It is stated by Captain Jervis, R.A., in the “Rifle Musket,” that “From experiments made in France, it has been found that the greatest range of the common percussion musket, with spherical bullet fired with the regulation charge, was at 25°; yet, by theoretical calculation, it should be 45°; also that the usual velocity was some 500 yards per second, whilst in vacuum it would be 19,792 yards per second. ~Elevation giving certain range.~ “At an angle of from 4° to 5°, the real range was about 640 yards; without the resistance of the air, and at an angle of 4¹⁄₂°, it would be 3,674, or six times greater.” ON THE EFFECT OF THE RESISTANCE OF THE AIR UPON THE MOTION OF A PROJECTILE. ~The effect of the air’s resistance upon the motion of a projectile.~ The effect of the resistance of the atmosphere to the motion of a projectile, is a subject of the greatest importance in gunnery. It has engaged the attention of the most eminent philosophers, and on account of the great difficulty of determining by experiment, the correctness of any particular hypothesis, much difference of opinion is entertained as to the absolute effect of this retarding force upon bodies moving in the atmosphere with great velocities; and although sufficient is known to guide the practical artillerist in that art to which he is devoted, still as a scientific question, it is one of considerable interest, but more on account of the difficulty of its solution, than from its practical importance. ~Mr. Robins’ discoveries.~ To our distinguished countryman, Mr. Benjamin Robins, is due the credit of not only being the first practically to determine the enormous effect of the resistance of the air in retarding the motions of military projectiles, but also of pointing out and experimentally proving other facts with regard to this resistance, which will be noticed when considering the subject of the deviation of shot from the intended direction. ~Result of Dr. Hutton’s experiments.~ After him, Dr. Hutton made a great number of experiments upon the same point, viz., the effect of the resistance of the air upon bodies moving in that medium, both with great and small velocities; and the inferences which he drew from these experiments, although not absolutely true, are sufficiently correct for all practical purposes. ON THE RESISTANCE OF A FLUID TO A BODY IN MOTION. ~Circumstances affecting the resistance which a body meets with in its motion in a fluid.~ The resistance which a body meets with in its motion through a fluid will depend upon three principal causes, viz:-- 1st. Its velocity, and the form and magnitude of the surface opposed to the fluid. 2nd. Upon the density and tenacity of the fluid or cohesion of its particles, and also upon the friction which will be caused by the roughness of the surface of the body.