burgh, and professor WINCKLER, of Leipsic, invented several improvements in the apparatus for conducting experiments. Dr. LUDOLF, of Berlin, first succeeded in setting fire to inflammable substances, by the electric fluid; and Mr. WAITZ, Mr. ALLAMAND, and others made some new observations, though chiefly of the smaller kind. To the experiments in Germany succeeded those of Dr. WATSON, in Great-Britain. He first ascertained that the friction of an electric did not produce, but only collected the mysterious matter which wrought such powerful effects; and also made a number of other interesting additions to the knowledge before existing on the subject. The year 1745 was distinguished by a discovery still more remarkable and important than any that preceded it; viz. the method of giving a shock, by accumulating the electric fluid in a jar, and discharging it by means of a conductor. This discovery was made by Mr. VON KLEIST, dean of the Cathedral in Camin; and the next year the experiment being repeated, in a different manner, and with better success, by Mr. CUNEUS, of Leyden, the jar so. filled became generally known by the name of the Leyden Phial, which it has retained to the present day. Soon afterwards, Mr. GRALATH, a German, first contrived to increase the shock by charging several phials at the same time, and making what is now called a battery.

About the same time experiments began to be made of the effects produced by electricity on animal bodies. In these inquiries the Abbé NOLLET greatly distinguished himself. He pursued his investigations with singular ingenuity, labour, and expense; and opened a new and noble field of electrical discoveries. The application of electricity to growing vegetables was first made by Mr. MAIMBRAY, of Edinburgh, who found that,

in certain cases, it expedited the progress of vege tation. In these experiments he was followed by the Abbé NOLLET, M. JALLABERT, of Geneva, Mr. Boze, before mentioned, and a number of others on the continent of Europe, who all drew the same conclusions.

In the midst of the general attention, and the deep interest which this subject now began to excite, throughout the philosophic world, Dr. FRANKLIN, in 1752, after having been for some time engaged in making new and interesting experiments, discovered the identity of the electric fluid and lightning a discovery of the greatest practical utility; and, perhaps, the only one in the science under consideration, which was the result of preconceived opinion, and of experiments instituted with an express view to ascertain the truth. Dr. Franklin's ideas were soon afterwards confirmed by Messrs. DALIBARD and DELOR, of France; who had come to a similar conclusion before they were informed of what had been done on this side the Atlantic. The same illustrious American also first discovered, in conjunction with his friend Mr. THOMAS HOPKINSON, the peculiar power of pointed bodies, to draw off the electrical matter, more effectually, and at a greater distance than others; founded on. which, was his ingenious invention for defending

g There are persons who believe, but probably without sufficient foun dation, that this fact, and several others, relating to electricity, generally supposed to be modern discoveries, were known to the ancients. Those who wish to see this opinion ingeniously and learnedly defended, will be gratified by a perusal of M. DUTEN's work, before quoted; and also, an interesting paper in the Memoirs of the Literary and Philosophical Society of Manchester, vol. iii. by WILLIAM FALCONER, M. D. F. R. S. To which may be added a curious passage in Signor BOCCALINI's Advertisements from Parnassus (Century 1. Chap. 46.) published more than one hundred years before the date of Franklin's discovery. For a reference to this passage, I am indebted to the Rev. Dr. NISBET, President of Dickinson College, Pennsylvania; a gentleman, whose profound erudition, embracing the literature and science of almost all cultivated languages, is well known to the public; and with whose friendship I consider it one of the most happy circumstances of my life to be honoured.

houses from the destructive effects of lightning, by the use of metallic conductors. About the same time, Dr. Franklin's friend, Mr. KINNERSLY, distinguished himself by rediscovering the apparently contrary electricities of glass and resin, or sulphur, which M. DU FAY had long before observed, but with whose discovery he and Dr. FRANKLIN were both unacquainted. To solve the difficulty arising from this fact, the Doctor, instead of recurring to the supposition of two different kinds of electric matter, as the French philosopher had done, proposed his celebrated theory of positive and negative electricity, or the plus and minus states of bodies charged with that fluid: a theory which had been before suggested by Dr. WATSON, and which was afterwards generally received throughout the scientific world; and, though by no means without opposition, still continues to hold a more extensive influence than any other.

