PROCESS FOR PURIFYING OILS AND GREASE. 297 
Allusion has already been made to the production of 
acetic acid in large amount by a modification in the above 
process. For this purpose the powdered bichromate and 
the sulphuric acid in the proportion of about 2 to 3, are to 
be first mixed in the retort so as to develope a large amount 
of free chromic acid. The alcohol is then introduced from 
the pipette as in the former case and with like precautions. 
During the violent action that ensues, much acetic acid 
passes over without the aid of external heat. When the 
alcohol thus added amounts to about twice the weight of 
the bichromate employed, the action having subsided, we 
apply a gentle lamp heat and obtain a large additional 
quantity of the acid. This we have found to be free from 
sulphurous acid and to contain little more than a trace of 
formic acid and aldehyde. 
American Journal of Science and Arts. 
ART. LXV.—NEW PROCESS OF REFINING AND PURIFYING 
ANIMAL AND VEGETABLE OILS AND GREASE. 
By Peter Bancroft. 
The nature of this invention consists in a process or pro- 
cesses of refining or purifying certain vegetable and animal 
oils, whereby they are better suited for lubricating the work- 
ing parts of machinery; also in a process of refining or puri- 
fying tallow, to improve its lubricating quality ; and likewise 
in a process of purifying and sweetening inferior descrip- 
tions of lard, and rendering them fit for human food, and 
applicable to all purposes for which the best Irish lard is 
now used. The vegetable oils which the patentee proposes 
to refine for the above purpose are, the common olive oils, 
