202 METHOD OF PREPARING CHROMIC ACID, ETC. 
sulphuric acid, but from its sidphatic solution by water, 
then there must exist a proportion between the sulphuric 
acid and water in which chromic acid is not soluble; to find 
out this proportion, I made a series of experiments, the re- 
sult of which was that the amount of water of the sulphu- 
ric acid came very near to the formula S0 3 2HO. In fact, 
if we consider the solution of the chromic acid in monohy- 
drated sulphuric acid as constituted according to the formula 
S0 3 ,HO+a?Cr0 3 , then CrO 3 is separated on the addition of 
1 atom ot water. 
The author then proceeds to describe a combination of 
chromic acid with sulphuric acid, which is obtained when 
the former is gradually conveyed into the latter, and the 
mixture shaken for some time in a well-stoppered bottle for 
the complete solution of the chromic acid. After some time 
no more chromic acid dissolves, and the dark-brown fluid, 
at first of an oily consistence, acquires an ochreous colour, 
and a pasty consistence, and even becomes sometimes 
granular. Its analysis is difficult, from the avidity with 
which it imbibes moisture. From the results obtained, how- 
ever, it would appear to be composed according to the for- 
mula SO 3 HO + CrO 3 . 
In conclusion, the author observes that the solution of 
chromic acid in monohyd rated sulphuric acid is preferable 
as an oxidizing agent to every other; its action on sugar 
or alcohol is so complete and quick, that the former, when 
not added in too large a quantity, may be entirely burnt 
into carbonic acid and water ; while the alcohol, according 
to the quantity and degree of concentration, may be con- 
verted at pleasure either into aldehyde or acetic acid, a 
change which deserves mention as a very instructive class 
experiment, because the product of the reduction is imme- 
diately visible to the eye, and the product of oxidation 
readily detected by the organs of smell.— Chem. Gaz.,from 
Liebig's Annalen. 
