234 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1919. 
For its production cheap water power is essential, and the raw mate- 
rials involved are bauxite, which we obtain from our Southern States 
or from France, and cryolite, a double fluoride of aluminum and 
sodium, for which the world is dependent upon Greenland. In 1883 
the United States produced only 80 pounds of aluminum, whereas 
our output in 1914 was 80,000,000 pounds. Our producing capacity 
at this time is greater than that of all other nations combined. 
Aluminum is of vast importance in the construction of airplanes and 
dirigible balloons, since it is the lightest metal available. It con- 
stitutes the framework of dirigibles and enters largely into the con- 
struction of their engines and that of automobile parts and engines. 
It is an essential constituent of the explosive ammonal and of thermit 
in its many applications as a constructive and destructive agent. 
Aluminum has, moreover, great potentialities and some present use 
as a substitute for copper in the transmission of electricity. 
The Lewis ground gun has an aluminum heat radiator surround- 
ing the barrel, and the shortage of aluminum actually held up for 
a short time the manufacture of gas masks by reason of the difficulty 
of securing pure aluminum sheet for the eyeglass rims, practically 
all the metal having been absorbed in the making of aluminum die 
castings for shell and other ordnance. For the same reason hun- 
dreds of valuable brain hours were spent in the development of hard- 
rubber die castings and complicated brass stampings merely to save 
the little bit of aluminum required for gas-mask mouthpieces. 
Troubles of this kind could be largely eliminated by the military 
man if in his peace-time studies of design he would allow the neces- 
sary large factor of safety between war-time supplies and demand. 
This is especially true, for example, in the case of design of ordnance, 
such as shell, for if the nose of a shrapnel fuse is made in peace time 
of an aluminum die casting, it is too late when war comes to substi- 
tute anything else, for the change would affect the entire ballistics of 
the shell and its ranging. 
The mineral magnesite, which is a carbonate of magnesium and 
essential to the steel industry by reason of its use for furnace linings, 
was imported previous to the war, but altogether adequate supplies 
are now received from great deposits located in Washington. The 
metal magnesium itself is much lighter and stronger than aluminum, 
but, unfortunately, is very susceptible to corrosion by oxidation. 
Although useful, therefore, in some alloys, as in those with aluminum, 
its chief war value is for flares and pyrotechnics, to which reference 
has already been made. Production in the United States began in 
1915 and in 1917 had reached 116,000 pounds and was increasing very 
rapidly. The electric furnace production of the metal from mag- 
nesium chloride requires cheap water power and coal. 
