88 
MISCELLANY. 
employed for the ordinary purposes of painting, no difference can be de- 
tected between it and the purest carmine ; by means of the microscope, it 
can be discovered that half of it is composed of wheat starch, which, inti- 
mately commingled with the minutely divided carmine, gives to it a bril- 
liancy, and considerably increases the clearness of its color. When this 
article is diffused through a large quantity of water, it remains for a long 
time suspended, and finally produces a deposit, similar in appearance to 
white lead, but readily distinguished from it, simply by its specific 
Weight, which is less. This sediment is nothing else than amidon, for 
it is rendered gelatinous by boiling water, and is colored blue by iodine. 
It may be interesting to artists to know that some colors of this kind, 
mixed with organic substances, although generally pretty permanent, are, 
nevertheless, subject to decomposition in a humid atmosphere, and that 
amidon, in consequence of its transparency, covers a less surface than 
white lead. Lon, Phil, Mag,, and Journ. de Pharm, 
Action of Nitroxanthic Mid upon the solution of Opium, by M. Muller. — 
Nitroxanthic acid, formed, as is known, by the action of nitric acid upon 
indigo, exhibits a characteristic reaction with the solution of opium. It 
instantaneously occasions, in these solutions, even when diluted, a cana- 
ry-yellow precipitate, while the liquid becomes colored wine-red. The 
precipitate collected upon a filter, has a reddish-yellow color, and an ex- 
tremely unctuous consistence ; it is soluble in alcohol and many of the 
essential oils, and partly in ether, the acids, and alkalies. 
This substance appears to be a combination of bitter of Welter, (carb- 
azotic or picric acid,) with the balsam of opium, and it may be named 
myroxanthe, (yellow balsam,) or picroxanthe, (yellow bitter. ) 
The nitroxanthic acid, in consequence of this reaction, may serve as a 
re-agent for opium, because it produces a precipitate with solutions of 
opium, even the most dilute, and because the unctuous substance deve- 
lopes the characteristic odor of opium when heated, even when the quan- 
tity is very small. Journ. de Pharm. 
