les.

Late on the day of the battle, when the enemy machines had finally
arrived from more distant airdromes, there was some good fighting in the
air, some of it at close quarters with collisions barely avoided. Twenty
enemy machines were accounted for in the fighting, some flopping about
until they broke up in the air and others being driven down on their
noses in yellow buttercup fields so far back of the fighting line that
no shell had ever marred the symmetry of the landscape.

Some of the most marvelous work was done by artillery airships. One
squadron of these alone, acting with several batteries of British
heavies, succeeded in silencing seventy-two German batteries before six
o'clock on the morning of the attack which began at 3.10 o'clock in the
morning. These planes also directed the firing on the enemy's guns en
route to the front, some of the big weapons being drawn by caterpillar
tractors. Wherever a thousand or more troops were observed forming for
possible counter-attacks the artillery planes directed "shoots" upon
them.

So complete was the British domination of the air along the front of
attack that not a single one of the British artillery observing
aeroplanes was lost during the week that the intense bombardment was
going on. During the battle British aeroplanes also attacked and
silenced a number of enemy machine-gun positions.

The growth of the aeroplane industry has developed as many makes of
machines as there are makes of automobiles, but in a general way
aeroplanes are divided into four classes--monoplanes, biplanes,
triplanes and hydroplanes. About 90 per cent of all designs are
monoplanes and biplanes, and the types are distinguished by their single
set of wings or planes or the double planes or wings. Both types have
their advantages in use, the biplane being regarded as more stable for
certain scouting purposes than the monoplane. It can carry heavier
weights--has greater lifting power--but is not capable of as great speed
or as easily maneuvered.

MACHINE ON PRACTICAL BASIS.

The War has placed the machine on an intensely practical basis. The
manufacturers have learned that machines constructed along certain lines
will travel at such and such a speed and have a certain lifting
capacity, will rise under a particular speed and may be expected to do
certain things under certain circumstances, but with all the advance
which has been made in the construction of the air machines, the
de