Sept. 6, 1888] 



NATURE 



445 





ductivity being in some cases reduced by as much as 50 per cent., 

 in consequence of the admixture of that which, under other 

 circumstances, would be looked upon as insignificant. 



Reverting to the question of big guns. According to the 

 present mode of manufacture, after we have rough-bored and 

 turned the A-tube (and perhaps I ought to have mentioned 

 that by the A-tube is meant the main piece of the gun, the 

 innermost layer, if I may so call it, that portion which is the full 

 length of the gun, and upon which the remainder of the gun is 

 built up) — after, as I have said, we have rough-bored and turned 

 this A-tube, we heat it to a temperature lying between certain 

 specified limits, but actually determined by the behaviour of 

 samples previously taken, and then suddenly immerse it per- 

 pendicularly into a well some 60 feet deep, full of oil, the oil in 

 this well being kept in a state of change by the running into it, 

 at the bottom, of cold oil conveyed by a pipe proceeding from 

 an elevated oil tank. In this way the steel is oil-hardened, with 

 the result of increasing its ultimate tensile strength, and also 

 with the result of raising its so-called elastic limit. In perform- 

 ing this operation it is almost certain that injurious internal 

 strains will be set up — strains tending to produce self-rupture of 

 the material. Experiments have been carried out in England, 

 by Captain Andrew Noble, and by General Maitland of the 

 Royal Gun Factory, by General Kalakoutsky, in Russia, and 

 also in the United States, to gauge what is the value, as repre- 

 sented by dimensions, of these strains, and we find that they 

 have to be recorded in the most minute fractions of an inch, and 

 yet, if the steel be of too "high " a quality (as it is technically 

 called), or if there has been any want of uniformity in the oil- 

 hardening process, these strains, unless got rid of or ameliorated 

 by annealing, may, as I have said, result in the self-rupture of 

 the steel. 



I have spoken of the getting rid of these strains by annealing, 

 a process requiring to be conducted with great care, so as not 

 to prejudice the effects of the oil-hardening. But take the case 

 of a hardened steel projectile, hardened so that it will penetrate 

 the steel face of compound armour. In that case annealing cannot 

 be resorted to, for the extreme hardness of the projectile must not 

 be in the least impaired. The internal strains in these projectiles 

 are so very grave that for months after they are made there is no 

 security that they will not spontaneously fracture. I have here the 

 point of an 8-inch projectile, which projectile weighs 210 pounds ; 

 this with others was received from the makers as long ago as March 

 of this year, and remained an apparently perfect and sound pro- 

 jectile until about the middle of August — some five months after 

 delivery, and, of course, a somewhat longer time since manu- 

 facture — and between August 6 and 8 this piece which I hold 

 in my hand, measuring 35 inches by 3J inches, spontaneously 

 flew off from the rest of the projectile, and has done so upon 

 a surface of separation which, whether having regard to its 

 beautiful regularity, or to the conclusions to be drawn from it 

 as to the nature of the strains existing, is of the very highest 

 scientific interest. Many other cases of self-rupture of similar 

 projectiles have been recorded. 



Another instance of the effect of the "next-to-nothing " in the 

 hardening and tempering or annealing of steel. As we know, 

 the iron and the carban (leaving other matters out of considera- 

 tion) are there. The carbon is (even in tool-steel) a very small 

 proportion of the whole. The steel may be bent, and will 

 retain the form given to it. You heat it and plunge it in cold 

 water ; you attempt to bend it and it breaks ; but if, after the 

 plunging in cold water, you temper it by carefully reheating it, 

 you may bring it to the condition fit either for the cutting-tool 

 for metal, or for the cutting-tool for wood,> or for the watch- 

 spring ; and these important variations of condition which are 

 thus obtained depend upon the " next-to-nothing" in the tem- 

 perature to which it is reheated, and therefore in the nature of 

 the resulting combination of the ingredients of which the steel is 

 composed. 



Some admirable experiments were carried out on this subject 

 by the Institution of Mechanical Engineers, with the assistance 

 of one of cur Vice-Presidents, Sir Frederick Abel, and the 

 subject has also been dealt with by an eminent Russian 

 writer. 



