MABERY. — SULPHUR PETROLEUMS. 17 



The quantities of bromine absorbed by distillates from the crude 

 sulphur oil were also determined : — 



Fraction. Percentage of Bromine absorbed. 



110°-150° 0.73 



150°-220° 1.74 



220°-257° 4.84 



257°-300° 5.04 



300°-330° 12.10 



Residue 19.50 



Throughout this investigation some reliance has been placed on the 

 absorptive capacity for bromine of crude oils and distillates obtained 

 from them as indicating a certain unsaturated condition. While it 

 should be borne in mind that a considerable proportion of the bromine 

 absorption is due to the sulphur constituents, there is besides a large 

 absorption in the crude oils and in the residues of distillation above 

 350^ by other constituents. There is much yet to be learned concern- 

 ing the decompositions in distillations at high temperatures, which are 

 indicated by the greatly increased bromine absorption, and the study 

 of the higher boiling portions will be greatly facilitated by the aid of 

 the Mahlke thermometers for observing temperatures below 550°. 



The characteristic qualities of Ohio oil appear also in the propor- 

 tions that distil at different temperatures ; 800 grams of the crude oil 

 collected in the following proportions beginning at 110° : — 



The distillates below 225° were colorless, and no odors resulting 

 from decomposition were observed. Above this point color appeared 

 in the distillates, with the odor of decomposition, which became more 

 marked with increasing temperatures. Above 275° the heavier 

 paraffine oils began to distil. In refinery distillation of Ohio petro- 

 leum it is therefore evident that cracking begins in the vicinity of 

 250°. No doubt crude sulphur petroleums undergo decomposition 

 spontaneously to some extent, since upon standing they always con- 

 tain hydric sulphide. We find that certain unstable constituents 

 separated from the crude oils gradually become darker in color, with 

 other indications of chemical change. At the beginning of the distil- 



VOL. XXXI. (n. S. XXIII.) 2 



