i879-j 
Proceedings of Societies. 387 
When the liquid is allowed to escape from the receiver into an 
open vessel it begins to boil, and in a few moments the temper- 
ature of the liquid is lowered by the ebullition below — 23 0 , the- 
boiling-point of the chloride. The liquid then remains for a 
length of time in a quiescent state, and may be used as a 
freezing agent. By increasing the rapidity of the evaporation by 
means of a current of air blown through the liquid, or better by 
placing the liquid in connexion with a good air-pump, the tem- 
perature of the liquid can in a few moments be reduced to — 55 0 , 
and large masses of mercury easily solidified. M. Vincent has 
recently constructed a freezing machine which will probably 
compete favourably with the ether and sulphurous acid freezing 
machines now in use, as it can be simply constructed, and as the 
vapour and liquid do not attack metal and are non-poisonous, the 
frigorific effects which it is capable of producing being moreover 
most energetic. The second and perhaps more important appli- 
cation of methyl chloride is to the manufacture of methylated 
colours. The application of methyl chloride to the preparation 
of violets and greens is not, however, due to M. Vincent. His 
merit is in establishing a cheap method by which perfectly pure 
chloride of methyl can be obtained, and thus rendering the pro- 
cesses of the manufacture of colours much more certain than 
they have been hitherto. Dr. Roscoe concluded his discourse 
by referring to this as another instance of the utilisation of waste 
chemical products and of the preparation on a large scale of 
compounds hitherto known only as chemical rarities. 
