BECCARIA (GIAMBATTISTA), a very ingenious and industrious electrician and practical astrono mer, was born at Mendovi, the 2d of October 1716, and entered the religious order of the Pious Schools in 1739. He became a professor of experimental' physics, first at Palermo, and then at Rome, and was appointed to the same situation at Turin in 1748: he was afterwards made tutor to the young Princes de Chablais and de Carignan, and continued to reside principally at Turin for the remainder of his life. In May 17.55, he was elected a Fellow of the Royal Society of London, to which he afterwards commu nicated several papers, relating to his favourite pur suits. He died 27th May 1781.
1. The most voluminous and most important of his works, entitled Dell Elettricismo Artificiale e Naturali, appeared at Turin, 1753, 4W ; and was reprinted in 1772. It was translated into English, and published, with the original' engravings, under the title of A Treatise upon Artificial Electricity, and an Essay on the Mild and Slow Electricity of the At mosphere. 4. Lend. 1771.
2. Risposta ad una Letters intorno al suo Elet tricismo. 4. Milan, 1753: 3. Lettere dell' Elettricismo Atmosferico Ed. 2. 4. Turin, 1758.
4. Ezperimenta et Obseroationes quibus Electrici tas vindes late constituitur atque ezillicatur. 4. Graz.
The accurate and elaborate experiments, related in these works, have obtained for their author the warm and repeated encomiums of the scientific histo rian Dr Priestley, and the approbation and friendship of other contemporary philosophers ; although it must be confessed, that amidst the multitude of important facts recorded in them, we sometimes observe a want of clearness of arrangement and closeness of reason ing ; nor must we attempt to claim for Beccaria either the originality of a Franklin, the mathematical pre cision of an £pinus, the enlarged views of a Caven dish, or the neatness and inventive talent of a Volta. The most remarkable novelties, which deserve to be distinguished among our author's experiments and opinions, relate to the limited conducting power of water, to the electrification of the -air and smoke, to the velocity of electricity, to the reduction of metals by its powers, to the illumination of the solar phos phori by the spark, to the light excited by the mo tion of the air, and to a variety of meteorological phenomena, especially lightning, storms, rain, water spouts, and atmospherical magnetism. The resistance exhibited by water to the passage of the electric fluid is demonstrated by the luminous appearance of its path, while it passes through more perfect con ductors without producing light; as well as by the explosion of glass tubes containing water, through which the spark is taken ; and this experiment- is extended to the construction of an electrical water gun, which is said to have carried a small bullet with considerable force.
' Father Beccaria observed, about the same time with Mr Canton, that the air surrounding an electri fied body was capable of becoming electric by slow degrees, and that it also parted slowly with its elec tricity ; and, by means of some property of this kind, he produced the appearance of a luminous at mosphere about an electrified ball, to which another was presented, in a partial vacuum. The smoke of colophony, surrounding an electrified body, enabled it to give longer sparks, but this smoke was little at tracted by the body when the heated spoon contain ing the colophony was insulated. Respecting the
velocity of electricity, he relates some experiments, which amply deserve to be confirmed or confuted. He found the effect of a spark occupy at least half a second in passing through 500 feet of wire, and 6i through a hempen cord of the same length, although, when the cord was wetted, it passed through it in 2 or S seconds. It is well known, that, in the earlier experiments of Watson, a shock was transmitted through a much longer circuit of wire, without oc cupying any perceptible interval of time in its pas sage. Many of the metals were revived from their oxyds, and mercury was reproduced from cinnabar by the powers of electricity ; and our author fancied that he had discovered a commou,principle in the dif ferent metals, as several of them gave the same co lour to the surface of the glass to which they were attached. The brilliancy of the electric light was demonstrated by the permanency of its effect on the solar phosphori ; and this subject was afterwards pur sued by various experiments of Canton, and others. The light often exhibited by the air rushing into a vacuum, is attributed by Beccaria to the friction of the air against the sides of the glass. , It may be re marked, that the phenomenon is, in all probability, of the same kind as the appearance of light observed long ago in the air-gun by its first inventor, Ctesibius of Alexandria. With respect to atmospherical elec tricity, Beccaria's researches were most laborious and extensive, and he made a great variety of experi ments illustrative of the nature of lightning, and of storms in general ; showing, for instance, the facility with which small bodies are forced into the course of the electric current, as light clouds are made to assist in conveying a stroke of lightning, and proving that evaporation, and the deposition of vapour, are always accompanied by electrical 'changes. Thunder-storms, in general, he attributes to terrestrial electricity, and supposes the clouds to be merely the channels by which the fluid is carried from one part of the earth's surface to another, the equilibrium having been first disturbed by chemical changes within the earth; and it must be confessed, that this opinion is, in some measure, encouraged by the frequent connection which is observable between these phenomena, and those of earthquakes and volcanic eruptions. Water spouts, he assures us, on the authority of several eye witnesses, may certainly be dispersed by. pointing swords and knives at them ; and, with respect to conductors erected for safety, though he appreciates their utility very highly, he thinks that every large building should be furnished with more than one or two. The electricitas vindex, so often mentioned, is the electricity made sensible in one body by the re moval of another which has been situated near it,—a property which afterwards led to the elegant inven tions of the electrophorus and the condenser of Wilke and Volta. Our author appears to be some • what disposed to exaggerate the importance of elec trical changes as the causes of other atmospherical phenomena, and, in particular, to overrate the inti macy of the connection of electricity with magne tism. The appearance of the aurora borealis he at tributes to the circulation of electricity through the higher regions of the atmosphere, and he was well aware of the magnetical changes which usually ac company this remarkable occurrence.