Hand-Book and Illustrated Catalogue of the Engineers' and Surveyor' Instruments of Precision

Hand-Book and Illustrated Catalogue of the Engineers' and Surveyor' Instruments of Precision

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 edition. Excerpt: ...water and make observations more difficult. To test the vertical adjustment of the wyes with the aid of an artificial horizon proceed thus: --Having previously verified the adjustments of the striding-level and instrument set it as near to an elevated object as can be conveniently observed, place the artificial horizon within 8 or 10 feet in front of the instrument; level up carefully and bring the bubble of the striding-level to the center of its graduation. Now, if with plates clamped, the vertical wire bisects both the object and its reflection in the artificial horizon, it is proof that the line of collimation lies in a truly vertical plane; but if not, remove half the difference by the wye adjustment and repeat until correct. Now make a memorandum of the deviation of the bubble of the striding-level as explained above in order to apply it as a correction in precise work. While, with the use of an artificial horizon, it is not actually necessary, it will be well to repeat this test with the telescope in reversed position to see if the object and its reflected image remain bisected. If not, it will indicate that the instrument has not been properly adjusted before the test was made. lest of the Equality of the Cylindrical Pivots of horizontal axis of revolution by means of the transverse striding-level resting at circle of contact in wyes. Carefully level up the instrument by the plate level. Next verify the adjustments of the transverse striding-level as explained on page 96 and then make the wye adjustment of the standards by reversing the instrument on its vertical center and, removing half the difference if any and repeating this operation until the bubble of the striding level remains in the center of its graduation. Now remove the..show more

Product details

  • Paperback
  • 189 x 246 x 6mm | 218g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236938208
  • 9781236938206