¹ Source: wiktionary.com
Definition of Penumbras
1. penumbra [n] - See also: penumbra
Lexicographical Neighbors of Penumbras
Literary usage of Penumbras
Below you will find example usage of this term as found in modern and/or classical literature:
1. The Sun by Charles Greeley Abbot (1911)
"Radial Motion in Spot penumbras. ALTHOUGH occasionally seen, and recorded much
earlier without recognition of their solar origin, the history of sun-spots ..."
2. The Annual of Scientific Discovery, Or, Year-book of Facts in Science and Art by David Ames Wells, George Bliss, Samuel Kneeland, John Trowbridge, Charles Robert Cross (1859)
"while the penumbras are cracked and gaped outward like old and wind-tossed palm
leaves. There is no certainty, therefore, that any but the principal spots ..."
3. The Sun by Charles Greeley Abbot (1911)
"Radial Motion in Spot penumbras. ALTHOUGH occasionally seen, and recorded much
earlier without recognition of their solar origin, the history of sun-spots ..."
4. Cosmos: A Sketch of a Physical Description of the Universe by Alexander von Humboldt, Elise C. Otté, Benjamin Horatio Paul (1858)
"He, moreover, had the merit of having facili tated the explanation of the penumbras,
by assuming, very much in accordance with the conjectures of Cardinal ..."
5. Mathematics Practically Applied to the Useful and Fine Arts by Charles Dupin, George Birkbeck (1827)
"PRINCIPLE OF penumbras. as we have just done to the sun, the visual rays which
are tangents to it, they determine on this object the limit of the points ..."
6. The Journal of Science by Calcutta Asiatic Society (1864)
"As there occur umbras without penumbras, so penumbras occur without ... The umbras,
when large, affect more compact and rounded forms than the penumbras, ..."
7. Science by American Association for the Advancement of Science (1896)
"... but simply to umbras and penumbras formed by rays emanating from different
points and falling upon coins of different thicknesses. In repeating Prof. ..."
8. The Proceedings of the Iowa Academy of Science by Iowa Academy of Science (1903)
"Two large and active groups were in south latitude from April 27th to May 14th,
one containing curiously shaped umbrae and penumbras, with many luminous ..."
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