To determine what products might be obtained in the oil, a portion of it was submitted to fractional distillation.[82] The temperature of the fluid was constantly regulated by a thermometer, the heat being applied first by a water bath, and then by a bath of linseed oil. This experiment was founded upon the belief that the crude product contained several distinct oils, having different boiling points. The quantity of material used in this experiment was 304 grammes. The thermometer indicated the degrees of the Centigrade scale, but, for convenience, the corresponding degrees of Fahrenheit’s scale are added. The water bath failed to distil any portion of the oil at 100° C. (= 212° F.), only a small quantity of acid water came over. An oil bath, linseed oil, was then substituted, and the temperature was regularly raised by slow degrees until distillation commenced. From that point the heat was successively raised by stages of ten degrees, allowing full time at each stage for complete distillation of all that would rise at that temperature before advancing to the next stage. The results of this tedious process are given in the annexed table—304 grammes of crude oil, submitted to fractional distillation, gave TEMPERATURE QUANTITY 1st Prod. at 100° C. = 213° F.(acid water) 5 gms. 2nd Prod. at 140° C. to 150° C.= 284° to 302° F. 26 gms. 3rd Prod. at 150° C. to 160° C.= 302° to 320° F. 29 gms. 4th Prod. at 160° C. to 170° C.= 320° to 388° F. 38 gms. 5th Prod. at 170° C. to 180° C.= 338° to 367° F. 17 gms. 6th Prod. at 180° C. to 200° C.= 356° to 392° F. 16 gms. 7th Prod. at 200° C. to 220° C.= 392° to 428° F. 17 gms. 8th Prod. at 220° C. to 270° C.= 428° to 518° F. 12 gms. Whole quantity distilled by this method 160 gms. ——— Leaving residue in the retort 144 gms. ——— Original quantity 304 gms. _Product No. 1_, as above remarked, was almost entirely water, with a few drops of colourless oil, having an odour similar to the original fluid, but less intense. _Product No. 2_ was an oil perfectly colourless, very thin and limpid, and having an exceedingly persistent odour, similar to the crude oil, but less intense. _Product No. 3_ was tinged slightly yellow, perfectly transparent, and apparently as limpid as the second product, with the same odour. _Product No. 4_ was more decidedly yellowish than the last, but was in no other respect distinguishable from it. _Product No. 5_ was more highly coloured, thicker in consistence, and had a decided empyreumatic odour.