This double end will not be so difficult of attainment as might at first sight seem, for the reason that the solution of any problem which represents a situation actually probable will automatically provide all the minor situations necessary to drill the various bodies; and the more inherently probable a situation is, the more probable will be the situations in which the various flag-officers, captains, quartermasters, engineers' forces, turret crews, etc., will find themselves. Of course, the prime difficulty in devising realistic problems is the fact that in war our whole fleet would be employed together against an enemy fleet; and as the staff cannot supply an enemy fleet, it must either imagine an enemy fleet, divert a small part of our fleet to represent an enemy fleet, or else divide our fleet into two approximately equal parts, one "red," and one "blue." _First Scheme_.--The first scheme has its usefulness in working out the actual handling of the fleet as a whole; and considering the purposes of strategy only, is the most important, though, of course, "contacts" with the enemy cannot be simulated. From the standpoint of fleet tactical drill, and the standpoint of that part of strategy which arranges for handling large tactical situations with success, it is useful, since it provides for the tactical handling of the entire fleet. This certainly is important; for if the personnel are to be so trained that the actual fleet shall be handled with maximum effectiveness in battle, training in handling that actual fleet must frequently be had; the fleet is a machine, and no machine is complete if any of its parts is lacking. It may be objected that it is not necessary for the staff at the department to devise such training, because drills of the entire fleet can be devised and carried out by the commander-in-chief; in fact that that is what he is for. This, of course, is partly true; and it is not the idea of the author that the staff in the department should interfere with any scheme of drills that the commander-in-chief desires to devise and carry out; but it is his idea that the staff should arrange problems to be worked out by the fleet, in which the tactical handling of the fleet should be subordinate to, and carried out for, a strategic purpose.