oil gas illumination, 

 compares oil gas to coal gas as 9 to 6 — not as 4 to 1, as just 

 stated ; and that, as a proof, a 10-holed Argand burner will con- 

 sume 2| cubic feet of oil gas per hour : yet at page 314 we are 

 told that 1| is sufficient ! Now an 18-holed Argand of coal gas 

 is never allowed more than five, and often only four, cubic feet 

 per hour, which is very near Mr. De Ville's proportion ! To sa- 

 tisfy ourselves that this last statement is much nearer the truth, 

 and that the random proportion of 4 to 1 is a something given 

 upon hearsay, and not the result of either theory or practice, 

 we have onlv to consider the two gases theoretically. 



Query ? What would be the proportion of light given off 

 during the combustion of 100 measures of oil gas and 100 of 

 coal gas, supposing the former to be all olefiant gas, and the 

 latter all light carburetted hydrogen ? Professor Brande says 

 that ^' the fitness of gas for illumination will be directly as its 

 specific gravity." Dr. Henry, in his late experiments to ascer- 

 tain the degrees of combustibility of the gases, recommends " the 

 finding experimentally the proportion of oxygen gas required for 

 their saturation, and of carbonic acid formed." 



The following table will theroiore show at one view, that by 

 either of these methods ohjiant gas can but possess double the 

 illuminating power of either light carburetted hydrogen or of 

 coal gas. 



Table*. 



Let 



• The above computations are taken from Dr. Henry's late experiments, 

 the coal gas being in each instance the average of the first seven hours' 

 product. It would have been desirable had Dr. H. given more particulars 

 as to the species and character of the Clifton coal, whether hard or soft} for 

 with us we have but little hard coal that is at all suited to the purpose of 

 illumination. He merely calls it " common coal of fair average quality." 

 But however fair the average may be with respect to Manchester, it appears 



to 



