^826.] of Carbon and Hydrogen, S^c. 99 



seems to be from this body downwards, to compounds reauirino- 

 250° or 300° for their ebullition. ^ ^ ^ 



In reference to these more volatile products, I may state that 

 I have frequently observed a substance come over in small quan- 

 tity, rismg with the vajaour which boils off at 50° or 60° and 

 crystallizing in spiculse in the receiver at 0°. A temperature of 

 » or 10 causes its fusion and disappearance. It is doubtless a 

 peculiar and definite body, but the quantity is extremely small, 

 or else it is very soluble in the accompanying fluids. I have not 

 yet been able to separate it, or examine it minutely. 



I ventured some time since upon the condensation of various 

 gases,* to suggest the possibihty of forming a vapour lamp 

 which containing a brilliantly combustible substance, liquid at 

 a pressure of two, three, or four atmospheres at common tem- 

 peratures, but a vapour at less pressure, should furnish a con- 

 stant light for a length of time, without requiring high, or involv- 

 ing inconstant pressure. Such a lamp I have now formed, feed- 

 ing It with the substance just described ; and though at present 

 It IS only a matter of curiosity, and perhaps may continue so, 

 yet there is a possibihty that processes may be devised, by 

 which the substance may be formed in larger quantity, and 

 render an apphcation of this kind practically useful. 



On the remaining Portions of the condensed Oil Gas Liquor. 



It has been before mentioned, that by repeated distillations 

 various products were obtained, boiling within limits of temper- 

 ature which did not vary much ; and which when distilled were 

 not resolved nito other portions, differing far from each other in 

 volatihty, as always happened in the earlier distillations. Though 

 conscious that these were mixtures, perhaps of unknown bodies 

 and certainly in unknown proportions ; yet experiments were 

 made on their composition by passing them over oxide of copper, 

 in hopes of results which might assist in suggesting correct 

 views of their nature. They all appeared to be binary compounds 

 of carbon and hydrogen, and the following table exhibits the 

 proportions obtained : the first column expressing the boilino- 

 temperature at which the products were distilled, as before men- 

 tioned ; the second the hydrogen, made a constant quantity ; 

 and the third the carbon. ^ ^ 



140° I 7-58 



150 ] 8-38 



160 1 7-90 



176 I 8-25 



190 I 8-76 



200 1 9-17 



210 1 8-91 



220 1 8-46 



" Quarterly Journal of Science, xvL 240. 

 H2 



