VARIETIES. 
81 
precipitated without an excess of carbonate of potash or carbonate of soda. 
When the excess of either of these reagents is used in its precipitation, the 
excess of the alkali decomposes a portion of the metallic carbonate, and 
becomes a sesqui or a bicarbonate. If a bicarbonate of the alkali be used 
to precipitate carbonate of manganese, the precipitant may be added in 
excess, and the precipitate exposed to the air with impunity. Manganese 
resembles the magnesian class of metals in its carbonate being undecom- 
posable by caustic ammonia; hence either of the carbonates of the volatile 
alkali may be used with effect to precipitate a carbonate of manganese that 
will remain persistent in the atmosphere. Carbonate of manganese, when 
exposed to any high temperature approaching near to redness, passes at 
once into the black oxide, without apparently going through any interme- 
diate state of oxidation. — Pharm. Jour., from PJiiL Mag. 
On the Detection of Sulphur. By Mr. J. W. Bailey. — Dr. Playfair's 
beautiful salt, the nitroprusside of soda, is justly recommended by its dis- 
coverer as the most delicate of all tests for alkaline sulphides [sulphurets], 
An application of it, which is very obvious, although not alluded to by Dr. 
Playfair, is to employ it not only as a direct test for alkaline sulphurets, 
but as an indirect one for sulphur in any of its compound. Any substance 
containing sulphur will yield an alkaline sulphuret if heated with carbonate 
of soda, either with or without the addition of carbonaceous matter, acording 
as a deoxidizing action is or is not required. The magnificent purple which 
is then produced by the addition of the fused mass to a drop of the solution 
of the nitroprusside will at once prove the presence of sulphur. This reac- 
tion is so easily obtained, and is so decisive, that the nitroprusside of soda 
must take its place among the most useful adjuncts of the blowpipe tests. 
By means of it, the presence of sulphur in the smallest particles of coagu- 
lated albumen, horn, nails, feathers, mustard seed, &c, which can be con- 
veniently supported on a platinum wire for blowpipe experiment, may be 
most distinctly shown ; and I have repeatedly obtained the characteristic 
purple tint in operating upon a piece of a single fibre of the human hair less 
than an inch in length. — Silliman's Journal, May, 1851. 
Combinat ions of Sugar and Lime. ByM. Peligot. [In a paper published in 
the Journal de Pharmacie, and republished in the Pharmaceutical Journal 
for July, 1851, the following table of the amount of lime taken into solution 
by syrup of various densities is found. M. Peligot infers from his experi- 
ments that the statement of Soubeiran, that the compound formed has a 
constant composition of 2 C 12 H n ll5 3 CaO, is incorrect, and that the com- 
pound always formed at first, is C J2 H n O n . CaO, which afterwards dissolves 
more or less of the base according to the density of the saccharine solu- 
tion. — Ed.] 
The following table shows, 1. The composition and the density of the 
