When in doubt tell the truth. It will confound your enemies and astound your friends.

In the space of one hundred and seventy-six years the Mississippi has shortened itself two hundred and forty-two miles. Therefore, in the Old Silurian Period the Mississippi River was upward of one million three hundred thousand miles long, seven hundred and forty-two years from now the Mississippi will be only a mile and three-quarters long. There is something fascinating about science. One gets such wholesome returns of conjecture out of such a trifling investment of fact.

This morning arrives a letter from my ancient silver-mining comrade, Calvin H. Higbie, a man whom I have not seen nor had communication with for forty-four years. . . . [Footnote: Roughing It is dedicated to Higbie.] . . . I shall allow myself the privilege of copying his punctuation and his spelling, for to me they are a part of the man. He is as honest as the day is long. He is utterly simple-minded and straightforward, and his spelling and his punctuation are as simple and honest as he is himself. He makes no apology for them, and no apology is needed.

A brown spotted lady-bug climbed the dizzy height of a grass blade, and Tom bent down close to it and said, "Lady-bug, lady-bug, fly away home, your house is on fire, your children's alone," and she took wing and went off to see about it -- which did not surprise the boy, for he knew of old that this insect was credulous about conflagrations, and he had practised upon its simplicity more than once.

The trouble with the world is not that people know too little; it's that they know so many things that just aren't so.

Of all God's creatures, there is only one that cannot be made slave of the leash. That one is the cat. If man could be crossed with the cat it would improve the man, but it would deteriorate the cat.

You can't depend on your eyes when your imagination is out of focus.