400 CYRUS MOORS WARREN. 



parallel series of hydrocarbons in the more volatile part of Pennsyl- 

 vanian petroleum, because he had opportunity to operate upon mate- 

 rials which had never been subjected to any treatment with chemicals. 

 His competitors, working upon commercial products which had been 

 " purified " by agitation with oil of vitriol, were at a manifest disad- 

 vantage. There are published results of such investigations, which go 

 to show that a large part of the members of one of the series had 

 actually been removed in some way from the petroleum before it was 

 subjected to scientific examination. 



In the course of time, when their contracts for coal-tar had lapsed, 

 and competition between the distillers of tar became sharp, the War- 

 rens paid less attention than they had formerly done to this branch 

 of their business, and turned their energies more particularly to the 

 asphaltum of Trinidad, aud to the rectification of this substance by a 

 process which consists essentially in driving off some thirty per cent of 

 water, which is entangled in the crude pitch as taken from the lake, 

 and removing some other mechanical impurities by processes of set- 

 tling or skimming. The product thus obtained, and known as refined 

 asphalt, is used for electrical purposes, as well as for paving and for 

 roofing. For some uses the purified asphalt is mixed with a certain 

 proportion of petroleum residues that are left in the stills when crude 

 petroleum is rectified. 



In the carrying out of these changes Cyrus Warren took a lively 

 interest and gave valuable aid. But it was characteristic of the man 

 that during all the long period of business strain his mind was full of 

 scientific interests and ideas. It is greatly to be regretted that the 

 results of these cogitations and of the experiments made from time to 

 time during this period have never been published. Warren himself 

 felt that several of them should be made known to the world, and he 

 fully intended in his last years to present to the Academy one or 

 more papers relating to these matters. He never ceased to lament 

 that the exigencies of business, in which he had become inextricably 

 entangled, kept him from entire devotion to scientific pursuits. But 

 perhaps the keenest of his regrets was felt when, after he was finally 

 disabled, his physician forbade him to enter his laboratory to do a last 

 work for science in gathering from his note-books and connecting the 

 fragments of the more important labors which had been performed 

 during the intervals of his business activity. 



One of his ideas was to make a systematic scientific analysis of that 

 portion of the heavier products of coal-tar which is known as anthra- 

 cene oil. Anthracene itself is obtained from this grease by pressing 



