Magnification, 4½ and 6½ diameters; Galilean type; object lens, 1¾ inches; interpupillary adjustment; tan leather finish; tan leather carrying case with compass; weight of glass, complete, with case, cord, and straps, 26 ounces; length of glass closed, 4½ inches. At a distance of 1,000 yards the field of view includes a diameter of 90 yards for the 4½ power, and 60 yards for the 6½ power. This glass is issued as a part of the fire-control equipment to field artillery. Price, $17.50. Type C: The type C is a high power glass of the porro prism type and is issued only to certain organizations of the field artillery, Signal Corps, and to all machine-gun platoons. _Description._--Magnification, 10 diameters; prismatic type; object lens, 1¾ inches; interpupillary adjustment; tan leather finish; sunshade; tan leather carrying case; weight of glass, complete, with case, cord, and straps, 46 ounces; length of glass closed, 7¾ inches. At a distance of 1,000 yards the field of view includes a diameter of 80 yards. This glass is issued to reconnaissance officers of field artillery. Price, $39.90. Type D: Purchase has been made for delivery in the near future of a supply of a new type of high power prismatic field glass for sale and issue. This new type of glass, to be known as type D, is considerably smaller than the type C glass, as is shown by figure 34. The glass in a tan-colored carrying case weighs 15 ounces, the field glass without the case weighing but 9 ounces. The magnification is 8 powers and the field of view (with both eyes) 5° 40´. The estimated cost will be $27. TELESCOPES ISSUED BY THE SIGNAL CORPS. Type A: This glass complete consists of a 2-inch prism terrestrial telescope, powers 18 and 24, with alt-azimuth, folding tripod, and carrying case. Type B: This telescope is a 19-27 power, 2-draw terrestrial telescope, in leather carrying case with sling. The leather carrying case also includes a holder which can be screwed into a tree, post, or other stationary wooden object. GENERAL SPECIFICATION NO. 263. [Revised February 10, 1910.] SERVICE FIELD GLASSES. 1. _Preliminary._--This specification covers the design and construction of field glasses, types A and B, each having two powers as hereinafter specified. 2. _Sample._--The bidder shall furnish with his proposal a sample of the glass which he will supply, and award will be made after comparison of the samples with models on file in the office of the Chief Signal Officer. The maker will be allowed to examine the model glasses in detail in the office of the Chief Signal Officer of the Army, Washington, D. C.