4*8 



ELECTRICITY. 



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on the fusion of metals by batteries, he was enabled to 

 determine the law which was followed in the mi-lting 

 of metallic wires. 



M r Bennet, bv his experiments, as well as by his inven- 

 tion of the gold leaf electrometer, anil the doubter ; Mr 

 Read, by his experiments on atmospherical clcitrk iu ; 

 Mr Morgan, by his various researches ; and Mr Henlry, 

 by his inventions and experiments, contributed greatly 

 to the advancement of the science. 



The conclusion of the 18th century was marked by 

 an electrical discovery, which excited the most general 

 attention. In I7!'<). M. (ialvani, professor of anatomy 

 at Bologna, discovered that muscular contraction could 

 be excited in a frog recently killed, cither by transmit- 

 ting through the nerve a small quantity of artificial or 

 atmospherical electricity, or by the mere contact of two 

 different metals. This singular experiment was every 

 where repeated and varied, and, during the discussions 

 to which it gave rise, professor Volta of Como was led 

 to the invention of the Voltaic or Galvanic battery ; 

 an instrument of enormous electrical power, which has 

 led to the creation of a new science, and given rise to 

 the most brilliant discoveries in chemistry. In our ar- 

 ticle GALVANISM, we shall have occasion to give a full 

 account of these splendid discoveries, and to review the 

 labours of Volta, Sir H. Davy, Dr WoIIaston, Biot, 

 Thenard, Humboldt, Dr Rohison, Dr Monro, Dr Hen- 

 ry, Dr Bostock, Messrs Nicholson and Carlisle, Mr 

 C'ruickshanks, Mr Sylvester, Mr Children, Mr Uittcr,De 

 Luc, Psaff, Van Marum, Simon. Wilkinson, Ilisenger, 

 Berzclius, Oersted, Erman and Brande. 



The science of electricity seemed tor a while to be 

 completely abandoned, and the attention of philoso- 

 phers wholly engrossed by the new science which had 

 been established. The 19th century, however, com- 

 menced under circumstances very favourable to the 

 science. 



The celebrated Count La Place, the Newton of the pre- 

 sent age, investigated the manner in which electricity 

 was distributed on the surface of ellipsoids of revolu- 

 tion. Coulomb had considered only the case of a con- 

 ductor perfectly spherical ; but La Place has shewn, from 

 an elegant application of the formula? which he used in 

 his researches on the figure of the earth, that the elec- 

 tricity will be distributed over the surfaces of all ellip- 

 soids of revolution, and that the thickness of the coat 

 f fluid at the pole will be to its thickness at the equa- 

 tor, as the equatorial is to the polar diametej". 



In this investigation, La Place was followed by M. 

 Biot, a mathematician and natural philosopher of dis- 

 tinguished eminence, whose labours and discoveries we 

 shall have frequent opportunities of reviewing in other 

 parts of our work. He extended the results obtained 

 by La Place to spheroids, differing but little from a 

 sphere, whatever be the irregularity of their figure ; 

 and he found that the quantities of fluid carried off by 

 discharging a glass plate by successive contacts, form a 

 geometrical progression. 



Our countryman Dr WoIIaston had the merit of be- 

 ing the first who decomposed water by a simple current 

 of sparks from an electrified conductor ; and the ar- 

 rangement by which this was effected, is marked by 

 that ingenuity and beautiful simplicity which is cha-. 

 ract* fistic of the labours < f tliat eminent philosopher. 



