 Box, n, has an arc of about 36° in extent, divided to half degrees, and figured from the centre or zero mark on either side. The needle, which is made as in other instruments, except that the arms are of unequal lengths, is raised or lowered by a lever...  Gurley Manual of Surveying Instruments ... - Page 66by Gurley, W. & L. E., Troy, N.Y. - 1871Full view - About this book
 | Centennial Exhibition - 1876 - 558 pages
...instrument to a horizontal position. The Needle-box has an arc of ____________ ' .V about thirty-six degrees in extent, divided to half degrees, and figured from...lengths, is raised or lowered by a lever shown in the engraving. The needle-box is attached, by a projecting arm to a tangent-screw, /, by which it is moved... | |
 | Horatio Nelson Robinson - Navigation - 1878 - 564 pages
...described constitute properly the solar apparatus. Besides these, however, are seen the needle box, n, with its arc and tangent screw, t, and the spirit levels,...extent, divided to half degrees, and figured from the center or zero mark on either side. The needle, which is made as in other instruments, except "That... | |
 | Charles Davies - Surveying - 1883 - 578 pages
...described constitute properly the solar apparatus. Besides these, however, are seen the needle-box, n, with its arc and tangent screw, t, and the spirit levels,...the whole instrument to a horizontal position. The Needle-Bos:, n, has an arc of about 36' in extent, divided to half degrees, and figured from the centre... | |
 | Charles Fitzroy Bellows, Francis Hodgman - Surveying - 1886 - 490 pages
...solar apparatus. Beside these, however, are seen the needle'box, n, with its arc and tangent-screw, t, and the spirit levels, for bringing the whole instrument to a horizontal position. 153. The Needle Box has an arc of about 36° in extent, divided to half degrees, and figured from the... | |
 | Daniel Carhart - Surveying - 1888 - 528 pages
...apparatus. 327. The Needle-Box n has an arc of about 86 degrees in extent, divided to half-degrees, and figured from the centre or zero mark on either...lengths, is raised or lowered by a lever shown in the cnt. The needle-box is attached by a projecting arm to a tangentscrew t, by which it is moved about... | |
 | Daniel Carhart - Surveying - 1888 - 530 pages
...described constitute properly the solar apparatus. Besides these, however, are seen the needle-box n with its arc and tangent screw t, and the spirit levels,...bringing the whole instrument to a horizontal position. 327. The Needle-Box n has an arc of about 86 degrees in extent, divided to half-degrees, and figured... | |
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