160 Dr Anderson on the Properties of PicoUne. 



completely in the watery fluid contained in the receiver. As 

 the distillation proceeded, another oil made its appearance, 

 which collected in a layer on the surface of the fluid which 

 had previously distilled. When about three-fourths of the 

 oil had passed over, the process was stopped, by which means 

 the oil, destitute of basic properties, which requires a very 

 high temperature for its distillation, was left behind in the 

 retort. The fluid in the receiver was now supersaturated 

 with sulphuric acid diluted with water, care being taken to 

 obtain a powerfully acid reaction. The peculiar odour which 

 the fluid possessed, was by this process entirely changed, but 

 not destroyed ; and, on distillation, the water which passed 

 over, carried with it all the pyrrol contained in the solution, 

 while the other bases were retained by the sulphuric acid. 

 Caustic potass was then added to the residue in the retort 

 until an alkaline reaction was manifest, and it was again 

 distilled ; the water which passed over carried with it the 

 oily bases, partly dissolved, partly floating on the surface of 

 the solution, exactly as in the first distillation. A few sticks 

 of fused potass were introduced into the product, and the 

 whole was left in repose ; as the potass dissolved, the oil, 

 which is entirely insoluble in solutions of the fixed alkalis, 

 rose to the surface and there collected in the form of a pale 

 yellow layer, still containing a considerable quantity of water, 

 which may amount to 30 or 40 per cent, of the bulk of the 

 oil. The oil was separated from the watery fluid by means 

 of a pipette and pieces of fused potass added so long as they 

 continued to become moist. The dry oil was then introduced 

 into a retort and distilled. A transparent and colourless oil 

 passed over, which was tested at intervals by allowing a drop 

 of it to fall into a solution of chloride of lime. So soon as 

 the reaction of aniline made its appearance the receiver was 

 changed. The first portion was now picoline in a state ap- 

 proaching to purity ; that which immediately followed con- 

 sisted of a mixture of picoline and aniline. The first portion 

 was again digested with fused potass and rectified; that 

 which distilled at 273° was collected apart, and constituted 

 pure picoline. 



