18 Profs. W. B. and R. E.. Rogers on the 
Arr. Il.—On a new process for obtaining Formic Acid, and on 
the preparation of Aldehyde and Acetic Acid by the use of the 
Bichromaie of Potassa ; by Profs. W. B. Rogers and R. E. 
Rocers of the University of Virginia. .. 
e! Process for Formic Acid. 
Since the important discovery of Débereiner, that foekiaie acid 
is evolved from a mixture of tartaric acid, peroxide of manganese 
and sulphuric acid, the progress of research has shown that ina 
large proportion of cases, where organic matters are exposed to 
powerful oxidating agencies, this acid is among the products 
developed; and hence several 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 dis- 
tilling a mixture in prescribed proportions, of peroxide . — 
nese, dilute sulphuric acid and starch or sugar. 
: The inconsiderable amount of acid yielded by this’ prookill, and 
its usually large admixture with other products, especially sul- 
phurous acid, suggested to us, some time ago, the trial of bi- 
chromate of potassa, as a substitute for peroxide of manganese, 
and has since led us to a method of operating, Semeased we pared 
presents decided advantages over that im general use. 
When bichromate of potassa, dilute. sulphuric ent and sugar 
are mingled in proper proportions and in a proper order, a rai 
amount of formic acid is developed, of which part passe 
during the first violent reaction, and the remainder is sieht 
by gentle distillation. Repeated experiments have convinced us 
that by mingling all the materials at once, before placing them in 
the retort, a-comparatively small product is obtained, partly from 
its being volatalized by the high temperature attending the re- 
action, and partly, we think, because more of the sugar is carried 
to its highest stage of oxidation in the forms of carbonic acid and_ 
water. We have therefore been led to another, and we believe, 
= 
' better mode of operating, of which the following details will 
serve as an example. 
Introducing into a retort, capable of holding about one quart, 
800 grains of bichromate of potassa and 10 cubic inches of water, 
we gently heat the mixture so as to dissolve the larger part of the 
bichromate. We then add 300 grains of powdered white sugar, 
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oe uate 
Sige ge ae 
