56 



Notes on the Crepuscular Glimmer or Red 



Glo^w. 



By W. a. Joxes. 



[Eead September 2, 1884.] 



There have been several theories suggested to explain the 

 phenomena, namely, volcanic dust, meteoric dust, ice, and 

 vapour. 



Although the dust theory has seemed most popular, I think 

 it can be shown that the mass of evidence against it is over- 

 whelming, and that the theory connecting the glows with some 

 peculiar deportment of vapour is the only one competent to 

 explain the most important phases. 



Having carefully observed for upwards of eleven months, I 

 have gleaned a number of interesting facts tendiug to prove 

 that some form of water is present. But, apart from these, 

 there are a number of facts controverting more or less the dust 

 theories. 



Bluish-green suns have been noticed at various times. To 

 my own knowledge the same appearances of the sun took place 

 in England in 1866 in the summer, and in Australia in 1879. 

 The statement that the sun is green is not borne out by experi- 

 ment with the polariscope, as if so the sun should appear green 

 when the light is dimished. The bluish-green appearance re- 

 ported appeared to be a subjective phenomenon to the exces- 

 sive light of the sun it not too brilliant to prevent its being 

 looked at for a short time. 



According to Captain Lee's experience of 12 years the 

 harmatan, a so-called dry fog, consists of remarkably fine red 

 dust — 1. The whole sky is tinted a dirty red. 2. The tiuge is 

 evident by moonlight. 3. The moon and sun are both reddened 

 as they set. 



But during the glow period the moon on setting and rising 

 portrays no sky colours and gives only a white misty twilight 

 that varies in brightness and extent with the moon's phases. 

 Ko cross polarization is observable in the moonlight before or 

 after she rises or sets. 



We have important evidence in the fact that the glow changes 

 in extent, intensity, in tint, in form, and in time of duration, as 

 my notes conclusivel}^ show. 



General Strachey has collected the barographs from the chief 

 meteorological stations, and shows that a great wave passed 



