September i8, 1890] 



NATURE 



503 



powder had been subjected to climatic influences, the variations 

 would have been much greater. 



The variatipns in energy of new powder were chiefly due to 

 the method of proof then in use, the Eprouvette mortar, than 

 which nothing can be conceived better adapted for passing into 

 the service powders unsuitable for the guns of that time. 



But with the want of accuracy of the gun itself, and the want 

 of uniformity in the propelling agent, it may easily be conceived 

 that a limit was soon reached beyond which it was mere waste 

 of ammunition to fire at an object even of considerable size, and 

 we can appreciate the reasons which led our naval commanders, 

 whenever possible, to close with their enemy. 



When we come to consider guns of the present day, the first 

 point that attracts our attention is the enormous increase in the 

 size and weight of the larger natures. It may fairly be asked, 

 indeed, if, weight for weight, the modern guns are so much 

 more powerful than the old, and, if we have command of such 

 great ranges, why such heavy guns should be necessary. 



The answer to this, of course, is that it has been considered 

 essential to have guns capable of piercing at short distances the 

 thickest armour which any ship can carry, and this demand has 

 led us from guns of 5 tons weight up to guns of no and 

 120 tons weight, and to the development of the important 

 mechanical arrangements for working them, to which I shall 

 presently refer. 



On the principles which guide the construction of these large 

 guns I shall say little, both because the subject is too technical 

 to be dealt with in an address, and because the practice of all 

 nations, though diff'ering in many points of detail, in essentials 

 is closely accordant. 



On three points of construction we lay particular stress in 

 this country. These points are : That the gun shall be strong 

 enough to resist the normal working pressure, even if the inner 

 tube or barrel be completely split. That whether we regard the 

 gun as a whole, or the parts of which it is composed, the 

 changes of form should be as little abrupt as possible, and that 

 any sharp angle or corner must be absolutely avoided. 



As in principles of construction, so in material employed, is 

 the practice of the great gun-making nations closely agreed. 

 The steel employed is ductile and subjected to severe specifica- 

 tions and tests, which differ slightly one from the other, but 

 exact, in effect, qualities of steel substantially the same. So far 

 as I know, the application of the tests in this country is more 

 severe than in any other, and I take this opportunity of entering 

 my protest against the statement which I have seen more than 

 once in the journals of the day — that English gun-steel is in any 

 way inferior to any that is produced in any part of the world. 

 Sheffield has in no respect lost its ancient reputation in the art 

 of steel-making, and to my certain knowledge has supplied large 

 quantities of steel, admitted to be of the first quality, to gun- 

 makers of the Continent. The steel made by Sir J. Whit worth 

 & Co. has likewise long been in great repute both at home and 

 abroad, and looking at the care devoted to the subject by the 

 Government, and the eagerness with which improvements in the 

 quality and mode of manufacture are sought for and acted on 

 by the steel-makers, we may be absolutely certain that to the 

 best of our knowledge the most suitable material is used in the 

 construction of our guns. 



As many of you are aware, the mild steel which is used for 

 the manufacture of guns is after forging and rough-boring sub- 

 jected to the process of oil-hardening, being subsequently 

 annealed, by which process it is intended that any detrimental 

 internal strain should be removed. This process of oil-hardening, 

 introduced first by Lord Armstrong in the case of barrels, is now 

 almost universally adopted for all gun forgings. Of late, how- 

 ever, there has been considerable discussion as to whether or 

 not this oil-hardening is necessary or desirable ; aid while ad- 

 mitting the increase of the elastic limit due to the process, it is 

 asked whether the same results would not be obtained by taking 

 a steel with, for example, a higher percentage of carbon, and 

 which should give the same elastic limit, and the same ductility. 

 The advocates of oil-hardening urge that steel with low carbon, 

 duly oil-hardened to obtain the elastic limit and strength de- 

 sired, is more reliable than steel in which the same results are 

 reached by the addition of carbon. Those who maintain the 

 opposite view point to the uncertainty of obtaining uniform 

 results by oil-hardening, to the possibility of internal strains, 

 and to the costly plant and delay in manufacture necessary in 

 carrying it out. The question raised is undoubtedly one of 

 jgreat importance, but it appears to me to be one concerning 



NO. 1090, VOL. 42] 



which it is quite within oar power in a comparatively short 

 time, by properly arranged experiments, to arrive at a definite 

 conclusion. 