There is, to my mind, another and very striking popular 

 instance (if I may use the phrase) of the importance of attention 

 to detail— that is, to the "next-to-nothing." Consider the 

 bicycles and tricycles of the present day — machines which 

 afford the means of healthful exercise to thousands, and which 

 will, probably within a very short time, prove of the very 



greatest possible use for military purposes. The perfection to which 

 these machines have been brought is almost entirely due to strict 

 attention to detail ; in the selection of the material of which the 

 machines are made ; in the application of pure science (in its 

 strictest sense) to the form and to the proportioning of the parts, 

 and also in the arrangement of these various parts in relation 

 the one to the other. The result is that the greatest possible 

 strength is afforded with only the least possible weight, and that 

 friction in working has been reduced to a minimum. All of us 

 who remember the hobby-horse of former years, and who con- 

 trast that machine with the bicycle or tricycle of the present day, 

 realize how thoroughly satisfactory is the result of this attention 

 to detail — this appreciation of the "next-to-nothing." 



Let me give you another illustration of the importance of 

 small things, drawn from gunnery practice. 



At first sight one would be tempted to say that the density of 

 the air on the under side of a shot must, notwithstanding its mo- 

 tion of descent, be so nearly the same as that of the air upon the 

 upper side as to cause the difference to be unworthy of con- 

 sideration, but we know that the projectiles from rifled guns tend 

 to travel sideways as they pass through the air, and that the 

 direction of their motion, whether to the right or to 'the left, 

 depends on the ' hand ' of the rifling. We know also, that the 

 friction against liquid or against gaseous bodies varies with the 

 densities of these bodies, and it is believed that, minute as is 

 the difference in density to which I have referred, it is sufficient 

 to determine the lateral movement of the projectile. This lateral 

 tendency must be allowed for, in these days of long ranges, in 

 the sighting and laying of guns, if we desire accuracy of aim, at 

 those distances at which it is to be expected our naval engage- 

 ments will have to be commenced, and perhaps concluded. We 

 can no longer afford to treat the subject as Nelson is said to have 

 treated it, in one of his letters to the Secretary of the Admiralty, 

 who had requested that an invention for laying guns more ac- 

 curately should be tried. Nelson said he would be glad to try 

 the invention, but that, as his mode of fighting consisted in 

 placing his ship close alongside that of the enemy, he did not 

 think the invention, even if it were successful, would be of much 

 use to him. 



While upon the question of guns, I am tempted to remark 

 upon that which is by no means a small thing (for it is no less 

 than the rotation of the earth), which in long-distance firing may 

 demand attention, and that to an extent little suspected by the 

 civilian. 



Place the gun north and south, say in the latitude of London, 

 and fire a 12-mile round such as I have mentioned, and it will be 

 found that, assuming the shot were passing through a vacuum, a 

 lateral allowance of more than 200 feet must be made to com- 

 pensate for the different velocity of the circumference of the 

 earth at 12 miles north or south of the place where the gun was 

 fired, as compared with the velocity of the circumference of the 

 earth at that place itself — the time of flight being in round 

 numbers one minute. 



At the risk of exciting a smile, I am about to assert that en- 

 gineering has even its poetical side. I will ask you to consider 

 with me whether there may not be true poetry in the feelings of 

 the engineer who solves a problem such as this : — Consider this 

 rock, never visible above the surface of the tide, but making its 

 presence known by the waves which rise around it : it has been 

 the cause of destruction to many a noble vessel which had com- 

 pleted, in safety, its thousands of leagues of journey, and was, 

 within a few score miles of port, then dashed to pieces upon it ! 

 Here is this rock. On it built a lighthouse. Lay your founda- 

 tions through the water, in the midst of the turmoil of the sea ; 

 make your preparations ; appear to be attaining success, and 

 find the elements are against you, and that the whole of your pre- 

 liminary works are ruined or destroyed in one night ; but again 

 commence, and then go on and go on until at last you conquer ; 

 your works rise above ordinary tide-level ; then upon these sure 

 foundations, obtained it may be after years of toil, erect a fair 

 shaft, graceful as a palm and sturdy as an oak ; surmount it with 

 a light, itself the produce of the highest application of science ; 

 direct that light by the built-up lens, again involving the highest 

 application of science ; apply mechanism, so arranged that the 

 lighthouse shall from minute to minute reveal to the anxious 

 mariner its exact name and its position on the coast. When you 

 have done all this, will you not be entitled to say to yourself, 

 " It is I who have for ever rendered innocuous this rock which 

 has been hitherto a dread source of peril " ? Is there no feeling, 

 do you think, of a poetical nature excited in the breast of the 



