SOURCE OF THE METALS. 
405 
non-nitrogenous organic principles, especially if a gentle heat 
be applied. 
OINTMENTS OE IODINE. 
Mr. II. Hall, to avoid the grittiness always objection¬ 
able in these unguents when carelessly or quickly prepared, 
proposes first to dissolve the iodide of potassium and the 
iodine in a small quantity of glycerine, and then to add the 
lard. In this way the compounds, he says, may be made 
perfectly smooth, and in a very short time. When large 
quantities are required, labour may be saved by heating the 
lard to a creamy consistency, and stirring in the solutions. 
SOLIDIFICATION OF CARBONIC ACID. 
Carbonic acid has been obtained by MM. Loir and 
Drion in the form of a colourless mass of transparent ice, 
which soon breaks up into large cubicular crystals, on ex¬ 
posure to air, returning to the gaseous state by the influence 
of liquid ammonia, lowered to the point of solidification, to¬ 
wards 81 °, and the pressure of three or four atmospheres. In 
about half an hour, the experimenters state, all that portion 
of the tube containing carbonic acid, which is plunged in 
ammonia, becomes covered with a thick stratum of crystals, 
which rapidly augments. 
SOURCE OF THE METALS. 
The theory seems to be gaining ground that water is the 
original source of the metals. Gold has been conjectured to 
be an oceanic deposit, and of silver an immense quantity is 
said to exist in an exceedingly diffused solution in the sea ; 
Captain Maury estimates it at no less than two hundred 
million millions of tons, and it has been calculated that, in 
the course of six years, the sheathing of the vessels of 
England, France, and America, acquires therefrom as much 
as nine tons of this metal. 
