he observes, when speaking of rifles, and the rotatory motion of the ball, "I have made some experiments on simpler methods of performing this, and applicable to iron bullets. My success as yet has not been what I could wish, but it has however been sufficient to encourage a farther prosecution, which, if I shall ever pursue farther, I know not." vol. i. p. 317. That eminent mathematician has left us no clue to discover what his plan was; but in his tracts, he dwells so much on the effects which the resistance of the air is capable of producing on the flight of shot, that one can hardly fail to be impressed with the idea, that it must have been in some way or other connected with that medium.

I shall now proceed to give a brief account of the experiments that have been made for the purpose of attaining the object in view. The first difficulty which presented itself, was that of applying the principle to shot of a spherical figure. The utter hopelessness of getting the air to act in the way desired, upon shot of this shape, soon led me to prefer the cylindrical to the spherical form, and it is to the improvement of that figure of shot accordingly, my subsequent endeavours have been directed.

My first experiments were made merely for amusement, for the purpose of shooting seals and sea-birds, in Bantry Bay, during the summer of 1821. Though not very successful, they were repeated from time to time as opportunity offered.

Hemispherical ends to the balls were thought of, and afterwards abandoned, as it was found desirable to dispose of the weight of the ball in such a manner as to give the greatest possible length to the sides. Grooves of various kinds were

tried, and narrow ones were found not to answer. They must be of sufficient width to expose their sides, upon which the air presses, to its action throughout their length. For, if the air has not a free passage through them (Plate I. fig. 2) it will act as backwater on a mill-wheel. It is upon this principle that the blades of a windmill will not act if placed against a wall; and that rifles with very narrow grooves are found not to answer. In the beginning of 1822, some further experiments were made at Woolwich. On the first occasion, 10 grooved leaden musket balls were fired from a plain barrel through a target, at the distance of 100 yards. The balls were well finished, but heavier behind than before; and from the marks left by them in the target in passing through it, two of them appeared to have turned in their flight. From the circular holes left in the target by the others, they appeared to have passed through without turning. In the next experiment, balls of a somewhat better construction were employed. Several were fired at 40 yards, into a mass of boards and clay prepared for the purpose; and out of the number so fired, three or four were found in the exact position in which they lodged, all point foremost.

A grooved wooden shot was then fired six times from a 51 inch howitzer, against a bank, at 50 yards. This experiment distinctly pointed out the necessity of balancing the two extremities, as that which was heaviest showed an evident tendency to drop lower and lower during the flight.

A wooden shot of the same form and proportions was then fired from the same gun, with a 3 lb. iron shot in its centre. This being properly balanced flew very steadily, hit the target, and then split without passing through it, but leaving

a circular hole in the target, and a deep indentation on the cone, where it came in contact with the target.

During the following summer of 1823, I made several hundreds of experiments with grooved leaden musket-balls, fired from a plain barrel, at all ranges. When constructed with sufficient accuracy, they were found to fire very true, and to strike invariably point foremost. In order to balance them, the content of the cone, that of the cavity, and that of the part surrounding the cavity, must all three be equal, and the depth of the cavity must be equal to two-thirds of the height of the cone (Plate I. fig. 1.) The experiments with respect to twist, were found to correspond with those of rifles; that is, the velocity of the ball was found to diminish, in proportion as the twist was increased. In some of the balls used, the obliquity of the grooves was carried as high as a turn in 6 inches, which was found to diminish the velocity so much, that the person marking the shots repeatedly supposed the ball to have passed, before it reached the target. Numerous experiments were made during the same year, with wooden shot from a 24 pounder at the fort of Kinsale. They were found to range 400 and 500 yards; the largeness of their size rendered their position and flight easily perceptible to the eye; any imperfection in their construction was easily detected; and by firing them into the sea, each shot bore to be discharged a great many times before it became unserviceable. Others were afterwards fired by night with lighted fuses fixed in their sides, in order to mark their revolutions with greater distinctness. It was found that they possessed the spiral motion, and that it was maintained undiminished throughout their flight.