| Sir J. Butler Williams - 1846 - 368 pages
...denoted by the vernier, the reading on or within the arc, that is the reading within the graduation. Next place the index about the same quantity to the...minutes and seconds on the arc of excess the reading off or without the arc; and half the difference of these numbers is the index error ; additive when the... | |
| Basil Jackson - 1847 - 410 pages
...The amount of the indexerror may be found in the following manner : — Clamp the index at about 30- to the left of zero, and, looking towards the sun,...arc, and half the difference of these numbers is the index-error: additive when the reading on the arc of excess is greater than that on the limb, and subtractive... | |
| Elias Loomis - 1855 - 510 pages
...nearly in contact, or overlapping each other. Then perfect the contact by moving the tangent screw, and call the minutes and seconds denoted by the vernier,...minutes and seconds on the arc of excess, the reading offtbe arc. Half the difference of these numbers is the index error ; additive when the reading on... | |
| Elias Loomis - 1860 - 518 pages
...nearly in contact, or overlapping each other. Then perfect the contact by moving the tangent screw, and call the minutes and seconds denoted by the vernier,...perfect, as before, and call the minutes and seconds dn the arc of excess, the reading o^the arc. Half the difference of these numbers is the index error... | |
| W.H.C. BARTLETT,LL.D., - 1865 - 494 pages
...again be examined. The adjustment may, however, be rendered unnecessary by correcting an observation by the index error. The effect of this error on an angle...seconds on the arc of excess the reading off the arc ; half the difference of these numbers is the index error ; additive when the reading on the arc of... | |
| Elias Loomis - 1865 - 516 pages
...nearly in contact, or overlapping each other. Then perfect the contact by moving the tangent screw, and call the minutes and seconds denoted by the vernier,...as before, and call the minutes and seconds on the are of excess, the reading offth& arc. Half the difference of these numbers is the index error; additive... | |
| James Pryde - 1867 - 506 pages
...nearly in contact, or overlapping each other. Then perfect the contact by moving the tangent screw, and call the minutes and seconds denoted by the vernier,...reading on the arc. Next place the index about the same distance to the right of zero, or on the arc of excess, and make the contact of the two images perfect... | |
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