The author's design of vessel illustrated has a capacity of gathering oysters from good ground at the rate of five thousand bushels per hour. The use of the submarine will make the recovery of oysters more nearly like the method of reaping a field of grain, where one "swath" systematically joins on to another, and the whole field is cleaned up at one operation. In many other fields of industrial and commercial enterprise the submarine is qualified to render valuable services. In general submarine engineering work; in the construction of breakwaters, lighthouses, driving piles and building abutments, and in the deepening and improvement of waterways and harbors, the submarine will be utilized. In prospecting for, and the recovery and separation of, gold from river-beds and sea-coast bottoms submarine devices have been found to be very efficient and economical. A new method of laying tunnels under water has been proposed in which adaptations of the submarine boat will play a great part. However, these latter developments of the submarine are so highly specialized and a description of them would be so very technical that mere mention of these possibilities will be sufficient for the purposes of this book. Thus it is evident that the submarine has a utility entirely apart from that of a military weapon. Its unique qualities fit it for the labors of peace as well as for those of war. Of course, in both cases, either as a naval weapon or as an industrial mechanism, it is the unique capacity of submergence possessed by the submarine which makes it of value, and in either case it is the question of accessibility which is all-important. In the war use the chief function of the submarine is to make itself inaccessible to the foe. It is immune from attack because it cannot be seen. It is able to strike at its foe with success because its presence is not detected by him. It is thus able to make use of its destructive energy in perfect safety. On the other hand, the chief value of the industrial submarine lies in the fact that it constitutes a means of access to places otherwise inaccessible to men. It is very desirable and very profitable for men to go down into the depths of the sea. There are things well worth doing on the bed of the ocean. Travel may be made safe, goods of great value may be brought up, foodstuffs of the first order may be obtained there; with submarines men may prosecute their labors beneath the sea with very little danger and at a minimum of cost. The diver's profession will become, through the use of this mechanism, an important factor in the economic affairs of the world. CHAPTER VIII THE DESTINY OF THE SUBMARINE Studies of the submarine which deal with the subject solely from the engineering or military standpoint, or which treat of the development of this weapon simply in the light of its strategic value, fail to recognize the human aspects of the problem.