Quinti Horatii Flacci opera omnia,: recensuit Filon.

Paris: A. Mesnier,, 1828. The second book to be printed with "one of the acknowledged miracles of microscopic printing, and in its quality unparalleled to this day... In spite of its exceedingly small size Didot's type is of great beauty and amazing clarity" (Bondy, p. 91). The Non Plus Ultra type of Henri Didot (1765-1852) first appeared the previous year in the Maximes of Duc de La Rochefoucauld. "This fount was a high achievement of the typefounder's art. The minuteness was such that the types could not be cast in the ordinary way; hence [Didot] invented a special apparatus, to which he gave the name of the 'polyamatype', and by means of which they were cast, a hundred letters at a time" (Bibliography of Printing). Sprinkled throughout the book is an ornamental line incorporating Didot's name in an even tinier type, which has been described as "certainly the smallest ever made" (Thurkow, p. 6). Non Plus Ultra measures 2.5 point; in comparison, the contemporary and well-known Diamond Classics miniature series of the English publisher William Pickering was printed in 4.5 point. An identical edition was published in the same year and city by A. Sautelet; both are scarce in commerce. Miniature, duodecimo (72 x 44 mm). Contemporary red morocco, spine lettered and framed in gilt, covers ruled with gilt French fillets, single gilt rule on board edges, turn-ins tooled in gilt, Nonpareil pattern marbled doublures and free endpapers, edges gilt. Text in Latin. Gilt parchment book label with baron's coronet initialled "DC". Binding bright, tiny bump and wear to corners, faint marginal damp stain to initial leaves, sporadic foxing to contents. A very good copy indeed. Bibliography of Printing, I, p. 177; Grolier, A Short List of Microscopic Books, 70 ("a true masterpiece of printing", p. 127); Welsh 3568. Louis W. Bondy, Miniature Books: Their History from the Beginnings to the Present Day, 1981; G. Thurkow, "Non plus ultra", Miniature Book News, no. 60, March 1989.