75 
NATURE FOR ITS OWN SAKE 
The strato- 
cumulus. 
The cumu- 
lus. 
feet above the earth, and though its movement 
is hardly perceptible to the eye, it may be drift- 
ing at the rate of fifty miles an hour. Its effect 
in making a hazy day is quite noticeable, and 
at sunset, when it lies across the western hori- 
zon in bars, it is often very pronounced in reds 
or chrome-yellows. 
The strato-cumulus (a) is another and per- 
haps more common form of the stratus. It is 
a heavier variety, darker in color, and more 
roll-like in form, caused by its having about it 
something of the lumpy nature of the cumulus, 
yet with enough of the stratus to make it form 
in a layer along the sky. It is a cloud that 
may send forth rain, though it often overhangs 
the earth in dark folds for days at a time with- 
out giving forth a drop. At times it looks like 
a compact, dense rain cloud, and when it as- 
sumes this shape it is often confused with the 
nimbus. 
CumuLus (3) is the name given to any cloud 
that has a heaped-up, mountainous, or lumpy 
look about it. The white patches that bowl 
across the sky on a summer’s day are detached 
portions of cumulus ; but the most noticeable 
form of itis the “heap” cloud that on warm 
afternoons lies off in the southern sky, rising 
