Application for the purchase of field glasses should be addressed to the Chief Signal Officer of the Army, Washington, D. C., inclosing post-office money order or check on the Treasurer or Assistant Treasurer of the United States for the amount, payable to the Disbursing Officer, Signal Corps, and Signal Corps Form No. 240 accomplished in duplicate.
The Government does not pay transportation charges for the shipment of articles sold to officers. Field glasses are sent from the Signal Corps General Supply Depot, Fort Wood, New York Harbor, by express, charges collect, unless purchase request is accompanied by funds so that field glasses may be sent by registered mail. Forwarding by registered mail is somewhat cheaper than by express, and the amount of postage required is 40 cents for Type D glass, 46 cents for Types A and B, and 74 cents for Type C. Express charges depend upon the distance from New York.
The Signal Corps has purchased many samples of field glasses from various manufacturers with a view of testing their suitability for the military service. These samples may be examined by officers of the army at the signal office in Washington. Among these samples there are many excellent glasses especially suitable for the military service, but the higher grades are too expensive for general issue to line organizations in large quantities. Officers desiring an especially fine field glass should inspect the samples referred to; these, however, are not for sale by the Government, but information will be supplied concerning dealers and cost.
No advice or fixed rule can be stated as to what constitutes the most suitable characteristics of a field glass. No single field glass can furnish maximum results under all conditions on account of varying conditions of the atmosphere.
A high-power glass is unsuitable for use at night, hazy atmosphere, or for use of a mounted man where the glass can not be rested against a firm support. A low-power glass with large object lens to permit as much light as possible is a necessary condition for use at night. The double power glass which is issued as a part of the visual signaling outfits was designed for the military service as a compromise for conflicting conditions.