+*3'' DR ANDERSON ON THE PRODUCTS OF THE 



brown by transmitted, and green, with the effect of opacity, by reflected light. 

 All these appearances, however, were very evanescent, and are only seen in the 

 newly distilled oil, for after a few days it becomes very dark coloured, and they 

 are then no longer visible. 



Both the more and the less volatile oils contain a variety of bases, and were 

 separately treated for their extraction. In neither, however, is the quantity 

 large. I obtained from the more volatile portion of three hundred pounds of 

 bone-oil less than two pounds of the mixed bases ; but as, in the course of the 

 various processes to which it Avas submitted, some small portions were lost, the 

 whole may perhaps amount to about three-fourths per cent, of the total quantity 

 of oil. The less volatile portion yields a larger quantity, which maybe estimated 

 at two or three per cent, of the crude oil. These, of course, are only rough esti- 

 mates, but they may serve to give an idea of the quantity of the products. 



Preparation of the Bases. 



For the preparation of the bases precisely the same processes were followed 

 throughout for both portions into which the oil was separated by distillation ; and 

 as the bases to be described in the present paper were contained in the more vo- 

 latile portion, I shall detail the steps followed in reference to that quantity only. 

 The oil was mixed in a cask with sulphuric acid diluted with about ten times its 

 weight of water, and the fluids left in contact for a week or two, diiring which 

 time they were frequently agitated. More water was then added, and the whole 

 drawn off, and the process repeated with fresh quantities of sulphuric acid as long 

 as any bases were extracted. The solution, which had a reddish and sometimes 

 very dark brown colour, contained the bases, along with a quantity of nonbasic 

 oil and of pyrrol. It was mixed with an additional quantity of sulphuric acid, 

 introduced into a glass distilling apparatus, and heat applied. As the fluid ap- 

 proached the boiling point, a quantity of the red resinous matter before alluded 

 to began to separate, and occasioned succussions of so violent a character as to 

 endanger the safety of the vessel, and render it necessary to interrupt the process 

 for the purpose of filtering it off, after which the distillation proceeded without 

 difficulty. A small quantity of oil distilled over, and the water which accompa- 

 nied it had exactly the smell of the water in a gas-meter, and contained pyrrol,* 

 which continued to pass over for a long time, during the whole of which the dis- 

 tillation M^as continued. This distillation I had recourse to at first, from a sus- 

 picion that some of the bases were separated from the acid, and volatilised during 

 the process ; but so soon as I had ascertained that this was not the case it was 



* These odours were so exactly alike, tliat I was induced to seek for pyrrol in the water of gas- 

 meters, and I foimd that when mixed with sulphuric acid and distilled, the product gave the cha- 

 racteristic reaction of pyrrol with fir-wood. Ammonia remained in combination with the sulphuric 

 acid. 



