CHAPTER VI.

DIVISION OF THE CIRCLE AND METHODS EMPLOYED IN TAKING ANGLES:--

Dividing Engine--Surfaces for Graduation--Vernier--Various

Sections--Reading Microscopes--Shades--Micrometers--Clamp and

Tangent Motions--of Limbs--of Axes--Use and Wear--Difference of

Hypotenuse and Base 175

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 6 / 26 章