122 PECKHAM — THE GENESIS OF BITUMENS. [April i, 



tors analyzed bitumens as if they were homogeneous substances. 

 They determined the carbon and hydrogen, added tlie percentages 

 together and subtracted the sum from one hundred, calling the 

 deficit oxygen. This went on for nearly fifty years. It is true that 

 Prof B. Silliman, Jr., fractionated petroleum by distillation, and 

 queried whether the liquids that he obtained were educt? or prod- 

 ucts. It was not until 1863 that Schorlemmer, in England, and 

 Pelouze and Cahours, in France, published researches that pro- 

 fessedly separated the compounds that were mixed together in 

 petroleum. They were soon followed by Warren and Storer in the 

 United States, who, by a superior method of condensation, suc- 

 ceeded in separating the hydrocarbons in coal-tar naphtha, naphtha 

 from Pennsylvania and Rangoon petroleum, naphtha from lime soap 

 of menhaden oil and also the hydrocarbons from oil of cumin. 

 These researches established the existence in these liquids of several 

 series gf hydrocarbons, the members of which were identical, 

 whether obtained from natural or artificial substances, and were also 

 in many cases recognized as identical with chemical compounds 

 already well known. ^ 



Since these results were published, a great amount of work has 

 been done with varying success upon a great variety of petroleums, 

 in which work progress has been observed along two lines, viz., 

 first, better methods of separation, and second, better methods of 

 ultimate analysis. It is only quite lately, however, that Prof, C. F. 

 Mabery has succeeded, by distilling in vacuo with Warren's hot 

 condenser, in so completely avoiding decomposition by cracking as 

 to reach results that are final. While this is said without any wish 

 to disparage the work of other investigators, it must be said with a 

 proper regard for truth." There is, however, a vast amount of 

 chemical research on record, a very complete resume of which can 



^ Theo. de Saussure, Ann. Chitn. et de Phys. (2), iv, 314-320. London Jour, 

 of Sci., iii, 411. B. Silliman, Jr., A?}i. Chemist, ii, 18. Moniteur Scientifiqiiey 

 No. 366. Am. Jour, of Gas Lighting, xvi, 83. Wagner's Ber., 1872, p, 848. 

 C. Shorlemmer, Chem. News, 1863, viii, 157; xi, 255. Am. Jour. Sci. (2)^ 

 xxxvi, 115. Rep. de Chim. Appliquee, 1863, p. 174. Jour, fur Phar., xxi, 320. 

 J. Pelouze and Aug. Cahours, Compies Rendus,\v\, 505 ; Ivii, 62, Ann. de Chim. 

 et de Phys. (4), i, 5. Am. Jour. Sci. (2), xxxvi, 412. C. J\I. Warren and F. H. 

 Storer, Mem. Am. Acad., n. s., ix, 121-176. Avi. Jottr. Sci. (2), xxxix, xl and 

 xli. Chetn. News, xii, 85, 261, et seq. 



2 C. F. Mabery, I^roc. Amer. Acad., n. s., xxiv; Amer. Chem. Jour. xix» 

 243. 374, 419- 



