 | Frederick Walter Simms - 1834 - 124 pages
...the index bring the image of the object to appear with the levels, which must have their air bubbles in the centre of their tubes. The reading of the instrument...if more than 90°, and depressed if less than 90°. THE ARTIFICIAL HORIZON. When the altitude of a celestial object is to be taken at sea, the observer... | |
 | Perry Fairfax Nursey - 1834 - 478 pages
...levels, which must have their air-bubbles in the centre of their tubes. The reading of the instruments will then show the supplement of the zenith distance,...more than 90°, and depressed if less than 90».''— p. 46. The division which treats of " Astronomical Instruments" is the largest of the work. We have... | |
 | 1834 - 494 pages
...levels, which must have their air-bubbles in the centre of their tubes. The reading of the instruments will then show the supplement of the zenith distance,...more than 90", and depressed if less than 90°.''— p. 46. The division which treats of "Astronomical Instruments" is the largest of the work. We have... | |
 | Frederick Walter Simms - 1850 - 184 pages
...must have their air-bubbles in the centre of their tubes. The reading of the instrument will then shew the supplement of the zenith distance, and its complement...if more than 90°, and depressed if less than 90°. THE ARTIFICIAL HORIZON. When the altitude of a celestial object is to be taken at sea, the observer... | |
 | William Davis Haskoll - 1868 - 252 pages
...image of the objects to appear with the small bubbles of the levels, when in the centre of their runs. The reading of the instrument will then show the supplement...its complement to 90° will be the angle required ; elevation if more than 90°, and depression if less. This obviates the necessity for an artificial... | |
 | William Davis Haskoll - 1886 - 354 pages
...image of the objects to appear with the small bubbles of the levels when in the centre of their runs. The reading of the instrument will then show the supplement...its complement to 90° will be the angle required ; elevation if more than 90°, and depression if less. This obviates the necessity for an artificial... | |
| |
... and moving the index bring the image of the object to appear with the levels, which must have their air-bubbles in the centre of their tubes. The reading of the instrument will then show the supplement of the zenith distance, and its complement to... 