The greatness of the British navy, compared with that of the British army and the other elements of Great Britain's government, has taken on magnified dimensions during the last half century. So long as war-ships used sails as their principal motive power, so long were they forced to employ methods of construction and equipment that forbade the efficient employment of high-power guns, the attainment of great speed, and the use of instruments of precision; so long, in other words, was their military effectiveness prevented from increasing greatly. But when the British navy decided to abandon sail power altogether and propel their ships by steam, a new phase was entered upon, in which every resource of the engineering arts and the physical sciences was called into requisition; and now, on board a dreadnaught, battle cruiser, destroyer, or submarine, can be found the highest examples of mechanical and electrical art and science. Every material resource which the brain and wealth of man can compass is enlisted in her naval defense; and in order to take advantage of the rapidity and certainty of movement they afford for operating fleets and ships, there has been a great advance in methods of operation, or, in military parlance, "staff work." To assist this work, the radio, the cable, and even the humble typewriter have contributed their essential share, with the result that to Great Britain's naval defense there has been devoted an extraordinary degree of efficiency, continuous effort, a more varied activity, and a larger expenditure of money than to any other object of man's activity.