In his appendix, the author explains the utility of a method of writing without alphabetic characters, by means of signs, which are to be used to denote all the principal ideas, the relative attributes being designated by small strokes added at right, acute, or obtuse angles, to the right or left; &c. Of principal or chief ideas he admits but forty, under which he ranges all the others, by that means forming a series of categories. His new language is calculated to afford great facility of comprehension, and new openings to the various processes of science. After so many attempts, more or less philosophical, and of different degrees of perfection, with others probably of which we know nothing, we must not overlook the efforts of the celebrated Leibnitz. His History and Development of a Characteristic Universal Language is very generally known. Leibnitz considered his universal characteristic as the art of inventing and judging. He stated his conviction that an alphabet might be formed, and of this alphabet such words as would afford a language capable of giving mathematical precision to all the sciences. "Men may thus acquire," says he, "as it were, a new organ, which would add energy to their moral faculties, as the microscopic lens increases the power of the eye. The compass is not more highly valuable to the navigator, than this philosophical language would be to him who embarks on the sea of reason and experiments, which is now so full of danger." In concluding this brief sketch, it may be enough to notice the ingenious method of the Abbé de l'Epée, who, by means of various gestures, dictated to his various deaf and dumb pupils certain discourses, which they wrote with equal readiness in four languages. No. XXXIII. To write with a needle and thread, white, or any other colour, upon white, or any other colour, so that one stitch shall significantly show any letter, and as readily and as easily show the one letter as the other, and fit for any language. NOTE. Vide Article LXXV. No. XXXIV. To write by a knotted silk string, so that every knot shall signify any letter, with comma, full-point, or interrogation; and as legible as with pen and ink upon white paper. NOTE.