Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn · leaf 27
he vernier marked 9 coincideswith a line of the limb. Hence, the reading is 32° 9. When the index moves from the zero line of the limb in adirection opposite to that in which run the numbers of thelimb, the number of minutes obtained as above must be sub-tracted from 30 to obtain the minutes… … Fig. 13 only fifteen spaces on each side of the zero line. When thevernier is turned to the right less than 15 past a division lineof the limb, read the lower figures on the left of the zero lineat any coincidence; if moved more than 15 past a divisionline of the limb, read the upper figures on the…
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