"What is the wind, Mamma?"
"Tis air in motion, child;"
"Why can I never see the wind
That blows so fierce and wild?"
"Because the Gases, dear,
Of which the air is made,
Are quite transparent, that is, we
See through, but see no shade."
"And what are Gases, Ma?"
"Fluids, which, if we squeeze
In space too small, will burst with force;"--
"And what are fluids, please?"
"Fluids are what will flow,
And gases are so light
That when we give them room enough,
They rush with eager flight."
"What gases, dear Mamma,
Make up the air or wind?"
"'Tis Oxygen and Nitrogen
That chiefly there we find;
And when the air is full
Of Oxygen we're gay,
But when there is not quite enough,
We're dull, or faint away."
THE FOG.
"What is the fog, Mamma?"
"Sometimes the air is light
And cannot bear up all the mists,
And then 'tis foggy, quite;
But when air heavier grows,
The fog is borne above,
And floated off, the cloudy stuff,--
Just see it, graceful, move."