POTASH AND POTASSIUM. 257 



is undoubtedly 5 j and potash is a compound of 

 1 atom potassium = 5, and 1 atom oxygen = 1 ; 

 consequently, its atomic weight is 6, as we found 

 it to be by the experiment related near the be- 

 ginning of this section. 



4. Potassium combines with an additional dose Peroxide of 

 of oxygen, and forms a solid yellow substance, pt 

 which has received the name of peroxide of 

 potassium. From the experiments of Gay-Lus- 

 sac and Thenard, it appears, that 100 grains of 

 potassium, when converted into peroxide, com- 

 bine with 177 cubic inches of oxygen gas. Now, 

 this is just three times as much as the quantity 

 necessary to convert potassium into potash ; for 

 100 grains of potassium were found to absorb 

 58*19 cubic inches of oxygen gas when con- 

 verted into potash and -^ = 59- Peroxide 

 of potassium must, therefore, be composed of 



1 atom potassium = 5 

 3 atoms oxygen = 3 



8 



And an integrant particle of it must weigh 8. 



It deserves attention, that this experiment of 

 Gay-Lussac and Thenard gives the atomic 

 weight of potassium different from their former 

 one. For 59 cubic inches of oxygen gas weigh 

 20*38 grains ; so that potash is composed, ac- 

 cording to this experiment, of 



VOL. I. R 



