106 PROCEEDINGS OP THE AMERICAN ACADEMY. 



points are not alkyl sulphides, mercaptans, thiophenes, nor ethylene sul- 

 phides. Their high specific gravity show that they belong to a new 

 series. The hydro-condition of the constituents of Pennsylvania, Ohio, 

 Canadian, Texas, and California petroleum corresponding to the series 

 C a H 2n , C„Ho n _ 2 , C„IIo n .-4, etc., has been described in former papers, and 

 the proportions of these series are indicated by the differences in specific 

 gravity. Canadian petroleum is composed for the most part of the series 

 of hydrocarbons poorer in hydrogen. Other constituents of petroleum 

 partake of a similar hydro-condition. The nitrogen compounds, for 

 example, in California petroleum, are tetrahydro- and octohydro-bodies, 

 with structure resembling the hydrochiuolines. 



Empirically the thiophanes are hydrothiophenes with long side chains, 

 methylene sulphides with numerous or long side chains, or simple ring 

 methylene sulphides. Either class of formulas will satisfy the results of 

 analysis. For example, 



The ready formation of sulphones, addition products with alkyl iodides, 

 and hydrates, is unlike the thiophenes, but the hydrothiophenes may behave 

 differently. It is improbable that rings with a very large number of car- 

 bon atoms can exist. A condensed ring structure like chinoline or nap- 

 tho chinoline with sulphur in place of nitrogen is exclude 1 by the series 

 C n H 2n . 



As shown above, the lowest member of the series separated from Cana- 

 dian petroleum was C H 12 S, boiling point 45°-50°, 50mm., which may be 

 hexamethylene sulphide, or methylpentamethylene sulphide. Higher 

 homologues may reasonably be considered as side chain derivatives : — - 



CH 3 

 / 

 CH 2 — CH 2 — CH 2X X CH 2 — CH 2x 



,S CH 2X ,S 



CH 2 — CH 2 — CH 2 CH 2 — CH 2 



Hexamethylene sulphide Methylpentamethylene sulphide 



