1872.] Mr. A. Liversidge on Supersaturated Saline Solutions, 499 



After waiting some time to be certain that nuclei had not gained admit- 

 tance, some of the alcohol was run out on to the surface of the solution by 

 momentarily loosening the stopper. 



This experiment was repeated many times, at different temperatures and 

 with alcohol of various strengths, but never did the alcohol act as a nucleus. 



Previous to the experiment the alcohol had been boiled to destroy nuclei. 



Exp. Concentrated sulphuric acid was substituted for the alcohol, but 

 likewise with no result. The smallest quantity of acid was added, so as to 

 prevent any undue rise in temperature, which would of course vitiate the 

 result. The flask was likewise kept cold by a stream of water. 



In a later form of these experiments, a small glass bulb with a long neck 

 blown from glass tubing, such as is used in the elementary analysis of a 

 fluid by combustion, was made use of. 



The bulb was first well heated in a Bunsen burner, so as to destroy any 

 nuclei which might adhere to it ; then, while still hot, the open end was 

 dipped into the alcohol or acid under trial, when, of course, as the air in the 

 bulb cooled some of the liquid was forced up into it ; its liquid contents 

 were then boiled and the open end again dipped into the fluid, and as the 

 vapour condensed more fluid was forced up into it. 



The tube was then surrounded by cotton-wool and inserted into the neck 

 of the flask, and the supersaturated solution boiled up for a moment, so as 

 to render the whole apparatus, cotton-wool included, inactive, the steam 

 escaping through the interstices of the cotton and not affecting the spirit. 

 When cold a drop of the spirit or acid was delivered by merely heating the 

 glass bulb. 



Exp. Trial was next made of several solid dehydrating substances, such 

 as calcic chloride, anhydrous chromic acid, phosphoric anhydride, freshly 

 ignited quicklime, &c. 



These bodies were placed in sealed thin glass bulbs and heated nearly to 

 redness and then dropped into the supersaturated solution ; the flasks were 

 plugged with cotton-wool, through which a glass rod passed, and boiled 

 up, after which they were allowed to cool for some hours ; when quite cold 

 the bulb was broken by means of the glass rod and its contents set free, 

 but, as in the case of the liquid, with no result. 



2o2 



