The phrase “fleet in being,” having within recent years gained much currency in naval writing, demands—like the word “jingo”—preciseness of definition; and this, in general acceptance, it has not yet attained. It remains, therefore, somewhat vague, and so occasions misunderstandings between men whose opinions perhaps do not materially differ. The writer will not attempt to define, but a brief explanation of the term and its origin may not be amiss. It was first used, in 1690, by the British admiral Lord Torrington, when defending his course in declining to engage decisively, with an inferior force, a French fleet, then dominating in the Channel, and under cover of which it was expected that a descent upon the English coast would be made by a great French army. “Had I fought otherwise,” he said, “our fleet had been totally lost, and the kingdom had lain open to invasion. As it was, most men were in fear that the French would invade; but I was always of another opinion, for I always said that whilst we had a fleet in being, they would not dare to make an attempt.” A “fleet in being,” therefore, is one the existence and maintenance of which, although inferior, on or near the scene of operations, is a perpetual menace to the various more or less exposed interests of the enemy, who cannot tell when a blow may fall, and who is therefore compelled to restrict his operations, otherwise possible, until that fleet can be destroyed or neutralized. It corresponds very closely to “a position on the flank and rear” of an enemy, where the presence of a smaller force, as every military student knows, harasses, and may even paralyze, offensive movements. When such a force is extremely mobile, as a fleet of armored cruisers may be, its power of mischief is very great; potentially, it is forever on the flank and rear, threatening the lines of communications. It is indeed as a threat to communications that the “fleet in being” is chiefly formidable.