60 Royal Society. 



ance either in a photological or a chemical point of" view *. My 

 only reason for not at once making it public, was a desire to 

 satisfy myself as to the real distinction (if any) between the 

 white and yellow precipitate formed, when the proportion of 

 lime-water to the platiniferous solution is in excess, and in de- 

 fect, as also to ascertain the nature of that sedimentary deposit 

 which is formed independently of the action of light. With 

 a view to this inquiry, I have now in preparation (as you have 

 seen in my laboratory,) a considerable quantity of the several 

 precipitates in question. 



Hamburg, June 12, 1832. J. F. W. Herschel. 



XVII. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 March 15. — A PAPER was read, entitled " Further Notice of 

 -^^ the new Volcano in the Mediterranean." By 

 John Davy, M.D. F.R.S. Assistant Inspector of Army Hospitals. 



The author states that since the 25th of October, the date of his 

 last communication to the Society, the crater of the volcano has un- 

 dergone several changes of form, and has now entirely disappeared. 

 He infers from the phasnomena observed, that the crater was one of 

 eruption, composed entirely of loose materials, thrown up by volcanic 

 action, and not one of elevation, that is, formed of rock which once 

 composed the bed of the sea. In Jidy the heat at Malta was very 

 close and oppressive, the thermometer rising more than once to 105° 

 of Fahrenheit, and the western sky had a dark lurid red hue : but 

 these atmospheric states are regarded by the author as independent 

 of the volcano, for the temperature of the air in its immediate vicinity 

 was very little affected by it. 



A Paper was also read, entitled " A method of deducing the Lon- 

 gitude from the Moon's Right Ascension." By Thos. Kerigan, R.N. 

 Communicated by Admiral Sir Edward Codrington, F.R.S. 



The author has recourse to the moon's right ascension as an ele- 

 ment for determining the true meridian of the place of observation : his 

 method being an extension of that given by him in the first volume of 

 his " Mathematical and General Navigation Tables." He gives exam- 

 ples of the application of this method, and considers that with the aid 

 of a chronometer showing the approximate mean time at Greenwich, 

 the longitude of any given place may be determined, either at sea or 

 on land, within very narrow limits of error, and with much greater 

 practical convenience than by the ordinary method of lunar distances. 



March 22. — The reading of a Paper, entitled " An Account of 

 some experiments and observations on the Torpedo," by John Davy, 

 M.D. F.R.S. Assistant Inspector of Army Hospitals, was com- 

 menced. 



* It may be proper to mention that these remarks are made by Sir John 

 Herschel, with reference to the article headed " Chemical Action of Light," 

 &c. given, from the Joiirnal de P/iarmmie, in the last Number of the Phil. 

 Mag. and Annals, p. 466. — Edit. 



