88 
MISCELLANY. 
mine at the same time, both the quantity of iodine and of chlorine in one 
and the same liquid : it is therefore indispensable to avoid every addition 
of chlorine. All these inconveniences are set aside by the use of a solu- 
tion of sulphate of copper in a concentrated aqueous solution of sulphur- 
ous acid. All the iodine existing in the liquid as hydriodate, is then 
completely precipitated, as an iodide of copper totally insoluble in 
the liquid which contains free sulphuric acid; while under the same cir- 
cumstances the chlorine and the bromine does not form an insoluble 
combination. The iodide of copper is collected on a filter of unsized paper 
well washed, dried, and finally heated to a temperature of 120° C, in a 
bath of chloride of calcium, in a small glass tube closed at one end, un- 
til it ceases to lose weight. Dividing the weight of the iodide of cop- 
per by 1,501, the result will be the quantity of the iodine. — A. G. V. 
Journ. de Pharm. 
On the Existence of Free Acid in Spiritus JElheris Nitrosi. By Mr. 
Harvey. — This spirit, however recently or carefully prepared, con- 
tains a portion of free nitrous acid, one effect of which is to decom- 
pose various substances, with which the spirit is frequently combined in 
prescriptions. Thus, if it is ordered in a mixture with iodide of potas- 
sium, it will liberate free iodine ; if prescribed with mistura ferri compo- 
sita, it will convert a portion of the proto-carbonate of iron into the inert 
peroxide; if added to simple infusion of roses, or to a mixture colored 
with red poppy syrup, it will gradually decolorize it. For mixtures such 
as the above, I use the Sp. iEth. Nit. deprived of its acid, by being kept 
standing on crystals of carbonate of potash. If the spirit be of full strength 
no appreciable quantity of the alkali or nitrate of potash is dissolved, and 
by the use of the Spiritus iEther Nitrosi so treated, all the objections 
above described are obviated. 
Pharmaceutical Journal and Transactions. Jan. 1842. 
