482 On some new analytical Researches 



off to the sides, suffers the brilliant surface of the po- 

 tassium to appear. When the potassium is cooled in this 

 state, it s aga n covered with the white crust. By heating a 

 second time, it swells considerably, becomes porous, and 

 appears crystallized, and of a beautiful azure tint ; the same 

 series of phenomena, as those before described, occur in a 

 continuation of the process, and it is finally entirely con- 

 verted into the dark olive- coloured substance. 



In this operation, as has been stated by MM. Gay Lussac 

 and Thenard, a gas which gives the same diminution by 

 detonation with oxygen as hydrogen is evolved, and am- 

 monia disappears. 



The proportion of the ammonia which loses its clastic 

 form, as I have found by numerous trials, varies according 

 as the gas employed contains more or less moisture. 



Thus eight grains of potassium, during its conversion into 

 the olive- coloured substance, in ammonia saturated with 

 water at 63° Fahrenheit, and under a pressure equal to that 

 of 29* 8 inches of mercury, had caused the disappearance of 

 twelve cubical inches and a half of ammonia; but the same 

 quantity of metal acted upon under similar circumstances, 

 except that the ammonia had been deprived of as much 

 moisture as possible by exposure for two days to potash that 

 had been ignited, occasioned a disappearance of sixteen cu- 

 bical inches of the volatile alkali. 



Whatever be the degree of moisture of the gas, the quan- 

 tities of inflammable gas generated have always appeared to me 

 to be equal for equal quantities of metal. MM. Gay Lussac 

 and Thenard are said to have stated, that the proportions in 

 their experiment were the same as would have resulted from 

 the action of water upon potassium. In my trials, they 

 have been rather less. Thus, in an experiment conducted 

 with every possible attention to accuracy of manipulation, 

 eight grains of potassium generated, by their operation upon 

 water, eight cubical inches and a half of hydrogen gas: and 

 eight grains from the same mass, by their action upon am- 

 monia, produced eight cubical inches and one-eighth of in- 

 flammable gas. This difference is inconsiderable; yet I have 



always 



