Hinks, Arthur R. (Arthur Robert), 1873-1945 · Cambridge, University press · leaf 138
rtical, and the test of verticalityis that the ends of the bubble B shouldnot move along the scale when theinstrument is rotated about V. Thebubble may not be central on the scale, but so long as it doesnot move along the scale when the instrument is rotated, theaxis is vertical. Hence the process…
Maps · Surveying
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