20 Sketch of the latest Improvemcnis [Jan. 



substance to the metallic state. He found that 100 mercury are 

 equivalent to 55*6 of palladium. Hence he considers the oxide of 

 palladium as composed of 



Palladium 87*56 100 



Oxygen 1 2-44 14-209 



100-00 



This will require a small correction, if we consider peroxide of 

 mercury as composed of 100 metal and eight oxygen. 



4. Oxides of Rhudluni. — The experiments of Professor Berzelius 

 on the oxides of this metal being detailed in the Annals of Philo- 

 sopJiy, iii. 252, I shall here state merely the results which he 

 obtained. He found three oxides of this metal: tlie first composed 

 of one atom metal + one atom oxygen ; the second, of one atom 

 metal + two atoms oxygen ; and the third, of one atom metal -|- 

 three atoms oxygen : and one atom of rhodium weighs 14-903. 

 Hence the oxides are composed respectively of 



Metal. 



Protoxide 100 + 6*71 



Deutoxide 1 00 + 13-42 



Peroxide 100 + 20-13 



5. Turis,sten. — There is hardly any metallic substance that occa- 

 sions greater difliculties to practical chemists than tungsten, both 

 on account of the want of a good process to obtain its peroxide in a 

 state of purity, and on account of the very high temperatuse which 

 is requisite to melt the tungsten after it has been reduced to the 

 metallic state. The experiments of the El Luyarts upon wolfram 

 are known to every chemist ; as are likewise the elaborate experi- 

 ments on the same metal of Vauquelin and Hecht. Messrs. Allan 

 and Aikin succeeded in reducing it to the metallic state, and 

 verified its great specific gravity as determined by the Spanish che- 

 mists. An elaborate set of experiments on this metal were pub- 

 lished some years ago by Bucholz. He ascertained that the methods 

 hitherto employed by chemists for procuring pure tungstate of 

 ammonia do not succeed ; and lie verified the great specific gravity 

 of this metal, having obtained it in grains of the specific gravity 

 17-4. Now this is the mean of I7-6 given by the El Luyarts, and 

 17-2 given by Allan and Aikin. But as I mean very speedily to 

 publish a translation of the experiments of Buciiolz in the Annals 

 of Philosophy, I do not consider it as necessary to enter into farther 

 particulars respecting them in this place. 



6. Plalmum. — The difficulty of reducing this metal to the 

 malleable state, and its great importance in the construction of 

 chemical vessels, are well known. Hitherto it has only been done 

 for sale in Paris and in l-ondon. Parisian platinum is by far the 

 dearest; as far as my experience goes, it serves very well for 



