ompletes our survey of the visible sources of potash in America.
In 1917 under the pressure of the embargo and unprecedented prices the
output of potash (K_{2}O) in various forms was raised to 32,573 tons,
but this is only about a tenth as much as we needed. In 1918 potash
production was further raised to 52,135 tons, chiefly through the
increase of the output from natural brines to 39,255 tons, nearly twice
what it was the year before. The rust in cotton and the resulting
decrease in yield during the war are laid to lack of potash. Truck crops
grown in soils deficient in potash do not stand transportation well. The
Bureau of Animal Industry has shown in experiments in Aroostook County,
Maine, that the addition of moderate amounts of potash doubled the yield
of potatoes.

Professor Ostwald, the great Leipzig chemist, boasted in the war:

America went into the war like a man with a rope round his neck
which is in his enemy's hands and is pretty tightly drawn. With
its tremendous deposits Germany has a world monopoly in potash,
a point of immense value which cannot be reckoned too highly
when once this war is going to be settled. It is in Germany's
power to dictate which of the nations shall have plenty of food
and which shall starve.

If, indeed, some mineralogist or metallurgist will cut that rope by
showing us a supply of cheap potash we will erect him a monument as big
as Washington's. But Ostwald is wrong in supposing that America is as
dependent as Germany upon potash. The bulk of our food crops are at
present raised without the use of any fertilizers whatever.

As the cession of Lorraine in 1871 gave Germany the phosphates she
needed for fertilizers so the retrocession of Alsace in 1919 gives
France the potash she needed for fertilizers. Ten years before the war a
bed of potash was discovered in the Forest of Monnebruck, near
Hartmannsweilerkopf, the peak for which French and Germans contested so
fiercely and so long. The layer of potassium salts is 16-1/2 feet thick
and the total deposit is estimated to be 275,000,000 tons of potash. At
any rate it is a formidable rival of Stassfurt and its acquisition by
France breaks the German monopoly.

When we turn to the consideration of the third plant food we feel
better. While the United States has no such monopoly of phosphates as
Germany had of potash and Chile had of nitrates we have an abundance and
to spare. Whereas we formerly