The geography of the heavens, and class-book of astronomy: (1858)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868 · New York, Mason brothers · leaf 312
rays of the Sun to afocus, and setting combustible substances onfire. Such glasses have been made powerfulenough to melt the most refractory substances,as platinum, agate, <fec. A len3 three feet indiameter, says Professor Gray, has beenknown to melt cornelian in 75 seconds, and apiece of white… … 312 ASTRONOMY. REFEECTION BY A PLANE MIRROR.
Constellations · Stars
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