Sylva Sylvarum (1631 English edition)

Natural History:

...but generally discharging the bullet, because it finds the easiest release there.

12

This motion upon pressure, and its reciprocal, which is motion upon tension original: "Tensure"; the state of being stretched or strained., we usually call by one common name: motion of liberty. This occurs when any body, having been forced to an unnatural size or dimension, releases and restores itself to its natural state. Examples include when a blown bladder, having been pressed, rises again; or when leather or cloth that has been stretched springs back. These two motions (of which there are infinite examples) we shall discuss in the proper place.

13

This motion upon pressure is also excellently demonstrated in sounds. For example, when someone strikes a bell, it sounds; but as soon as he lays his hand upon it, the sound stops. Similarly, the sound of a virginal term: "Virginal"; a rectangular keyboard instrument similar to a harpsichord, popular in the Renaissance and Baroque periods. string stops as soon as the quill of a jack term: "Jack"; the wooden mechanism in a virginal or harpsichord that holds the plectrum (quill) used to pluck the strings. falls upon it. These sounds are produced by the subtle striking of the tiny parts of the bell or string against the air. This is exactly like the way water is made to leap by the subtle striking of the tiny parts of the glass against the water, which we spoke of earlier in the ninth experiment. You must not assume it is the overall shaking of the bell or string that causes the sound, as we will fully explain when we come to discuss sounds later.

14

Take a glass with a rounded belly and a long neck original: "Neb"; here referring to the narrow spout or neck of a glass vessel.; fill the belly partially with water. Take also another glass and put a mixture of claret wine and water into it. Turn the first glass upside down with the belly at the top, blocking the neck with your finger. Then dip the mouth of it into the second glass and remove your finger. Keep it in that position for a while, and it will separate the wine from the water. The wine will rise and settle at the top of the upper glass, and the water will descend and settle at the bottom of the lower glass. This movement is visible to the eye; you will see the wine rising through the water like a small vein. For convenience (since the process takes a little time), it would be good to hang the upper glass from a nail. However, as soon as enough pure and unmixed water has gathered in the bottom of the lower glass so that the mouth of the upper glass is submerged in it, the motion stops.

15

If the upper glass contains wine and the lower contains water, no motion occurs at all. If the upper glass contains pure water and the lower contains colored water (or vice versa), no motion occurs at all. But it has been tested that even if the mixture of wine and water in the lower glass is three parts water and only one part wine, it does not stop the motion. This separation of water and wine appears to be caused by weight, for it only works with bodies of unequal weight; the heavier body must always be in the upper glass. But also note that since the water is suspended, and there is a great weight of water in the belly of the glass held up...