122 COMBINATIONS OF OXIMURIATIC CAS AND OXIOEN. 



and Qxigen for the metaU of the hxed alkalis. I burnt a 

 grahi of potassium in oxigeu gas, in a retort of green glass, 

 furnished with a stopcock, and heated the oxide formed to 

 redness, to convert it into potash : half a cubical inch of 

 znS ©xirauri- oxigen was absorbed. The retort was exhausted, and very 

 Aticgasa * pure oximuriatic gas admitted. The colour of the potash 

 instantly became white ; and by a gentle heat the whole wa» 

 MttariaU of converted into muriate of potash : a cubical inch and ^^ of 

 ^ H th'^""^:'* oximoriatic gas were absorbed, and exactly half a cubical 

 pea gtirea out. inch of oxigen generated. The barometer during this ope- 

 ration was at 30*3, the thermometer at 62 Fahrenheit. I 

 made several experiments of the sam* kind, but this is^ the 

 only one on whi«;h I can place entire dependence. When I 

 attempted to use larger quantities of potassium, the retort 

 usually broke during the cooling of the glass, and it was 

 not possible to gain any accurate results in employing me- 

 tallic trays. The potassium was spread into a thin plate» 

 and of course was much oxidated before its admission into 

 the retort, which rendered the absorption of oxigen a little 

 less than it ought to have been. In the process it waa 

 Seated in vacuo before the combustion, to decompose the 

 water in the crust of potash ; for in cases when this pre* 

 caution was not taken, I found that hydrat of potash 

 sublimed, and lined the upper part of the retort, and 

 from this the oximuriatic gas separated water a& well a& 

 oxio'en. 

 W»t«r separat- The phenomenon of the separation of water from hydrat 

 •f potash by"^^ of pota&h by oximuriatic gas was happily exemplified in an 

 •oiimuriatic experiment in which I introduced oximuriatic gas to the per- 

 *^ oxide of potassium, formed in a large retort, and in which 



the potassium had been covered with a considerable crust 

 of hydrat of potash. The upper part of the retort and its 

 neck contained a while sublimate of hydrat, which had 

 risen in combustion, and which was perfectly opaque. As 

 soon as the gas was admitted, it instantly became transpa- 

 tent from the evolution of water; and on heating the glass 



Messrs. Gay-Lwssac and Tlienard have convinced themselves, that 

 »otassinm and sodium are not hydrurets of potash and soda, by a 

 :|p«thod similar to that which I adopted and published some months 

 before, namely, by producing neutral salts from thezo. 