The science of electricity was now destined to re- 

 ceive the most brilliant accessions from the application 

 <)f the higher analysis. M. Poisson, a young mathe- 



matician of rare talents, and well known by his di>- Hixory. 

 coveries ui the higher branches of astronomy, adopt- V *^Y"^ P ' 

 ing the hypothesis of two fluids, has determined ana- ^ 0: 

 lytically tlie manner in which electricity is di>tribu- 

 ted on the .surface of two spheres of different diame- 

 ti rs placed in contact, and the results which IK 

 obtained coincide wonderfully with the experiments of 

 Coulomb. He then applies the analysis to the case 

 where the two fluid- occur at the same time upon 

 the surface of the same body ; and in the case of two 

 spheres whose radii are as 1 to 3, and the distance of 

 whose nearest surfaces is equal to the radius of tin- 

 smaller sphere, he has computed tables, .shewing the 

 thickness of the coating of lluid at nine different poi.it 

 of tile two spheres, and die kinds of electricities which 

 they possess. These results also agree with the 

 ]H-riments of Coulomb, so far as he lias carried them, 

 and appear to furnish a confirmation of the theory of 

 two fluids. The case of two spheres leads to equ.i' 

 with variable differences, and with two indejendent 

 variables, which, M. Poisson observes, is the first time 

 that an equation of this kind has presented itself in the 

 solution of a physical problem. 



In another part of the present article, we have given 

 as full an account as we were able of the researches of 

 this eminent mathematician ; but we trust, that in some 

 other part of our work we shall find an opportunity of 

 again calling the attention of our readers to this inte- 

 resting subject. 



In the different parts of the following article we have R c fercixr 

 already made references to the various works from to general 

 which our facts have been derived. The following is a tremtiMi on 

 list of the principal treatises on electricity: Desagu- elcc:: 

 liers on Electricity, Lond. 1742. Martenson de Etec- 

 (ricitritc, Upsal, 1740, 1742. Winckler's Gedanken von 

 der Electricitat, Leipz. 1744. Winckler's Eigentchaflen 

 der Electrisclien m/i/erie, Leipz. 1745. Boze, Tentami- 

 tia Electrica, Wittenb. 1741. Nollet Essai sur CElec- 

 tru-it,'; Par. 1746. Nollet Richcrthcs sur I'Elccli 

 Par. 1749. Nollet Lett res sur I'Electricite, Par. 1753, 

 1760. Waiz Abhandlung von der Electricitat. Berlin, 

 1715. Pideritrfc Electricitalc, Marburg, 1745. Muller 

 Ursach nnd n'utxcn der Electricitat. 1746. Martin on 

 Electricity, Bath, 1748. Recueil dc Traites sur I'Elec- 

 f ricitc, Par. 1748. Jallabert sur /' Electricity, Par. 1749. 

 Boulanger Traite d' Elect ricitc; Par. 1750. Secondat 

 Observations Physiques, Par. 1750. Verrati sur I'Elec- 

 tricili; Montpell. 1750. Wilson's Short view of Electri- 

 city, Lond. 1780. Franklin on Electricity, Lond. 

 1769, 1774. Klingemtierna Tal om de nyaste ran vii! 

 Electrkitalcn, Stockh. 1755. Egelin de Eleclricitale. 

 Dalibard, Hist. Abrceee de F Etectriciti; 2 vols. Par. 

 1766. Saussure de Eteclricitate, Gene v. 1766. Lullin 

 de ElectricitaU; Geneva, 1 766. Priestley's Introduction 

 to Electricity, Lond. 1769- Priestley's History and 

 Present State of Electricity, Lond. 1 "67. James Fer- 

 guson's Introduction to Electricity, Lond. 1771. Si- 

 gaud de la Fond, Traite de I Electricite, Par. 1771. Id. 

 Precis tics Ptienumcties Electriques, Par. 1781. Jacquct 

 Precis de I'Electriciti; Vienna, 1775. Becket on Elf r. 

 tricity. Weber E/eclrische Versuche. Prince Gallit- 

 zin sur I'Electriciti; Petersb. 1778. Herbert Theoria 

 nhenoinenorum Elect ricorum, Vienna, 1778. Lord Ma- 

 non's Principles of Electricity, Lond. 1779. Lyon's 

 AV' .Vy.v/fw of Electricity, Lond. 1780. Marat Rc- 

 ckerches Physiques sur I'Electriciti; Par. 1782. La Ce- 



Vc-t Lt^ma if t'EttU fformalc, vol. vil. p. 85; aod Bulletins ilc La Society Pkilvmatiytt, 1801, No. 51, p. 21. 



