from which it could rise, and where it could receive repairs and supplies, enabled them to operate a long distance off the coast and made them the "eyes of the fleet." They could give warning of the approach of a hostile squadron long before it hove in view. They could announce to France and England, as they frequently did, the coming of raiding Zeppelins and airplanes.
For photographic work, the airplane proved invaluable. The camera was truthful and never in a hurry. What the airman's eyes frequently could not see was recorded by the camera, to be carefully deciphered at headquarters later on. In this way, trenches and fortifications could be clearly traced, and operations could be intelligently based upon these records.
At first the airplane was chiefly relied on by both sides for an aid to the artillery in directing its fire. But gradually it fell into disuse for this purpose. The height at which it had to fly made its directions often inaccurate and then too the increasedly skillful use of camouflage in concealing the gun locations of the enemy thwarted the observer's efforts.
Gradually this use of the airplane was discarded, and the kite balloon took its place. The work of the observer stationed in the balloon was less spectacular than that of the aviator, but far more accurate, and in many respects more important. His work was not marred by haste. He had powerful glasses that gave him a radius of 10 miles. He had time to study a suspicious thicket or clump of trees, and see whether it really marked a concealed gun position. He could keep constantly in touch with his batteries by telephone.
To be sure, his work was extremely hazardous. But he had to be a fatalist and remain quietly in his position. His balloon offered an alluring target for the enemy's long-range guns. Hostile aviators swooped down at the great bag and sought to puncture it with bullets. If an incendiary bullet penetrated the fabric and ignited the hydrogen gas, the balloon was doomed. Not more than 15 or 20 seconds would elapse before the explosion came. The observer's only salvation then was the parachute with which each was equipped. In the 17 days before the armistice was signed, the American army alone lost 21 balloons in this way, but in return our own aviators and artillery brought down 50 German balloons in the same period.
When the war began, the Germans had about 100 kite balloons of the Drachen type. The Allies had practically none. They set to work, however, and eventually produced the Caquot balloon, which proved to have so many advantages over the Drachen that Germany herself finally adopted it.
The Caquot balloon has a length of 93 feet, while its largest diameter is 28 feet. It has a capacity of 37,500 cubic feet of hydrogen gas, and this proves sufficient to lift the mooring cable, the basket, two observers and all necessary equipment to a height, if desired, of
