450 Proceedings of the Pvoycd Society 
Another peculiar feature of these sunsets is the very remarkable 
amount of after-glow which has sometimes been observed. So 
brilliant is this after-light that to many it has seemed as if 
the liglit had returned and increased in brilliancy. This im- 
pression is, however, only subjective. If we watch the moon, 
it will be seen to become more and more brilliant, as the colour 
phenomena change, which would not be the case if the after- 
glow increased the light. The apparent increase seems to be due 
to the sensitiveness of the eye becoming restored, after being 
fatigued by the bright light of day, and part of the apparent increased 
brightness is due to the increased sensitiveness of the eye, and part 
is due to the illumination becoming coloured. These remarks are, 
of course, altogether apart from the wonderful increase of twilight 
lately enjoyed, which has lengthened the day by nearly an hour, 
and refer only to the apparent increase and return of the light. 
The increased amount of red light which fell on the earth at and 
after sunset produced some very remarkable changes in the appear- 
ance of surrounding objects, causing all red or reddish-coloured 
objects to glow with a strange brightness, and destroyed the relation 
of the colours of the different objects to which we are accustomed. 
Dead beech leaves, for instance, which under ordinary conditions 
of light are not conspicuous, shone out brightly. But perhaps the 
most remarkable effect was observed when looking down on a town. 
Most of the houses were bathed in a uniform grey light; but all 
the tiled roofs shone out brilliantly, and looked very much as if 
they had just been painted with vermilion. 
