348 Mr. Mallet on the Physical Conditions 



As respects proportionate deviation in range and in direction, and hence probability 

 of striking a given object, it appears from the French Tables of actual practice in service, 

 that the mean deviation of 13-inch shells, at elevations of 45°, and extreme ranges (2630 

 yards), is about 102 feet in range, and 152 feet in direction. It has also been found, that 

 the probable accuracy of fire with solid projectiles, point-blank, increases in the ratio of 

 the square of the weight, for the same density, and directly as the density of the projectile. 

 This should also apply to the causes of deviation m flight, alone, of shells. The density of 

 the 36-inch shell is not quite 5S great, in the proportions proposed, as that of the 13-inch 

 shell, but may be made so. In that case, the probable accuracy of fire, at equal ranges, 

 would be as 2966- : 200^ or as 8797156 : 40000, or as 219 : 1 ; or, at double the range of a 

 13-inch shell, the increased probable accuracy of fire would be about as 100 : 1. 



This takes no account of any causes of deviation but those operative in flight, — making 

 the most ample allowance for all others, the accuracy of fire of these large shells, must 

 be assumed at least thirty times as great, as that of 13-inch shells. The French Tables of 

 probability of shell-firing show, from a base of thirty years' practice, that of 100 13-inch 

 shells, at ranges of about 550 yards, 3'38 shells are dropped within a circle of 25 feet 

 diameter: at 1100 yards range, therefore, at least 45 per cent, of the 36-iuch shells fired 

 might be expected (after due experience) to fall within that circle, or within a space less 

 than half the breadth and one-eighth the length of a ship of the line. 



The cost of each 13-inch shell, in flight, may be estimated at about £2 2s.; and that 

 of each 36-inch shell at about £25, or as nearly 1 : 12 ; but to transfer to the point of efl'ect 

 the same weight of bursting-powder, 55 13-inch shells must be fired; or — 



55 shells, at £2 2s., .... £115 10 

 1 36-inch shell, at £25, ... 25 



Saving in favour of large shell, . £90 10 



And this assumes that tlie 55 smaller shells cozdd do the work of the single large one. 



I shall conclude and support this Note by quoting the following opinion of General 

 Piobert, " Traite D'Artillerie," torn i., p. 286 : — 



" Les mortiers, premiers bouches a feu qui soient parvenues a un certain degre de 

 perfection, sent encore susceptibles de recevoir de notables ameliorations, malgre les 

 changements apportes, il y a soixante ans, dans leur construction. EnCn, les pierriers, qui 

 sont les plus anciennes bouches a feu, sont restes dans un grand etat, d'lmperfection, et 

 I'efficacite de leur tir, est meme inferieure a ce qu'elle etait, a I'origine de 1 'artillerie. II 

 resulte de la, que les feux verticaux, qui seraient susceptibles de jouer un role important 

 dans lattaque et dans la defense des places, laissent beaucoup a desirer sous plusieurs rap- 

 ports, aussi toutes les ameliorations dont I'ancien materiel de I'artillerie etait susceptible 



