Why was the prussian army a superior force?

The Prussian, as well as the German in general, makes capital stuff for a soldier. They are, withal, among the most pugnacious people in the world, enjoying war for its own sake, and often enough going to look for it abroad, when they cannot have it at home. From the Landsknechte of the middle age to the present foreign legions of France and England, the Germans have always furnished the great mass of those mercenaries who fight for the sake of fighting. if the French excel them in agility and vivacity of onslaught, if the English are their superiors in toughness of resistance, the Germans certainly excel all other European nations in that general fitness for military duty which makes them good soldiers of any circumstances