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SELECTED ARTICLES. 
nitrous ether. In its preparation, there is commonly seen a de- 
position, upon the interior of the glass cylinder, of a small quan- 
tity of a resinoid substance, of a yellowish white aspect, — as 
Daniell has already observed. This acid offers a very acid 
reaction; added in equal parts to sulphuric acid and heated, it 
becomes of a pale yellow color, less deep than that of the acid 
from sulphuric ether under the same circumstances. When we 
boil it with a solution of chloride of gold in a glass vessel, 
the interior surface does not become coated with a pellicle of 
gold, but all the metal is precipitated in an extremely divided 
metallic state. Submitted to ebullition, with an aqueous 
solution of chloride of platinum, the metal is not reduced; 
but, if a few drops of ammonia be added, and the heating 
continued, a small quantity of ammoniated hydrochlorate of 
platinum separates without any reduction of the metal, even 
after a prolonged boiling. When it is boiled for a long time 
with deutoxide of mercury, the greater part of this oxide is 
reduced to the state of metallic mercury, recognisable partly 
under the form of a thin gray pellicle, on the surface of the 
liquid, and partly under that of gray globules, extremely 
divided; but another portion of the oxide gave, by solution, 
a colorless liquid, from which hydrosulphate of ammonia 
precipitated sulphuret of mercury, and a solution of iodide of 
potassium, the protiodide of mercury, of a beautiful yellow 
color, a difference which distinguishes it from the acid from 
sulphuric ether. When it is boiled with a solution of nitrate 
of silver, all the silver is separated in a metallic state. The 
same treatment, with a solution of chloride of mercury, 
produces the separation of a very great quantity of proto- 
chloride of mercury, and a little metallic mercury; if, after 
this separation has taken place, a solution of iodide of potas- 
sium is added to the hot liquid, the red iodide of mercury is 
formed, which is re-dissolved by the addition of a greater 
quantity of the iodide of potassium ; the solution is not 
then yellow, but is without color. Although the acid from 
nitrous ether offers, as has been said above, a very acid re- 
action, the addition of a solution of carbonate, or even of 
