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POPULAR SCIENCE REVIEW. 
green, compounds are obtained similar in colour to the well-known green, 
but containing formic, butyric, or valerianic acid in place of the acetic. For 
the preparation of cupric formo-arsenite, four parts of cupric formiate were 
dissolved iu as little water as possible, and added to four parts of arsenious 
acid, dissolved in about fifty parts of water by the aid of a little caustic 
soda ; both solutions being at the boiling-point. The yellowish precipitate 
which appeared soon became of a very bright green, with a slightly more 
j T ellowish tinge than the acetic compound. The butyric and valerianic 
greens were made in a similar manner, but with different proportions of 
cupric salt and arsenious acid. 
Hydrogen and Mercury Amalgam. — In a late number of the Scientific Ame- 
rican Dr. Loew has a paper, describing the experiments of others and his own 
observations on this preparation. He thinks that Schoenbein, in his search 
for ozone, found a method for making the peroxide of hydrogen, which 
brought him to the very threshold of discovering hydrogenium. Schoen- 
bein's experiment was this — An amalgam of zinc and mercury is violently 
agitated in water ; the water is then filtered, and, on being examined with 
iodide of starch and protosulphate of iron, will be found to contain peroxide 
of hydrogen or oxygenated water. Dr. Loew has carried the investiga- 
ion further, and has, instead of oxidising the hydrogen, succeeded in com- 
bining it with the mercury. He takes an amalgam composed of not more 
than three or four per cent, of zinc, and shakes it with a solution of bichlo- 
ride of platinum ; the liquid becomes black, and a dark powder settles to 
the bottom. The contents of the flask are then thrown into water, and 
hvdrochloric acid added to dissolve the excess of zinc. The amalgam of 
hydrogen and mercury at once forms a brilliant voluminous mass, resembling 
in every way the well-known ammonium amalgam. It is soft and spongy, 
and rapidly decomposes, but without any smell of ammonia. The hydrogen 
escapes, and soon nothing but pure mercury is left in the dish. The experi- 
ment appears to show conclusively that an amalgam of hydrogen and mer- 
cury can be formed, and that hydrogen is really a metal. It would also 
throw some doubt upon the existence of the amalgam of ammonium and 
mercury, and offer an explanation of that compound on the basis of its 
being the same amalgam of hydrogen and mercury that is prepared in the 
way now pointed out by Dr. Loew. The smell of escaping ammonia must 
be traced to some other source than the existence of that radical in com- 
bination with mercury. 
A licll-jar and Beaker with Bunsen's Bump. — Mr. Albert It. Leeds, writing 
to the Journal of the Franklin Institute , gives the following account of this 
contrivance. Instead of the cumbrous bottle generally employed, the plate 
of an air-pump may be advantageously substituted, and a receiver, with an 
India-rubber cork, through which the neck of the funnel is passed. In 
order to prevent loss by the bursting of bubbles of air at the end of the tube 
of the funnel, it is continued low down into the beaker by an India-rubber 
tube. The latter can easily be removed at the end of a filtration, and the 
drops of adhering liquid washed with water from the spritz into the 
filtrate. This simple arrangement obviates the necessity of a transfer from 
one vessel to another, and permits all the operations of an analysis to be 
carried on as usual, in beakers. Instead of an air-pump plate, a sheet of 
