Sermo mirabilis: or The silent language. [electronic resource] : Whereby one may learn prefectly [sic] in the space of six hours, how to impart his mind to any friend in any language, English, French, Dutch, &c. tho never so deep and dangerous a secret, without the least noise, word or voice; and without the knowledge of any in company. Being a wonderful art kept secret for several ages, in Padua, and now only published to the wise and prudent, who will not expose it, as a prostitute, to every foolish, and ignorant fellow. / By Monsieur La Fin, once secretary to his Eminence the Cardinal of Richlieu.