38 THE ROYAL SOCIETY OF CANADA 



the rubber was evaporated on a water bath, the rubber dissolved 

 in carbon tetra chloride and filtered through glass wool, and the 

 solution poured slowly with stirring into approximately twice its 

 volume of methyl alcohol. The rubber precipitated as a white 

 gummy mass. This was warmed in a steam oven for an hour to 

 drive ofï the excess of solvents and the remainder, drawn olï under 

 suction. 



7^ grams of rubber dissolved in 150 c.c. carbon tetrachloride, 

 11 .62 g. powdered potassium permanganate, and 150 c.c. water were 

 placed in a 500 c.c. glass stoppered bottle and shaken for five days 

 at room temperature. At the end of this time the permanganate 

 colour had disappeared. The contents of the bottle was then 

 filtered on a large Buchner funnel. The water and carbon tetra- 

 chloride in the filtrate was separated in a separating funnel. The 

 carbon tetrachloride sol-ution was concentrated to half its bulk under 

 suction and at a temperature not exceeding 45°. 



The clear colourless solution was poured into twice its volume of 

 pure methyl alcohol in an erlenmeyer flask. Here it was washed by 

 décantation with acetone, ethyl alcohol and methyl alcohol. The 

 white pasty mass was then freed from solvent by a high vacuum in 

 the cold. Samples of this were analysed, giving the following results: 



Analyses (1) 

 Substance H2O COo %C %H %0 



Although the greatest care was taken to exclude free oxygen in 

 the drying of this product and in removing the last traces of solvent, 

 yet for certainty the preparation and purification was carried out 

 twice again. The additional precaution was taken of dissolving the 

 preparation finally in petroleum ether (B.P. 31-42) and evaporating 

 the solvent in a high vacuum in the cold, in this way assisting in the 

 removal of any traces of methyl alcohol which was the washing liquid 

 used just prior to solution in the petroleum ether. This solution in 

 petroleum ether and evaporation was repeated. In this way it was 

 reasonably certain that every trace of oxygen holding solvent was 

 removed. In the second repetition this was also done, using benzol 



