222 MAGNUS ON THE DEVIATION OF PROJECTILES, 



experiments, which were executed in my presence, the members 

 of the Commission were kind enough to undertake the observation 

 of the several projectiles. The results were as follow: — 



During the motion of the projectile, the observers placed on 

 both sides of the trajectory all agreed that the axis of the pro- 

 jectile coincided almost with the tangent of the trajectory. In 

 the descending branchy however, it was observable that the 

 point was situated somewhat higher than it would have been 

 had the axis been exactly tangential. 



At the same time in all the shots it was evident, as well from 

 the projectile's motion through the air as from the shape of the 

 furrow it ploughed in the earth, that the point, at the moment 

 of striking the ground, was deflected somewhat to the right. 

 This is approximately represented by fig. 4, Plate III., where 

 AB shows the original direction of the shot, CD the direction 

 of the furrow produced, and a b the direction of the axis at the 

 moment the projectile struck the earth. 



When a projectile falls on the ground in the direction named, 

 and its point first touches, it not unfrequently happens, as it 

 pierces deeper, that the hinder part is turned to the front. 

 This was actually the case in most experiments ; for the pro- 

 jectiles which remained fixed in the earth, had in general, 

 with respect to the range, the position shown in fig. 5, Plate III., 

 where AB represents the range, and ab the position of the 

 projectile's axis in the earth; whereby, however, the point b 

 must be imagined as being situated much deeper than the hinder 

 part «. 



These observations prove, not only that the axis of the pro- 

 jectile, during its translatory motion, does not exactly coincide 

 with the tangent of the trajectory, but also that it makes an 

 angle with the vertical plane through the tangent, and in such 

 a manner that the projectile^s point is always to the right of the 

 observer behind the gun. 



If we suppose that the projectile's axis along the whole length 

 of the trajectory has the above-named inclination towards the 

 vertical plane through the tangent, then it is evident that the pro- 

 jectile will devij^te also towards the right, owing to the resistance 

 of the air a,cting on it then as a force against an inclined plane. 

 Jf, therefore, the presence of a force, acting on the projectile's 



