May 24, 1900J 



NATURE 



89 



smokeless, but the smoke is much less dense and disperses much 

 more rapidly than does the smoke of ordinary powder. Its 

 great advantage, however, was that it eroded steel very much 

 less than any other powder with which I experimented, while its 

 great disadvantage was due to the deliquescent properties of 

 ammonium nitrate necessitating the keeping of the cartridges in 

 air-tight cases. 



Next on the diagram comes B.N. or Blanche Nouvelle 

 powder, an explosive which, while free from wave action, is 

 remarkable, as you will note if you follow the curve, in develop- 

 ing a much higher velocity than the other powders in the first 

 few feet of motion, and less in the later stages of expansion. 



Thus, if you compare this curve with the highest curve on the 

 diagram, that of the four-tenths cordite, you will note that the 

 B.N. curve for the first eight feet of motion is the higher, and 

 that at about eight feet the curves cross, the B.N. giving a final 

 velocity of 2786 foot-seconds, or 500 feet below the cordite 

 curve. 



Then follows ballistite, which, with much lower initial pressure, 

 gives a velocity of 2806 foot-seconds, or somewhat higher than 

 that of B.N. Then follow three different sizes of cordite, the 

 highest of which gives a muzzle velocity of 3284 foot-seconds, or 

 a velocity nearly double that of the early R.L.G. 



Table WX.—d-inch Gun, iod Calibres long. Velocities atid 



Energies realised with High Explosives. Weight of Projectile, 



100 lbs. 



18 10 12 24 Z« 



TRAVEL OF SHOT IN FEET. 



In the somewhat formidable-looking Table III. I have placed 

 on the wall are exhibited the velocities and energies realised in 

 a 6-inch gun with the various explosives I have named, and the 

 Table, in addition, shows the velocities and energies in guns of 

 the same calibre but of 40, 50 and 75 calibres in length, as well 

 as in that of 100 calibres. 



If you compare the results shown in the highest and lowest 

 lines of this table, that is, the results given by the highest and 

 lowest curves on the diagram, you will see that the velocity of 

 the former is nearly twice as great as that of the latter, while 

 its energy and capacity for penetration is nearly four times as 

 great. 



I need hardly remind most of you that in artillery matters it 

 is the energy developed, not the velocity alone, that is of vital 

 importance. I venture to insist upon this point, because so 

 many of those who desire to instruct the authorities, write as if 

 velocity were the only point to be considered. In a given gun 

 with a given charge, if the weight of the shot, within reasonable 



NO. 1595, VOL. 62] 



limits, be made to vary, the ballistic advantage is greatly on the 

 side of the heavier shot, and for three principal reasons. 



(1) More energy is obtained from the explosive. 



(2) Owing to the lower velocity the resistance of the air is 

 greatly reduced. 



(3) The heavier shot has greater capacity for overcoming tne 

 reduced resistance. 



You will observe th<it on this velocity diagram, upon which 1 

 have kept you so long a time, is shown, not only the travel of 

 the shot in feet, but the position of the plugs which gave the 

 velocities. Further, on the higher and lower curves, the ob- 

 served velocities are shown where it is possible to do so. Near 

 the origin of motion the points are so close that is is not possible 

 to insert them without confusing the diagram. 



At the risk of fatiguing you, I show, in Fig. 3, curves 

 showing the pressure existing in the bore at all points, these 

 pressures being deduced from the curves of velocity. 



You will note the point to which I drew your attention, with 



