THE AERIAL OCEAN IN WHICH WE LIVE. 75 
us wherever we walk in the daytime, instead of those 
deep black shadows which we can see through a tele- 
scope on the face of the moon. 
Again, it is electricity playing in the air-atoms in 
the upper parts of the atmosphere, where the air is 
very thin and rare, which gives us the beautiful light- 
ning and the grand aurora borealis, and even the 
twinkling of the stars is produced entirely by minute 
changes in the air. If it were not for our aerial ocean 
the stars would stare at us sternly, instead of smiling 
with the pleasant twinkle-twinkle which we have all 
learned to love as little children. 
All these questions, however, we must, leave for 
the present ; only I hope you will be eager to read 
about them wherever you can, and open your eyes to 
learn their secrets. For the present we must be con- 
tent if we can even picture this wonderful ocean of 
gas spread round our earth, and some of the work it 
does for us. 
We said in the last lecture that without the sun- 
beams the earth would be cold, dark, and frost-ridden. 
With sunbeams, but without air, it would indeed have 
burning heat, side by side with darkness and ice, but 
it could have no soft light. Our planet might look 
beautiful to others, as the moon does to ils, but it 
r could have comparatively few beauties of its own. 
With the sunbeams and the air, we see it has much 
to make it beautiful. But a third worker is wanted 
before our planet can revel in activity and life. This 
worker is water; and in the next lecture we shall 
learn something of the beauty and the usefulness of 
the " drops of water " on their travels. 
