CHAPTER XIV.

INSTRUMENTS OF REFLECTION:--Octant or Quadrant--Reflecting

Circle--Sextant--Principle--Parallax--Construction--Examination--

Adjustment--Artificial Horizon--Sounding Sextant--Box-Sextant--

Supplementary Arc--Improvements upon this--Optical Square--Optical

Cross--Apomecometer 422

Surveying and Levelling Instruments, Theoretically and Practically Described. For construction, qualities, selection, preservation, adjustments, and uses; with other apparatus and appliances used by civil engineers and surveyors in the field. · 第 14 / 26 章