The greatest advance, however, has been in the perfection of man-killing machinery. Upon this one subject have been expended all the resources of modern metallurgical and chemical skill until the pfojectile weapon of the day, whether gun or small-arm, is a marvel of strength, accuracy and convenience. From the rude tube of our forefathers we have passed to engines of complicated structure, deadly be yond the limits of unaided vision, and of a rapidity of fire undreamed of even 30 years ago. So great is the volume of fire, so de structive the shrapnel, that in field artillery duels the question of success is reduced to that of being the first to get the range. Each class of guns must now have its special propelling agent, and a serious effort is making to dis cover some means of launching in safety the frightfully destructive explosives due to modern chemical research.
Side by side with this sort of development has marched that of the art of protection. But here, in contrast with the increasing complexity of the means of offense, we remark the increas ing simplicity of the means of defense. At the dawn of the century, the genius of Vauban still prescribed the bastion system for any and all sites to be fortified. Just as in the field, rigid and pedantic notions governed all troop-evolu tions, so in fortification the prevailing idea in each case was to furnish a rigid geometrical solution. But later the idea was first of all to adapt the work to the site, independently of the type. Steel turrets, cupolas, armored case mates, were provided for specially exposed points — a solution made possible by the great general advance in metallurgy. Concrete dis placed masonry, and the face presented to the enemy was always either of earth or, where that was impossible, of steel.
Upon the general question of fortifications, authorities were divided into two camps. Those of the first asserted that fortresses covered a mobilization, retarded the enemy, allowed a defeated army to refit under shelter. Their op ponents, on the other hand, maintained that they tied down an army, reduced the numbers of the field armies; that forts would be covered and not reduced; that they would not keep out a superior, and would be useless against an in ferior, enemy; and that a government could not afford to man them, if the antagonists we e otherwise evenly matched. In the meantime, the frontiers of Europe bristled with forts, and most important capitals were the centre of a vast entrenched camp. The great contribution of the 19th century to the question of fortifica tion was not so much one relating to the type, though this was marked, as one relating to the occasion. From hasty or improvised entrench
ments these latter days have seen the evolution to such defenses as those first of Petersburg, then of Plevna, and lastly of the battlefields of the War of 1914, erected not with the deliberation of peace, but under the stress of war, to meet its exigencies as they arise. See FORTIFICATIONS.
The principles hereinbefore set forth came to their full growth during the World War. The nation in arms, the importance of communica tion, the application of mechanical resources, the power of artillery, all these and other mat ters as well, received in that war an extension undreamed of before. To these must be added aeronautics and the use of the motor vehicle. So marked has been the effect of all these ele ments, that on one front, the western, war may be said to have changed its face, in that it passed from field fighting to trench-fighting; it is within the compass of the truth to say that on this front we have had the phenomenon of two armies besieging each other. And this example is typical of future conflicts between two numerous, brave, highly-trained and com pletely equipped adversaries.
The principle of the °nation in arms* coupled with growth of population (Germany) or with the existence of a great population (Russia) has led to the formation of armies so vast that operations pure and simple are continental in range, e.g., western front, from the Channel to Switzerland; eastern, from the Baltic to Rumania. Hence violations of neu trality with consequent degradation of interna tional law. The needs of the vast modern hosts call for an equally vast development of the systems of transportation. Hence not only are railway systems increased in time of peace, sometimes merely for future military necessi ties, but motor transport has been, and will in future be, called upon to the limit of its possi bilities. An excellent illustration is furnished by the French at Verdun, regularly supplied by a train of over 6,000 motor vehicles. But the application of motor resources is only one item of the °mobilization of industries" by a nation at war, a mobilization as vital to suc cess as the science of the generals and the valor of the men on the line, and that will as suredly be a factor of dominating importance in any war to come. In other words, whenever a great nation goes to war, not only must it put into the field and there maintain enormous armies, whose effectives are numbered by mil lions, but the energies of the people at home must be wholly concentrated upon the supply of those armies in the field. The expression "the nation in arms" has taken on a new and significant meaning.