| William Galbraith - 1842 - 216 pages
...an index error, to be applied according to its sign, which must be carefully noted. This index-error is best determined by repeating the observation of an altitude, or depression in reversed positions of the telescope and vernier-plate, then half the difference will be the error ;... | |
| Sir J. Butler Williams - 1846 - 368 pages
...the deviation be small, note the quantity of deviation as an index error, and apply it, + or — , to each vertical angle observed. This deviation is...the reversed positions, both of the telescope and vernier-plate: the two readings will have equal and opposite errors, ajid the half of their difference... | |
| Basil Jackson - 1847 - 410 pages
...to the middle of the tubes, by merely giving motion to the capstanheaded screws at each end of them. The vernier of the vertical arc may now be attended...readings will have equal and opposite errors, one half of the difference being the index error. Such a method of observing angles is decidedly the best, since... | |
| P. O'Shaughnessy (Civil engineer) - 1848 - 110 pages
...what is perhaps better, note the quantity of deviation as an index error, and apply it more or less to each vertical angle observed. This deviation is...observation of an altitude or depression in the reversed position, of both the telescope and verneir plate : the two reading will have an equal and opposite... | |
| John Ainslie - 1849 - 586 pages
...an index error, to be applied according to its sign, which must be carefully noted. This indexerror is best determined by repeating the observation of an altitude, or depression in reversed positions of the telescope and vernierplate, then half the difference will be the error ;... | |
| Sir Henry Edward Landor Thuillier - 1851 - 826 pages
...vertical angle observed. This deviation is best determined by repeating the observation of an altitude of depression in the reversed positions, both of the...two readings will have equal and opposite errors, one-half of their difference being the index error. Such a method of observing angles is decidedly... | |
| William Davis Haskoll - 1868 - 252 pages
...or minus, to each vertical angle observed. This, however, necessitates making a note of the error. This deviation is best determined by repeating the...observations taken with the telescope reversed in its T'S must be free from the effects of any error that may exist in the adjustment of the vernier, or... | |
| J. L. Robinson - 1882 - 356 pages
...head from zero, when the Theodolite is perfectly adjusted) is best obtained as follows: — repeat the observation of an altitude or depression in the...reversed positions both of the telescope and the vernier circle. The two readings will have equal and opposite errors ; the index error is half their difference.... | |
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