The New Thoughts of Galileo

wrapping causes it to press the cylinder all the more as it is pulled from top to bottom; so that it resists all the more as its folds and twists are in greater number, and closer together, because the rope touches the cylinder in a greater number of parts. And because there is a great multitude of similar wrappings in hemp ropes, it happens that they resist marvelously before breaking when pulled. From this it also comes that a rope wrapped around the axis of cranes and other engines, which serve to lift very heavy loads, does not slip, even though it is not tied to any peg, and a man holds the end with a single hand.

To this relates the invention of the small cylinder hollowed all around, in the form of a helix or screw, in order to make a rope slide, which serves for descending from the top of a tower without injuring one's hands: so that one can rest when one wishes, and descend more or less quickly, according to how much one presses the rope against the said cylinder, which is covered