J 63 



too small to produce any effects but those of magnetism, and also 

 muscular contractions in the limbs of frogs. The animal electricity 

 of the torpedo produces most of the effects of voltaic electricity, ex- 

 cepting the evolution of heat and light. The general conclusion de- 

 duced by the author from these researches is, that electricity, what- 

 ever be its source, is perfectly identical in its nature. 



In the concluding chapter of the present paper, the author endea- 

 vours to establish some relation by measure between common and 

 voltaic electricity. He shows, by experiment, that whenever the same 

 absolute quantity of electricity, whatever be its intensity, passes through 

 the galvanometer, the deflecting force exerted upon the magnetic 

 needle is invariably the same. Hence this deflecting force may be 

 taken as the measure of the absolute quantity of transmitted electri- 

 city ; a principle which establishes the value of the galvanometer as 

 an instrument of measurement in all cases of electricity in motion. 

 The power of chemical decomposition he finds to be also directly as 

 the quantity of transmitted electricity. 



January 24, 1S33. 



The Rev. WILLIAM BUCKLAND, D.D., Vice-President, in the 



Chair. 



A paper was read, entitled, " Magnetical Experiments, made prin- 

 cipally in the South of Europe and Asia Minor, during the years 1827 

 and 1832." By the Rev. George Fisher, M.A. F.R.S. 



This paper is divided into five sections. The first gives an account 

 of a series of experiments made with a view to determine the relative 

 intensities of the forces soliciting a horizontal magnetic needle, and 

 also the forces in Ihe direction of the dipping needle, at London, Lis- 

 bon, and Gibraltar 5 premising a minute description of the apparatus 

 employed, and a circumstantial statement of the methods used for 

 conducting the investigation. 



The second section gives the details and results of similar experi- 

 ments made at London, Malta, Syracuse, Catania, Messina, Naples, 

 Baia, Constantinople, Egina, and Athens ; and also on the plain of 

 Troy, and at Vourla in Asia Minor. 



The third section contains an account of experiments on the diur- 

 nal variation in the intensity of the magnetic force soliciting a hori- 

 zontal needle in the island of Malta. 



In the fourth section, experiments are related on the diurnal va- 

 riation of the magnetic needle suspended horizontally at Malta. 



The fifth section is occupied by an account of the results of similar 

 experiments made on the bases and edges of the craters of Vesuvius 

 and /Etna ; and also on Gibraltar rock, and the neutral ground below : 

 from which it appears, that the forces soliciting both the horizontal 

 needle and that in the position of the dip, were considerably greater 

 on the elevated than on the lower situations. 



From the whole of the observations made in different parts of the 

 Mediterranean, and contained in this paper, it appears that great 



