only with the particular word _Thames_, if he was brought to any other river, would he not readily call it a _Thames_? This, in reality, is no more than what they, who are well acquainted with the general word, are very apt to do. An Englishman, describing any great river which he may have seen in some foreign country, naturally says, that it is another Thames. The Spaniards, when they first arrived upon the coast of Mexico, and observed the wealth, populousness, and habitations of that fine country, so much superior to the savage nations which they had been visiting for some time before, cried out, that it was another Spain. Hence it was called New Spain; and this name has stuck to that unfortunate country ever since. We say, in the same manner, of a hero, that he is an Alexander; of an orator, that he is a Cicero; of a philosopher, that he is a Newton. This way of speaking, which the grammarians call an Antonomasia, and which is still extremely common, though now not at all necessary, demonstrates how much mankind are naturally disposed to give to one object the name of any other, which nearly resembles it, and thus to denominate a multitude, by what originally was intended to express an individual. It is this application of the name of an individual to a great multitude of objects, whose resemblance naturally recalls the idea of that individual, and of the name which expresses it, that seems originally to have given occasion to the formation of those classes and assortments, which, in the schools, are called genera and species, and of which the ingenious and eloquent M. Rousseau of Geneva[28], finds himself so much at a loss to account for the origin. What constitutes a species is merely a number of objects, bearing a certain degree of resemblance to one another, and on that account denominated by a single appellation, which may be applied to express any one of them. Footnote 28: Origine de l’Inegalité. Partie premiere, p. 376, 377, Edition d’Amsterdam, des Oeuvres diverses de J. J. Rousseau. When the greater part of objects had thus been arranged under their proper classes and assortments, distinguished by such general names, it was impossible that the greater part of that almost infinite number of individuals, comprehended under each particular assortment or species, could have any peculiar or proper names of their own, distinct from the general name of the species. When there was occasion, therefore, to mention any particular object, it often became necessary to distinguish it from the other objects comprehended under the same general name, either, first, by its peculiar qualities; or, secondly, by the peculiar relation which it stood in to some other things. Hence the necessary origin of two other sets of words, of which the one should express quality; the other relation.