a very ingenious and industrious electrician and practical astronomer, was born at Mondovi on the 2d of October 1716, and entered the religious order of the Pious Schools in 1732. 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 during the remainder of his life. In May 1755 he was elected a fellow of the Royal Society of London, to which he afterwards communicated several papers relating to his favourite pursuits. He died on the 27th of May 1781.
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1 In the mathematical calculations connected with this subject, he was assisted, as he himself states, by Frisi, Professor of Mathematics at Pisa; and in the mechanical part by his brother Annibale. 1. The most voluminous and most important of his works, entitled *Dell' Elettrismo Artificiale e Naturale*, appeared at Turin, 1753, 4to, 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 Atmosphere*. Lond. 1771, 4to.
2. *Risposta ad una Lettera intorno al suo Elettrismo*. Milan, 1753, 4to.
3. *Lettere dell' Elettrismo Atmosferico*. 2da, Ed. 2. Turin, 1758, 4to.
4. *Experimenta et Observationes quibus Electricitas vindex late constituitur atque explicatur*. Graz. 4to.
The accurate and elaborate experiments related in these works obtained for their author the warm and repeated encomiums of the scientific historian 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 reasoning; nor must we attempt to claim for Beccaria either the originality of a Franklin, the mathematical precision of an Æpinus, the enlarged views of a Cavendish, 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 phosphori by the spark, to the light excited by the motion of the air, and to a variety of meteorological phenomena, especially lightning, storms, rain, waterspouts, 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 conductors 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 electrified body was capable of becoming electric by slow degrees, and that it also parted slowly with its electricity; and, by means of some property of this kind, he produced the appearance of a luminous atmosphere 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 attracted by the body when the heated spoon containing 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 six and a half through a hempen cord of the same length, although when the cord was wetted, it passed through it in two or three seconds. It is well known, that, in the earlier experiments of Watson, a shock was transmitted through a much longer circuit of wire, without occupying any perceptible interval of time in its passage. 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 common principle in the different metals, as several of them gave the same colour 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 pursued by various experiments of Canton and others. The light often exhibited by the Beccaria air rushing into a vacuum is attributed by Beccaria to the friction of the air against the sides of the glass. It may be remarked 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 electricity, Beccaria's researches were most laborious and extensive, and he made a great variety of experiments 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. Thunderstorms, 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 countenanced 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 removal of another which has been situated near it—a property which afterwards led to the elegant inventions of the electrophorus and the condenser of Wilke and Volta. Our author appears to be somewhat disposed to exaggerate the importance of electrical changes as the causes of other atmospherical phenomena, and, in particular, to overrate the intimacy of the connection of electricity with magnetism. The appearance of the aurora borealis he attributes to the circulation of electricity through the higher regions of the atmosphere, and he was well aware of the magnetical changes which usually accompany this remarkable occurrence.
5. His papers in the *Philosophical Transactions* are all in Latin. The first is entitled *Experiments in Electricity, in a Letter to Dr Franklin*. (Phil. Trans. 1760, p. 514.) These experiments relate principally to the subject of electrical attractions and repulsions, which the author attempts to reduce to the effect of currents of air displaced by the immediate action of the electric fluid. He supposes the air between two bodies, in dissimilar states, to be rarefied by the interchange of their electricity, so as to produce the appearance of attraction; and when the bodies are in similar states, he imagines the air interposed to be the immediate object of their apparently mutual repulsion. The paper is accompanied by a note of Dr Franklin, explanatory of the apparatus employed.
6. *An Account of the Double Refractions in Crystals*. (Phil. Trans. 1762, p. 486.) The double refraction of rock crystal had been observed by Huygens. Beccaria seems to have imagined that it was not discoverable when the surfaces concerned were parallel to each other; but later observations have shown that his observations were defective in this respect, at the same time that they have confirmed his conjecture respecting the existence of a similar property in almost all crystallized substances.
7. *Novorum quorundam in re Electrica Experimentorum Specimen*. (Phil. Trans. 1766, p. 105.) In this paper our author defends the simpler theory of Franklin against Mr Symmer's doctrine of the existence of two separate elec- Beccaria. tric fluids. He also enumerates a great variety of cases of the excitement of positive or negative electricity by the friction of different substances with glass, hare-skin, a silk stocking, sealing-wax, and sulphur.
8. A second paper, with the same title, appeared in the Philosophical Transactions for 1767, p. 297. It contains an account of a repetition of experiments on the modification produced in the charge of two or more glass plates, by separating them, and by removing and replacing their coatings. These investigations were principally suggested by the well-known observations of the Jesuits, made at Pekin many years before, and by some subsequent experiments of Mr Symmer. The author calls the effect an oscillation of electricity; it depends on the same causes as the "vindicating electricity," which he has elsewhere described.
9. De Atmosphera Electrica libellus. (Phil. Trans. 1770, p. 277.) The phenomena of induced electricity are here discussed, but not with great precision: the author adverts, however, to the Newtonian demonstration of the equilibrium of the force of a gravitating substance, distributed through the surface of a sphere, with respect to a particle within it, and gives somewhat clearer views of the theory of electricity than his former works had exhibited, but still falls far short of the perfection which Æpilinus had attained more than ten years before.
10. A short Letter to Mr John Canton, on his new phosphorus receiving several colours, and only emitting the same, is printed in the Philosophical Transactions for 1771, p. 212. Our author admitted the sun's light through green, red, and yellow glass, and found that the pieces of sulphureted lime exposed to it emitted only a light similar to that which had been thrown on them. A multiplicity of later experiments have however shown, that the contrary result is by far the most common; and Zanotti's earlier observations have been fully confirmed by Wilson, Grosser, and Seebeck.
11. In 1759 Beccaria received orders from his sovereign, in consequence of a suggestion of Boscovich, to measure the length of a degree of the meridian in the immediate neighbourhood of Turin: the measurement was completed in 1768, and an account of it was published under the title of Gradus Taurinensis, Turin, 1774, 4to; prefaced by a proper compliment to the memory of the monarch who patronized the undertaking, and to the virtues of his successors, under whose auspices it was completed. The result did not, however, exhibit the appearance of any great accuracy or good fortune; for there is not only a difference of one seventieth of the whole in the lengths of the degree computed from the northern and southern portions of the arc, of 27' and 41' respectively, but the length deduced from the whole arc, which is 5746859 French toises, is 445 toises more than would be inferred from other measurements in the neighbouring latitudes; hence it appears to have been thought necessary by later astronomers to reject the northern portion altogether, and to make some corrections in the calculation from the southern, by which the length of the degree has been reduced to 57069 toises. The zenith sector employed for the observations was made on Boscovich's construction, the length of the tangent being measured instead of that of the arc, a method by no means calculated to lessen the chances of error. A portable syphon barometer is also described, by means of which the elevations were ascertained; and a number of heights of places in the mountains of Piedmont are recorded.
12. This volume appears to have been the last of Beccaria's publications: An Essay on Storms and Tempests is mentioned without approbation in the Dictionnaire Historique, but it was probably extracted from some of his other works. In his private history and adventures there appears to have been little for a biographer to relate; his ambition having been in a great measure limited, by the religious profession which he had adopted, to the acquirement of literary celebrity, his taste was guided by his prevailing pursuits. His only luxuries consisted in his library and instruments; and on these he expended a considerable part of the remuneration which he received for his services to the public and to his royal pupils.