Chemistry. xlitt 
Vienna, M. Prechtel, director of the Polytechnic Institute, hag 
fused platinum in furnaces by subjecting it to a heat of 180° 
Wedgewood. The fusion however seems to have been rather 
imcomplete ; for if it had been complete, one cannot see how 
the specific gravity should have sunk 211 to 172.—(See Annals 
of Philosophy, xiii. 229.) 
Vv. ACIDS. 
In this department, as well as in several others, a considerable 
number of new facts have been brought to view. Several 
new acids, chiefly from the vegetable kmgdom, have been dis- 
covered; and several bodies, formerly considered as peculiar 
‘acids, have been shown to be nothing more than varieties of 
other acids previously known. I shall endeavour to place these 
facts before the eye of the reader mm as few words as possible. 
1. Combination of Oxygen with Acids—Thenard thought, as 
has been stated in the Annals of Philosophy, xiii. 1, that oxygen 
may be united with muriatic, nitrous, sulphuric, and, indeed, all 
the acids tried in any proportion whatever, by combining with it 
the peroxide of barytes, and then throwing down the barytes by 
means of sulphuric acid; but he has since found that the oxygen, 
in reality, unites not with the acids but with the water, convert- 
ing it into a deutoxide of hydrogen. 
2. Hydriodic Acid.—It would appear from a set of experi- 
ments by Houton Labillardiere, of which an account has been 
given in the Anais of Philosophy, xi. 233, that when equal 
volumes of hydriodic acid and bihydroguret of phosphorus, 
both in the gaseous state, are mixed together, the two gases 
are condensed into a solid matter of a white colour, and crys- 
tallize in cubes. This compound is decomposed by water and 
alcohol; one volume of common phosphuretted hydrogen gas, 
and two volumes of hydriodic acid gas, likewise condense over 
mercury into a white solid matter. 
3. Sulphuretted Hydrogen—M. Gay-Lussac has given a for- 
mula for preparing this gas, which must prove very acceptable 
to practical chemists. ‘Two parts of iron filings, and one part 
of flowers of sulphur, are to be mixed together and put into a 
matrass. As much water is to be added as will convert the 
whole into a paste; the matrass is then to be heated, to favour 
the union of the sulphur and iron. This union is indicated by 
the disengagement of a great quantity of heat, and by the black 
colour which the whole mass assumes. Sulphuric acid diluted 
with four times its weight of water, disengages suiphuretted 
hydrogen gas, from this compound, with almost as much ra- 
pidity as from an alkaline hydrosulphuret. There is no ad- 
vantage in preparing this substance, till it is gomg to be used; 
for it is speedily altered, and a very short time is sufficient for 
preparing it. Gay-Lussac is of opinion that this singular com- 
pound is a hydrosulphuret of irom. (Ann. de Chim. et Phys. 
