in the college of Ragusa; but
after residing there for several years he returned to his native city,
where he became a professor in the Collegio Nazareno, and began to form
the fine mineralogical cabinet in that institution. His leisure was
dedicated to geological researches in the papal states. His account of
the aluminous district of Tolfa and adjacent hills, published in 1786,
gained for him the notice of the king of Naples, who invited him to
inspect the mines and similar works in that kingdom, and appointed him
professor of mineralogy to the royal artillery. The vast works for the
refining of sulphur in the volcanic district of Solfatara were erected
under his direction. He afterwards made many journeys through the
ancient Campania to illustrate its geology, and published in 1798 his
_Topografia fisica della Campania_, which contains the results of much
accurate observation. Breislak also published an essay on the physical
condition of the seven hills of Rome, which he regarded as the remains
of a local volcano,--an opinion shown to be erroneous by the later
researches of G.B. Brocchi. The political convulsions of Italy in 1799
brought Breislak to Paris, where he remained until 1802, when, being
appointed inspector of the saltpetre and powder manufactories near
Milan, he removed to that city. The mineral Breislakite was named after
him. He died on the 15th of February 1826. His other publications
include:--_Introduzione alla geologia_ (1811, French ed. 1819); _Traite
sur la structure exterieure du globe_, 3 vols. and atlas (Milan, 1818,
1822); _Descrizione geologica della provincia di Milano_ (1822).

BREITENFELD, a village of Germany in the kingdom of Saxony, 5-1/2 m.
N.N.W. of Leipzig, noted in military history. The first battle of
Breitenfeld was fought on the 17th of September 1631, between the allied
Swedish and Saxon armies under Gustavus Adolphus and the imperial forces
under Count Tilly. The battlefield is a low ridge running east and west
between the villages of Gobschelwitz and Breitenfeld, the position of
the Imperialists lying along the crest from Gobschelwitz on the right to
a point about 1 m. short of Breitenfeld on the left; opposite this
position, and behind a group of villages on the Loberbach stream, lay
the Swedish forces, flanked on their left by the Saxon contingent under
the elector, who was assisted by Arnim. The villages formed the only
obstacle on the gentle slope lying between the Lob