The minute systematic study which is thus devoted to the resources of every European country gives a basis for judging of its fighting power far more certain than the collection of mere military statistics. For the reference index is only a groundwork upon which the military study of the countries can be founded. It is not the product of the three divisions, but of the geographical and statistical section, which belongs to the auxiliary establishment, and in this way it prepares the materials upon which the three divisions are to work. The index is no longer given to the world; but the volumes already published are a monument of systematic research, and reveal the depth and breadth of the foundation upon which the great general staff builds, in other words, the accuracy and fulness of the knowledge at the disposal of its chief when he frames a plan of operations. It is therefore not a matter of surprise that in 1866 the chief of the Prussian general staff was well informed concerning the position and condition of every part of the Austrian army up to the time when the special preparations for the war began; was able to gauge very fairly the time that would be required for its mobilization and transport, and knew perhaps as well as any one in Austria the difficulties in which that empire would be placed by an effort to continue the struggle. A still more complete knowledge of the adversary's military and other resources was revealed by the German general staff at the opening of the campaign of 1870. The German staff has now no longer a monopoly of these studies, as may be seen by a glance at the _Revue Militaire de l'Étranger_, published fortnightly (since 1872) by the second bureau of the French general staff. The intelligence division[4] of our own War Office performs somewhat similar duties of geographical and statistical research. The transport of the portions of the army from their peace quarters to the places of assembly selected for the commencement of operations has been referred to in the account of the campaign of 1866. It was then effected partly by marching, partly by railway. Immediately after that campaign the veteran critic Jomini, in an essay upon its lessons, urged the importance of "the serious study of the modifications which railways will cause from this time onwards in the general direction of the operations of war, _i.e._ in strategy," and spoke of the want of this study as "the gap at present existing in the theory of the art of war."[5] The gap, one would think, had been pretty well filled up already by a staff which in twenty-one days had moved 197,000 men, 55,000 horses, and 5,300 military vehicles over distances varying from 120 to 360 miles without a single accident, and without any serious departure from the pre-arranged time-tables.