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be taken simultaneously. The horizontal circle reads to three minutes by vernier and has a concealed rack adjustment for rapid dialling. The swinging frame and bottom plates can be locked at 360° for converting the instrument to a plain dial. Vertical arc attached below the level of compass and reading to half degrees. Metal head with parallel plates and four levelling screws, and clamp to horizontal motion.

Hedley Steward Miners’ Dial with Double Sights. Fig. 3.

8. Wide Angle Poeket Sextant. (Fig. 4.)

Designed by Mr. John Blakesley, for measuring angles from 0° to 180°, and without error from parallax. The arc, which has a radius of 64 mm, is divided on solid silver and reads by vernier to one minute. The sextant is fitted with an erecting telescope and with a plain aperture sight and tinted glasses. It is furnished also with two index mirrors, mounted on a common vertical axis, the upper mirror being fixed, and the lower one attached to, and moving with the vernier arm by rack and pinion adjustment. The horizon mirror which is

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