OF ARTS AND SCIENCES. 221 



iuterruption to continuous distillation than at atmospheric pressure. 

 From 1,000 grams of the oil at the end of the sixth distillation, with 

 a tension of 150 mm., the following weights were obtained : — 



Temperatures 105-110° 110-115° 115-120° 120-125° 125-130° 130-135° 

 Grams ... 31 30 83 47.5 59 66 



Temperatures 135-140° 140-145° 145-150° 150-155° 155-160° +100° 

 Grams ... 69 56.5 75 36 40.5 230 



Total 921.5 



At the end of the twenty-second distillation, with the tension re- 

 duced to 100 mm., the products collected to a large extent within 

 well defined limits of temperature and several determinations of 

 sulphur gave the following results: — 



Fraction .... -76° 80-90° 98-101° 13-5-145° 148-155° 185-200° 

 Per cent sulphur . . 2.60 7.34 18.23 15.52 16.44 14.21 



All fractions containing sulphur gave precipitates with alcoholic 

 and with aqueous mercuric chloride, which were either crystalline, 

 or, with the less volatile products, thick viscous oils. The latter 

 usually became solid on standing, or when crystallized from benzol. 

 As a qualitative test for sulphur, we depended upon the exceedingly 

 delicate nitro-prussid reaction, which was especially serviceable in 

 separating sulphur oils from those containing no sulphur. The 

 platinum compounds RjSPtCl^ were readily formed with chlor- 

 platinic acid with evolution of hydrochloric acid. With bromine all 

 fractions united with great energy with the formation of oils heavier 

 than water. These reactions suggested the presence of sulphides, or 

 with sulphur free oils the reaction with bromine indicated unsaturated 

 hydrocarbons. 



"When distilled at temperatures above 140° atmospheric pressure, 

 the oils became thick and dark in color, and hydric sulphide was 

 freely evolved. Since at lower temperatures the decomposition was 

 slight, the fractional separation of the products collected below 101° 

 (P = 100 mm., see above) was carried further. The products thus 

 collected below 125° united readily with concentrated hydrobromic 

 acid when heated, forming oils heavier than water. The fraction 

 80 — 90° was nearly all converted into the heavy addition product, 

 and the fraction 90—100° separated into two products, one heavier 



