 | Frederick Walter Simms - Astronomical instruments - 1834 - 124 pages
...covers its image, as seen directly; and any error is easily rectified by turning the small screw, i, at the lower end of the frame of the glass. To examine...zero on the limb, if you direct your view to some object, the sun for instance, you will see that the two images (one seen by direct vision through the... | |
 | Frederick Walter Simms - Astronomical instruments - 1844 - 190 pages
...observer; and vice versS. The consequence is just reversed, if the inverting telescope is employed.' To examine the Parallelism of the Planes of the two...zero on the limb, if you direct your view to some object, the sun for instance, you will see that the two images (one seen by direct vision through the... | |
 | Basil Jackson - Military reconnaissance - 1847 - 410 pages
...covers its image as seen directly ; and any error is easily rectified by turning the small screw, i, at the lower end of the frame of the glass. TO EXAMINE THE PARALLELISM OF THE PLANES OF THF. TWO GLASSES, WHEN THE INDEX IS SET TO ZERO. This is easily ascertained ; for, after setting the... | |
 | Benjamin Pike - Science - 1848 - 356 pages
...covers its image, as seen directly ; and any error is easily rectified by turning the small screw, i, at the lower end of the frame of the glass. To examine...zero on the limb, if you direct your view to some object, the sun for instance, you will see that the two images (one seen by direct vision through the... | |
 | Benjamin Pike (Jr.) - Scientific apparatus and instruments - 1848 - 482 pages
...covers its image, as seen directly ; and any error is easily rectified by turning the small screw, i, at the lower end of the frame of the glass. To examine...zero on the limb, if you direct your view to some object, the sun for instance, you will see that the two images (one seen by direct vision through the... | |
 | Sir Henry Edward Landor Thuillier - Surveying - 1851 - 826 pages
...covers its image as seen directly; and any error is easily rectified by turning the small screw, i, at the lower end of the frame of the glass. To examine...zero on the limb, if you direct your view to some object, the sun for instance, you will see that the two images (one seen by direct vision through the... | |
 | Basil Jackson - Military reconnaissance - 1853 - 420 pages
...covers its image as seen directly ; and any error is easily rectified by turning the small screw, i, at the lower end of the frame of the glass. TO EXAMINE...ascertained; for, after setting the zero on the index to the zero on the limb, if you direct your view to some object, the sun for instance, you will see that... | |
| |
... Horizon-glass, and set it perpendicular to the Plane of the Sextant. The position of this glass is known to be right, when by a sweep with the index, the reflected image of any object passes exactly over or covers its image, as seen directly; and... 