l in
mind half a century before Germany, France, and England came to
grips on the long line from the North Sea to the Vosges.

Asphyxiating gas, whether liberated from a shell, or released along
a trench front to roll slowly down before a wind upon its
defenders, was a novelty of this war. But in some degree it was
merely a development of the "stinkpot" which the Chinese have
employed for years. So too the tear-bomb, or lachrymatory bomb,
which painfully irritated the eyes of all in its neighbourhood when
it burst, filling them with tears and making the soldiers
practically helpless in the presence of a swift attack. These two
weapons of offence, and particularly the first, because of the
frightful and long-continuing agony it inflicts upon its victims,
fascinated the observer, and awakened the bitter protests of those
who held that an issue at war might be determined by civilized
nations without recourse to engines of death and anguish more
barbaric than any known to the red Indians, or the most savage
tribes of Asia. Neither of these devices, nor for that matter the
cognate one of fire spurted like a liquid from a hose upon a
shrinking enemy, can be shown to have had any appreciable effect
upon the fortunes of any great battle. Each, as soon as employed by
any one belligerent, was quickly seized by the adversary, and the
respiratory mask followed fast upon the appearance of the chlorine
gas. Whatever the outcome of the gigantic conflict may be, no one
will claim that any of these devices had contributed greatly to the
result.

But the airplane revolutionized warfare on land. The submarine has
made an almost equal revolution in naval warfare.

Had the airplane been known in the days of our Civil War some of its
most picturesque figures would have never risen to eminence or at
least would have had to win their places in history by efforts of an
entirely different sort. There is no place left in modern military
tactics for the dashing cavalry scout of the type of Sheridan,
Custer, Fitz Lee, or Forrest. The airplane, soaring high above the
lines of the enemy, brings back to headquarters in a few hours
information that in the old times took a detachment of cavalry days
to gather. The "screen of cavalry" that in bygone campaigns
commanders used to mask their movements no longer screens nor masks.
A general moves with perfect knowledge that his enemy's aircraft
will report to their headquarters his roads, his strength,