It certainly requires a considerable strain to bring the `right of First Discovery' under the notion of `right to the produce of one's labour' Hence Locke and others have found it necessary to suppose, as the ultimate justification of the former right, `a tacit consent' of mankind in general that all things previously unappropriated shall belong to the first appropriator. But this must be admitted to be a rather desperate device of ethico-political construction: on account of the fatal facility with which it may be used to justify almost any arbitrariness in positive law.