Oct., 1904.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



247 



.Asia. There is imich in this theory to attract the best atten- 

 tion of the zoologist, althoiisjh the absence of any evidence 

 that wild horses ever existed iu North .Vfrica mihtates against 

 an African origin for the bay stock. Moreover, when the 

 author suggests that the white " stocking " on the fetlock of 

 the Arab recalls the white rings on the foot of the zebras he is 

 treading on dangerous ground, although he appears to have 

 abandoned his wild theory that the .Arab and the thoroughbred 

 are descended from Grevy's zebra. 



CORRESPONDENCE. 



The Later History of tKe Horse. 



'l\i ihil Eoirons oi- '• Know li-.ix.k." 

 Sirs, — Mr. Lydekker, in his interesting paper c Ksou- 

 LEDGE," .•\ugust, 1904, p. 171), makes a very usual error in 

 dealing with the relative degrees of finish exhibited in I'aheo- 

 lithic and Neolithic iinplements. Without previous know- 

 ledg3 of the subject of prehistoric inipleincnts, a reader would 

 gather that all I'aheolithic inipleinents are rude, and that all 

 Neoliths are ground or polished. This impression would to a 

 certain degree receive confirmation l)y a visit to ISioomsbury. 

 Nothing in truth could be more misleading. If I'alaolithic 

 implements are regarded as a cla?s, they show, especially with 

 regard to later types, a remarkable proficiency in the working 

 of flint. The only type which as a class can be termed rude 

 are the oft-abused 1-oliths : the l^abeoliths certainly do not 

 merit such a term, .\gain. it was the exception during Neo- 

 lithic times to grind or polish implements. It is not a little 

 significant to point out that, viewed as a class. Neolithic 

 implements are actually ruder than PaUeoliths — the propor- 

 tion of polished or ground impUnnents to those showing only 

 rough workmanship is infinitesimal. I am aware that the 

 museums do not illustrate this condition of things, but it is an 

 old grie\ance of the man in the field that on this point the 

 museums are misleading. 



Might I suggest that the blocks of Tigs. 2 and 3 in Mr. 

 Lydekker's paper appear to be wrongly placed ? 



^'ours faithfully, 



J. KussiiLi, Lakkhv. 

 Bromley, Kent. 



A Ba.ll-Bearing Rifled 

 Gui\. 



In spite of the improvements of modern firearms, the device 

 by which rotation is imparted to the projectile as it leaves the 

 gun-bore has remained stereotyped. \'et a brief considera- 

 tion of the method of " rifling ' which imparts the rotatory 

 motion will show that it must interfere with one of the funda- 

 mental aims of the gun designer, which is to get his projectile 

 out of the gun with the greatest velocity possible. The pro- 

 jectile, in order that it may be susceptibleof receiving rotatory 

 motion, is provided with a band of metal into which the edges 

 of the rifled groove have to force their way. Consequently a 

 large portion of the energy developed by the charge is dissi- 

 pated in heat in the gun barrel. .'\n American inventor, Mr. 

 Orlan C. Cullen, has devised a method, quite sitiiple, and to 

 all appearance practicable, of avoiding this waste of energy. 



He uses a cylindrical projectile of perfectly smooth, bard 

 steel, travelling upon the smooth and almost frictionless 

 path aftbrded by hard steel ball bearings. In the barrel a 

 number of grooves, usually eight, are cut of completely circular 

 section, except that a small arc is cut off so that each com- 

 municates with the bore by a narrow slot. Into these grooves 

 are fitted steel balls, which project through the slots to the 

 extent of about one-twentieth of their diameter, with the result 

 that the projectile travels upon a rolling bed which offers the 

 least possible resistance to both its forward and its rot.itory 

 motions. At first sight it might be supposed that the arrange- 

 ment would not be gas-tight. That, however, is not the case ; 



the projectile is made to fit closely to the balls, and its elasticity, 

 combined with that of the walls of the grooves and of the b.ills, 

 insures that the gas dors not escape p.ist the bullet, which, 

 moreover, may be imagined as moving so easily and so r,i|)idly 

 that the gas has scarcely time to gel ahead of it. 



The races, or grooves, in which the balls revolve .it the 

 breech end extend back to the powder cliumber, the projectile 

 lying so that its head just engages with the first ball in each 

 groove. .Vt the muzzle end the; grooves are closed with what 

 the inventor terms recoil-cushions, the twist of the grooves 

 ceasing for a short distance from the muzzle in order to admit 

 of their insertion. These cushions .are constructed either with 

 glvcerine or with steel springs, but, whichever device is used, 

 matters are so arranged that tlie compression transmitted 

 along each row of balls begins as soon as the projectile rulers 

 the bore and is complele as it leaves the muzzle. In this way 

 the inventor claims that recoil is done away with; the bullet 

 has a course so open and free from resistance that the initial 

 recoil is very small, and what there is is taken up by the recoil 

 cushions, the tendency of the bullet being rather to drag the 

 gim after it than to kic-k it away behind it. 



In regard to performance, the inventor stales that lie gets 

 40 per cent, greater average velocity, penetration, and range 

 than can be obtained with the same weight of projectile and 



.Sectiun^ showing Rifling and Ball iiearings. 



charge in guns made on the old system. His • 50 ; gun has a 

 muzzle velocity of -j^oo foot-seconds, and .1 point-blank range 

 of 650 yards, compared with the 480 of the I'ritish service rifle 

 of the same bore, using exactly the same charge, and, while the 

 latter can drive its bulli;t through 72 one-inch boards, the 

 Cullen gun can penetrate 116. The Cullen gun of the same 

 calibre is 6 ins. or 7 ins. shorter, though its weight is about the 

 same, because the barrel is thicker, and its rifling makes four 

 complete turns, against three in the Lce-lCnfield. The balls 

 used in the grooves of a rifle of this calibre are one-tentli of 

 an inch in diameter ; in a 4-in gun they are lliree-quarters of 

 an inch. 



.'\nother advantage claimed for the gun, due to the compara- 

 tive absence of friction between the bullet and the ball bear- 

 ings, is that the barrel does not heat ; so markedly is this the 

 case that with Maxim guns it is said to be possible to dispense 

 with the cooling jackets which have given so much trouble in 

 Tibet. The absence of recoil (which, however, can be obtained 

 by contracting the bore, if it is wan ted for any reason, as for work- 

 ing the Maxim-firing mcchanisiii) again has important conse- 

 quences, since it does away with the necessity for complicated 

 carriages and mountings intended to take up the recoil. Mr. 

 Cullen has a sixpounder which he fires regularly with no more 

 elaborate mounting than a block of wood, and he claims that 

 his guns, except when they are so heavy as to require 

 mechanical appliances for training, could quite well be used 

 with the anti(|ue gun-carriages which now serve no more use- 

 ful purpose than to afford a pictures(|ue decoration to some of 

 our public places. Ships, loo, should no longer need to have 

 their structures specially strengthened iu order to withstand 

 the strains set up by the firing of their ordnance. 



