November 4, 19 15] 



NATURE 



26 c 



mittee on Plates and Guns, received the appoint- 

 ment of Assistant Inspector of Artillery, and 

 entered the proof department of Woolwich 

 Arsenal. Almost immediately after this he was 

 made an associate member of the Ordnance Select 

 I ommittee and a member of the Committee on 

 Ixplosives. He was thus in closest touch with 

 the burning- questions that presented themselves 

 for solution on the introduction of rifled guns. 

 At this time (i860) the Government might possibly 

 have secured his services for a further consider- 

 able period if they had promptly offered him a 

 position suited to his growing reputation as a 

 gunner of original ideas and untiring energy ; 

 ,but the Government acted too late, and a good 

 offer found that he had already bound himself by 

 contract to enter the Elswick firm as the director 

 of its ordnance department. He, however, was 

 retained on several Government committees, upon 

 which his presence was invaluable, as he had the 

 means at Elswick of carrying out many special 

 researches, the results of which he freely placed 

 at the disposal of the Government. 



Noble's first important work in exterior ballistics 

 appears to have been his experiments with the 

 electro-ballistic apparatus of Navez, which had the 

 object of making a close determination of initial 

 velocity. He ascertained the causes which affect the 

 velocity both with smooth-bore and rifled guns, and 

 in particular he showed that with reduced powder 

 charges the air-space in the powder chamber had 

 a notable effect. He also discussed at length the 

 law of dependence of the resistance of the air 

 upon velocity in connection with previous re- 

 searches of Probert, St. Robert, Mayevski, and 

 Didion. The next paper, " On the Ratio between 

 the Forces tending to produce Translation and 

 Rotation in the Bores of Rifled Guns," was of 

 much importance at the time it was written. 

 Rifled guns were getting bigger every day, and 

 there was much difference of opinion as to the 

 best method of rifling and. in particular, as to the 

 relative merits of uniform and increasing twist. 

 He showed that with the uniform twist the force 

 required to give rotation was only a small frac- 

 tion of that required to give translation, and that 

 in all cases the increment of gaseous pressure due 

 to rifling was insignificant. With regard to the 

 increasing twist (parabolic system of rifling) he 

 also made a thorough mathematical investigation, 

 and found again that the pressure on the studs 

 due to rifling is only about 2\ per cent, of the 

 pressure required to give translation ; also that 

 the substitution of parabolic for uniform rifling 

 reduces by about one-half the maximum pressure 

 on the studs ; and that the increment of gaseous 

 pressure due to rifling, tending to burst the gun, 

 is exceedingly small and less than that which 

 obtains when the rifling is uniform. 



His researches in interior ballistics properly so 

 called commenced when he first went to Elswick, 

 but the first publication appears to have been in 

 the Proc. Roy. Inst, for 1871, "On the Tension 

 of Fired Gunpowder." Previous investigators, 

 de la Hire, Robins, Count Rumford, Cavalli, 

 NO. 2401, VOL. 96] 



Neumann, Mayevski, Rodman, had obtained results 

 for the pressure exerted by gunpowder fired in a 

 closed vessel varying from 1000 to 100,000 atmo- 

 spheres. Bunsen and Schischkoff later found 

 4374 atmospheres, about 29 tons on the square 

 inch, for the pressure which the gases may ap- 

 proximate to but can never reach. Commencing 

 in the year 1861, Noble, in conjunction with Sir 

 W. Armstrong, carried out a large number of 

 experiments, employing a chronoscope specially 

 invented by himself. This beautiful instrument 

 was able to measure a millionth of a second of 

 time with ease. It was used in conjunction with 

 a series of crusher gauges in determining the pres- 

 sures exerted by the powder gases at various 

 places along the bore extending from the powder 

 chamber to the muzzle. The results were of first- 

 rate importance. It was shown that the maxi- 

 mum pressure of fired ordinary gunpowder of unit 

 density is not much above 40 tons to the square 

 inch, but that in large guns, owing to the violent 

 oscillations produced by the ignition of a large 

 mass of powder, the pressure is liable to be locally 

 exalted to an extent which endangers the endur- 

 ance of the gun while detracting from the useful 

 effect. It was also found that the intensity of this 

 wave action is directly influenced by the position 

 of the vent or firing point, and that it is desirable 

 to have as short a powder cartridge as possible. 



Noble's remaining researches in gunnery, ex- 

 tending over nearly fifty years, may be for the 

 most part summed up under the title " Researches 

 on Explosives." In these he was for many years 

 associated with Sir Frederick Abel and Sir James 

 Dewar. The objects in view were to ascertain 

 the products of combustion of powders fired in 

 circumstances similar to those which exist in 

 guns — to ascertain the pressure exerted by the 

 products of combustion at the moment of explo- 

 sion and the law of its variation with the gravi- 

 metric density; to find the influence of the size 

 of grain ; to find the effect upon the products of 

 a change in the pressure under which firing takes 

 place ; to measure the volume of the permanent 

 gases liberated ; to compare the explosion in a 

 closed chamber with that in the powder chamber 

 of a gun ; to find the heat generated ; and, finally, 

 the work which the explosive is capable of per- 

 forming on a projectile in the bore of a gun. That 

 this lengthy programme was successfully carried 

 out was largely due to Noble's extraordinary 

 ability and energy. The results obtained were of 

 the utmost importance to the manufacture of guns 

 of all calibres. When fired in a closed space the 

 temperature of the explosion of gunpowder was 

 found to be 2200° C. The total work of gun- 

 powder when indefinitely expanded was found to 

 be 332,000 grm. -metres per gramme of powder, or 

 486 foot-tons per lb. of powder. 



It is impossible in this short notice to say 

 more upon these results, which are fully set forth 

 in communications printed in the Transactions of 

 fhe Royal Society between the years 1875 and 

 1879. The experiments were repeated as gun- 

 powder gradually altered in physical characters. 



