For instance, 1 lb. moving through a distance of 12 inches in a given time represents an amount of power which may be employed either as 1 lb. moving a foot, 2 lbs. moving six inches, or 1⁄2 lb. moving through 24 inches, in the same space of time, the amount of the power or duty remaining the same in each case, the method of utilization merely having differed.
It is an inexorable law of nature that power is concentrated in proportion as the amount of its motion is diminished, or distended in precise proportion as such motion is increased.
Fig. 3351.
Suppose, for example, that in [Fig. 3351] l is a lever having its fulcrum at f, which is 4 inches from end a, and 8 inches from end b, and (leaving the weight of the lever out of the question) if we place an 8 lb. weight on a it will just balance 4 lbs. at b.
If the lever is moved, the amount of motion will be twice as much at end b as it is at end a.
If we apply the power at a, the lever has become a means of converting 8 lbs. moving a certain distance into 4 lbs. moving twice that distance, and nothing has been either gained or lost.
If we apply the power at b, the lever has merely been used as a means of converting 4 lbs. moving a certain distance into 8 lbs. moving one half that distance, and nothing has been gained or lost.
Suppose that end a was moved an inch, and the power at that end will be 8 inch pounds or 8 lbs. moving an inch, whereas at the end b the power is 4 lbs. moving 2 inches; we have, therefore, reduced the weight in the same proportion that we have increased the distance moved through.