damp rising out of it, then you have some real idea how moisture
may be drawn up by heat from the earth.

A little foreign niece of mine, only four years old, who could
scarcely speak English plainly, was standing one morning near the
bedroom window and she noticed the damp trickling down the
window-pane. "Auntie," she said, "what for it rain inside?" It
was quite useless to explain to her in words, how our breath had
condensed into drops of water upon the cold glass; but I wiped
the pane clear, and breathed on it several times. When new drops
were formed, I said, "Cissy and auntie have done like this all
night in the room." She nodded her little head and amused
herself for a long time breathing on the window-pane and watching
the tiny drops; and about a month later, when we were travelling
back to Italy, I saw her following the drops on the carriage
window with her little finger, and heard her say quietly to
herself, "Cissy and auntie made you." Had not even this little
child some real picture in her mind of invisible water coming
from her mouth, and making drops upon the window-pane?

Then again, you must learn something of the language of science.
If you travel in a country with no knowledge of its language, you
can learn very little about it: and in the same way if you are to
go to books to find answers to your questions, you must know
something of the language they speak. You need not learn hard
scientific names, for the best books have the fewest of these,
but you must really understand what is meant by ordinary words.

For example, how few people can really explain the difference
between a solid, such as the wood of the table; a liquid, as