104 Scientific Intelligence. 
washing this powder, it is dissolved in muriatic acid, evaporated until 
the silica separates as a gelatinous mass ; it is then diluted with water 
and filtered. It must not be evaporated to dryness for the more com- 
plete separation of the silica, because the chloride of Ruthenium is 
thereby decomposed into an insoluble protochloride. The filtered sos 
lution, which is of a beautiful orange yellow color, is evaporated down 
to a very small volume, and mixed with a concentrated solution of chlo- 
ride of potassium, when the salt KCl4+-RuCl? separates in reddish 
brown crystals. Jal. 8. 
5. New Acid in Human Urine, (Chem. Gaz., Nov. 1844, p. 479.) 
—W. Hernrz has obtained a minute quantity of a new acid from fresh 
human urine; it contains nitrogen, and differs from hippuric acid. Its 
properties have not yet been fully investigated, nor is there any name 
given to it. Jada, Bs 
6. Atomic Weight of Zinc; by M. A. Expmann, (Pogg. Ann., Ixii, 
p. 611, and Chem. Gaz., Jan. 1845, p. 14.)—It was determined by as- 
certaining the amount of oxygen absorbed by a given weight of pure 
zinc. ‘The number furnished by this method is 406:591, oxygen being 
100. This is 3°365 higher than that admitted by Gay Lussac, and 
7-409 lower than that announced by Jacque.in. im For. 
7. Researches upon the Metallic Acids; by M. Fremy, (Ann. de 
Chim. et de Phys., Nov. and Dec. 1844.)—It would be impossible to give 
here any thing like a sketch of these elaborate and highly interesting 
researches ; all that can be done is to state the principal facts discover- 
ed by the author. The capacity of saturation of aluminic acid was 
determined by forming a crystallized aluminate of potash, which ought 
to be considered a neutral salt ; an analysis of it, showed that the oxy- 
gen of the acid is to the oxygen of the baseas 3tol. The ferric acid 
was discovered by M. Fremy, (FeO*), and is prepared by a method 
already well known to chemists; but the one preferred by M. Fremy, 
will be mentioned in these abstracts. It was found that chlorine, pass- 
ed over chromate of potash heated to redness, furnished beautiful 
erystals of oxide of chrome; it is an easy process. The protoue 
ide of tin was obtained under different forms, brown, black and red. 
Two modifications of stannic acid were discovered, both having the 
same composition, but requiring different amounts of bases to form neu- 
tral salts; the acids are called stannic and metastannic. Bismuth was 
found to form an acid with oxygen, Bi2?0*. The peroxide of lead, 
PbO2, formerly thought to be indifferent, turns out to be a true metallic 
acid, combining with the various bases. The plumbate of potash is 
rkable for its beautiful crystalline forms. By treating this last salt 
a solution of the protoxide of lead in an alkali, hydrated minium 
ed by double decomposition. Copper forms with oxygen an acid, 
