82 
Miscellany. 
is not the slightest excess of the cyanide, as this would cause a solution 
of part of the product, and the formation of soluble double cyanides. The 
cyanide thus made, is to be well washed with pure water, and dried in a 
dark place. M. Pourche, who has used it successfully in syphilis and 
scrofula, recommends its administration in the form of frictions on the 
ongue, mixed with powdered orris root, well washed in alcohol and 
dried : 
Cyanide of gold, gr. i. 
Powdered orris root, gr. iij. 
In pills, he prescribes : 
Cyanide of gold, gr. i. 
Ext. Mezereon gr. iij. 
Powdered Mallows, q.s. 
for pills of five grains. 
In children, the dose at first should never exceed one-fifteenth of a 
grain. Journ. de Pharm. 
Combinations and properties of Zinc. Besides the different metals tha^ 
have been long since known to exist in the zinc of commerce, M. Schin- 
dler has recognized in it the presence of uranium, and of a combination 
of carbon with zinc. Both are found in the blackish residue obtained by 
the solution of zinc in sulphuric acid ; uranium, however, in small quan- 
tity, one grain from two pounds of zinc. It is to the presence of the 
carburet that the odour always possessed by hydrogen obtained from 
commercial zinc, is to be attributed. M. Schindler attributes the yellow 
colour, which the oxide of zinc obtained by calcination almost always 
displays, not to iron, as is generally supposed, but to the presence of a 
new metal, which he has not been able to separate. Although oxide of 
zinc is readily soluble in a solution of potash, it is with difficulty, and 
only in small quantity, dissolved by aqua ammonia ; the presence of 
an arseniate or a phosphate even in very small quantity, enables water 
of ammonia to dissolve it in considerable proportion. Ammonia cannot 
be said to precipitate oxide of zinc, as the oxide retains a quantity of 
the alkali, which cannot be separated without great difficulty, and which 
attracts carbonic acid. 
He has obtained a hydrate of the oxide of zinc in small rhombohedral 
crystals, by plunging into water of ammonia, iron and zinc, connected to- 
gether. A very abundant disengagement of hydrogen takes place, and 
the crystals are deposited on the sides of the vessel and on the zinc ; 
they are very brilliant, and on the application of heat are converted into 
an anhydrous oxide ; they are composed of one atom of oxide and one 
of water. The hydrated sulphuret of zinc can be obtained in small crys- 
tals, composed of one atom of sulphuret, -f one atom of water; heat 
