298 Science and Human Welfare
A special use of Pyrex is found in the construction of a
telescope with a 200-inch, 20-ton reflecting mirror. For elec-
trical insulation, glass filaments are spun and make a flame-
proof wire coating for use in heavy bombers. Glass fiber
boards are used for heat insulation in fighting planes and in
the new Arctic shelters for the Army Air Forces where the
temperature falls to 650 below, with howling snowstorms.
Glass foam has found use in displacing cork in life preservers
and life boats. Spun glass is used as a fireproof textile. Some
of the newer optical glasses use no sand at all, but depend
upon the rare earth elements such as tantalum, tungsten,
and lanthanum. The glass made from these materials is
highly satisfactory for use in aerial photography lenses, giving
more sharply defined images at higher altitudes.
The basic idea which is stimulating industrial activity is
generally chemical information. The enormous industrial
plant, consisting of an amazing variety of machines and
equipment, is the scientific outcome of translating this
knowledge into useful production. For instance, in the mak-
ing of fertilizers, explosives, and other chemical compounds,
nitrogen is extracted from air’s inexhaustible supply. From
raw sulphur is made sulphuric acid—the use of which may
be taken as the index of a country’s industrial activity. From
common salt comes, by electrolysis, caustic, chlorine, and
hydrogen. Phosphate rock is chemically altered to fertilizer
and other valuable phosphorus compounds. When sufficient
heat is applied, shell and clay become cement; clay is changed
to brick and tiling; sand becomes glass; coal yields coke for
our steel mills, ammonia for fertilizer and tar for innumerable
uses. Cane and beets supply us with our rationed sugar.
Wood is distilled for acetic acid, turpentine, and rosin, or is
chemically disintegrated to furnish high-grade cellulose for
paper, viscose, and nitro-cellulose. There are the mammoth