irst, our lakes would freeze from the bottom upward; as soon as the
surface became frozen, or even colder than the water underneath, it
would drop to the bottom, the warmer water below coming up by a
well-known law--that the warmer fluid rises and the colder falls. This
circulation would continue until ice began to form, which would
immediately drop to the bottom, and this process would go on until the
whole mass were frozen solid. In the same way our rivers in the northern
climates would freeze from the bottom, and in time our valleys would
fill up with ice to a thickness that the summer's sun would never melt,
and gradually all north of a certain zone would become a great glacier,
rendering not only the lakes and rivers but also the surface of the
earth unfitted for animal life.

Those who believe that the laws of nature are the creations of a
beneficent and all-wise Intelligence will see in this exception to the
general law in the case of freezing water a striking evidence of design.
But those who have no such belief will say it is a most fortunate though
fortuitous circumstance (a saying they will have to make, regarding
thousands of other things in nature), and go on floundering in the
interminable sea of "I don't know."

The atom when it is acting under the direction of a fixed law is a giant
in strength. And when its individual strength is multiplied by billions
upon billions the combined energy exerted produces a power that is
irresistible. Not only has nature endowed these atoms with this
wonderful power, but she has also willed that they arrange themselves in
lines of beauty. In confirmation of this we need only to study the work
of the frost upon our window panes. As we lie in our beds on a cold
night and exhale moisture from our lungs it settles upon the window
panes of our bedrooms, where Nature--that wonderful artist--forms it
into beautiful pictures that gladden our eyes when we awake:

Most beautiful things; there are flowers and trees,
And bevies of birds, and swarms of bees,
And cities, and temples, and towers, and these
All pictured in silver sheen.

CHAPTER XXV.

GLACIERS.

Glaciers are rivers of ice, and, like other rivers, some of them are
small and some very large. They flow down the gorges from high
mountains, whose peaks are always covered with a blanket of eternal
snow. Summer and winter the snow is precipitated upon these mountains,
and from time to time the hea