54 



But as the phenomenon wore on the blue and green disap- 

 peared, and there remained only the deep red and a reflected 

 light rose colour. The red always appeared, as it usually 

 does, on the horizon, especially when much visible vapour 

 is present in the neighbourhood of the setting or the rising 

 sun. But every time these red and rose colours were visible 

 they seemed to spring up from behind a mass of cumulus 

 cloud in front of where the sun had set or was about to rise. 

 And when the sky over the cumulus was carefully ex- 

 amined a light vapour was quite discernible, which could 

 only be ascribed to the higher evaporation of the cumulus. 

 That this light vapour was over or above the cumulus, and 

 consequently higher than it in the sky, was obvious, and, 

 therefore, could only have originated in it. There seems no 

 room to doubt that this was the case ; and this evaporation 

 taking place in the greatest angle of refrangibility, the light 

 passing through it would be seen as various shades of red. 

 This red was nearly always reflected though much dispersed, 

 and rendered a beautiful rose colour by other light clouds in 

 the sky which happened to be Ijing in the line of the rays 

 that passed through the vapour from the cumulus. The blue 

 and the green would disappear as the otherwise invisible 

 vapour condensed and descended into the lower regions of 

 the air ; and this doubtless caused the continuous fogs that 

 prevailed more or less from the 7th of December. The red. 

 and yellow, and sometimes the light rose colour, are still 

 visible when the sky is not overspread with nimbus, and 

 when it is comparatively clear in the neighbourhood of the 

 rising and setting sun. This is easily accounted for if we 

 take into account the present high temperature, together 

 with the tremendous amount of visible vapour which pre- 

 vails, and the consequent great amount of cloud evaporation 

 that must be going on immediately above the lowest cloud 

 region of the atmosphere. 



Corrigendum. 

 Page 2, line 16, for B=--j^^mmi read B: 



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