198 Miscellanies. 
presence and estimating the quantity of arsenic in phosphorus is as fol- 
lows: burn an ounce of phosphorus in six or seven successive portions in 
a porcelain capsule, in the middle of a large plate, and covered with a 
large glass receiver, phosphoric and arsenious acids are formed—the com- 
bustion terminated, allow the apparatus to cool; wash, and collect the 
washings; separate the oxide of phosphorus by a filter, and precipitate 
the arsenic by hydrosulphuric acid. 
The following are the effects of ordinary water upon phosphorus. 
When perfectly pure, it does not become colored except under the influ- 
ence of light. Its purity does not prevent its being covered by degrees 
with a white opake coating without any brown or yellow shade; this coat- 
ing has been considered by Pelouse the hydrate of phosphorus. Dupas- 
quier has found it to contain traces of lime. In distilled water, and free 
from the contact of light, it is preserved without losing its transparency 
or whiteness; it is understood that the water must contain no air. Phos- 
phorus plunged in water at the ordinary temperature decomposes it, with 
the formation of phosphoric acid and phosphuretted hydrogen; this de- 
composition takes place more rapidly under the direct action of the light 
of the sun, but it happens even in complete obscurity. 
Drayton’s Method of Silvering Glass. (Chem. Gazette, Nov. 1844, 
p. 474.)—It consists in depositing silver from solution upon glass by de- 
oxidizing the oxide of silver on solution in such a manner that the pre- 
cipitate will adhere to the glass. A mixture is made of one ounce of 
coarsely pulverized nitrate of silver, one half ounce spirits of hartshorn, 
and two ounces of water; which, after standing for twenty four hours, is 
filtered and mixed with three ounces of spirits of wine of 60° or naph- 
tha; from twenty to thirty drops of oil of cassia are then added; and 
after remaining for about six hours longer, the solution is ready for use. 
The glass to be silvered with this solution must have a clear and polished 
surface; it is to be placed in a horizontal position, and a wall of putty 
formed around it, so that the solution may cover the glass to the depth of 
from an eighth to a quarter of an inch. After the solution has been 
poured upon the glass, from six to twelve drops of a mixture of oil of 
cloves and spirits of wine (in the proportion of one part by measure of 
oil of cloves and three of spirits) are dropped into it at different places; 
or the diluted oil of cloves may be mixed before it is poured upon the 
glass. When the deposit is obtained, which takes place in an hour or 
two, the solution is poured off, and as soon as the silver is perfectly dry, 
it is varnished with a composition formed by melting together equal quan- 
tities of bees’ wax and tallow. 
Tests for Coloring Substances in Wine, by M. Jacon, (Chem. Gazette, 
Aug. 1844, p. 346.)—It is found that the basic acetate of lead on the one 
hand, and sulphate of alumina with carbonate of ammonia on the other, 
3 
