Brocklesby, John, 1811-1889. [from old catalog] · New York, Sheldon and company · leaf 142
ord nucleus, a kernel. 3. Penumbra, from the Latin pene, almost, and umbra, a shadow, i. e.,a light shade. Describe the spots? Are they permanent? Describe the changes incident to them?la the umbra necessarily black? Do the spots usually appear singly? 130 SOLAR SYaTE:.I. observed by Davis, in…
Astronomy
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