Electricity seems to have been first applied to medical purposes, by Mr. KRATZENSTEIN, Professor of Medicine at Halle, in 1744. From that period it gradually grew into notice, by means of the experiments of the Abbé NOLLET, JALLABERT, of Geneva, SAUVAGES, of Montpellier, BOHADSCII, of Prague, Dr. WATSON, before mentioned, Dr. FRANKLIN, and many others. The medical virtues of this wonderful fluid soon excited attention and inquiry throughout the scientific world. And although the repetition of experiments, which has been constantly going on from that period to the present, has served to correct many errors into which the enthusiastic fell in the beginning; yet electricity, after undergoing many revolutions of fashion, is now well established as an important article of the Materia Medica.

After the interesting discoveries of Dr. FRANKLIN, the next great experimenters and discoverers

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in electricity were Mr. CANTON, of Great-Britain, Signor BECCARIA, of Italy, and Mr. WILCKE, of Germany, who considerably enlarged the sphere of our knowledge respecting the conducting powers of different substances; and threw farther light on the plus and minus states of electrics. The doctrine of FRANKLIN, that these two states arise from a redundancy or deficiency of the same matter, was but little opposed, until 1759, when Mr. SYMMER, an English philosopher, revived the ideas of DU FAY, with some new modifications of his own. He taught the existence of two electric fluids, not independent, but always co-existent, and counteracting one another. In this opinion he has been followed by some gentlemen of very respectable character, in Great-Britain, and on the continent of Europe; though by far the greater number of the learned appear still to be in favour of the Franklinian theory."

The progressive improvements of electrical machines, and of the various instruments for exhibiting the phenomena of this science, have generally kept pace with the gradual developement of its principles. Hence the honour of these improvements is, in general, due to the gentlemen already named. Beside these, several artists of respectable character have done much to forward the mechanical part of this branch of philosophy.

Soon after the grand discoveries of Franklin, Mr. PINUS, a philosopher of high character in the Imperial Academy of St. Petersburgh, assuming his principles, offered to the world some new and interesting views on this branch of science. Struck with the resemblance between the phenomena of electricity and magnetism, and believing that the

The above stated facts relating to the rise and progrees of electricity, are chiefly taken from Dr. PRIESTLEY's History of Electricity, 1794, Lonsdon, 4to.

attractions and repulsions of each might be reduced to regular and similar classes, he attempted to throw the laws of both into a perfectly systematic form, and to introduce the most precise mathematical calculations into regions which were before supposed, from their indefinite and mysterious character, least of all susceptible of being explored in this manner. It is believed by many, that this hypothesis, to the unquestionable claim of ingenuity, adds that of being founded in truth; and that it will probably lead to the solution of many difficulties, hitherto deemed insolvable. However this may be, it must be confessed the ingenious Russian has enabled us, by his mathematical principles, to class many of the phenomena of which he treats, with a most plausible precision, and to predict the result of proposed experiments with very pleasing success.

During the last thirty years of the eighteenth century, though it cannot be said that so much has been done in electricity as in the like period immediately preceding; yet several important discoveries, within that time, have been announced. The inventions of the Electrophorus, and the Condenser by professor VOLTA, and of the Doubler of electricity, by the Rev. Mr. BENNET, of GreatBritain; the discovery of the effects produced by the electric matter on permanently elastic fluids, and on water, by Mr. CAVENDISH, and others; and the correction of former errors, with respect to the influence of electricity on vegetables, by Dr. INGENHOUZ, may be considered among the most interesting of recent improvements. Mr. CAVEN

See

* See Theoria Electricitatis et Magnetismi, 1759, Petersburgh, 4to. also a good abstract of the doctrines of pinus, in the Supplement to the Encyclopædia, published at Philadelphia by Mr. Dobson.

j For a more full account of the above recent discoveries and improvements see the last vol. of Cavallo's Electricity, 3 vols. 8vo. edition 1795. and the art. Electricity in the Encyclopædia, and the Supplement.