The word time may be used in the same manner upon numberless occasions to express the duration of any movement which is performed by the force of men, or horses, wind, water, or any mechanical power.
"Did the horses in the mill we saw yesterday, go as fast as the horses which are drawing the chaise?" "No, not as fast as the horses go at present on level ground; but they went as fast as the chaise-horses do when they go up hill, or as fast as horses draw a waggon."
"How many times do the sails of that wind-mill go round in a minute? Let us count; I will look at my watch; do you count how often the sails go round; wait until that broken arm is uppermost, and when you say now, I will begin to count the time; when a minute has past, I will tell you."
After a few trials, this experiment will become easy to a child of eight or nine years old; he may sometimes attend to the watch, and at other times count the turns of the sails; he may easily be made to apply this to a horse-mill, or to a water-mill, a corn-fan, or any machine that has a rotatory motion; he will be entertained with his new employment; he will compare the velocities of different machines; the meaning of this word will be easily added to his vocabulary.
"Does that part of the arms of the wind-mill which is near the axle-tree, or centre, I mean that part which has no cloth or sail upon it, go as fast as the ends of the arms that are the farthest from the centre?"
"No, not near so fast."
"But that part goes as often round in a minute as the rest of the sail."
"Yes, but it does not go as fast."
"How so?"