Lanterna Rally

Author: Sarah Frances Whiting

Publisher: Rarebooksclub.com

Published: 2013-09

Total Pages: 28

ISBN-13: 9781230174570

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 edition. Excerpt: ...at lower temperature will absorb light given out by the same at higher temperature. If white light be transmitted through vapors at lower temperature, it will be deprived of the wave lengths characteristic of each vapor. It will give a broken spectrum. 4. A widening of lines in general indicates that the source of light is undergoing pressure. 5. Doppler's principle. A displacement of lines toward the red end of the spectrum indicates that the source of light is receding; a displacement toward the blue, that the source is approaching. 6. A coincidence of reversed lines in the spectrum of sun or star, with bright lines obtained from some element in the laboratory, indicates the presence of that element. 7. Zeeman's principle. If a source of light is placed in a magnetic field, the simple lines of its spectrum will be resolved into triplets or more complex forms. EXERCISE XXV USE OF CLOCKS Clocks are of two kinds: 1. Those which keep sidereal time; that is, the actual time of the earth's rotation. These " sidereal clocks" begin the day, 0h 0m 0!, at what is called " sidereal noon," the instant when the vernal equinox crosses the meridian. They are graduated into twenty-four hours. 2. Those which keep " mean time"; that is, which mark noon when the fictitious sun crosses a certain meridian. They may keep a. Local mean time; that is, mark noon when the fictitious sun crosses the meridian of the place. b. Standard time; that is, mark noon when the fictitious sun crosses the standard meridian. c. Civil mean time, which begins the day at midnight. "d. Astronomical mean time, which begins the day at noon. Description of clocks at Whitin Observatory.i 1. The sidereal clock is by E. Howard & Co. of Boston. It...