104 Mr, Lardner Vanuxem on [Feb, 



such quantity of vapour as to make it brightly illuminating; and, 

 even the vapoiir of those portions which require temperatures 

 of 170°, 180°, or higher for their ebullition, is so dense as to be 

 fully sufficient for this purpose in small quantities. A taper was 

 burnt out in a jar of common air over water ; a portion of fluid 

 boiling at 190° was thrown up into it, and agitated ; the mixture 

 then burnt from a large aperture with the bright flame and 

 appearance of oil gas, though of course many times the quan- 

 tity that would have been required of oil gas for the same light 

 was consumed : at the same time there was no mixture of blue- 

 ness with the flame, whether it were large or small. Mr. Gordon 

 has I understand proposed using it in this manner. 



The fluid is also an excellent solvent of caoutchouc, surpass- 

 ing every other substance in this quahty. It has already been 

 applied to this purpose. 



It will answer all the purposes to which the essential oils are 

 applied as solvents, as in varnishes, &c. and in some cases 

 where volatility is required, when rectified it will far surpass 

 them. 



It is possible that, at some future time, when we better under- 

 stand the minute changes which take place during the decom- 

 position of oil, fat, and other substances by heat, and have more 

 command of the process, that this substance, among others, may 

 furnish the fuel for a lamp, which remaining a fluid at the pres- 

 sure of two or three atmospheres, but becoming a vapour at less 

 pressure, shall possess all the advantages of a gas lamp, without 

 involving the necessity of high pressure. 



Article VI. 



Experiments on Anthracite, Plumbago, S^c. By Lardner 

 Vanuxem.* (Communicated by the Author.) 



These experiments were undertaken with a view to deter- 

 mine whether the globules obtained by Prof. Silhman, from the 

 above substances, were owing to a fusion of their carbon, or 

 merely to the impurities or foreign matter contained within 

 them. They were long delayed by my waiting for some sheet 

 zinc necessary to repair a Deflagrator intended to be used for 

 the purpose of obtaining the globules ; but this not arriving, I 

 resolved to avail myself of the suggestion of Professor Silliman, 

 namely, that of using the compound blowpipe, which answered 

 perfectly well. In the experiments with the blowpipe, the sub- 

 stances were placed upon platina foil, spread upon a lump of 

 magnesia ; the size of the pieces subjected to its action was 



* FiomtheJournalof the Academy of Natural Sciences of Philodelpliia. 



