BREISLAK, SCIPIONE. - Piarist geologist, b. in Roma on 16 Aug. 1750, d. in Milano on 15 Feb. 1826. He taught physics and mathematics in various houses of the Piarist Schools, especially at Ragusa and Urbino. Appointed in 1781 to the Nazareno college in Roma, he made his name famous through the magnificent academies in which experiments in physics and chemistry were conducted such as had never previously been seen in Roma. In 1787 he went to Napoli, where he applied himself to volcanological studies, from which arose his specialization in geological subjects, in which he subsequently acquired great renown, also through the publication of fundamental works. An ardent plutonist, he opposed Hutton’s metamorphic theories, maintaining that gneisses and other crystalline rocks represent the product of the cooling of the magma of the upper zone of the fluid terrestrial globe, that is, the earth’s primitive crust. He studied central and southern Italy in particular, especially the volcanic regions, publishing various works on terrains and phenomena.
Napoleone appointed him inspector of the manufacture of saltpetre and gunpowder in the kingdom of Italy, and later director of the alum works at the Solfatura. From the surname B. derives breislabite, extremely delicate reddish-brown fibres found in the cavities of the lava of Capo di Bove and in the trachytes of monte Olbano: it has the form of pyroxene.