Elementary astronomy; a beginner's text-book (1899)
Holden, Edward Singleton, 1846-1914 · New York, H. Holt and company · leaf 137
unwind the string. Smalladjustments are best made by gentlyturning the spool. Many improvements have been made in pendulum-clockssince they were first invented by Huyghens (pronouncedhigenz) in 1657, and they are now extraordinarily accu-rate. Chronometers are merely very perfect watches.Their… … 116 ASTRONOMY. Circles.—Angles can be measured by circles divided todegrees, etc. If the arc SS* is so divided and if it has aradial bar ES that can be moved around a pin at thecentre of the circle at E, the angle between any two starscan be measured in the following way : 1st. Place the circle so…
Astronomy
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