On the tontinent ordinary alcohol is
cheaper than wood spirit, and hence
purchasers of the latter sometimes find
it more or less adulterated with the
former. To detect this fraud Riche and
Bardy heat the suspected sample with
sulphuric acic, dilute with water, and
distil. They then mix the distillate
with peroxide of manganese and sul
phuric ecid, thus converting theethylic
aicohol into aldehyde, and add a solu
tion of hyposulphite of soda, and finally
some magenta. If common alcohol is
present, eveu to the extent of one tenth
per cent, the magenta takes a violet
color. Chemical i.'eri'eir.
