CompoJttionefAzote.'^Prujffiate o/Pot-aJk. tjt 



12. When the vapours of water are pafled through a gun-barrel, which has already been 

 ufed a number of times in this kind of experiment, and is intirely oxided within, hydro- 

 gen gas is no longer obtained, but azote \ the iron being no longer capable of combining 

 with all the oxigen which the water prefents to it. This experiment of Mr. Yeling ha$ 

 been confirmed to me by Mr. Mayer. 



13. An experiment made by Mr. Lampadius, appears to me to afford very fatisfaiJiory 

 proof that oxigen is contained in azote gas. He fufed arfenic in the pureft azote prepared 

 by the combuflioii of phofphorus. The metal was fublimed^ and after the experiment, he 

 found that it was partly changed into oxide of arfenic. 



14. When in the combufl.ion of the two gafes to prodoce water, the quantity of hy- 

 drogen is too great, a produft of nitric acid is obtained. 



15. The following experiment defcribcd by Scheele, appears tome to be a new proof 

 that azote is nothing elfe but an oxide of hydrogen. Thus it is that this famous cheraift 

 exprefles liimfelf, in his treatife on Air and Fire, "I filled a bladder with air obtained 

 •' from iron filings, diflblved in vitriolic acid, and I refpired this air. After twenty in- 

 " fpirations I found myfelf obliged to flop. When I had recovered, I emptied my lungs 

 " as much as poffible, and again refpired the inflammable air. After ten infpirations 'X 

 *' could proceed no farther. The air upon examination was no longer inflammable, and 

 " produced no cloud in lime water; in a word it was corrupted air" (azote gas). 



(To be continued.) 



VI. 



Fuitker Remarks on the Preparation of PruJJlate of Pot-aPi-~Method of purifying Cauflic 

 and carbonated Alcalis from Sulphate of Pot-ajh. By Mr. William Henry. 



Martchajler, June 16, 1 800. 



To Mr. NICHOLSON. 



SIR, 



I 



N your Journal for April lafl (p. 30), I communicated a new method of preparing the 

 pruffiate of pot-afli. The only objeftion I am aware of, that can be urged againft this 

 procefs, is the expenditure of a confiderable quantity of prulhated barytes, a fait which it 

 may not be in the power of every one to prepare. As the fole advantage, obtained by its 

 employment, is the decompofition, by double affinity, of fulphate of pot-afli ; it has fincc 

 occurred to me, that a confiderable faving of prufliated barytes would be gained, by firft 

 faturating the alcali, in the common way, with PruiTian blue, and afterwards digefting 

 the impure priiflTiate of pot-alh, thus obtained, with prufliate of barytes. To a folution of 

 common prufliate of pot-afh, which immediately precipitated muriate of barytes, I added, 



Z a " therefore. 



