PRESIDENT’S ADDRESS. 37 
The former methods employed for making these gems 
were difficult, slow, and expensive, but they can now oe 
prepared by a simpler process, viz., by merely fus ng 
alumina, mixed with a chromium salt to impart the red 
colour, in the electric furnace. 
ALUMINIUM. 
Aluminium, which was, I think, first publicly shown 
at the Paris Exhibition of 1855, and described as the 
“silver from clay,” is now being manufactured on a large 
scale at the Falls of Foyers, and the output is equal to and 
perhaps greater than that of any other works—rendered 
possible by the use of the Falls for generating electricity at 
a cheap rate. 
Until within quite recent years aluminium remained 
almost a chemical curiosity. It is true that years ago it 
was used for making small ornamental articles, and for 
making an alloy with copper (aluminium bronze), but now 
that the chemistry of its preparation is reduced to the 
simple process of deoxidation in the electric furnace, it 
can be obtained in a pure form at a very cheap rate. 
The chief advantages of aluminium are its lightness or 
low specific gravity, the readiness with which it forms most 
valuable alloys, and its highly electro-positive character. 
Aluminium is particularly adapted for culinary utensils 
on account of its lightness, freedom from corrosion, and 
great thermal conductivity. It is also used im place of the 
expensive and heavy Solenhofen stone in “ Lithography.” 
The stone requires a heavy and powerful machine; the 
thin plates of aluminium do not, and, further, they can be 
curved round cylinders and the “lithograph” can be 
inserted with the type, and be printed from at the same 
rate as the letter-press. 
Aluminium is not only being used for army equipments, 
but also for the construction of passenger railway carriages. 
In France a train is being built in which all the parts usu- 
ally made of brass, copper, or iron (except the axles, wheels, 
springs, brake-beams, and couplings) are of aluminium, 
