] 866.] derived from Coal-tar, 



135 



of non-oxidized hydrocarbons, containing a small quantity of an oxygen- 

 compound. The solution of the sodium-salt was evaporated on the water- 

 bath, the residue distilled with diluted sulphuric acid, and the distillate 

 rectified. It smelt strongly of acetic acid, and also slightly of butyric acid. 

 By neutralization with carbonate of sodium, a crop of crystals of acetate of 

 sodium was obtained, which were converted into the crystallized silver- 

 salt. 



- 1 335 of this salt gave 0-86 1 of silver. 



Calculated for Found. 

 CaHgAgOs. 



64*67 per cent. Ag. 64*50 per cent. Ag. 



The syrupy mother-liquor of the sodium-salt gave, with nitrate of 

 silver, a white precipitate, which, on boiling the hquid, decomposed with 

 effervescence and separation of metallic silver, showing the presence of 

 formic acid ; from the filtered liquid small warty crystals of a silver-salt 

 separated. 



0*1314 of this salt gave 0*842 of silver, or 64*1 per cent. Ag. 



The mother-liquor gave on evaporation again crystals of acetate of silver. 



0*2196 gave 0*1418 silver, or 64*56 per cent. 



The volatile acids produced by the oxidation of the hydrocarbons are 

 therefore carbonic acid, acetic acid, formic acid, and perhaps a trace of an 

 acid richer in carbon. 



The resinous substance left in the retort is an acid which dissolves in 

 caustic potash, and is precipitated from this solution as a brown greasy 

 substance, easily soluble in alcohol. The alcoholic solution, neutralized 

 with ammonia, gave, with nitrate of silver, a white flocculent precipitate of 

 a silver-salt, which dried into a brown resinous mass, not fit for analysis. 



As these hydrocarbons were obtained by the action of sulphuric acid on 

 coal-tar oils boiling below 120°, and as they differ by C2 H^, it appears to 

 me almost certain that they are polymers of the hydrocarbons of the 

 acetylene series, Cn^2n-2i formed in the same way as diamylene is 

 formed, by treating amylene with sulphuric acid. The products of oxida- 

 tion are also in accordance with this view. 



In order to test this theory, I have made some experiments with the 

 two isomers Cg 11^^, namely, diallyl and hexoylene. By acting with sul- 

 phuric acid on these compounds, I obtained, besides large quantities of 

 tarry matter, polymeric modifications boiling above 200°, having a smell 

 similar to the hydrocarbons described above, giving also similar nitro- 

 compounds ; but the quantities which I got were not large enough for a 

 more exact examination. 



The sulphuric acid which was used to purify the coal-tar oils contains 

 an organic substance in solution, which can be isolated by neutralizing the 

 acid liquid with carbonate of calcium, filtering, evaporating to dryness in 

 the water-bath, extracting the residue with alcohol, and evaporating the 

 alcoholic solution. It forms a yellow amorphous mass, which has a faint. 



