202 Royal Society of London* 



Norway. — 105. Examination of Madreporite.-~-106\ Phar- 

 macolite. — 107. Scorza. — 108. Exami nation of the Fibru- 

 ous Sulphate of Barytes.— 109. Tabular Spar (Safel-spath). 

 — 110. Examination of Miemite.- — 111. Examination of 

 the prismatic Magnesian Spar, from the Territory of Gotha. 

 . — 1 12. Examination of the striated grav Ore of Manganese. 

 — 1 13. Earth v, black Oxide of Manganese. — 1 14. Exami- 

 nation of the Asphaltum from Albania. — 115. Earthy 

 brown Coal.-^-llG. The Hungarian Pearl Stone. 



XXXVI. Proceedings of Learned Societies, 



ROYAL SOCIETY OF LONDON. 



J\(Ir. Smithson Tennant has discovered two new metals 

 in the black powder which remains after dissolving platina, 

 of which he has given an account in a paper communicated 

 to the society. Mr. Tennant's first experiments were made 

 last summer, when they were communicated to the learned 

 president, after which an account of one of these metals 

 appeared in France by M. Descotil and M. Vauquelin, who 

 ascribe to it the following properties : — 1. That it reddens 

 the precipitates of platina made by sal-ammoniac : 2. That 

 it dissolves in marine acid: 3, That it is precipitated by 

 galls and prussiate of potash. The properties mentioned 

 by Mr. Tennant are, that it dissolves in all the acids, but 

 least in marine acid, with which it forms octaedral crys- 

 tals. The solution with much oxygen is deep red, with a 

 smaller proportion green or deep blue. It is partially pre- 

 cipitated bv the three alkalies when pure. AH the metals, 

 excepting gold and platina, precipitate it. Galls and pre- 

 cipitate of potash take away the colour of this solution, but 

 without any precipitate, and afford an easy test of its pre- 

 sence. The oxide therefore loses its oxygen by water alone. 

 When combined with gold or silver, it cannot be separatee! 

 by the usual process of refining these metals. As the French 

 chemists have not given a name to the metal, Mr.. Tennant 

 inclines to call it iridium, from the various colours of it in 

 solution. 



The second new metal is obtained b'y heating the black 

 powder with pure alkali in a silver crucible. The oxide of 

 this metal unites with the alkali, and may be expelled by an 

 acid and obtained by distillation, being very volatile. The 

 oxide has a very strong smell, from which Mr. Tennant 

 has called it osmium, It does not redden vegetable 



"blues, 



