234 
MISCELLANY. 
potatoes ; the results which I obtained are those above alluded to, and 
I have also completely convinced myself of the correctness of the 
opinions of MM. Cahours and Dumas, who regard the fusel of potatoe 
brandy as analogous to alcohol and pyroxylic spirit. 
I will call this oil, on account of this analogy, amyloid and will only 
remark that it acts with finely divided platinum in the same manner as 
spirit of wine and pyroxylic spirit : thus, when it is put in contact with 
these liquids, in presence of atmospheric air or oxygen, it absorbs four 
atoms of this gas, and forms one atom of valerianic acid and three atoms 
of water. 
In a German vinegar manufactory, I remarked, some time ago, a 
very evident odor of valerianic acid, and I very soon discovered that, 
for the perparation of vinegar, potatoe brandy, which had not been 
disinfected, was used. It would certainly be interesting to ascertain 
whether, in the vinegar-mother liquors, there is not alcohol alone, but, 
also, potatoe oil or amylol, which might be oxygenised, and whether 
we might not find, in commerce, vinegars made from alcohol con- 
taining valerianic acid. It appears probable that pyroxylic spirit, 
diluted with much water, might be oxidised in these apparatus and 
converted into formic acid ; it is an experiment which I recommend to 
those who are in a position to make it. — London Chemist, 
New Method of delecting the Frescnce of Sugar in Diabetic Urine, By 
Dr. Cappezuoli. — This author does not use the blue solution adopted by 
Frommchers and Taddei (a compound of albumen, potash and oxide of 
copper), but a few grains of hydrated oxide of copper and a solution of 
caustic potash in sufficient quantity to render the liquid distinctly 
alkaline. The operation takes place at ordinary temperatures. The 
urine is obtained fresh, placed in a cylindrical vessel, either conical 
or straight, the copper and potash then added, the mixture shaken, 
and then laid aside. It becomes troubled from the precipitation of 
the phosphates which were dissolved in it, and from the oxide of 
copper which it contains in suspension. It gradually however be- 
comes clear, in consequence of the subsidence of a voluminous de- 
posit, which is at first of a sky-blue colour, but at the end of a few 
hours a canary-yellow circle is perceived to form upon its surface, 
and usually to pervade the whole mass ; subsequently a red colour, 
more or less deep, in the form of a zone, replaces the yellow, either 
wholly or in part. This phenomenon, which takes place in 24 hours, 
is owing to the reaction of the sugar on the oxide of copper. In 
fact, this base is gradually deprived of its oxygen until the metal is 
reduced. The sugar, by absorbing oxygen, is transformed princi- 
pally into formic acid, which combines with the potash. The reac- 
