In 1914 the brilliant and remarkably versatile English engineer, Frederick William Lanchester, published a series of articles which he later consolidated into a book entitled, Aircraft in Warfare: The Dawn of the Fourth Arm. The best-remembered result of his intellectual excursion into military theory is a simple mathematical expression of the principle of concentration, called the "n-square Law," that defines what Lanchester called the relative "fighting strengths" of military forces in terms of their "numerical strengths" and the "fighting values," of the individual units.
Taylor, Theodore C.
"Tactical Concentration and Surprise-in Theory,"
Naval War College Review: Vol. 38
, Article 4.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol38/iss3/4