408 On some new Electrochemical Researches 



phaenomena which I have described in the Bakerian lecture 

 for I807. Nearly six cubical inches of hydrogen were 

 produced. No charcoal separated; no carbonic acid was 

 evolved, or found dissolved in the water. Whether the 

 metals of potash or soda were formed by electricity, or by 

 the action of ignited iron on the alkalies, the results were 

 the same. When charcoal is used in experiments on po- 

 tassium or sodium, they usually contain a portion of it in 

 combination ; and it appears from M. Curaudau's method 

 of decomposing the alkalies, that his metals must have 

 been carburets not of potash and soda, but of potassium 

 and sodium. 



M. Ritter's argument, in favour of potassium and sodium 

 being compounds of hvdrogen, is their extreme lightness. 

 This argument I had in some measure anticipated, in my 

 paper on the decomposition of the earths ; no one is more 

 easily answered. Sodium absorbs much more oxygen than 

 potassium, and on the hypothesis of hycjrogenation, must 

 contain much more hydrogen ; yet though soda is said to 

 be lighter than potash, in the proportion of 13 to 17 

 nearly*, yet sodium is heavier than potassium in the pro* 

 portion of 9 to 7 at least. 



On the theory which I have adopted, this circumstance 

 is w^hat ought to be expected. Potassium has a much 

 stronger affinity for oxygen than sodium ; and must con- 

 dense it much more, and the resulting higher specific gra- 

 vity of the combination is a necessary consequence. 



M. Ritter has stated, that of all the metallic substances 

 he tried for producing potassium by negative Voltaic elec- 

 tricity, tellurium was the only one by which he could not 

 procure it. And he states the very curious fact, that when 

 a circuit of electricity is completed in water, by means of 

 two surfaces of tellurium, oxygen is given off at the posi- 

 tive surface, no hydrogen at the negative surface, but a 

 brown powder, which he regards as a hydruret of tellurium, 

 is formed and separates from it; and he conceives that the 

 reason why tellurium prevents the metallization of potash 

 is, that it has a stronger attraction for hydrogen than that 

 alkali. 



These circumstances of the action of tellurium upon 

 waler, are so different from those presented by the action 

 of other metals, that they can hardly fail to arrest the at- 

 tention of chemical inquirers, i have made some experi- 

 nients on the subject, and on the action of tellurium on 



♦ Hasscrtfratz, Annal. de Chim. tome xxviii. p. 11. 



potassium, 



