auto goggles and gas masks as well
as for windows in leather curtains and transparent coverings for index
cards. A new use that has lately become important is the varnishing of
aeroplane wings, as it does not readily absorb water or catch fire and
makes the cloth taut and air-tight. Aeroplane wings can be made of
cellulose acetate sheets as transparent as those of a dragon-fly and not
easy to see against the sky.

The nitrates, sulfates and acetates are the salts or esters of the
respective acids, but recently true ethers or oxides of cellulose have
been prepared that may prove still better since they contain no acid
radicle and are neutral and stable.

These are in brief the chief processes for making what is commonly but
quite improperly called "artificial silk." They are not the same
substance as silkworm silk and ought not to be--though they sometimes
are--sold as such. They are none of them as strong as the silk fiber
when wet, although if I should venture to say which of the various makes
weakens the most on wetting I should get myself into trouble. I will
only say that if you have a grudge against some fisherman give him a fly
line of artificial silk, 'most any kind.

The nitrate process was discovered by Count Hilaire de Chardonnet while
he was at the Polytechnic School of Paris, and he devoted his life and
his fortune trying to perfect it. Samples of the artificial silk were
exhibited at the Paris Exposition in 1889 and two years later he started
a factory at Basancon. In 1892, Cross and Bevan, English chemists,
discovered the viscose or xanthate process, and later the acetate
process. But although all four of these processes were invented
in France and England, Germany reaped most benefit from the new
industry, which was bringing into that country $6,000,000 a year
before the war. The largest producer in the world was the Vereinigte
Glanzstoff-Fabriken of Elberfeld, which was paying annual dividends of
34 per cent. in 1914.

The raw materials, as may be seen, are cheap and abundant, merely
cellulose, salt, sulfur, carbon, air and water. Any kind of cellulose
can be used, cotton waste, rags, paper, or even wood pulp. The processes
are various, the names of the products are numerous and the uses are
innumerable. Even the most inattentive must have noticed the widespread
employment of these new forms of cellulose. We can buy from a street
barrow for fifteen cents near-silk neckties that look as well as those