Friend and, in a sense, collaborator of Winckelmann was Raphæl Mengs the artist, no less eager than his archæological fellow-countryman to understand the nature of that beauty which the one studied as a critic while the other produced it as a painter. Remarking, writes Mengs, that of the two chief duties of a painter, the imitation of appearances and the selection of the most beautiful objects, much has been written on the former, while the latter "has scarcely been touched by the modems, who would have been ignorant of the art of drawing were it not for the statues of ancient Greece";[21] pondering this, "I read, asked and looked at everything likely to throw light on the subject, but never was I satisfied; either they spoke of beautiful things or of qualities which are the attributes of beauty, or they pretended to explain, as the saying is, the obscure by the more obscure, or even confused the beautiful with the pleasing: so that finally I determined to search for the nature of beauty on my own account."[22] One of his works on this subject was published during his lifetime by the advice and assistance of Winckelmann (1761); many others appeared posthumously (1780), all were reprinted several times and translated into several languages. In his _Dreams of Beauty_ he says, "I have been sailing a long time on a vast sea seeking the understanding of beauty, and still I am far from any shore and in great doubt how to shape my course: gazing around, my sight is confounded by the immensity of the subject."[23] In truth it seems as though Mengs never arrived at a formula satisfactory to himself, although he conformed more or less to Winckelmann's doctrine that "beauty consists in material perfection according to our ideas; and since God alone is perfect, beauty is divine"; it is the "visible idea of perfection" and stands in the same relation to it as does a visible to a mathematical point. Our ideas proceed from the purposes which the Creator has willed to fulfil in various things; hence the multiplicity of beauties. In general, Mengs finds the types of things in natural species: _e.g._ "a stone, of which we have the idea that it should be uniform in colour"; which" is called ugly if it happen to be spotted"; or a child "would be ugly if he were like a man of mature age, just as a man is ugly when shaped like a woman, and a woman when she is like a man." He adds surprisingly, "As among stones there is but one perfect species, the diamond; among metals, gold; and among animated creatures, man only; so there is difference and distinction in every order, and very rarely is there perfection."[24] In his _Dreams of Beauty_ he considers beauty as "a middle disposition, including perfection on the one hand and the pleasing on the other"; in reality it is a third thing, differing from perfection and the pleasing, and deserving a special name for itself.[25] The art of painting arises from four sources: beauty,