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 XL VI. Proceedings of Learned Societies. 



ROYAL SOCIETY, 



To bring up our arrear of proceedings, we refer back to the 20th 

 of November 1828, when a paper was read, intitled, " An Ac- 

 count of some experiments on the Torpedo," by Sir Humphry 

 Davy, Bart., F.R.S., kc. 



The author, after noticing the pecuHarities discovered by Walsh 

 in the electricity of the torpedo, and the opinion of Cavendish that 

 it resembles the action of an electrical battery weakly charged, ad- 

 verts to the conjecture of Volta, who considered it as similar to that 

 of the galvanic pile. Being on the coast of the Mediterranean in 

 1814' and 1815, the author, desirous of ascertaining the justness of 

 Volta's comparison, passed the shocks given by living torpedos 

 through the interrupted circuit made by silver wire through water, 

 but could not perceive the slightest decomposition of that fluid ; 

 the same shocks made to pass through a fine silver wire, less than 

 one-thousandth of an inch in diameter, did not produce ignition. 

 Volta, to whom the author communicated the result of these expe- 

 riments, considers the condition of the organs of the torpedo to be 

 best represented by a pile of which the fluid substance was a very 

 imperfect conductor, such as honey, and which, though it commu- 

 nicated weak shocks, yet did not decompose water. 



The author also ascertained that the electrical shocks of the tor- 

 pedo, even when powerful, produced no sensible effect on an ex- 

 tremely delicate magnetic electrometer. He explains these nega- 

 tive results, by supposing that the motion of the electricity in the 

 torpedinal organ is in no measurable time, and wants that conti- 

 nuity of current requisite for the production of magnetic! effect. 



Nov. 27. — A paper was read, intitled, " A Descripton of a Mi- 

 croscopic Doublet," by W. H. Wollaston, M.D., V.P.R.S. 



The author, considering that in all microscopes distinct vision is 

 impeded instead of being assisted by whatever light may be thrown 

 upon the object beyond what is fully commanded by the object- 

 glass, obviates this evil by collecting the admitted light to a focus in 

 the same as the object to be examined. For this purpose he em- 

 ploys a plane mirror to direct the light, and a plano-convex lens to 

 collect it; the plane side of the lens being towards the object to be 

 illuminated. Availing himself of the property possessed by that 

 form of eye-piece for astronomical telescopes called the Huygenian, 

 of correcting both chromatic and spherical aberration, the author 

 conceived that, by applying to a microscope the same combination 

 reversed, he might obtain similar advantages. The construction he 

 employed resembles two thimbles fitted one within the other by 

 screwing, and with a perforation at the extremity of each. In these 

 perforations are fixed two suitable plano-convex lenses, which may 

 thus have their axes easily brought into the same line by means of 

 their plane surfaces, while their distance from each other may be 

 adjusted by screwing, so as to produce the best effect of which they 



