210 



Mr. C. Tomli-nson on 



[Mar. 13, 



olive, and sperm. I did not allow these oils once to enter my laboratory, 

 but kept them in my library, and never opened the phials except in the 

 open air. 



The flasks and dropping-tubes were washed in strong sulphuric acid, 

 and rinsed in tap-water, the tubes being kept immersed in clean water 

 in the open air. The solutions were filtered into the flasks, and these, 

 being covered with small beakers, were reboiled until steam issued from 

 the orifice. 



The flasks were then taken into my garden, and when cold an oil was 

 dropped upon the surface of each solution. If the oil formed a well- 

 shaped lens, there was no separation of salt ; and in many cases, instead 

 of restoring the small beaker to its place, a well-fitting cork was driven 

 into the neck, and the flasks were thus left for a time, on some occasions 

 extending to the next day. 



In order to avoid the objection that during the shaking crystallization 

 might be produced by some of the solution splashing against the cork, 

 many of these experiments were repeated in a pear-shaped flask, nearly 

 12 inches in height, and containing about 2 or 3 ounces of the solution. 

 Most of the experiments were tried in globular flasks of 5 ounces capacity, 

 with straight cylindrical necks 4 inches high. 



Experiment 1. Sodic sulphate — 1 salt, 1 water. Solution in tall flask 

 covered with a small beaker. Next day oil of sweet almonds was dropped 

 into it, and the flask corked. After about an hour a circular motion was 

 given to the flask, so as to disperse the oil into minute globules through 

 the solution, giving it the appearance of an emulsion. The flask was left 

 at rest during about an hour, then suddenly shaken, so as to rattle the 

 solution against the side, when all at once, as if with a flash, it became 

 solid. 



Now in this case it may be objected that a crystal of the sodic sulphate 

 hydrate was derived from one of the following sources : — (1) from the 

 air, (2) from the oil, (3) from the cork, or (4) from the' side of the flask. 

 (1) It could not be derived from the air, either of the laboratory or of 

 the garden, because the solution remained liquid long after the flask had 

 been corked. (2) It could not have been derived from the oil, because 

 this was dispersed through the solution in myriads of globules, without 

 any nuclear action, and the flask was left to repose for an hour after the 

 oil had been so dispersed. (3) Nor could any nucleus have been derived 

 from the cork, because the solution never touched it. Nor could a mi- 

 nute speck of the sodic sulphate hydrate have fallen from the cork ; for the 

 latter had been put into hot water, out of which it was taken the moment 

 it was put into the flask. It could not have been derived from any of 

 the hot water from the cork streaming down the side of the flask to the 

 solution, because sodic sulphate in solution is in the non-nuclear anhy- 

 drous state, and also because two hours had elapsed between the cork- 

 ing of the flask and the solidification of the solution. (4) A crystal could 



