396 CYRUS MOORS WARREN. 



points, and the complete separation of them had been as good as im- 

 possible before the invention of Warren's method of fractioning. In 

 point of fact, the existence of the double series had caused no little 

 annoyance to chemists, in that they had been able to separate at one 

 time some of the members of one series, and at other times members 

 of the other series, with the result that much confusion prevailed. All 

 uncertainty as to this matter was done away with at once by the pub- 

 lication of Warren's memoir. His discovery was seen to be true the 

 moment attention was called to it. The causes of the previous con- 

 fusion became manifest, and many of the earlier statements which had 

 seemed to be conflicting were found to be fairly harmonious. He 

 found furthermore that the less volatile portion of petroleum, instead 

 of containing, as had been supposed, higher homologues of the bodies 

 just now referred to, is composed of hydrocarbons of another class, 

 C„H n + 2 ; and of these defines he separated three, boiling respect- 

 ively at 175°, 196°, and 216° C. The difference between the 

 boiling-points of contiguous members of this third series he found 

 to be about 20°, and not 30°, as in the other series. Fortunately, 

 an elaborate statement of these results will soon appear, for a com- 

 pleted memoir relating to them was found among Warren's papers 

 after his death. 



It is interesting to note the fact that the high degree of purity of the 

 products obtained by Warren compelled him to take special pains to 

 analyze them with particular accuracy. The ordinary methods of 

 ultimate organic analysis had seemed sufficient for the compara- 

 tively impure substances studied by his predecessors, — perhaps because 

 the errors due to the impurities known to be present were supposed to 

 be larger than those inherent to the processes of analysis. But the 

 inadequacy of the old methods was shown at once on attempting to 

 study pure hydrocarbons by means of them, and Warren was forced 

 to turn aside for a moment from his legitimate work in order to invent 

 new methods of combustion in oxygen gas, and subsequently to devise 

 a new method of determining the density of vapors. 



The years devoted by Warren to the study of the hydrocarbons were 

 the most fruitful of his scientific life. From 1863 to 1866, he had in 

 Boston a thoroughly well equipped private laboratory, in which he 

 gave himself up wholly to research. Eight papers were communicated 

 by him to the Academy at that time, and were published in its Memoirs 

 and Proceedings. Besides the discovery of new substances and the 

 better definition of others which were already known, these papers 

 describe novel and ingenious methods of his invention for the analysis 



