NATURE FOR ITS OWN SAKE 
Light seen 
through 
clear air, 
Light seen 
Srom moun- 
tain tops. 
porarily make the sky and distant hills look 
bluer, the sun whiter, the light purer. Cold 
that is intense enough to rid the air of moisture 
will also make a noticeable difference in the 
quality of the light. In Manitoba, where the 
thermometer often sinks many degrees below 
zero, a bright winter day reveals an air the moist- 
ure of which is frozen into floating crystals of 
hoar-frost, the sky appears cobalt-blue, the sun 
is white, and when it rises in the morning it is 
accompanied by two sun-dogs or parhelia, one 
on each side, and almost as brilliant as the sun 
itself. The result is a bewildering display of 
white light that borders upon blue. Every 
snow crystal glitters, the cup of the sky seems 
to be lifted into infinite space, the snow shad- 
ows are intensely blue, and the running waters 
are dark-purple in hue. 
As we rise above the denser strata of at- 
mosphere that lie along the earth, by ascend- 
ing mountain heights or otherwise, the light 
changes even more positively. From the top 
of Mt. Blane the stars are seen at midday shin- 
ing upon a dark blue-violet field that extends 
down to the horizon ; from Pike’s Peak thesky 
is seen to be of a violet hueat times, and not in- 
frequently blue-black ; and from Mt. Whitney 
