23 



me to enter the following verbatim remark in my notes at 

 the time : — "My spectroscopic observations of to-nigbt, taken 

 as tbey were about 5° above the horizon, 'prove unquestionably 

 to my mind that these wondrous sunset phenomena are not due 

 to vapour. Not even at that altitude was earth moisture 

 detected of any note." It is, however, noteworthy that lemon- 

 yellow effects have lately prevailed at sunset to the exclusion 

 of the red, and that the telluric bands in the spectrum rapidly 

 darken, indicating rapid absorption as the sun sinks. 



Again, on April 7th : — " No deep red after glow was visible, 

 yet the air, by hygrometer and spectroscope, was Jry, and the 

 red glow might have been confidently expected ; and the 

 barometer was high." 



In conclusion, I have great difficulty at present in connecting 

 these abnormal sunset effects absolutely with any meteoro- 

 logical factors of which we are cognisant at the earth's surface; 

 and I can only look to the primary cause, high in the atmo- 

 sphere, whose effects may be regulated by atmospheric con- 

 ditions. 



