MABERY AND QUAYLE. — CANADIAN PETROLEUM. 107 



The structure of these bodies will doubtless have to be referred to the 

 methylene ring, yet the precise form of the ring with reference to the 

 number of carbon atoms it contains is still uncertain. For instance, 

 the central group may be a penta-, hexa-, or hepta-methylene ring. It 

 has therefore seemed advisable to adopt a comprehensive name that 

 shall include any possible arrangement, and the term thiophane has been 

 adopted. Without doubt, the structure of these sulphur derivatives will 

 be defined with greater precision when the structure of the hydrocarbons 

 of the series C n H 2n , C n H 2n _ 2 , C n H 2n _ 4 , etc., which constitute the greater 

 part of the constituents of petroleum with high boiling points from any 

 source, are better understood. 



Unsaturated Hydrocarbons op the Series C n H 2n . • 



The need of more accurate information concerning the presence of hy- 

 drocarbons of the ethylene series C n H 2n in petroleum was explained in a 

 former paper of this series. Notwithstanding persistent attempts in the 

 numerous treatises on petroleum to show that these bodies have been 

 identified, a critical examination of published results fails to reveal ade- 

 quate proof of sufficient foundation for these statements. The statement 

 in " Petroleum and its Products," by Redwood, that De la Rue and Muel- 

 ler proved the presence in preponderating quantities of the ethylene 

 group in Rangoon petroleum is not supported by the results nor by the 

 conclusions of those authors. Concerning the results of Warren, Schor- 

 lemmer, and Chandler, it is not true as asserted by Redwood that those 

 chemists found the ethylene series in Pennsylvania petroleum. There 

 are no allusions to this series in Schorlemmer's published papers. 



Beyond adopting the general nomenclature then accepted for the ethy- 

 lene series, Warren evidently left it an open question as to what should 

 be the structural formulae of the products he separated from Pennsyl- 

 vania petroleum. There are no statements in his papers to show that he 

 made any further preparation of his products for analysis than boiling 

 with sodium, and no further examination to prove structural forms. Cer- 

 tainly it would have been easy to demonstrate the unsaturated condition 

 of those bodies had they contained double bonded carbon, and in view of 

 Warren's clear-sighted and painstaking methods, he could not have over- 

 looked the importance of those tests. In none of his papers on Pennsyl- 

 vania petroleum does the term olefine or ethylene appear. 



The assertion of Hoefer that members of the olefine series, C 2 H 4 to 

 C 30 H 60 have been found in American petroleum has no foundation. In 



