of Luminous Meteors. 891 



has been already adverted to ; and indeed it is a matter of daily 

 observation, that two parties, both perfect in their perception of 

 colour, will differ in their mode of explaining the tint even of 

 stationary objects ; how much more may we expect them to diflfer 

 when a coloured light is suddenly presented up in the sky, and 

 as suddenly disappears ! Cases in point are not wanting. A 

 meteor which Mr. Lowe designated as yellow, appeared " of a 

 beautiful clear blue colour" to Mr. T. W. Webb*. But a more 

 curious instance occurred last autumn. The meteor of Septem- 

 ber 12, 1858, was described in the Times newspaper by several 

 eye-witnesses, of whom F. A. B. states it to have been " green 

 at first;" N. R. "green surrounded by white;" W. Rowlett, 

 " white ;" and T. W. "vivid whitish blue ;" while B. H. declares 

 it was " primrose." Such opposite statements would overthrow 

 entirely our confidence in the recorded observations, were it not 

 that the greatness of the discrepancy leads us to the belief that 

 the meteor in question must have been one that changed in 

 colour, and thus actually presented a different appearance in this 

 respect to observers in different places. 



It is also quite possible that a meteor may emit rays which in 

 the aggregate would produce one colour, and yet may affect the 

 observer with a sensation of a different colour. This may arise 

 from absorption, intensity, or contrast. 



Absorption. — Thin mists and long reaches of air have a ten- 

 dency to absorb or disperse the more refrangible rays emitted 

 from a luminous body, while they suffer the less refrangible to 

 pass. Thus eveiyone has noticed how red the sun, and how 

 orange the moon appear under certain circumstances, especially 

 when near the horizon. This effect must frequently be produced 

 on the light of meteors during their passage through our atmo- 

 sphere. 



A row of street lamps in misty weather exhibits the same 

 phaenomenon on a smaller scale ; and it may be observed even 

 in clear weather by looking, not at the jets of flame themselves, 

 but at the streamers which appear to issue from them when we 

 nearly close our eyelids. The streamers from the nearer gas- 

 lamps appear yellowish white, from those further removed green- 

 ish or orange, and from the most distant almost red. A caudle 

 seen through a mixture of a little milk with a large quantity of 

 water, also exhibits in a striking manner the non-transmission of 

 the more refrangible rays. 



This suggests a simple explanation of the fact, that those 

 meteors which appear to change colour during their passage 

 through the misty skies of England almost invariably terminate 

 in red. It may not, however, be the sole reason. 

 * British Association Rejxjrt, 1852, p. 189. 



