292 PREPARATION OF ALDEHYDE AND ACETIC ACID. 
II. On the preparation of Aldehyde and Acetic Acid by 
the use of the Bichromate of Potassa. 
In the process described by Liebig,(Chem. Org., p. 378,) 
and which is the one hitherto generally used for preparing 
aldehyde in the regular way, the product is obtained from 
the reaction of peroxide of manganese and sulphuric acid 
upon dilute alcohol. This operation furnishes a liquid 
which is so weak in aldehyde, and so mixed with water 
and formic ethers, and as we have found with acetic acid 
also, as to present the characteristic reactions only in a 
feeble degree, and to require two rectifications over chloride 
of calcium, before it can be used in forming the subacety- 
lite or aldehydite of ammonia. 
In the course of some experiments upon the reactions of 
bichromate of potassa and sulphuric acid upon alcohol, we 
have been led to a process which affords a larger and much 
purer product, and which is entirely under the control of 
the operator. The distinctive features of this method are 
the substitution of bichromate of potassa for the peroxide 
of manganese, and the peculiar mode of bringing the react- 
ing materials together. In the use of the bichromate we 
have since found that we were anticipated by Prof. Kane., 
who, at page 922 of his Elements of Chemistry, recom- 
mends it as a means of obtaining a purer product, and spe- 
cifies briefly the manner in which he conducted the process. 
As however his method is not noticed in other chemical 
works, and as our mode of proceeding and some of the 
results we have obtained, are, we think, not without 
novelty and interest, we deem them worthy of a brief notice 
in your Journal. 
When alcohol is added to a strong aqueous solution of 
chromic acid in a retort, a very brisk reaction ensues, and 
upon applying a gentle heat there passes over a clear 
liquid, containing a considerable amount of aldehyde, with 
a faint trace of acetic and probably formic acids. The 
