aluminum, with about ten per
cent. of potash. It contains a lot of extra alumina, but after roasting
in a kiln the potassium sulfate can be leached out. The alunite beds
near Marysville, Utah, were worked for all they were worth during the
war, but the process does not give potash cheap enough for our needs in
ordinary times.

[Illustration: Photo by International Film Service

IN ORDER TO SECURE A NEW SUPPLY OF POTASH SALTS

The United States Government set up an experimental plant at Sutherland,
California, for the utilization of kelp. The harvester cuts 40 tons of
kelp at a load]

[Illustration: THE KELP HARVESTER GATHERING THE SEAWEED FROM THE
PACIFIC OCEAN]

[Illustration: Courtesy of Hercules Powder Co.

OVERHEAD SUCTION AT THE SAN DIEGO WHARF PUMPING KELP FROM THE BARGE TO
THE DIGESTION TANKS]

The tourist going through Wyoming on the Union Pacific will have to the
north of him what is marked on the map as the "Leucite Hills." If he
looks up the word in the Unabridged that he carries in his satchel he
will find that leucite is a kind of lava and that it contains potash.
But he will also observe that the potash is combined with alumina and
silica, which are hard to get out and useless when you get them out. One
of the lavas of the Leucite Hills, that named from its native state
"Wyomingite," gives fifty-seven per cent. of its potash in a soluble
form on roasting with alunite--but this costs too much. The same may be
said of all the potash feldspars and mica. They are abundant enough, but
until we find a way of utilizing the by-products, say the silica in
cement and the aluminum as a metal, they cannot solve our problem.

Since it is so hard to get potash from the land it has been suggested
that we harvest the sea. The experts of the United States Department of
Agriculture have placed high hopes in the kelp or giant seaweed which
floats in great masses in the Pacific Ocean not far off from the
California coast. This is harvested with ocean reapers run by gasoline
engines and brought in barges to the shore, where it may be dried and
used locally as a fertilizer or burned and the potassium chloride
leached out of the charcoal ashes. But it is hard to handle the bulky,
slimy seaweed cheaply enough to get out of it the small amount of potash
it contains. So efforts are now being made to get more out of the kelp
than the potash. Instead of burning the seaweed it is fermented in vats
producing acetic acid (vine