Horses can be used, as well as men, for this work.
[Sketch of man pulling log].
Accumulation of Efforts.--South American Indians are said to avail
themselves of their forest trees, and of the creepers which stretch from
branch to branch, in moving very heavy weights, as in lifting a log of
timber up on a stage to be sawn, in the following ingenious manner. The
labourer gets hold of one of these creepers that runs from the top boughs
of a tree in the direction in which he wants to move his log, and pulling
this creeper home with all his force, bending down the bough, he attaches
it to the log; then he goes to another creeper and does the same with
that; and so on until he has accumulated strain of many bent boughs,
urging the log forward and of sufficient power to move it.
Short cords of india-rubber with a hook at either end, are sold under the
name of "accumulators." It is proposed that each of these should be
stretched and hooked by one of its ends to a fixed ring, and by the
other, to the body to be moved; by applying a number of these, in
succession, an immense accumulation of force can be obtained.
Levers.--A piece of green wood has insufficient strength to be used as a
crowbar; it must first be seasoned. (See "Green Wood, to season.")
Other Means of Raising Weights.--I do not propose to take space by
describing jacks, ordinary pulleys, differential pulleys, Chinese
windlasses, and the like.
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