With respect to the diction of Proclus in this work, its general character is that of purity, clearness, copiousness, and magnificence; so that even the fastidious critic, who considers every Greek writer as partially barbarous who lived after the fall of the Macedonian empire, must, however unwillingly, be forced to acknowledge that Proclus is a splendid exception. The sagacious Kepler, whose decision on this subject, outweighs in my opinion, that of a swarm of modern critics, after having made a long extract from the commentaries of Proclus on Euclid, gives the following animated encomium of his diction. “Oratio fluit ipsi torrentis instar, ripas inundans, et cœca dubitationum vada gurgitesque occultans, dum mens plena majestatis tantarum rerum, luctatur in angustiis linguæ, et conclusio nunquam sibi ipsi verborum copiâ satisfaciens, propositionum simplicitatem excedit.” i.e. “His language flows like a torrent, inundating its banks, and hiding the dark fords and whirlpools of doubts, while his mind full of the majesty of things of such a magnitude, struggles in the straits of language, and the conclusion never satisfying him, exceeds by the copia of words, the simplicity of the propositions.” If we omit what Kepler here says about the struggle of the mind of Proclus, and his never being satisfied with the conclusion, the rest of his eulogy is equally applicable to the style of the present work, so far as it is possible for the beauties of diction to be combined with the rigid accuracy of geometrical reasoning.