Intelligence in War: The Value--And Limitations--Of What the Military Can Learn About the Enemy by John Keegan Read Free Book Online Page B

against 800, and cost only a fifth as much to build, it might be expected that they would have been turned out in much larger numbers. Such was not in practice the case. In 1793, at the start of the Wars of the French Revolution, the Royal Navy had 141 first- second- and third-rates, battleships with between 100 and 74 guns; of fifth- and sixth-rates, frigates of between 44 and 20 guns, it had only 145; 1 by 1798, there were still only 200. Little wonder Nelson, then the Mediterranean admiral, warned that, if he died, “want of frigates would be found written on his heart.”
    Essential though frigates were as scouts, their value was restricted by the limitations of the signal system then in use. It was not simply that flags—and flags were the principal means of communication—were difficult to discern at long distance, even with a telescope. No comprehensive system of arranging them to transmit information had yet been devised. Various conventions had been in use since the seventeenth century, such as then, for example, hoisting a red flag at the mizzen-top to order a particular manoeuvre. By the late eighteenth century there had been a great deal of elaboration and in 1782 Admiral Howe, then in command of the Channel Fleet, had issued a codebook, superseding many others, which allowed a commander to say 999 different things with three flags and 9,999 with four. Howe’s signal book was not, however, double-entry. The recipient could work out what a signal meant by looking it up, finding the flags picture by picture on the page. The sender, however, had to know what flags he needed to hoist before he composed his message. Not until 1801, when Home Popham published his
Telegraphic Signals or Marine Vocabulary,
were sender and recipient put on equal footing. Popham, a sailor of great clarity of mind, simply had a flash of insight into the obvious which had evaded thousands of other sea officers before him. His achievement compares with that of his near contemporary Roget in compiling the first thesaurus. He analysed how language was used and saw that words might be given a numerical value, to be signalled by a set of numerical flags; 212, for example, could be made to stand for “cable,” with the numerical flags 2, 1 and 2. Adding a fourth numerical flag, 3, made the signal read “Can you spare a cable?” To make the first signal, the sender looked up “cable” in his double-entry book and chose the appropriate set of flags or “hoist”; to read it, the recipient looked up 2123 and got the message. 2 By the use of special indicators it could also be signified that flags had alphabetical rather than numerical value and should be read simply as letters, spelling out an unusual word not in the vocabulary. Popham’s final signal book allowed 267,720 signals to be made with twenty-four flags (of which ten doubled as numbers) and 11 special indicators.
    His system remains in use to this day. It was not yet so in 1798, when the Royal Navy still sought to speak fluently between ships through the medium of Admiral Howe’s single-entry book. A great deal of time was wasted, therefore, in frigates closing up to each other or to the main body in order to transmit information unambiguously or to receive precise questions or clear orders. The days when a flag lieutenant could snap his telescope shut and confidently interpret to his superior the meaning of a flash of coloured bunting glimpsed at the extreme limit of visibility on a clear Mediterranean day lay well in the future.
    The fallibility of signalling was not a crucial factor in the conduct of maritime operations in the last decade of the eighteenth century. It counted for much less than want of frigates. It counted as a factor, nonetheless, particularly to an admiral like Horatio Nelson, whose mind never rested, who calculated the relative positions of ships and shorelines as a master chess player does pieces and squares, who consumed information of every sort with the