 To set the glasses perpendicular to the plane of the quadrant there are two sunk screws, one before and one behind each glass: these screws pass through the plate on which the frame is fixed into another plate, so that by loosening one and tightening...  A complete epitome of practical navigation - Page 154by John William Norie - 1839Full view - About this book
 | Robert Gibson - Surveying - 1811 - 580 pages
...the glass may be turned a few degrees on its axis, in order to set it parallel to the Index glass. To set the glasses perpendicular to the plane of the...the frame is fixed into another plate, so that by looseningoneand tightening the other of these screws, the direction of the frame, with its mirror,... | |
 | George Adams - Geometry - 1813 - 648 pages
...parallel to the index glass. The lever has a contrivance to turn it slowly, and a button to fix it. To set the glasses perpendicular to the plane of the...mirror, may be altered, and thus be set perpendicular to the plane of the instrument. Of the shades, or dark glasses, K. There are two red or dark glasses,... | |
 | George Adams - Geometry - 1813 - 576 pages
...parallel to the index glass. The lever has a contrivance to turn it slowly, ani a button to fix it. To set the glasses perpendicular to the plane of the...are two sunk screws, one before and one behind each £ - lass ; these screws pass through the plate, on which the frame is fixed, into another plate, so... | |
 | Robert Gibson - Surveying - 1814 - 558 pages
...the glass may be turned a few degrees on its axis, in order to set it parallel to the Index glass. To set the glasses perpendicular to the plane of the...fixed into another plate, so that by loosening one and lightening the other of these screws, the direction of the frame, with its mirror, may be altered,... | |
 | Robert Gibson - Surveying - 1821 - 594 pages
...the glass may be turned a few degress on its axis, in order to set it parallel to the Index glass. To set the glasses perpendicular to the plane of the...mirror, may be altered, and thus be set perpendicular to the plane of the instrument. The Dark Glasses, or Shades /, are used to prevent the bright rays of... | |
 | Robert Gibson - Surveying - 1832 - 290 pages
...the glass may be turned a few degrees on its axis, in order to set it parallel to the index glass. To set the glasses perpendicular to the plane of the...mirror, may be altered, and thus be set perpendicular to the plane of the instrument. The dark glasses, or shades, /, are used to prevent the bright rays of... | |
 | Robert Gibson - Surveying - 1833 - 436 pages
...turned a few degrees on its axis, in order to set it parallel to the index glass. To set the jglasses perpendicular to the plane of the quadrant there are...mirror, may be altered, and thus be set perpendicular to the plane of the instrument. The dark glasses, or shades, /, are used to prevent the bright rays of... | |
 | Robert Gibson, James Ryan - Surveying - 1839 - 452 pages
...the glass may be turned a few degrees on its axis, in order to set it parallel to the index glass. To set the glasses perpendicular to the plane of the...sunk screws, one before and one behind each glass i these screws pass through the plate on which the frame is fixed into another plate, so that by loosening... | |
 | Benjamin Pike (Jr.) - Scientific apparatus and instruments - 1848 - 482 pages
...set it parallel to the index glass ; the lever has a contrivance to turn it slowly. To set this glass perpendicular to the plane of the quadrant there are two sunk screws, one before and one behind the glass ; these screws pass through the plate on which the frame is fixed, into another plate, so... | |
 | Benjamin Pike - Science - 1848 - 356 pages
...set it parallel to the index glass ; the lever has a contrivance to turn it slowly. To set this glass perpendicular to the plane of the quadrant there are two sunk screws, one before and one behind the glass ; these screws pass through the plate on which the frame is fixed, into another plate, so... | |
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