Sir F. Abel has in his Presidential Address given us so 

 masterly a resume of the present state of the steel question in its 

 metallurgical and chemical aspects that it is unnecessary for me 

 to add anything on this head. I will only remark that in select- 

 ing steel for gim-making, individually I should prefer that which 

 is on the side of the low limit, to that which is near the high 

 limit, of the breaking weight prescribed by our own and other 

 Governments. I have this preference because, so far, expe- 

 rience has taught us that these lower steels are safer and more 

 reliable than the stronger — and in guns we do not subject, and 

 have no business to subject, the steel to stresses in any way 

 approaching that which would produce fracture. 



Of course if our metallurgists should give us a steel or other 

 metal which with the same good qualities possesses also greater 

 strength, such a material would by preference be employed, bat 

 it must not be supposed that the introduction of such new 

 material would enable us, to any great extent, to reduce the 

 weight of our guns. As a matter of fact, the energy of recoil of 

 many of our guns is so high that it is undesirable in any case 

 materially to reduce their weight. As an illustration, I may 

 mention that some time ago, in re-arming an armour-clad, the 

 firm with which I am connected was asked if by using the 

 ribbon construction it would be possible, while retaining the 

 same energy in the projectile, to reduce the weight of the main 

 armament by three tons per gun. The reduction per se was 

 quite feasible, but when the designs came to be worked out it 

 was found that, on account of the higher energy of recoil, no 

 less than 4 tons weight per gun had to be added to strengthen 

 the mounting, the deck, and the port pivot fastenings. 



The chamber pressures with which our guns are worked do not 

 generally exceed seventeen tons per square inch, or say 2500 

 atoms. It must not be supposed that there is any difficulty in 

 making guns to stand very much higher initial tensions ; but little 

 would be gained by so doing. Not only can a higher effect be 

 obtained from a given weight of gun if the initial pressure be kept 

 within moderate limits, but with high pressures the erosion (which 

 increases very rapidly with the pressure) would destroy the bores 

 in a very few rounds. 



In fact, even with the pressures I have named, the very high 

 charges now employed in our large guns (1060 lbs. have 

 frequently been fired in a single charge), and the relatively 

 long time during which the high temperature and pressure of 

 explosion are maintained, have aggravated to a very serious 

 extent the rapid wear of the bores. In these guns, if the highest 

 charge be used, erosion, which no skill in construction can 

 obviate, soon renders repair or relining necessary. Reduced 

 charges, of course, allow a materially prolonged life of the bore, 

 and there is also a very great diffierence in erosive effect between 

 powders of different composition, but giving rise in a gun to the 

 same pressures. Unfortunately, the powder which has up to the 

 present been found most suitable for large guns is also one of the 

 most erosive, and powder-makers have not so far succeeded in 

 giving us a powder at once suitable for artillery purposes, and 

 possessing the non-eroding quality so greatly to be desired. 



An amide powder made by the Chilworth Company, with 

 which I have, not long ago, experimented, both gave admirable 

 ballistic results, and at the same time its erosive effect was very 

 much less than that of any other with which I am acquainted. It 

 is by no means certain that the powder would stand the tests 

 which alone would justify its admission into the service, but the 

 question of erosion is a very serious one, and has hardly, I think, 

 received the attention its importance demands. No investigation 

 should be neglected which affords any prospect of minimising this 

 great evil. 



On the introduction of rifled artillery the muzzle velocities, 

 which you will remember had been with smooth-bore guns and 

 round shot about 1600 f.s., were, with the elongated projectiles 

 of the rifled gun, reduced to about 1200 f.s. In the battle 

 between plates and guns these velocities were with armour-pierc- 

 ing projectiles gradually increased to about 1400 f.s., and at 

 about this figure they remained until the appointment by the 

 Government of a Committee on Explosives. By the experiments 

 and investigations of this committee it was shown that, by im- 

 proved forms of gunpowder and other devices, velocities of 

 1600 f.s. could be obtained without increasing the maximum 

 pressure, and without unduly straining the existing guns. Similar 

 advances in velocity were nearly simultaneously made abroad, 



