468 



SCIENCE. 



[X. S. Vol. II. Xo. 41. 



world, science is asserting its supremacy 

 even to a greater extent in every depart- 

 ment of war. And perhaps this application 

 of science affords at a glance, better than 

 almost any other, a convenient illustration 

 of the assistance which the chemical, phys- 

 ical and electrical sciences are affording 

 to the engineer. The reception of warlike 

 stores is not now left to the uncertain judg- 

 ment of 'practical men,' but is confided to 

 officers who have received a special train- 

 ing in chemical analysis and in the applica- 

 tion of physical and electrical science to 

 the tests by which the qualities of explo- 

 sives, of guns and of projectiles can be as- 

 certained. For instance, take explosives. 

 Till quite recently black and brown pow- 

 ders alone were used — the former as old as 

 civilization, the latter but a small modern 

 improvement adapted to the increased size 

 of guns. But now the whole family of 

 nitro-explosives are rapidly superseding the 

 old powder. These are the direct outcome 

 of chemical knowledge and not of random 

 experiment. The construction of guns is 

 no longer a haphazard operation. In spite 

 of the enormous forces to be controlled and 

 the sudden violence of their action, the re- 

 searches of the mathematician have enabled 

 the just proportions to be determined with 

 accuracy ; the labors of the physicist have 

 revealed the internal conditions of the ma- 

 terials employed and the best means of their 

 favorable emploj-ment. The chemist has 

 rendered it clear that even the smallest 

 quantities of certain ingredients are of 

 supreme importance in affecting the tenacity 

 and trustworthiness of the materials. The 

 treatment of steel to adapt it to the vast 

 range of duties it has to perform is thus the 

 outcome of patient research. And the use 

 of the metals — manganese, chromium, 

 nickel, molybdenum — as alloj'S with iron 

 has resulted in the production of steels 

 possessing varied and extraordinary prop- 

 erties. The steel required to resist the 



conjugate sti-esses developed, lightning fash- 

 ion, in a gun necessitates qualities that 

 would not be suitable in the projectile which 

 that guns hurls with a velocity of some 

 2,500 ft. per second against the armored 

 side of a ship. 



The armor, again, has to combine ex- 

 treme superficial hardness with great tough- 

 ness, and during the last few years these 

 qualities are sought to be attained by the 

 application of the cementation process for 

 adding carbon to one face of the plate and 

 hardening that face alone by rapid refriger- 

 ation. The introduction of metal cartridge- 

 cases of complex forms drawn cold out of 

 solid blocks or plate has taxed the inge- 

 nuity of the mechanic in the device of ma- 

 chinery and of the metallurgist in produ- 

 cing a metal possessed of the necessary 

 ductility and toughness. The cases have to 

 stand a pressure at the moment of firing of 

 as much as 25 tons to the square inch. 

 There is nothing more wonderful in practi- 

 cal mechanics than the closing of the breech 

 openings of guns, for not only must they be 

 gas-tight at these tremendous pressures, 

 but such that one man bj^ a single contin- 

 uous movement shall be able to open or 

 close the breech of the largest gun in some 

 ten or 15 seconds. The perfect knowledge 

 of the recoil of guns has enabled the re- 

 action of the discharge to be utilized in 

 compressing air or springs by which guns 

 can be raised from concealed positions in 

 order to deliver their fire, and then made to 

 disappear again for loading, or the same 

 force has been used to run up the guns 

 automatically immediatelj' after firing, or, 

 as in the case of the Maxim gun, to deliver 

 in the same way a continuous stream of 

 bullets at the rate of ten in one second. 



In every department concerned in the 

 production of warlike stores electricity is 

 playing a more and more important part. 

 It has enabled the passage of a shot to be 

 followed from its seat in the gun to its 



