MATTERHORN, one of the best known mountains (14,782 ft.) in the Alps. It rises S.W. of the village of Zermatt, and on the frontier between Switzerland (canton of the Valais) and Italy. Though on the Swiss side it appears to be an isolated obelisk, it is really but the butt end of a ridge, while the Swiss slope is not nearly as steep or difficult as the grand terraced walls of the Italian slope. It was first conquered, after a number of attempts chiefly on the Italian side, on the 14th of July 1865, by Mr E. Whymper's party, three members of which (Lord Francis Douglas, the Rev. C. Hudson and Mr Hadow) with the guide, Michel Croz, perished by a slip on the descent. Three days later it was scaled from the Italian side by a party of men from Val Tournanche. Nowadays it is frequently ascended in summer, especially from Zermatt. MATTEUCCI, CARLO (1811-1868), Italian physicist, was born at Forlì on the 20th of June 1811. After attending the École Polytechnique at Paris, he became professor of physics successively at Bologna (1832), Ravenna (1837) and Pisa (1840). From 1847 he took an active part in politics, and in 1860 was chosen an Italian senator, at the same time becoming inspector-general of the Italian telegraph lines. Two years later he was minister of education. He died near Leghorn on the 25th of June 1868. He was the author of four scientific treatises: _Lezioni di fisica_ (2 vols., Pisa, 1841), _Lezioni sui fenomeni fisicochimici dei corpi viventi_ (Pisa, 1844), _Manuale di telegrafia elettrica_ (Pisa, 1850) and _Cours spécial sur l'induction, le magnetisme de rotation_, &c. (Paris, 1854). His numerous papers were published in the _Annales de chimie et de physique_ (1829-1858); and most of them also appeared at the time in the Italian scientific journals. They relate almost entirely to electrical phenomena, such as the magnetic rotation of light, the action of gas batteries, the effects of torsion on magnetism, the polarization of electrodes, &c., sufficiently complete accounts of which are given in Wiedemann's _Galvanismus_. Nine memoirs, entitled "Electro-Physiological Researches," were published in the _Philosophical Transactions_, 1845-1860. See Bianchi's _Carlo Matteucci e l'Italia del suo tempo_ (Rome, 1874).