"Non sum Lysippus; nec Apelles; nec Policletus, Nec Zeuxis; nec sum nobilis ære Myron. Sum Florentinus Leonardus Vincia proles; Mirator veterum discipulusque memor. _Defuit una mihi symmetria prisca_: peregi Quod potui: veniam da mihi posteritas." "It is evident that these sentiments are not to be attributed to the imagination of the poet." Bossi, having no glimpse of the great principles for which Leonardo sought in vain, says: "Since, then, this great man could not satisfy himself in the difficult task of dimensions, while on other points he seems to dread no censure, it should give us a strong idea of the difficulty of determining the laws of beautiful symmetry, and preserving it in works with _that harmony which is felt, but cannot be explained, and which varies in every figure, according to the age, circumstances, and particular character of each_. "And when we recollect that, though Leonardo sought successfully in Vitruvius the proportions which Vitruvius himself seems to have drawn from the Greeks, he yet lamented that he did not possess the ancient symmetry, it is easily seen that he did not mean by this science, as already stated, a determinate general measure for man, but _that harmony of parts which is suited to each individual, according to the respective circumstances of sex, age, character, and the like_." Again, how clearly does this point to the harmonic method of proportion to be presently explained! "But," Bossi proceeds, "how difficult it is to combine the beautiful and elegant, with easy and harmonic measures, may be judged from the vain attempts of many otherwise ingenious men, as I will here relate for the benefit of artists. The difficulty will be still more evident if we reflect how arduous a task it is to make the proportions that the Greeks denominated numerical, harmonic, and geometrical, agree together, and to apply them thus agreeing, to the formation of rules and measures of a visible object so various in its component parts as the human body."--In despair, Bossi tries to show its absolute impossibility!