Meanwhile, upon that same day, August 3rd, following with superstitious exactitude the very hour upon which, on the very same day, the French frontier had been crossed in 1870, the Germans entered Belgian territory. The Foreign Office's thesis underlying the declaration of its spokesman, Sir Edward Grey, carried the day with the politicians in power, and upon Tuesday, August 4th, Great Britain joined Russia and France, at war with the Prussian Power. There followed later the formal declaration of war by France as by England against Austria, and with the first week in August the general European struggle had opened. PART II. THE FORCES OPPOSED. Here, then, at the beginning of August 1914, are the five great Powers about to engage in war. Russia, France, and Great Britain, whom we will call the Allies, are upon one side; the German Empire and Austria-Hungary, whom we will call the Germanic Powers, are upon the other. We must at the outset, if we are to understand the war at all, see how these two combatant groups stood in strength one against the other when the war broke out. And to appreciate this contrast we must know two things--their geographical situation, and their respective weight in arms. For before we can judge the chances of two opponents in war, we have to know how they stand physically one to the other upon the surface of the earth, or we cannot judge how one will attack the other, or how each will defend itself against the other. And we must further be able to judge the numbers engaged both at the beginning of the struggle and arriving in reinforcement as the struggle proceeds, because upon those numbers will mainly depend the final result. Having acquired these two fundamental pieces of information, we must acquire a third, which is _the theories of war_ held upon either side, and some summary showing which of these theories turned out in practice to be right, and which wrong. For, after a long peace, the fortune of the next war largely depends upon which of various guesses as to the many changes that have taken place in warfare and in weapons will be best supported by practice, and what way of using new weapons will prove the most effective. Until the test of war is applied, all this remains guess-work; but under the conditions of war it ceases to be guess-work, and becomes either corroborated by experience or exploded, as the case may be. And of two opponents after a long peace, that one which has had the most foresight and has guessed best what the effect of changes in armament and the rest will effect in practice is that one who has the best chance of victory. We are going, then, in this Second Part, of the little book, to see, first, the geographical position of the belligerents; secondly, their effective numbers; and, thirdly, what theories of war each held, and how far each was right or wrong. (1) THE GEOGRAPHICAL POSITION OF THE BELLIGERENTS.