ing absolutely constant for more than half an hour, a constancy 
of boiling-point not exceeded by that of distilled water. This 
state of purity, I think I may safely assert, has never before 
been attained from such mixtures, by any system of fractional 
distillation. 
As I shall soon be prepared to present to the Academy de- 
tailed results of the investigations above referred to, I may omit 
further allusion to them on this occasion. : 
I would remark, in conclusion, that it seems to me not cath 
probable that this process may ultimately prove to be of grew 
value in the arts. It is not too much to anticipate that, — 
ever the various constituents of the mixtures referred to pe 
have been separately and thoroughly studied in a pure eer 
some of them may be found to possess properties which W . 
give to them great commercial value, sufficient to justify the ex 
penditure necessary to separate them in large quantities. 
