1859.] on the Colours of Shooting Stars and Meteors. 147 



at Lambeth : — " As it brightened it displayed the most lovely colours, 

 which could be distinctly traced to the radial colours produced by the 

 sun ; at one period green, violet (deep), pale red, &c., and their etfects 

 through the thin stratum of clouds which were in its path were most 

 gorgeous." In a most graphic description, given by a lady, of a 

 meteor that appeared over Hampstead, we find the remarkable state- 

 ment : — " It shot forth several liery coruscations, and while we were 

 gazing at it, broke into an intensely radiant cloud. ... It cast a 

 most brilliant light on the houses there, brighter than moonlight, and 

 unlike any light I ever saw. It appeared of a blue tint on the bricks, 

 but there was no blue light in the cloud itself." 



In discussing these reputed facts it is necessary to take into account 

 certain illusions to which observers are subject. Thus, at the outset, 

 there is the diversity of names given to the same colour by different 

 persons. No two individuals, however perfect their perception of 

 colour, would perhaps agree in their mode of naming the colours of all 

 the stationary objects around them, how very likely then would they be 

 to disagree in naming the colour of a light which appeared suddenly 

 and unexpectedly in the sky, and as suddenly disappeared ! Many 

 instances of this discrepancy might be cited from the accounts of 

 observed meteors ; but the most curious instance with which the speaker 

 was acquainted had occurred in the descriptions of the beautiful meteor 

 that travelled over England on the 12th of last September, being 

 visible in the evening before even the daylight had disappeared. Of 

 the many eye-witnesses who described the phenomenon in the Times 

 newspaper, five mentioned its apparent colour ; of whom F.A.B. states 

 it to have been " green at first ;" N.R. " green, surrounded by white ;" 

 W. Rowlett, " white ;" and W. " vivid, whitish blue ;" while B.H. 

 asserts that it was " primrose." Here, however, the discrepancy is so 

 great as to lead us to the conviction that the meteor of Sept. 12, 1858, 

 was really one of those that change colour during their passage through 

 our atmosphere, and thus present different appearances to observers in 

 different places. 



It is quite possible that a meteor may emit rays which in the aggre- 

 gate would produce one colour, and yet may affect the observer with a 

 sensation of a different colour. This may arise either from absorption, 

 intensity, or contrast. 



In illustration of the effect of absorption Dr. Gladstone exhibited 

 the prismatic spectrum by means of the electric lamp, and showed how 

 certain glasses produced a similar absorption of the rays to that which 

 takes place in the common phenomena of the red sun, or orange moon. 

 The effect of dispersion was rendered visible by the non-transmission of. 

 the extreme blue and violet rays through water into which a little milk 

 had been poured. This " sky-blue " mixture, produced by a substance 

 itself colourless, represented the light clouds and vapours which must 

 frequently affect the apparent colour of meteors, and suggested a simple 

 explanation of the fact that of the variable meteors observed in the 

 misty skies of England, so many terminate in red. Smoke has much 

 the same effect on the spectrum as milk and water. 



