3/31/2024 0 Comments Use a military protractorAlthough the illustration is correct in the 1921 catalog, the description is of the form advertised in the 19 catalogs. (New York, 1936), 203 Catalogue of Keuffel & Esser, 39th ed. (New York, 1921), 119 Catalogue of Keuffel & Esser, 38th ed. (New York, 1916), 172 Catalogue of Keuffel & Esser, 36th ed. (New York, 1913), 172 Catalogue of Keuffel & Esser, 35th ed. Cooke, "Scales for Determining Slope from Topographic Maps," The Professional Geographer 20, no. K&E noted in the 1943 catalog that the changed form was manufactured according to the specifications of the Corps of Engineers. The design of the instrument changed again between 19. K&E began to sell this form of military protractor between 19, so this object may have been in use during World War I (as the markings suggest). Army Corps of Engineers in the 19th and 20th centuries. The United States Engineering Department was part of the U.S. Maker's and owner's marks are near the lower edge: KEUFFEL & ESSER CO. The first is marked by thousands of yards from 1,000 to 8,000 the second is marked by 500 yards from 500 to 2,500 and the third is marked by 500 yards from 500 to 1,000. Each scale is divided in 100-yard increments. Below that scale are three scales for 1", 3", and 6" to the mile, respectively. The scales for each set of slope measurements are not indicated, but they presumably are standard scales for American military engineering, such as 1:63,360 and 1:25,000.Ī scale of inches divided to tenths and marked by ones from 0" to 5" appears on the interior of the protractor. These allow draftsmen to read or draw topographical contours indicating slopes in landforms of 7° and 3-1/2° 8°, 4°, 2°, and 1° 10°, 5°, and 2-1/2° and 12°, 6°, 3°, and 1-1/2°, respectively. A small hole near the 160° mark permits a weight to be suspended so that the protractor functions as a rough clinometer, to measure angles of elevation or slope.įour slope scales appear on the bottom edge of the instrument. It is divided by degree and marked by tens from 10° to 170° and from 190° to 350°, both in the clockwise direction. The purchaser is responsible for conforming to all applicable state and local laws.This yellow xylonite (celluloid-like plastic) rectangular protractor is contained in a paper wrapper marked: MILITARY PROTRACTOR (/) MADE BY (/) KEUFFEL & ESSER CO. All items will be shipped with SIGNATURE REQUIRED. The purchaser is responsible for conforming to all applicable Country, State and Local laws. Usually available for pickup in our store in Las Vegas, or would ship ASAP. GOOD LUCK TO YOUR MISSION Features of the Protractor: Moisture is a common malfunction of the GPS. It can be jammed and detected when near or behind enemy lines. GPS readings are distorted during thunderstorms, electronic interference and when bombing support is very close on enemy positions. The GPS will not penetrate sandstorms, rainstorms, snowstorms, smoke, structures, forest canopies, and thick cloud cover. Protractors without the conversion formula will provide a reading that is off the exact grid coordinate position. The RM Military Protractor is the only protractor with a printed formula and a diagram to align map grid north to match the compass magnetic north. The only known BACK-UP of the GPS when it malfunctions is your ability to use a military protractor and military compass.
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