334 BOILING OF LIQUIDS IN GLASS VESSELS. 
the glass, and has not been separated by the action of strong 
acids and other substances repeatedly boiled in the vessel. 
[We have omitted the description of an apparatus of 
which a figure was attached, used by Mr. Redwood for his 
experiments in the distillation of balsam of copaiba, which 
consists of a flask with a U tube for a receiver, connected 
with the flask by a small tube. — Ed. Am, Jour. Pharm7\ 
The introduction of pieces of platinum wire or clippings 
into the flask or retort has been recommended for prevent- 
ing irregularity of ebullition in some liquids, especially in 
the distillation of oil of vitriol ; but I have not found this 
to be a complete remedy for the evil alluded to in any case, 
and in most cases it appears to be of no use. 
A French Chemist, M. Lambert, has proposed the em- 
ployment of fragments of a species of quartz (quarzitej 
which are to be introduced into the glass retort, in the dis- 
tillation of oil of vitriol. It is stated that the presence of a 
few angular pieces of this substance in the retort will render 
the distillation of several pounds of the acid quite manage- 
able and easy. I have not been able to ascertain with cer- 
tainty what mineral is referred to by the name ofguarzite, 
but I find that fragments of rock crystal produce the eflect 
indicated remarkably well. Pieces of rock crystal suitable 
for this purpose, consisting of the chippings formed in 
making spectacle-glasses, may be obtained at a lapidary's 
or optician's. In all cases of irregular ebullition in which I 
have tried the use of this substance, it has proved com- 
pletely successful. The effect of introducing five or six 
pieces of the rock crystal into a liquid, such as the mixture 
of balsam of copaiba and water, which cannot be distilled 
alone in a glass vessel, is most marked and satisfactory; the 
irregularity of ebullition instantly ceases, and the process 
may be continued for any length of lime without a return 
of the bumping. This is certainly the most simple and 
easy method of preventing the evil alluded to. 
