The second distinguishing characteristic of naval warfare which relates to the communication idea is not so well marked, but it is scarcely less important. It will be recalled that this characteristic is concerned with lines of communication in so far as they tend to determine lines of operation. It is a simple question of roads and obstacles. In land warfare we can determine with some precision the limits and direction of our enemy's possible movements. We know that they must be determined mainly by roads and obstacles. But afloat neither roads nor obstacles exist. There is nothing of the kind on the face of the sea to assist us in locating him and determining his movements. True it is that in sailing days his movements were to some extent limited by prevailing winds and by the elimination of impossible courses, but with steam even these determinants have gone, and there is practically nothing to limit the freedom of his movement except the exigencies of fuel. Consequently in seeking to strike our enemy the liability to miss him is much greater at sea than on land, and the chances of being eluded by the enemy whom we are seeking to bring to battle become so serious a check upon our offensive action as to compel us to handle the maxim of "Seeking out the enemy's fleet" with caution. The difficulty obtruded itself from the moment the idea was born. It may be traced back--so far at least as modern warfare is concerned--to Sir Francis Drake's famous appreciation in the year of the Armada. This memorable despatch was written when an acute difference of opinion had arisen as to whether it were better to hold our fleet back in home waters or to send it forward to the coast of Spain. The enemy's objective was very uncertain. We could not tell whether the blow was to fall in the Channel or Ireland or Scotland, and the situation was complicated by a Spanish army of invasion ready to cross from the Flemish coast, and the possibility of combined action by the Guises from France. Drake was for solving the problem by taking station off the Armada's port of departure, and fully aware of the risk such a move entailed, he fortified his purely strategical reasons with moral considerations of the highest moment. But the Government was unconvinced, not as is usually assumed out of sheer pusillanimity and lack of strategical insight, but because the chances of Drake's missing contact were too great if the Armada should sail before our own fleet could get into position.