COMMUNICATIONS 
TO THE 
MONTHLY MEETINGS, 
1861 . 
March 5.—Wm. Procter, Esq., F. C. S., read a paper on 
“ Aluminium.” He traced the history of the discovery of Aluminium 
from the time of Davy to that of Wohler and Deville, who first ob¬ 
tained it in any quantity, and described the process adopted by the 
latter chemist for procuring Aluminium by the decomposition of its 
chloride by metallic sodium. Certain difficulties attendant on this 
process led Dr. Percy to suggest the mineral called Cryolite, afiuoride 
of aluminium and sodium, as a source of aluminium. The process 
consists in heating the powdered mineral, with common salt and sodium, 
for two hours in a covered crucible; at its conclusion the metal is 
found at the bottom of the slag. The price of the metal, when it was 
first obtained, was £40 for thirty-five ounces. In 1806 Deville had 
reduced it to £3 per ounce, and is now usually worth five shillings per 
ounce, although Mr. Gerhard, who is engaged in preparing the metal 
from cryolite on a large scale at Battersea, stated at a meeting of the 
Society of Arts, that he had undertaken a contract at 3s. 9d. per ounce. 
Aluminium is a white metal, with a bluish tinge, and a lustre infe¬ 
rior to that of silver. Its specific grav. is 2*6, or about one-fourth that 
of silver, a property of importance, as this lightness causes a given 
weight of aluminium to go as far in the manufacture of articles as 
four times the quantity of silver. It is malleable, and ductile, and 
possesses considerable tenacity ; when pure it is as hard as silver, hut 
it has no great elasticity, and requires rather a high temperature to 
fuse it. It is not oxidised by exposure to air, even at high tempe¬ 
ratures ; it resists the action of sulphur and sulphuretted hydrogen 
which so rapidly tarnish silver, and is insoluble in any of the ordinary 
acids, except the muriatic ; potass, soda, and ammonia in solution dis- 
