A tree nowhere offers a straight line or a regular curve, but who doubts that root, trunk, boughs, and leaves embody geometry?

Nothing cools so fast as undue enthusiasm. Water that has boiled freezes sooner than any other.

Error held as truth has much the effect of truth. In politics and religion this fact upsets many confident predictions.

Nature is full of by-ends. A moth feeds on a petal, in a moment the pollen caught on its breast will be wedding this blossom to another in the next county.

A calculating engine is one of the most intricate forms of mechanism, a telegraph key one of the simplest. But compare their value.

Is any knowledge worthless? Try to think of an example.

Ignorance may find a truth on its doorstep that erudition vainly seeks in the stars.