"Auri argentique mentionem comitatur lapis quem coticulam appellant, quondam non solitus inveniri, nisi in flumine Tmolo, ut auctor est Theophrastus: nunc vero passim; quem alii Heraclium, alii Lydium vocant. His coticulis periti, cum e vena ut lima rapuerint experimentum, protinus dicunt quantum auri sit in ea, quantum argenti vel æris, scripulari differentia, mirabili ratione, non fallente." This is the substance referred to in the apothegms of Lord Bacon, that "gold is tried by the _touchstone_, and men by gold." The French, from the same practice, know the same substance by the name of _Pierre de touche_. The use of the touchstone, at the present day, is thus described by Ure in his _Dictionary of Arts and Mines_, under the head of "Assay:" "In such small work as cannot be assayed, by scraping off a part and cupelling it, the assayers endeavor to ascertain its fineness or quality by the touch. This is a method of comparing the colour and other properties of a minute portion of the metal, with those of small bars, the composition of which is known. These bars are called _touch needles_, and they are rubbed upon a smooth piece of black basaltes, or pottery, which _for this reason is called the touchstone_." W. W. E. T. 66. Warwick Square, Belgravia. _Early Edition of Solinus_ (Vol. vi., p. 435.).--"Solinus _de Situ et Memor. Orbis_, editio princeps, folio, Venet. 1473." My copy was described as above in the catalogue of the bookseller of whom I purchased it. It contains a very fine illuminated initial letter, red, blue, and gold. It has no pagination. At the end, in capitals: "IVLII SOLINI DE SITV ORBIS ET MEMORABILIBVS QVAE MVNDI AMBITU CONTINENTVR LIBER IMPRESSVS VENETIIS PER NICOLAVM IENSON GALLICVM. M.CCCC.LXXIII." Should any gentleman wish to see it, I shall be happy to oblige him. Mine is marked "6s.," and below this price, "sold 10s." A. DUNKIN. Dartford. {143} _Straw Bail_ (Vol. vii., p. 85.).--Part of this Query may be answered by the following extract: