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NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEPGE

in length to 9 divisions of the fixed scale and divided into 10 equal parts,
the degree of accuracy thus obtained being -005 of an inch.

The millibar vernier is equal to 39 divisions of the fixed scale, but
instead of being divided into 40 parts, the vernier is divided into 10
equal parts, thus giving a wider spacing of the divisions making it
easier to read without loss of accuracy, the nearest reading obtainable
being one-tenth of a millibar.

Fig. 12.—Barometer luck Scale and Vernier. The Reading is 29*684,
The figoze illustrates a barometer scale and vernier graduated in
inches- AB is the fixed scale, CD the sliding vernier, D is the top of
the mercury column. The reading is 29-684 arrived at as follows:
The point D Ees between 29-650 and 29-700, the lower reading 13
noted, 23*65 and the additional part is got from the vetnier. The