§ 37. Individual value of Ships or Units. The factor the most difficult to assess in the evaluation of a fleet as a fighting machine is (apart from the personnel) the individual value of its units, when these vary amongst themselves. There is no possibility of entirely obviating this difficulty, since the fighting value of any given ship depends not only upon its gun armament, but also upon its protective armour. One ship may be stronger than another at some one range, and weaker at some longer or shorter range, so that the question of fleet strength can never be reduced quite to a matter of simple arithmetic, nor the design of the battleship to an exact science. In practice the drawing up of a naval programme resolves itself, in great part at least, into the answering of the prospective enemy's programme type by type and ship by ship. It is, however, generally accepted that so long as we are confining our attention to the main battle fleets, and so are dealing with ships of closely comparable gun calibre and range, and armour of approximately equivalent weight, the fighting value of the individual ship may be gauged by the weight of its "broadside," or more accurately, taking into account the speed with which the different guns can be served, by the weight of shot that can be thrown per minute. Another basis, and one that perhaps affords a fairer comparison, is to give the figure for the energy per minute for broadside fire, which represents, if we like so to express it, the horse-power of the ship as a fighting machine. Similar means of comparison will probably be found applicable to the fighting aeroplane, though it may be that the downward fire capacity will be regarded as of vital importance rather than the broadside fire as pertaining to the battleship.
§ 38. Applications of the n-square Law. The n-square law tells us at once the price or penalty that must be paid if elementary principles are outraged by the
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