424 
POrULAR SCIENCE REVIEW. 
the solution could not be rendered permanently acid till the whole of the 
carbonate was dissolved. — Chemical News. 
Method of Treating Native Sulphides, fyc. — The Moniteur scientifique for 
August contains a paper on this subject, by Dr. E. Kopp. He first alludes 
to the mineral resources of Italy, which appear to be far greater and of 
more value than is generally known or suspected. The difficulty of render- 
ing these treasures industrially available is the great scarcity of fuel. Under 
these conditions, a series of experiments have been made, to ascertain whether 
it might be possible to apply cheap and readily-accessible chemical re-agents 
to act upon the above-named minerals (without simultaneously affect- 
ing the gangue), so as thereby to render them in a state fit for being readily 
converted into metals. As reagents available for the purposes alluded to, 
the author has found common salt, chloride of iron, and hydrochloric acid 
readily to suit the requirements. Among the practical suggestions found in 
this paper, is the fact, that the most economical method to extract the small 
quantity of copper present in previously-burnt pyrites, consists in first ex- 
posing the burnt substance for a time to air and moisture, and then to pour 
over the material a solution of common salt. A small addition of hydro- 
chloric acid is very useful ; the copper thus becomes converted into a soluble 
chloride. 
Hydrogenium Amalgam. — A great deal of interest attaches to all attempts 
with this substance. We therefore give the following account of Dr. Loew’s 
attempts as set forth in the Journal fur prakt. Chemie (Nos. 6 and 7). He 
prepares the hydrogenium amalgam by shaking together, in a vessel to be 
kept very cool, a mixture of mercury containing from 1 to 2 per cent, of 
metallic zinc, along with an equal bulk of a solution of chloride of platinum 
containing 10 per cent, of solid chloride. A slimy mass is obtained, devoid 
of metallic lustre and prone to decomposition, owing to the presence of some 
zinc and some compounds of that metal ; but, on treating the mass with 
dilute hydrochloric acid, a body having the consistence of butter is obtained, 
which, according to the author, is a true amalgam of mercury and hydro- 
genium. 
Calorific Value of certain Gases. — In a paper read before the American 
Association at Salem, by Professors B. Silliman and II. Wurtz, there are 
some conclusions which will be of interest to our readers. From the second 
table it is clear — 1. That, of all known gases, the highest calorific effects, 
under ordinary atmospheric conditions, are obtainable from carbonic oxide, 
whose calorific value, above 100° C.,is about 3,000° C. 2. That, in absolute 
calorific value, below 100° C., in the atmospheric medium, hydrogen sur- 
passes the volume of any other gas, giving a temperature of about 3,200° C. 
3. That for all modes of application — that is, for producing both high and 
low temperatures — the total maximum calorific effectiveness of carbonic 
oxide is a constant quantity. 4. Compound condensed submultiple volumes 
of hydrogen, like that in marsh gas, have much less total calorific value in 
a'.r than their volume of free hydrogen. 6. Condensed compound submul- 
tiple volumes of gaseous carbon, like that in olefiant gas, have no greater 
total calorific value in air, below 100° C., than their own volume of carbon 
gas in the form of carbonic oxide ; while above 100° C. their value is even 
considerably less. 
