The ancient gems, cameos and pastes are invaluable. They repeat in fact on the smallest scale, yet with consummate finish, the entire survey of sculpture, from the simple figure of a god, through all the varied forms of grouping to every possible kind of conceit in dainty delight and prettiness. Winckelmann, however, observes with regard to the Stosch collection[197]: "It was while looking at this that I was made aware of a truth, which afterwards became to me of great value in elucidating monuments, very difficult to understand; and the truth is this, that on cut stones, no less than on imposing works of sculpture, we very rarely come across events which took place after the Trojan war, or after the return of Odysseus to Ithaca, if we only except the one case of the Heracleidae and the descendants of Hercules; for in this latter case the limits of history and fable still overlap, and fable is the main subject of these artists. Only one example of the tale of the Heracleidae, however, is known to me personally." As for gems, the genuine and most consummately executed figures are of the greatest beauty, fine as the work of organic Nature, and may be inspected through a magnifying glass without any loss to the purity of their delineation. I refer to this fact in proof that the technique of art in such cases is almost an art of intuition; the fineness is such that the artist is unable as the sculptor is to follow the work with his eyes, but is rather compelled to _feel after_ it. He holds the stone which is made fast on wax against tiny sharp wheels which are made to spin by means of a flying-wheel, and in this way cuts out the forms. By this process what we have is a kind of instinctive sense, which takes in and directs so consummately the conception, the intention of line and drawing, that we can almost fancy ourselves to have before us in these stones, when one sees them properly illuminated, a relief work. The work on cameos is to be contrasted with the above. These represent figures finely cut in out of the stone. The onyx was particularly utilized as material for this kind of work. In dealing with these, the ancients were expert in setting off to advantage and with taste the various strata, in particular the white and yellow-brown. Aemilius Paulus had a number of such stones and other trinkets carried to Rome.