Flag kits were not used to any great extent by the American Expeditionary Forces, although large quantities of these were produced in this country.
The Signal Corps originally had jurisdiction over all war photography, either of land or air, except for a small amount conducted by the engineers in connection with their own operations; but later aerial photography became a branch of the Military Aeronautics and Aircraft Bureaus. After that the Signal Corps was charged with taking all photographs of historical nature or other interest.
In connection with this work two types of cameras were necessary—still cameras and motion-picture cameras. Later in the war there was being developed a new motion-picture camera which was expected to be the ideal type for use in the field.
It was with great difficulty that a sufficient number of photographic lenses was obtained for the use of military cameras, since the large lens factories of America were tied up with other war orders. A campaign was conducted by the leading newspapers and magazines of the country which resulted in the Government's securing from amateur photographers a large number of high-grade lenses, mostly of foreign manufacture.
The Signal Corps scattered its camera operators broadcast over the country, photographing cantonments and other war activities to the most minute details. These photographs and films were then made public in newspapers, periodicals, and motion-picture theaters throughout the United States, with the result that the people saw with their own eyes how their soldiers were preparing themselves for the defense of the Nation.
An interesting development of war photography was the production of motion pictures showing the training of soldiers. Many pictures were taken to show graphically on the screen the different chapters of the Army drill regulations. These pictures will have a future use to the Government in training soldiers efficiently in the shortest possible time.
The Signal Corps photographers also developed a new kind of history of the war, a history written entirely in pictures for future generations to scan.
PIGEONS.
Although nearly every European army for 40 years has trained the carrier pigeon to be a field messenger, the American Army never adopted the bird until 1917. In a single year the Signal Corps established hundreds of pigeon lofts in this country and overseas and bought and trained more than 15,000 pigeons for service in France. In actual use on the field the pigeons delivered more than 95 per cent of the messages intrusted to them, flying safely through the heaviest shell and gas barrages.
The standard pigeon loft adopted by the Signal Corps had a unique trap arrangement which permitted the entry but not the exit of returning pigeons, and an electrical alarm which automatically notified the attendants of an arrival. Such lofts, however, were of the stationary type and not practicable for use in France. For the American Expeditionary Forces the Signal Corps purchased mobile lofts. It was found that pigeons would come home as well to mobile lofts, which were constantly changing position, as they would to stationary lofts. The first mobile lofts built in the United States were top-heavy, but this defect was overcome by increasing their width and adding heavier wheels. They were all built by the Trailmobile Co., of Cincinnati, Ohio.