BERTHOLLET, Claude Louis, one of the most distinguished chemists of the French school, was born at TaUoire, near Annecy, in Savoy, in 1748. He studied first at Chambery, and subsequently at Turin, where he took his degree as a physician. In 1772 he settled at Paris, and soon became the medical attendant of Philip, duke of Orleans. By the publication of a volume of chemical essays, he gained such reputation that he was admitted in 1781 into the Académie des Sciences. He was appointed Government superintendent of the establishment for the improvement of dyeing; and in 1791 he published his essay Sur la Teinture, a work that first systematized and chemically explained the principles of the art. It was translated into English by Dr William Hamilton, 1794. Berthollet early adopted the chemical views of Lavoisier, and took part with him in the formation of a new system of chemical nomenclature. He confirmed and extended the discoveries of Priestley on ammonia, discovered fulminating silver, and greatly extended our knowledge of the dephlogisticated marine acid of Scheele, for which the name of oxymuriatic acid was then proposed, and which is now termed chlorine. It was he who in 1785 first proposed to apply it to bleaching. He discovered the remarkable salt now called chlorate of potash; and we owe to him also an excellent essay on the chemical constitution of soaps. Berthollet’s contributions to chemistry are scattered through the pages of the Journal de Physique, Annales de Chimie, Mémoires de VInstitut, and Mémoires d’Arceuil. At the commencement of the French Revolution the scarcity of saltpetre for the manufacture of gunpowder was much felt; and Berthollet was placed at the head of a commission for improving the processes for obtaining and purifying this important ...

BERTHOUD, Ferdinand, a celebrated Swiss chronometer-maker, was born in Neufchâtel. The date of his birth is variously given as 1725, 1727, and 1729. His father was an architect, and the son was intended for the church; but, showing a taste for mechanics, he was placed under an experienced workman to be instructed in clock and watch making, and was afterwards sent to Paris to improve himself in the knowledge and practice of the art. He settled in Paris in 1745, and applied himself to the making of chronometers, an art which was then in its infancy. He soon attained distinction for the excellence of his workmanship and the accuracy of his chronometers. Fleurieu and Borda, by order of the French Government, made a voyage from La Rochelle to the West Indies and Newfoundland for the purpose of testing them, and they found that they gave the longitude with an error of only a quarter of a degree, after a cruise of six weeks. Satisfactory results were also obtained in the expedition of Verdun, Borda, and Pingré, which was appointed to try these chronometers and those of his only rival, Le Roy. Sully, an English watchmaker established in Paris, was the first who in that city attempted the construction of chronometers for finding the longitude; and this he did in 1724. In 1736 the chronometers of the English artist Harrison were tried at sea. In France, however, there were no chronometer-makers of note after Sully, till Pierre le Roy and Ferdinand Berthoud, between whom there was some discussion about the priority of their discoveries and improvements. Ferdinand Berthoud’s chronometers were long the most esteemed of any in France. Louis Berthoud, his nephew and successor, introduced some improvements, and made chronometers of a smaller size and therefore more portable. ...