SEARCH
0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Prev | Current Page 221 | Next

Humboldt, Alexander von, 1769-1859

"COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1"



[footnote] *'Relation Historique', t. i., p. 80, 213, 527. If in falling
stars, as in comets, we distinguish between the head or nucleus and the
tail, we shall find that the greater transparency of the atmosphere in
tropical climates is evinced in the greater length and brilliancy of the
tail which may be observed in those latitudes. The phenomenon is therefore
not necessarily more frequent there, because it is oftener seen and
continues longer visible. The influence exercised on shooting stars by the
character of the atmosphere is shown occasionally even in our temperate
zone, and at very small distances apart. Wartmann relates that on the
occasion of a November phenomenon at two places lying very near each other,
Geneva and Aux Planchettes, the number of the meteors counted were as 1 to
7. (Wartmann, 'M??m. sur les Etoiles filantes', p. 17.) The tail of a
shooting star (or its 'train'), on the subject of which Brandes has made so
many exact and delicate observations, is in no way to be ascribed to the
continuance of the impression produced by light on the retina. It sometimes
continues visible a whole minute, and in some rare instances longer than the
light of the nucleus of the shooting star; in which case the luminous track
remains motionless.


Pages:
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233