. Machinery and processes of the industrial arts, and apparatus of the exact sciences. and 127. The parts marked r are silvered on one side, andthose more darkly shaded on the other. Theparts unshaded are transparent. The box ismounted on a tripod by means of a central pivot,around which it may revolve horizontally. Thispivot is fixed to the tripod by a ball and socketjoint, which allows the plane of revolution, if Fig. 126. necessary, to be inclined. Two telescopes arealso attached to the apparatus, each making aright angle in the interior of the box; a rectangu-lar glass prism being placed i
. Machinery and processes of the industrial arts, and apparatus of the exact sciences. and 127. The parts marked r are silvered on one side, andthose more darkly shaded on the other. Theparts unshaded are transparent. The box ismounted on a tripod by means of a central pivot,around which it may revolve horizontally. Thispivot is fixed to the tripod by a ball and socketjoint, which allows the plane of revolution, if Fig. 126. necessary, to be inclined. Two telescopes arealso attached to the apparatus, each making aright angle in the interior of the box; a rectangu-lar glass prism being placed in the angle to changethe direction of the rays by total reflection. Theeye-pieces of these telescopes are presented atright angles to the axis of the box in opposite directions. The distancebetween the centers of the mirrors is one meter. In the sides of the boxopposite the mirrors are openings to admit the light from the objectto be observed. The use of the instrument may be thus explained. Let us suppose, atfirst, that the two mirrors are at an angle of forty-five degrees to the.
Size: 2158px × 1158px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectmachinery, booksubjectscientificappa
