Herschel, John F. W. (John Frederick William), Sir, 1792-1871 · London : Longman, Rees Orme · leaf 100
highest, and must be lowered. Astronomicallevels are furnished with a divided scale, by which theplaces of the ends of the bubble can be nicely marked;and it is said that they can be executed with such de-licacy, as to indicate a single second of angular deviationfrom exact horizontality. (143.)… … F 94? A TREATISE ON ASTRONOMY. CHAP. li- able in one with it on a horizontal axis G, which mustbe like that of a transit, susceptible of reversal (seeart. 127.), and with which the circle is inseparablyconnected. Direct the telescope on some distant well-defined object S, and bisect it by its…
Astronomy
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