At night when the room grows dark we push a button and there is light.

If we happen to be cold we push another button and the electric stove
spreads its pleasant glow through our study.

On the other hand in summer when it is hot the same electric current
will start a small artificial storm (an electric fan) which keeps us
cool and comfortable.

We seem to be the masters of all the forces of nature and we make them
work for us as if they were our very obedient slaves.

But do not forget one thing when you pride yourself upon our splendid
achievements.

We have constructed the edifice of our modern civilization upon the
fundament of wisdom that had been built at great pains by the people of
the ancient world.

Do not be afraid of their strange names which you will meet upon every
page of the coming chapters.

Babylonians and Egyptians and Chaldeans and Sumerians are all dead and
gone, but they continue to influence our own lives in everything we do,
in the letters we write, in the language we use, in the complicated
mathematical problems which we must solve before we can build a bridge
or a skyscraper.

And they deserve our grateful respect as long as our planet continues to