The plea that Silesia was necessary to Prussia, that the existence of Prussia could only be prolonged or her people safeguarded or fed if Silesia were hers, may be dismissed at once. Necessity is the usual pillar of a claim to extend the area of dominion over lands lately rescued from barbarism. The Law of Nations declares that, when under such conditions two civilised states desire the same territory, one may further its claim by showing that without this addition the territory which it already has would be rendered worthless. But what might give a good title to Fashoda would be absurd if applied to Breslau. Frederick had himself investigated the subject nine years before when studying under Hille at Cüstrin. He then concluded that Silesia did Prussia commercial injury by exporting to her goods at lower rates than the merchants of Brandenburg could afford to take. This state of things, he and Hille thought, demanded a protective tariff. It could not by any stretch of imagination dictate or justify the annexation of a province. Nor from a military point of view was there imperative necessity for acquiring Silesia. It was no doubt desirable for Prussia that she should avert future danger by thrusting a wedge between Saxony and Poland, and that more than one-fifth of the road from Vienna to Berlin, by way of Breslau, should be in Prussian hands. But no Prussian could maintain in 1740 that if Glogau and Breslau remained Austrian his state would be imperilled in the same sense as the German Empire would have been imperilled if Metz and Strasburg had remained French in 1871, or as the British Empire would be imperilled to-day if Pretoria and Johannesburg were still in hostile hands. The plea of hereditary right, not that of necessity, was put forward by Frederick as the basis of his claims. In 1740 the latter would have seemed equally absurd in law and in fact.