162 Biographical Notice ofM. Piazzi. 



professorship of the higher mathematics at the Academy of 

 Palermo. On his arrival there he reformed the method of 

 teaching, by substituting modern institutes for the works of 

 Wolff, and by rendering those of Locke and Condillac fami- 

 liar, which were previously almost unknown. By his know- 

 ledge he powerfully contributed to dispel the darkness, which, 

 under the combined influence of the Inquisition and the Jesuits, 

 still enveloped the territory of Sicily. Not satisfied with 

 having rekindled the love of letters, he obtained from the 

 prince of Caramanico, the viceroy of the island, permission to 

 establish an observatory at Palermo. 



He visited France and England, in order to procure the 

 instruments necessary for his new establishment, and to form 

 an acquaintance with those astronomers who were most cele- 

 brated for their labours and knowledge. He was acquainted 

 with Lalande, Jeaurat, Bailly, Delatnbre, and Pingre. He 

 took advantage of the departure of Cassini, Mechain, and Le- 

 gendre, who were deputed to determine the difference of the 

 two meridians of Paris and Greenwich, to visit England, where 

 he became intimate with Maskelj'ne, Herschel, and Vince, 

 and especially with Ramsden, to whom he entrusted the con- 

 struction of his instruments. He frequented the Greenwich 

 observatory, and from it he observed the solar eclipse of 1788, 

 of which he gave an account in a memoir inserted in the Phi- 

 losophical Transactions. 



Being desirous of avoiding the uncertainty which quadrants 

 always leave in the mind of the observer, Piazzi engaged 

 Ramsden to construct for him a vertical circle of five feet in 

 diameter, accompanied with an azimuth, and divided with the 

 precision of which that artist was then alone capable. He 

 went every day to the workshop to hasten the work ; and be- 

 ing dissatisfied with Ramsden's slowness, he conceived that he 

 might stimulate his self-love by a letter addressed to Lalande, 

 on the life and labours of this optician. The trick succeeded ; 

 in a short time after Piazzi had the satisfaction to see his great 

 circle finished, and he also obtained a transit instrument, 

 a sextant, and some other less important machines. The 

 English minister pretended that the circle belonged to the 

 class of discoveries, and consequently that it was subject to the 

 prohibitory duties of England ; but Ramsden protested that 

 if it was a new invention the mei'it of it belonged to Piazzi, 

 whose instructions he had merely executed. This declara- 

 tion obviated every difficulty, and Piazzi returned to Sicily, 

 carrying with him all the instruments. He put the new ob- 

 servatory in activity, and it was the most southei'n which 

 then existed, that of Malta having been destroyed by fire in 



1789. 



