PREPARATION OP FORMIC ACID. 
289 
ART. LXIV. — ON ANEW PROCESS FOR OBTAINING FORMIC 
ACID, AND ON THE PREPARATION OF ALDEHYDE AND 
ACETIC ACID BY THE USE OF THEpMCHROMATE OF POT- 
ASS A. By Professors W. B. Rogers and R, E. Rogers of the Uni- 
versity of Virginia. 
I. Process for Formic Acid. 
Since the important discovery of Dobereiner, that formic 
acid is evolved from a mixture of tartaric acid, peroxide of 
managanese and sulphurie acid, the progress of research 
has shown that in a large proportion of cases, where or- 
ganic matters are exposed to powerful oxidating agencies^ 
this acid is among the products developed ; and hence seve- 
ral other processes have been devised for its preparation, on 
the large scale and in the laboratory. Of these the one 
generally in use consists, as is well known, in distilling a 
mixture in prescribed proportions, of peroxide of manga- 
nese, dilute sulphuric acid and starch or sugar. 
The inconsiderable amount of acid yielded by this pro- 
cess, and its usually large admixture with other products, 
especially sulphurous acid, suggested to us, some time ago, 
the trial of bichromate of potassa, as a substitute for perox- 
ide of manganese, and has since led us to a method of 
operating, which we think presents decided advantages 
over that in general use. 
When bichromate of potassa, dilute sulphuric acid and 
sugar are mingled in proper proportions and in a proper 
order, a large amount of formic acid is developed, of 
which part passes off during the first violent reaction, and 
the remainder is separable by gentle distillation. Repeated 
experiments have convinced us that by mingling all the 
materials at once, before placing them in the retort, a com- 
paratively small product is obtained, partly from its being 
volatilized by the high temperature attending the reaction, 
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