VOLTA, ALEXANDER, was born at Como on the 18th February 1745, and was descended from an ancient family of that city. Among the mis fortunes of his infancy, his friends have enume rated that of having a foolish nurse, and to this cause they have ascribed the slow development of his mental powers. The first exhibition of his talent was a piece of poetry; hut even in his poems, which were composed in Latin and Italian, he already pointed out the subjects which were likely to demand the efforts.of his genius. He soon pub lished, indeed, a paper in prose on the phenomena of electricity, and on a new apparatus destined to carry on discoveries in this branch of physics.
After having completed the course of studies in the university of Como, he was appointed regent of it, and subsequently obtained the chair of natu ral philosophy. From Como he went to the uni versity of Pavia, where he devoted to science the labours of thirty years, and dignified the name of his country with deeds of intellectual renown, which fixed the attention of Europe, and formed an era in the history of the human mind.
One of the first inventions of Volta was that of the electrophorus, which he described in June, 1775, and of which he published an account in Rozier's Journal de Physique, for September 1776. This ingenious instrument consists of a metallic and a resinous plate, by the successive contact of which electricity may be perpetually developed. M. Wilcke had made some considerable approaches to that invention, and consequently the honour of it has been claimed for him by his countrymen; but there can be no doubt that the electrophorus, as an instrument, is an invention entirely new, and that its eminent author was not even acquainted with the previous experiments of the German phi losopher.* During his summer vacations, he was in the habit of performing journeys of considerable length. In 1777 he travelled through Switzerland, and, ac companied by his friend the Count J. B. Giovio, he,. paid a visit to the celebrated Haller at Berne, when that great man was sinking under the accu mulated infirmities of age and disease. They
visited also Voltaire at Ferney.
In 1770 and 1777 Volta published some remark able letters on the inflammability of air disengaged from marshes. They were addressed to Father C. J. Campi, and were afterwards translated into French and German. In the same year he invented his hydrogen lamp, and his electrical pistol, in struments which are well known to all who have attended an experimental course of chemistry and physics. The hydrogen lamp now forms an ele gant piece of furniture, in which a light can be at all times obtained. A stream of hydrogen gas is made to issue from a small aperture by means of the pressure of a column of water, and the gas is kindled by a spark from an electrophorus placed below. About the same time Volta discovered the process of determining the relative proportions of the two gases, oxygen and azote, which compose atmospherical air. A given mea sure of hydrogen gas being put into a glass tube with a quantity of atmospheric air, it was inflamed by the electric shock, and the quantity of oxygen was indicated by the diminution of volume.
During his travels in Tuscany, in 1780, he studied with particular care the fires which burn among the Apennines, on the road from Bologna to Florence, and which are known by the name of the Vulcanneto di Pietra .0htla. Of these he pub lished a description, in which he first explained how these fires, as well as those which spring from the ground near the ancient city of Vellega, arise from the combustion of atmospheric air disengaged from the ground.
In 1782 Volta invented an electrical condenser for rendering sensible small quantities of electric fluid; and in the same year he performed a tour through Germany, along with his celebrated col league M. Scarpa. After his friend parted with him, he extended his tour to Holland, England, and France. On his return from that journey, he introduced into Lombardy the culture of the po tato, which he had observed in Savoy; and the peasants who first cultivated this valuable article of food were rewarded with the prize offered by the Patriotic Society of Milan.