QS Royal Society. 



being those wliich have traversed the older tertiary deposits of the 

 A'icciitin and other tracts. The Apennines, on the contrary, offer 

 proofs, ])ariicularly on their western shores, not only of recent os- 

 cillations, but also of copious volcanic eruptions. Tlius, as was re- 

 cently shown, subaqueous volcanos were intensely active during the 

 penultimate ]jeriod, alonij a baud parallel to and flanking the Apen- 

 nines, which had been raised at a former epoch. After these fires 

 were spent and their dejections raised up into the western lands of 

 the Papal and Neapolitan States, we have no proofs of subacirial 

 volcanicity until "\^esuvius burst forth, save the case of the volcano of 

 Latium *, whose period of activity is lost in the maze of time, and 

 the notable examples among the early Greek settlements in the Bay 

 of Na])les. 



liastly, let us recollect, that in the tract of Western Tuscany 

 which has been the special subject of this memoir, we also read a most 

 instructive lesson upon the efforts of subterranean iyneous forces 

 to deveJope themselves at successive pei'iods alovg one and the same 

 established band of active change in the crust of the globe. For whilst 

 one extremity of this band is marked by the eruptions of Ischia and 

 Vesuvius, where volcanic action has prevailed in the historical period, 

 we have only to follow such zone from Naples to the N.N.W. to see 

 that it passes along a portion of the Papal States replete with earlier 

 volcanos, and is directly coincident with tracts powerfully affected in 

 much more remote periods, along one of which volcanic actiou is still 

 partially developed in the hot vapour issues of the Tuscan Maremma. 



" '■ X. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



"1. l^XPERIMENTAL Researches in Electricity." Twenty- 

 -Li fourth Series. On the possible relation of Gravity to Elec- 

 tricity. By Michael Faraday, Esq., D.C.L., F.R.S. &c. 



Under the full persuasion that all the forces of nature are mu- 

 tually dependent, and often, if not always, convertible more or less 

 into each other, the author endeavoured to connect gravity and 

 magnetic or electric action together by experimental results, and 

 though the conclusions were, when cleared from all error, of a nega- 

 tive nature, he still thinks that the principle followed and the ex- 

 periments themselves deserve to be recorded. Considering that some 

 condition of the results produced by gravity ought to present itself, 

 having a relation to the dual or antithetical character of the mag- 

 netic or electric forces, it seemed to the author that the approxi- 

 mation of two gravitating bodies towards each other, and their separa- 

 tion, were the only points which offered this kind of coincidence ; 

 and therefore, using the earth as one gravitating body, he employed 

 a cylinder of metal, glass, resins, or other substances, as the other, and 

 endeavoured to ascertain when the latter was allowed to fall, being 

 surrounded by a helix of wire, whether any electric current was 



* Quart. Jonrn. Geol. Soe. vol. vi. p. 294. 



