Ball, R[obert] S[tawell], Sir, 1840- [from old catalog] · New York, H. Holt and company · leaf 21
13 minutes, 11seconds, and four-tenths of one second. B 2 Astronomy. We shall now explain what is meant by a graduatedcircle. Let the circumference of a circle adb (fig. i)be divided into 360 parts of equal length. The divi-sion lines separating these parts are denoted by o°,i°, 20, &c., up to… … 270° There is, however, no difficulty in finding at a glancethe number appropriate to any intermediate division.To facilitate this operation the divisions 5°, 150, 250,which are situated half-way between each of the num-bered divisions, are sometimes marked with a longerline, so that they can be…
Astronomy
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