Table of Propositions

...nevertheless several very slow movements produce great sounds. 3.
III. Determine whether Sound is the movement of external air, or internal air, which is within the bodies that produce the sound; and whether sound can be made without the movement of one or the other. 6.
IV. Determine whether sound can be made in a universal or particular vacuum. 8.
V. Explain how the air moves when its motion produces sound, and which motions produce no sound. 9.
VI. Sounds have the same ratio Original: "raison." In 17th-century mathematics and music theory, this term refers to mathematical ratios or proportions. between them as the movements of the air by which they are produced. 11.
VII. Explain how low and high sounds are made, and what makes them strong or weak. 12.
See the 16th Proposition of the book on the Voice, where I speak more extensively of this.
VIII. Sound is not communicated in an instant, as light is, throughout its entire extent, but in a space of time. 14. Note that one must correct everything said about the speed of sound in this Proposition, following what is in the 9th Proposition of the Utility of Harmony.
IX. Sound does not depend as much on the bodies by which it is produced as light does on the illuminating body. 16.
X. Explain in what way sound is more subtle than light, and if it reflects. 18.
XI. Sound represents the size and other qualities of the bodies by which it is produced. 19.
XII. Determine in what proportion sounds diminish from the place where they are produced until they cease entirely. 20.
XIII. Determine whether sound is faster than the movement of the bodies by which it is produced. 22.
XIV. Determine whether sound passes through transparent Original: "diafanes." and opaque bodies, and how it is aided or hindered by all kinds of bodies. 24.
XV. The sphere of sound's reach is all the larger as it is stronger, although two or more sounds are not heard twice or several times as far as one of them. 25.
XVI. Determine whether sounds have all kinds of dimensions—namely length, width, and depth—and what the other properties or circumstances of sound are. 28.
XVII. Determine why one hears better at night than by day; and if one can know how much rarer hot air is than cold, and how much rarer it is than water. 30.
XVIII. Determine why one hears sounds from outside a room better when one is inside than those from inside when one is outside. 33.
XIX. Determine whether sound is heard better from bottom to top than from top to bottom. 33.
XX. Sounds hinder each other when they meet. 34.
XXI. Sounds can serve to measure the earth, and to provide news of what is happening throughout the world in a short time. 36. See the ninth Proposition of the Utility of Harmony.
XXII. One can use the sounds of each musical instrument, and the different movements given to them, to discourse upon all kinds of subjects and to teach the sciences. 39.
XXIII. The strength of sounds is multiplied by rhythmic movements, and by the quality of the bodies and the strikes by which they are produced. 41.