BREISLAK, SCIPIONE. — Geologist, born in Rome on 16 Aug. 1750, died in Milan on 15 Feb. 1826. He taught physics and mathematics in various houses of the Piarist Schools, especially in Ragusa and Urbino. In 1781 he was assigned to the Nazareno College in Rome, where he made a name for himself with splendid public demonstrations in which physics and chemistry experiments were performed that had never before been seen in Rome. In 1787 he went to Naples, where he devoted himself to volcanological studies, from which his specialization in geological matters developed; he later gained great renown in this field, also through the publication of fundamental works. A staunch Neptunist, he opposed Hutton’s metamorphic theories, maintaining that gneiss and other crystalline rocks represent the product of the cooling of the magma in the upper zone of the fluid terrestrial globe, i.e., the primitive crust of the earth. He studied in particular central-southern Italy, especially volcanic regions, publishing various works on terrains and phenomena.
He was appointed by Napoleon inspector of the manufacture of niter and gunpowder in the Kingdom of Italy and later director of the alum works in the Solfatara. From his surname B. derives breislakite, very delicate reddish-brown fibres found in the cavities of the lava of Capo di Bove and in the trachytes of Monte Olbano; it presents the form of pyroxene.