In the cave dweller's time, combatants used a stone hatchet which was the best weapon that science could produce. To-day by land and sea they have used all the powers of destruction known to modern man; all the scientific brains of Europe have been at the disposal of commanders. Yet no single revolutionary invention has appeared in the course of the war. The idea of the gas was old. Man already had learned to fly. Guns have been larger and shells more powerful, but the principle is the same. Weapons have been further developed, but the types have not changed. All the essential lessons which the Germans applied they learned in the Russo-Japanese War. The line of trenches throughout the winter of 1904-05 before Mukden were much the same type as those along the Aisne. There were trenches in the Civil War and in the Crimea, and in the American Revolution and in many wars before that. So far as one can learn, there has not been a single invention by a civilian which would have been of any use to the British navy in fighting submarines. All have been devised and applied by naval experts who knew conditions. No profession is more expert than soldiering and none is older, because it began when Cain killed Abel. War being the ultimate resort of force, then the poet, the dreamer, the scholar, the doctor and the organizer of the arts of peace may succumb to the bully with the square jaw, the low brow and flesh-tearing incisors, unless the civilized man uses his resources and talents to make weapons which are stronger than the bully's fist. This is precisely what civilization does in order to protect itself. The two forces which were really prepared for this war were the British navy and the German army. The British navy has kept command of the seas and the German army has planted its trenches on foreign soil. For any nation which is separated from other nations by the sea, the military lesson of this war is that the sea is the first line of defense. You will escape bloody trenches at home if you never allow an enemy to land. He cannot land until he has driven your navy off the seas. The other lesson is that a nation should know its method of defense and have it as complete, practicable and ready as the German army and British navies were. For three or four years, the Belgians saw the Germans constructing railroad sidings at Aix and making their preparations for the blow they struck. Yet the Belgians did not modernize their forts, or adequately strengthen their army for defense. If to the staffs of England and France war seemed inevitable, their governments refused to be convinced.