"I think, sir," said Fred, "we shall soon begin to feel at home, for I am sure, from what I saw today, our lessons in the lower classes will help us very much. We are going to try hard, for father has promised to send us to the Institute by and by, if we learn all we can now.""Suppose you tell me something about today"s lesson, as we walk along," said Mr. Wilson. "Well," said Willie, "the first thing we learned was that new word matter. We know now that the name matter means every substance that exists.""I think I understand, sir," said Fred, "what you mean by molecules of matter, although it seems difficult toimagine particles so small that they cannot be seen e ven with the help of a powerful microscope. We learned from our lesson that matter of every kind-solid,liquid, and gas-is made up
of extremely small particles, a n d t h e s e p a r t i c l e s a r e called molecules. A molecule is the name for the smallest particle of matter that can possibly exist.""Quite right, Fred," said Mr. Wilson. "If you will keep two things in your mind, you will be pretty clear about these molecules of matter.