American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 432
beadjusted. At the upper end of the arm a, a small, adjustable sight vane sv is placed.This vane is shown separately, and enlarged, at the left of the figure. The instrument is adjusted and used as follows: The sight vane and the mirrorare set facing the distant station when the sun s is in the… … THE HELIOGRAPH. 362 AMERICAN TFXEGRAPHY. Fig. 274. M and the arm carrying the sight vane, are then so adjusted that the hole in the centreof the mirror, and the hole in the sight vane, below the v, are in a straight linewith the distant station. When so adjusted, the dark spot in the reflection,…
Telegraph
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