To reduce these divergencies to a mean of efficiency some kind of joint Staff is necessary, and to ensure its smooth working it is no less desirable to ascertain, so far as possible, the principles and method on which it should proceed. In the best recent precedents the process has been for the Army Staff to present the limits of coast-line within which the landing must take place for the operation to have the desired effect, and to indicate the known practicable landing points in the order they would prefer them. It will then be for the Naval Staff to say how nearly in accordance with the views of the army they are prepared to act. Their decision will turn on the difficulties of protection and the essentials of a landing place from the point of view of weather, currents, beach and the like, and also in a secondary measure upon the extent to which the conformation of the coast will permit of tactical support by gun-fire and feints. If the Naval Staff are unwilling to agree to the point or points their colleagues most desire, a question of balance of risk is set up, which the higher Joint Staff must adjust. It will be the duty of the Naval Staff to set out frankly and clearly all the sea risks the proposal of the army entails, and if possible to suggest an alternative by which the risk of naval interference can be lessened without laying too heavy a burden on the army. Balancing these risks against those stated by the army, the superior Staff must decide which line is to be taken, and each service then will do its best to minimise the difficulties it has to face. Whether the superior Staff will incline to the naval or the military view will depend upon whether the greater danger likely to be incurred is from the sea or on land. Where the naval conditions are fairly well known the line of operations can be fixed in this way with much precision. But if, as usually happens, the probable action of the enemy at sea cannot be divined with sufficient approximation, then assuming there is serious possibility of naval interference, the final choice within the limited area must be left to the admiral. The practice has been to give him instructions which define in order of merit the points the army desire, and direct him to select the one which in the circumstances, as he finds them, he considers within reasonable risk of war. Similarly, if the danger of naval interference be small and the local conditions ashore imperfectly known, the final choice will be with the general, subject only to the practicable possibilities of the landing place he would choose. During the best period of our old wars there was seldom any difficulty in making things work smoothly on these lines. After the first inglorious failure at Rochefort in 1757 the practice was, where discretion of this kind had been allowed, for the two commanders-in-chief to make a joint coast-reconnaissance in the same boat and settle the matter amicably on the spot.