1894.] on Destructive Effects of Projectiles. 229 



Lis interesting surgical experiences of the Crimean war. Even this 

 instance finds a priori a more reasonable explanation in syncope, and we 

 shall see directly that the wind of the shot not only cannot under any 

 circumstances kill a man, but also that its energy is far too slight 

 for it to have any destructive effect whatever. It is rather curious to 

 find that but few attempts have been made directly to estimate the 

 wind of the shot, and those by Pelikan and others are only for large 

 shot and by too coarse methods to be applicable in the case of a bullet, 

 as the following experiment shows. 



An extremely light vane of paper carrying a delicate mirror is 

 suspended to a cocoon fibre, and carefully protected from currents of 

 air in the room. A very gentle puff causes the vane to fly out most 

 vigorously, yet we shall find that the ■ 380 bullet moving 1000 feet 

 a second may pass within 8 inches of it without causing the least 

 deviation of a ray of light reflected from the mirror. It is only when 

 the bullet passes within an inch or two of the edge of the vane that 

 there is some slight rotation. The ■ 303 magazine service rifle, with 

 a velocity of twice that of the larger bullet, produces little more than 

 the same result. It is therefore obvious in this case that the far 

 higher velocity is more than compensated for by the lesser sectional 

 area of the projectile displacing the air. Although there was no 

 proof of much displacement of the air, it was pretty generally held 

 that when the bullet entered any substance the compressed air driven 

 before it exercised an explosive effect. This opinion was more par- 

 ticularly supported by the Belgian physicist Melsens, who actually 

 described it by the term " projectile air." The matter was taken up 

 from the point of view of pure physics, and Magnus demonstrated that 

 if a body like a bullet entered water, e.g. in falling the funnel which the 

 displaced water makes in the axis of the body as soon as that is fully 

 immersed, entangles air, and that it is this air which is carried by 

 the body into the fluid, rather than that any air is forced in in front 

 of the bullet. In answer to Magnus, Laroque invented the following 

 ingenious experiment. He allowed a long body, incapable of wholly 

 sinking, to drop into the water, and then found that there was air 

 driven in in front of it ; while, by the nature of the experiment, he 

 had, of course, excluded the possibility of any air following the base 

 of the projectile. I have repeated all these experiments (employing 

 in Lnroque's a slender rod of wood) and found that while his conten- 

 tion that air is driven in front of the bullet is completely substantiated, 

 yet Magnus' observation is so far correct that air is also drawn in 

 after it, the fact being that the two conditions are not opposed but 

 simultaneous. Magnus' view was further supported by the adverse 

 criticism of the theory of projectile air of the celebrated French 

 artillerist Morin, which criticism amounted to this, that when a 

 projectile was directed against a solid body it must necessarily follow 

 that so elastic a substance as air should be completely reflected from 

 the surface. I should like to draw your attention to this word solid, 

 because I believe that in that we find the key to the difficulty, and 



