The mode in which a modern army on the anticipation of war prepares itself for the field is extraordinarily rapid in point of time as compared with the mode found necessary in the time of Napoleon Bonaparte; and it is this rapidity of mobilization and concentration which strikes the observer as the greatest change or progress of the century in connection with armies. But it is a mere consequence of railroads and telegraphs, and is only the application to military purposes of those increased facilities of locomotion which have played so great a part in the progress of the century. Mobilization is, of course, the union at points fixed beforehand of the men of the reserves who bring the army up to its war footing, and the clothing and equipment of these men, and the distribution to the mobilized regiments of their full materials of war. The cavalry and horse artillery kept upon the frontier are now in a condition of permanent readiness in the principal military countries, as they would be used to cover the mobilization of the remainder of the army. The moment mobilization is accomplished concentration takes place—on the frontier in the case of the principal powers. Near the line of concentration are forts, which play a greater part in the French scheme of defence than they do in the German. The French in the days of their weakness after 1870 both constructed a line of intrenched camps and built a kind of wall of China along the most exposed portion of their eastern frontier; whereas the Germans are prepared to rely upon their field armies, supported by a few immense fortresses, such as those (on their western frontier) of Metz and Strasburg. The French keep in front of their fortresses at Nancy a strong division, which is virtually always on a war footing, and both in France and Germany the frontier corps are at a higher peace strength than those of the interior, and are meant to take the field at once so as to help the cavalry and horse artillery to protect the mobilization and concentration of the remainder, and, if possible, to disturb the mobilization and concentration of the foe. Those who would study modern armies for themselves should visit Nancy and Metz, but should not neglect the Swiss annual manœuvres.