How many combinations can be made of 4 things, and an example will be given with 4 numbers, that is 1 2 3 4. [Tabulated:] 1 / 2 / 3 4 / 122 / 13 / 14 / 23 / 244 / 34 — 'simple': 1 1 1, 12 13 14; 2 2 2, 12 13 14; 3 3 3, 12 13 14.

Of combinations. 1 2 3 4 [with a table running] 1 1 1 1 / 2 3 4 / 2 / 3 4 / 3 / 4 / 3 3 4 5 / 3 3 5 6 / 3 7 7 8 7 8 7 9 7 10 / 15 15 15 16 15 17 / 30 31 / 127 30 / 128 32 / 255 123. If from 4 numbers one makes 21 combinations, what will be made from 8 combinations? 1 2 3 4 5 6 7 8 / 1 1 1 1.

Percussion is the terminus of incident motion and the beginning of the reflected motion, made in indivisible motion, time and place. What difference is there between compressing glue within itself by force and compressing it by a blow? Percussion is a power reduced into a small time.

Drawing with the letters and numbers, d b e c - 8 6 4 2 0. The power of the 8 at a, arrived at d, remains 6, and at b 4, and weighs one; and if it strikes and terminates at b, it leaves there that power of 4. The immediate blow is more powerful than the interposed blow; that is, the blow given by the striker is more powerful than that given by means of an intermediary. The blow given by the second cause is more powerful than that given by the third. The first is the man, the second is the hammer, the third is the nail struck by the hammer. The blow will be of greater power which meets greater resistance; that is, with equal weight, motion and time, greater will be the percussion given by the hammer upon the anvil than that given upon the sponge interposed between the anvil and the hammer.

Of throwing things from afar, which are of various figures and weights. Of double weights on the balance, which are not double in motion. Of the condensation of the medium where the motion of weights takes place.

Of the percussion of a united moving body. Of the percussion of a disunited moving body: of equal weights, the disunited to the striker. Of the percussion of a disunited moving body of which the disunited has more weight than the striker. Of the disunited percussion of which the striker has more weight than the disunited. Of the disunited striker of several disunions. Of the striker of various materials. Of the disunited striker of various thicknesses.

What difference is there between moving the struck toward the striker, and moving the striker toward the struck. Of the percussion of things resistant to the blow. Of the percussion of things that yield to the blow. Of percussion made at different angles in the struck object. Of the percussion of the rare in the rare. Of the percussion of the rare in the dense. Of the percussion of the dense in the rare. Of the percussion of the dense in the dense. Of the percussion of two dense bodies that with equal motions run one against the other. Of the percussion of dense bodies that run one against the other with various distances of run and motions equal in speed. Of the percussion of moving bodies that run one against the other with motions equal in length and various in speed. Of the strikers that do not strike on the central line of the motion. Of the strikers of various weights and motions. Of strikers of various figures.

Whether the third or fourth or fifth object in contact feels the last as it does the first. Percussion of soft things, such as lead or red-hot iron or potter's clay or the like. Of the percussion of liquids, such as air, fire and water and dust and sand and the like. Of percussion with various lengths of the length of a stick. Of percussion of two long bodies at the middle or third or fourth of their length. Of percussion of long bodies of unequal thickness at different places of their length. Of percussion of bundles of withies, that is of things disunited in thickness. Percussion of things disunited in every direction, such as a sack of sand or of water and the like.

If from 4 numbers one makes 21 combinations, what will be made from 8 combinations? 1 2 3 4 5 6 7 8 [with a triangular table:] 1 1 1 1 1 1 1 / 2 3 4 5 6 7 8 / 3 3 3 3 3 3 / 4 5 6 7 8 9 / 7 7 7 7 7 / 8 9 10 11 12 / 15 15 15 15 / 16 17 18 19 / 31 31 31 / 32 33 34 / 63 63 / 64 65.