110 Scientific Intelligence. 
it suddenly while hot, becomes turbid from the separation of a peculiar 
_ phosphate of magnesia; at the same moment the phosphoric acid be- 
gins to crystallize like granular sugar deposited in honey, a form as: 
cribed by Pexicor to the bibasic or pyrophosphoric acid. If the same 
temperature be kept up for fifteen minutes, the whole of the magnesia 
separates in the form of a powder which is quite insoluble in acids or 
water; when cold the mass is digested with water, which dissolves the 
phosphoric acid, leaving the phosphate of magnesia as a heavy, fine, 
snow-white powder, of a faint silky lustre. The filtered liquid is free 
from every trace of magnesia, and may be considered as pure phospho- 
ric acid. If the bones contain chloride of sodium a trace of phosphate 
of soda will remain—in this case the burnt bones after being pulverized, 
should be boiled with water to remove the chloride. Dr. GreGory re- 
commends this process as a simple one for obtaining pure phosphoric 
acid. The phosphate of magnesia formed is a peculiar and anomalous 
salt. From six analyses Dr. Grecory deduces the formula 2MgO+ 
$8P205, that is, an acid sesquiphosphate of magnesia according to the 
older notions of phosphoric acid. It is insoluble in water or the acids, 
boiling nitric acid and aqua regia are almost entirely without action up- 
on it. : Jeli 
20. New Observation on the Chemico-dynamical action of Plati- 
num; by J. W. Dorsereiner, (Annalen der Chem. und Pharm., Feb., 
1845.)—Spongy platinum prepared in the ordinary way by heating the 
double chloride of platinum and ammonia, becomes ignited to redness 
when moistened with formylic acid, and decomposes it into carboni¢ 
acid and water, two atoms of oxygen being absorbed. It has no effect 
upon alcohol or pyroligneous spirit, except an alkali be mixed with them, 
then the sponge becomes incandescent, and the spirits are decomposed. 
So that by the presence of an alkali, the platinum sponge acquires the 
property possessed by platinum black, of absorbing oxygen largely. 
J. L. 8. 
21. On the quantitative determination of Soda, and ils separation 
from Potash; by Dr. Wirrstein, (Buckner’s Report, xxxvi, 3, a0 
Chemist, May, 1845, p. 215.) —The two bases are first converted into sul- 
phates, then calcined, weighed, and the sulphuric acid found in them 
determined by a salt of baryta. On subtracting the acid from the saline 
mixture, the sum of the quantities of the two alkalies becomes known. 
The quantity of potash may be ascertained, if we first subtract from 
the sum of the weight of the two salts, the product obtained by multi- 
plying the weight of the sum of the two bases by the quotient, result- 
ig from the division of the atomic weight of the sulphate of soda by 
he atomic weight of soda, and then dividing this by the difference result- 
subtracting the quotient obtained by dividing the atomic weight of 
