Ages ago, the bit of wood fell into a stream, where the water was largely impregnated with some chemical matter which had the power to eat out the fibre of the wood, and in each spot thus left empty to deposit itself in an exact image of the wood it had eaten away.

Molecule by molecule, in a mystery too small for human eye to detect, even had a watchful human eye been lying in wait to observe, the marvellous process went on; until, after the lapse of nobody knows how many centuries, the wood was gone, and in its place lay its exact image in stone,--rings of growth, individual peculiarities of structure, knots, broken slivers and chips; color, shape, all perfect.

Men call it agatized wood, by a feeble effort to translate the mystery of its existence; but it is not wood, except to the eye.

To the touch, and in fact, it is stone,--hard, cold, unalterable, eternal stone.

The slow wear of monotonous life in a set groove does very much such a thing as this to human beings.