402 Mr. Elliott on Oil Gas. 



depend upon the delicacy of their ear, or the accuracy of an 

 index, for information which is of the last importance. If you 

 admit the oil too slowly, the gas is generated in small quanti- 

 ties ; and I believe, though I would not assert, that it is thereby 

 injured. If the oil is admitted too rapidly, there is no trifling 

 risk of converting most, if not all, into a condensable vapour. 

 The plan adopted was this : — A glass, which for strength was 

 of an egg-like form, was ground on the outside of the lower 

 end for the space of three-eighths of an inch : this was fitted 

 into the top of the pipe leading into the retort. At the top 

 part of the glass one end of a tap entered, which was connected 

 with the oil cistern, and through which the fluid must pass in 

 its way to the retort. The rate at which the oil entered was 

 of course seen through the glass, each end of which was ground 

 to make it aix-tight, and thus one of the principal difticulties 

 was obviated at a very trifling expense. The taps which fit 

 into the glass above mentioned, are capable of great improve- 

 ment when oil of an inferior quality is used. I constantly em- 

 ploy them, though their absolute necessity might admit of a 

 doubt, were the oil carefully filtered and kept free from dirt 

 and impurities. I have mentioned the risk we run, by a too 

 hasty admission of the oil, of converting it into a condensable 

 vapour. This is a fluid of a very singular and peculiar descrip- 

 tion. It is frequently destitute of colour, whilst above it there 

 floats a very dense oily liquid. Its taste is caustic in the ex- 

 treme ; if a drop is placed upon the tongue, it produces a sen- 

 sation similar to that we should experience if a needle had en- 

 tered. It is very inflammable; for if a quantity be thrown upon 

 a sheet of water, and a light brought into contact with it, the 

 whole surface is in a blaze, throwmg up dense volumes of 

 smoke. I intend making some further experiments on this 

 body, the particulars ot which, should the results be in- 

 teresting, may furnish matter for another communication. 



Dr. Bostock, in his experiments on whale oil (Annals of Phil. 

 Jan. 1821), mentions the pi'oduction of acetic acid, in combi- 

 nation with an inflammable gas. The spirit to which I have al- 

 luded has similar properties. It acts pov/erfuUy upon lead, 

 reducing it to a pulpy mass, which resembles the acetate of that 

 metal. This action is exerted onl}'^ where the gas first enters 

 the lead piping, corroding and dissolving it for two or three 

 inches. My opinion at present is, that tin pipes would answer 

 better ; but I have not made any direct experiments which 

 warrant a positive assertion. (See Mr. Mills on Block Tin 

 Pipes, Edinburgh Philosophical Journal, vol. v. p. 121.) — 

 A large quantity of spirit always left an increased quantity of 



carbon 



