40 



SCIENCE 



[N. S. Vol. XXXVIII. No. 967 



to 15.21° for a tube length of 200 mm. It 

 is, however, very unfortunate that we have 

 no information as to the source of this very 

 remarkable sample. 



Nearly fifty years later, in connection 

 with their researches upon the petroleum 

 of the Caucasus,* Markownikow and 

 Ogloblin examined the natural "white 

 naphtha" as well as some petroleum distil- 

 lates, and, finding these samples inactive, 

 they did not continue this subject any 

 farther. In 1885, however, Demski and 

 Morawski" examined some of the more im- 

 portant mineral oils of commerce, among 

 which one rotated the plane of polarization 

 1.2° to the right. In 1898, Soltsien" found 

 that the commercial paraffin oils are dex- 

 trorotatory, and that the amount of rota- 

 tion increases with their specific gravity. 

 Since that time general interest has been 

 awakened in this subject and petroleums 

 from all parts of the world have been ex- 

 amined polarimetrically. In general, it 

 has been found that the lightest and least 

 colored oils (including the so-called white 

 naphthas) manifest little or no optical ac- 

 tivity, while the heavier, dark and viscous 

 oils yield active products.'' 



In a typical Kansas oil, examined in con- 

 nection with the work of the University 

 Geological Survey, slight optical activity 

 was detected in the upper kerosene fraction 

 which distilled between 250° and 300° 

 under ordinary atmospheric pressure. The 

 higher boiling portions of this oil after 

 fractional distillation under diminished 

 pressure were dextrorotatory, the amount 

 of rotation gradually increasing with the 

 rise in boiling point until, in the neighbor- 



* Annales de cMm. et de phys. (6), t. II., 387, 

 1884. 



^ Dingier 's Polytech. Jr., 258: 82, 1885. 



" Chemisohes Centralhlatt, I.-, 869; II., 455, 1898. 



' Zaloziecki and Klarfeld, Chemiker ZeiUmg, 

 1170, 1907. 



hood of 280° at 27 mm., it reached almost 

 one degree of arc.^ 



In some oils a maximum activity has been 

 observed in the vacuum distillates collected 

 at about 275°, and in the case of a German 

 oil a second maximum was reached at a 

 temperature of 310°. Javanese petroleum 

 yields vacuum fractions boiling about ISO- 

 ISO" which are la?vo rotatory, but the 

 higher boiling fractions are dextrorota- 

 tory." A sample of petroleum from Borneo 

 yielded a distillate collected between 260° 

 and 340° under atmospheric pressure which 

 was liEvo rotatory." A Isvorotatory activ- 

 ity has also been reported in an oil from 

 Argentine Republic. ^^ 



But the fractions obtained in the distil- 

 lation of petroleum do not represent dis- 

 tinct chemical individuals, but consist of 

 more or less complex mixtures. Hence it is 

 necessary for us to make use of other proc- 

 esses before we can isolate the optically ac- 

 tive constituents. The fact that the distil- 

 lation products of petroleum have found 

 such a ready market without the necessity 

 of chemically transforming them has, no 

 doubt, greatly hindered the development 

 of chemical methods for their utilization. 

 But in recent years competition in the re- 

 fining of illuminating oils is beginning to 

 force the refiners to look to the utilization 

 of their waste products. In Russian re- 

 fineries the alkaline sludges are now treated 

 so as to recover the so-called naphthenic 

 acids which find a ready market for the 

 manufacture of cheap soaps. 



The fact that the naphthenic acids de- 

 rived from kerosene show greater optical 



' Univer. Geol. Survey of Kansas, Vol. IX., p. 

 317, 190S. 



° ' ' Die neueren Ansichten iiber die Entstehung 

 des Erdols," C. Engler, Berlin, p. 55, 1907. 



"Jones and Wootton, Jr. Cliem. Soc, 91: 1146, 

 1907. 



"Longobardi, "Petroleum," VI., 552, 1911. 

 Jr. Suss. Phys.-Cliem. Soc, 43: 792, 1911. 



