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| Keywords: grugan heliograph heliographe signal corps signalcorps united states army signal corps unitedstatesarmysignalcorps grugan heliograph gruganheliograph heliógrafo blackandwhite monochrome sketch drawing black and white Heliographs are optical communications instruments that communicate by flashes of mirror reflected sunlight using Morse or Myer code. To learn more, see: Wikipedia : Heliograph Frank Carter Grugan has been credited as the inventor of the American heliograph. After testing the British Mance and Begbie models, Grugan was dissatisfied with them, and developed his own, with the initial design for his heliograph developed by 1879, which he perfected by 1882. This figure is from U.S. Patent 239,095 to F.C. Grugan, issued March 22, 1881. The Grugan heliograph became quite popular with the United States Army Signal Corps, and their standard heliograph adopted in 1888 was very similar. The standard heliograph, however, had a single-blade shutter that operated on a horizontal axis, rather than the vertical axis of the Grugan. It also had mirrors 4.5 inches square vs. the 3.5 inches square of the Grugan. The shutter, or "screen" of the American heliograph underwent an extended evolution, passing through the vertical axis shutter shown here, to the horizontal axis of 1888, the dual-blade horizontal axis system of 1892 (the "Kilbourne screen"), and finally ending in a six-blade horizontal shutter. In 1893, the Chief of the Signal Corps, A.W. Greely gave an extended discussion of the evolution of the heliograph screen up to that point in time. This figure is annotated - pass your mouse over the screen to see the annotation rectangles, and over the rectangles to see the annotation text. This figure is public domain in the United States, since it was published before 1923, and I claim no copyright on it. You are free to use it as your laws permit. You may prefer to work from the original patent which is available from many sources, some of which may have higher resolution than the Google Patent link I provide above. Heliographs are optical communications instruments that communicate by flashes of mirror reflected sunlight using Morse or Myer code. To learn more, see: Wikipedia : Heliograph Frank Carter Grugan has been credited as the inventor of the American heliograph. After testing the British Mance and Begbie models, Grugan was dissatisfied with them, and developed his own, with the initial design for his heliograph developed by 1879, which he perfected by 1882. This figure is from U.S. Patent 239,095 to F.C. Grugan, issued March 22, 1881. The Grugan heliograph became quite popular with the United States Army Signal Corps, and their standard heliograph adopted in 1888 was very similar. The standard heliograph, however, had a single-blade shutter that operated on a horizontal axis, rather than the vertical axis of the Grugan. It also had mirrors 4.5 inches square vs. the 3.5 inches square of the Grugan. The shutter, or "screen" of the American heliograph underwent an extended evolution, passing through the vertical axis shutter shown here, to the horizontal axis of 1888, the dual-blade horizontal axis system of 1892 (the "Kilbourne screen"), and finally ending in a six-blade horizontal shutter. In 1893, the Chief of the Signal Corps, A.W. Greely gave an extended discussion of the evolution of the heliograph screen up to that point in time. This figure is annotated - pass your mouse over the screen to see the annotation rectangles, and over the rectangles to see the annotation text. This figure is public domain in the United States, since it was published before 1923, and I claim no copyright on it. You are free to use it as your laws permit. You may prefer to work from the original patent which is available from many sources, some of which may have higher resolution than the Google Patent link I provide above. | ||||
