Mr. Elliott on Oil Gas. 403 



carbon in the retort; and I felt persuaded, that if 1 could avoid 

 making the spirit, I should also lose the carbon. Mr. Brande, 

 in speaking of the apparatus constructed by Messrs. Tajlor, 

 mentions, that the oil is decomposed and converted almost en- 

 tirely into charcoal. After many fruitless attempts, I have at 

 last discovered, that if the oil is admitted only when the retort 

 is intenselv hot, the whole of the carbon is dissipated, and only 

 a very trifling portion of spirit formed. That the process may 

 be effectual, the gas is made to pass through another retort, 

 which completes the decomposition of that portion of the oil 

 which might not have before been sufficiently heated. These 

 views are not in unison with those entertained by Dr. Henry 

 (Phil. Trans. 1821), who says ; " So far as my experience goes, 

 no temperature short of ignition is sufficient for the decompo- 

 sition of oil into permanent combustible gas ; but the lower 

 the heat that is employed, provided it be adequate to the effect, 

 the heavier and more combustible is the gas, and better suited 

 to artificial illumination." It has been remarked by writers on 

 this subject, that the retort would only retain its decomposing 

 power for a certain time, and that after this period the heated 

 metal* ceased to act upon the fluid. To remedy this defect, 

 tiles and pieces of brick were introduced, upon the surfaces of 

 which the oil acted ; until, like the retort, they also were satu- 

 rated. On the removal of these, and introduction of fresh 

 masses, the process might be I'enewed and continued ad iiifi- 

 nitum. The respectability of the writers, though no proof of 

 the truth of their assertions, on most occasions, induces us to 

 believe their statements are correct. Yet I must confess, that 

 the resiUts mentioned are such as I never ha^'e oblamed. 



My retort is of cast-u'on, and I have regularly used it for 

 twelve months past without perceiving any inclination to act 

 otherwise than as at first. Anticipating the evil just alluded to, 

 I had a large brass plug ground into the top part of my retort, 

 wliich, when taken out, leaves an aperture sufficiently large for 

 the introduction of my hand. A short time ago 1 had this 

 plug removed, that I might satisfy myself of the truth of some 

 of ray statements ; and on bringing my hand out of the retort, 

 I found that it was scarcely soiled ; the bottom was quite clear 

 of all carbonaceous residue, and in every respect equal to one 

 just put dowTi. Thus dissipating the black residuum is a very 

 valuable improvement. The apparatus requires no tlissection 

 to clean it; the pipe through which the oil is uitroduced, and 

 which reaches nearly to the bottom, runs no risk of being 



• If, indeed, the metal may be considered in any other light than as an 

 agent in the transmission of heat. 



8 E 2 choked 



