Do you remember, good mother mine, the impression you experienced as a little girl, when some one first showed you the inside of a watch in motion?
You were satisfied that there was a restless little animal inside the case, who worked twenty-four hours a day at turning the hands.

If the hands stopped going, you said: 'It is because the little animal is dead.' Yet possibly he was only asleep.
"It has since been explained to you that a watch contains an assemblage of parts well fitted to each other and kept well oiled, which, being wound, can be considered to move spontaneously in a perfect correspondence.

If a spring become broken, if a bit of the wheel work be injured, or if a grain of sand insinuate itself between two of the parts, the watch stops, and the children say rightly: 'The little animal is dead.' But suppose a sound watch, well made, right in every particular, and stopped because the machinery would not run from lack of oil; the little animal is not dead; nothing but a little oil is needed to wake him up.
"Here is a first-rate chronometer, made in London.

It runs fifteen days without being wound.

I gave it a turn of the key yesterday: it has, then, thirteen days to run.