Mr. Horner afterwards informed me, that the late Dr. Menish of Chelmsford had presented to the Geological Society a specimen which he had received, with some other volcanic productions, from Sicily, but which had been collected in the Lipari Islands; the box containing them being marked “ Produziani Volcaniche Raccolte nelle Isole Eolie da Gius Lazzari—Lipari.” He found it to consist of boracic acid, and it perfectly resembled that I have just described, having the same yellow colour from an admixture of sulphur, and a similar crust of this substance adhering to one side.
Any future traveller visiting those countries would do well to examine them with a view to this particular object. The boracic acid may be a more extensive volcanic product than has hitherto been imagined; for in the account given of its discovery some years ago by Messrs. Hoëfer and Mascagni, near Monte Rotando, to the west of Sienna, we can have no doubt of its volcanic origin in those places, from the substances which are there described to accompany it.
