hing is a
real military man, and has been notably absent from such things as
banquets and other functions where by talking he might get into the lime
light. It is true that he was jumped over the heads of a number of
officers by President Roosevelt, but he has carved his way by his own
efforts, and no man could have more fittingly been sent to take charge
of the American forces abroad than "Jack" Pershing.

CHAPTER XX.

CHEMISTRY IN THE WAR.

SUBSTITUTES FOR COTTON--NITRATES PRODUCED FROM AIR--YEAST A REAL
SUBSTITUTE FOR BEEF--SEAWEED MADE TO GIVE UP POTASH--A GANGRENE
PREVENTATIVE--SODA MADE OUT OF SALT WATER--AMERICA CHEMICALLY
INDEPENDENT.

It is when men are put to the test that they develop initiative and are
inspired to great things. In the stress of circumstances there were
created through and in the great war many unusual devices and much that
will endure for the benefit of mankind in the future. It is probable
that the advancements made in many lines would not have been attained in
years but for the necessity which demanded the exertion of men's
ingenuity, and in no field was this advancement greater than in that of
chemistry.

Any struggle between men is, in the last analysis, a battle of wits, but
it remained for those planning and scheming to defeat their fellow men
or protect themselves in the world conflict to make for the first time
in history the fullest use of the chemist's knowledge. Largely the
successes of the war have been due to the studies and activities of the
chemists, working in their laboratories far from the actual field of
strife.

Not only has their knowledge been turned to the creation of tremendously
destructive explosives, the like of which have never before been known
in warfare, but the same brains which have been utilized to assist man
in his death-dealing crusades have been called upon to thwart the
efforts of the warring humans and save the lives of those compelled to
face the withering fire of cannon, the flaming grenade and the
asphyxiating gas bomb.

In the food crisis which confronted the nations, chemists drew from the
very air and the waters of the river and sea, gases and salts to take
the place of those which became limited in their supply because of the
demands of the belligerents.

The chemist is one of those who fights the battles at home. The
resisting steel, the penetrating shell, the poisonous gas, the
power-producing oil, the powerful explosive--al