24-0 Royal Society. 



Of Bismuth. — State of bismuth in nature. Atomic weight of bismuth. 

 Compounds of bismuth. 



Sect. VI.— Metals of the Sixth Class. 



Of Silver. — Extraction of silver from its ores. Properties of silver. 

 Oxides of silver. Detection of silver. 



Of Mercury or Quicksilver. — State of mercury in nature. Properties of 

 mercury. Oxides of mercury. Sulphurcts of mercury. Detection of mercury. 



Of Gold. — Extraction and properties of gold. Detection of gold. 



Of Palladium. 



Of Platinum. — State of platinum in nature. Different forms of platinum. 

 Compounds of platinum. Detection of platinum. 



Iridium and its compounds. 



Rhodium and its compounds. 



Chapter XIV. [XV.] On the General Properties and Constitu- 

 tion of Salts. — General characters of salts. 



XXXV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from vol. xviii. p. 141 *.] 

 November 26 {Continued), 'T^HE following papers were read : — 



1840. -*- Description of a Percussion Shell to 



explode at the bottom of the Sea. By Captain J. Norton. Commu- 

 nicated by S. Hunter Christie, Esq., M.A., Sec. R.S., &c. 



An iron tube, like the barrel of a musket, is screwed into a shell 

 of any size, water-tight. A rod of iron, about half a pound in weight 

 and a foot in length, is suspended within the tube, by means of a 

 split quill passing through a hole in the upper end of the rod, the 

 other end being armed with a percussion-cap. The mouth of the 

 tube is closed with a screw lid also water-tight. Tin or brass wings 

 being attached to the upper end of the tube will keep it in a vertical 

 position during its descent to the bottom of the sea ; and the shock 

 on its striking the bottom will cause the bar of iron within the tube 

 to fall, and produce the percussion and explosion. 



Should it be found difficult to make the shell water-proof, I am 

 satisfied that percussion powder made from silver will explode by 

 friction or percussion even when mixed with water. 



Memorandum addressed to the Royal Society. By T. Whai'ton 

 Jones, F.R.S. 



The following is the memorandum in the words of the author : — 



On the 18th of June, 1835, a memoir, entitled, " On the Ova of 

 Man and Mammiferous Animals, as they exist in the Ovaries before 

 Impregnation, and on the discovery in them of a Vesicle analogous 

 to that described by Professor Purkinje in the Immature Egg of the 

 Bird \" was laid before the Royal Society. 



[* The two abstracts of papers now inserted were accidentally omitted 

 from their proper place ; they are the notices referred to in vol. xviii., p. 547 ; 

 and are followed in order of reading by those given at p. 307 of that 

 volume.] 



[t An Abstract of this memoir appeared in L. and E. Phil. Mag., vol. 

 vii. p. 209.] 



