Ten men, battalions, or divisions, fighting fifteen men, battalions, or divisions, conquer—that is, kill or take captive—all the others, while themselves losing four, so that on the one side four and on the other fifteen were lost. Consequently the four were equal to the fifteen, and therefore 4x = 15y. Consequently x/y = 15/4. This equation does not give us the value of the unknown factor but gives us a ratio between two unknowns. And by bringing variously selected historic units (battles, campaigns, periods of war) into such equations, a series of numbers could be obtained in which certain laws should exist and might be discovered.