Minutes of proceedings of the Royal Artillery Institution (1858)
Great Britain. Army. Royal Artillery Institution · Woolwich, Eng., : The Institution · leaf 62
consists of a plate-glass prism, bound in brass, baying tbe angle BAC carefully ground to 88° 34' 3", tbe back, BBEC, being silvered, so as to act as a mirror. Its cost is great, owing to tbe care which bas to be given to cutting tbe angle accurately. In practice, tbis instrument, small as it is,… … palm tree, A. Tbe observer moves along tbe line CF until be sees the palm tree and tbe eye of tbe soldier at C coincide. Tbe soldier at C, provided witb a similar instrument, sees tbe palm tree and tbe eye of the observer at B reflected in a similar way. Then each of tbe angles ABC, ACB = 88° 34'…
Artillery -- Periodicals · Artillery -- Great Britain -- Periodicals
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