For the present these all-important points need not be elaborated further. As we proceed to deal with the methods of naval warfare they will gather force and lucidity. Enough has been said to mark the shoals and warn us that, admirably constructed as is the craft which the military strategists have provided for our use, we must be careful with our navigation. But before proceeding further it is necessary to simplify what lies before us by endeavouring to group the complex variety of naval operations into manageable shape. II. TYPICAL FORMS OF NAVAL OPERATIONS In the conduct of naval war all operations will be found to relate to two broad classes of object. The one is to obtain or dispute the command of the sea, and the other to exercise such control of communications as we have, whether the complete command has been secured or not. It was on the logical and practical distinction between these two kinds of naval object, as we have seen, that the constitution of fleets was based in the fulness of the sailing period, when maritime wars were nearly incessant and were shaping the existing distribution of power in the world. During that period at any rate the dual conception lay at the root of naval methods and naval policy, and as it is also the logical outcome of the theory of war, we may safely take it as the basis of our analysis of the conduct of naval operations. Practically, of course, we can seldom assert categorically that any operation of war has but one clearly defined object. A battle-squadron whose primary function was to secure command was often so placed as to enable it to exercise control; and, _vice versa_, cruiser lines intended primarily to exercise control upon the trade routes were regarded as outposts of the battle-fleet to give it warning of the movements of hostile squadrons. Thus Cornwallis during his blockade of Brest had sometimes to loosen his hold in order to cover the arrival of convoys against raiding squadrons; and thus also when Nelson was asked by Lord Barham for his views on cruiser patrol lines, he expressed himself as follows: "Ships on this service would not only prevent the depredations of privateers, but be in the way to watch any squadron of the enemy should they pass on their track.... Therefore intelligence will be quickly conveyed, and the enemy never, I think, lost sight of."[15] Instructions in this sense were issued by Lord Barham to the commodores concerned. In both cases, it will be seen, the two classes of operation overlapped. Still for purposes of analysis the distinction holds good, and is valuable for obtaining a clear view of the field. [15] Nelson to Barham, 29 August 1805.