TRANSACTIONS OF THE SECTIONS. ^53 



degree. If a flange of ordinary depth is occasionally dangerous, one of double the 

 depth, of proportionate strength, will prove in comparison more than doubly safe; 

 and in case even of a defective condition of a sleeper or rail, the more powerful 

 gripe of an enlarged flange wiU most materially lessen the risk of diversion. 



On Elongated Projectiles for Rifled Fire-arms. By T. Astox. 



After alluding to the improvements that have been made in war projectiles, 

 which have residted in the elongated form, he proceeded to notice the advantages 

 which it possesses over the old spherical shape. The elongated projectile, present- 

 ing to the resisting atmosphere a sectional area considerably less than the spherical 

 of the same weight, is less retarded in its progress through the air. It follows, 

 therefore, that, although the spherical projectile with a similar charge of gunpowder 

 is more easily set in motion, and has a gi-eater initial velocity than the elongated 

 form, and to that extent has at the outset an advantage, the elongated form is much 

 better able to overcome the resistance of the atmosphere, and, owing to its superiority 

 of momentum, preserves its progressive power for a much longer period ; at the 

 same time, it is less disturbed by the varying conditions of the elastic medium 

 through which it is propelled. In short, it has a longer and truer flight. The 

 essential condition to the ethciency of the long projectile is, that it shall move 

 onwards with its point foremost ; if it turns over in its path, it presents a large 

 surface to the action of the air, its flight at once becomes irregular, and is rapidly 

 retarded. The action of the common spinning-top suggests at once the idea that 

 the best mode of making the elongated projectile move steadily through the air 

 with its point foremost is to give it rotation round its axis of progression. The 

 rapid revolution of the body causes its inherent inequalities to be rapidly carried 

 round a constant axis in regular order, and a kind of balance is thereby established, 

 which gives the body a steady motion. Various plans have been from time to time 

 tried with the object of imparting to long projectiles a steady flight; they have 

 been made with spiral grooves cut externally on their periphery, or internally from 

 front to rear, in the expectation that the resisting action of the atmosphere acting 

 on the inclined surfaces would give the requisite spinning motion. Again, they 

 have been made very long and furnished with fins or featliers, in order that they 

 may be propelled on the principle of the aiTow, but no practicallj' successful results 

 have as yet brought projectiles of this kind into use. The required object is, as is 

 well known, readily and successfully effected by propelling the elongated projectile 

 from a rifled barrel, that is, a tube having its interior made of such a spiral form 

 that the projectUe while it is propelled from the breech to the muzzle is turned 

 round its axis of progi-ession : a rotatory motion is thus imparted, which is retained 

 by the advancing projectile and gives it the required steady motion. The elongated 

 bullet was first used with rifled small-arms, either poly-grooved or fluted, or, like 

 the Enfield, having three grooves. The length, however, was limited ; and various 

 attempts were made to fire longer projectiles compounded of various metals and of 

 various shapes, so that by changing the position of the centre of gravity they might 

 be propelled point foremost. But, if made beyond a certain length, they were 

 always found to turn over at moderately long ranges. Mr. Whitworth was the 

 first to enunciate the principle that projectiles of any requisite length coidd be 

 successfully fixed by giving them rapid velocity of rotation, which should be in- 

 creased in proportion with their increased length. He, as is well known, uses rifles 

 having a spiral polygonal bore, in which all the interior surfaces are made effective 

 as rifling surfaces. The success of the elongated projectile having been established 

 in the case of small-arms, their emplojTnent with ordnance followed as a natural 

 consequence. Rifled ordnance were, therefore, called into existence to meet the 

 requirements of the time. In fact, the rifled cannon may be considered as a rifled 

 musket made with enlarged proportions. Directing our attention more particularly 

 to the two systems of Armstrong and Whitworth, we see in the fonner the coiled 

 barrel and fluted bore fonnerly used for the rifled small-ami, applied on an en- 

 larged scale. In the "^Hiitworth cannon the same system and form of rifling are 

 used which are employed for the Whitworth musket. There is, however, a change 

 required for the projectiles ; they cannot, like the small-arms bullets, be made of 

 lead, for obvious reasons, such as the cost of the metal, its liability to distortion of 



