5. His papers in the Philosophical Transactions are all in Latin. The first is entitled, Experiments in Electricity, in a Letter to Dr Franklin. (Ph. Tr. 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 in terchange 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 re pulsion. The paper is accompanied by a note of Dr Franklin, explanatory of the apparatus employed.
6. An Account of the double Refractions in Crys tals. (Phil. Trans. 1762, p.486.) The double refrac tion of rock-crystal had been observed by Huygens. Beccaria seems to have imagined, that it was not dis coverable 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 con jecture respecting the existence of a similar proper ty in almost all crystallized substances.
7. Novorum quorundam in re Electrica Experi mentorum Specimen. (Phil. Trans. 1766, p. 105.) In this paper, our author defends the simpler theory of ' Franklin against Mr Symmer's doctrine of the exist ence of two separate electric fluids. He also enu merates a great variety of cases of the excitement of positive or negative electricity by the friction of dif ferent substances with glass, hareskip, a silk stock ing, 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 re. moving and replacing their coatings. These investi gations 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 os cillation of electricity ; it depends on the same causes as the " vindicating electricity," which he has elsewhere described.
9. De Atmosphere Electrica libellus. (Philosophical ' Transactions, 1770, p. 277.) The phenomena of in duced 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 th&ory of electricity than his former works had ex hibited, but still falls far short of the perfection which &pinto had attained more than ten years be fore.
phosphorus receiving several colours, and only omitting the same, is printed in the Philosophical Transac tions for 1771, p. 212. Our author admitted the sun's light through green, red, and yellow glass, and found that the pieces of sulfureted lime exposed to it, emitted only a light similar to that which had been thrown on them. A multiplicity of later ex periments have however shown, that the contrary result is by far the most common ; and Zannotti'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 Bosco vich, to measure the length of a degree of the meri dian in the immediate neighbourhood of Turin ; the measurement was completed in 1768, and an ac count of it was published under the title of Gradus Taurinensis, 4. Turin, 1774 ; prefaced by a proper compliment to the memory of the monarch who pa tronised 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 57468.59 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 alto gether, and to make some corrections in the calcu lation 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 Iliatorique, but it was probably extract ed 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 great measure limited, by the religious pro fession which he had adopted, to the acquirement of literary celebrity, his taste was guided by his pre vailing pursuits. His only luxuries consisted in his library and instruments ; and on these he expended a considerable part of the remuneration which he received, as a 'recompense for his services to the - public, and to his royal pupils. (a. as.)