OK tHB IliETALS OF THE ALKALIS. ^5 



" Mr. Daw savs it is evident* that the method we employ Experiments 

 , 11- • 1 r o" phosphorut 



in our endeavours to show, that his experiments on phospUo- ^nd phosphu- 



ru» and phosphuretted hidiogen are not accurate, do not rt^^titi *^i<lfO^ 

 apply to the case he has in contemplation. * They have ^ 

 acted,' he adds, • on the phosphuret of potassium with hot 

 water, and thus they form phosphate of potash, and a large 

 quantity of phosphuretted hidiogen gas; whereas, when 

 strong muriatic acid is employed, the muriate of potassium 

 is produced, and the oxigen is furnished solely, or princi- 

 pally te the potassium. We cannot form just conclusions, 

 unless when the potassium alone is oxided ; and my design 

 in employing but a small quantity of acid was to oxide this 

 iubstance alone." 



** We shall observe, Ist, that we have treated the phos- 

 phuret of potassium not with hot water only, but with acids 

 also ; and that in eVery case we have proved, that more phos- 

 phuretted hidrogen gas was obtained, than was required to 

 represent the hidrogen gas, that the potassium of this phos- 

 phuret was capable of furniihing with water; and that 

 therefore Mr. Davy has nothing to object to the means we No oxigen ex- 

 have employed to refute his opinion, or to demonstrate, that ^^^s in mem. 

 no oxigen exists either in phosphuretted hidrogen, or in 

 phosphorus.'* 



** Mr. Davy accuses us of contradicting ourselves, as we Potassium lit 

 have said, Mem, d'Arc, vol. II, p. 304, that potassium, when hidrogen from 

 heated in phosphuretted, sulphuretted, or arsenicated hidro- phosphuretted, 

 gen, absorbs the phosphorus, sulphur,orarsenic, and a portion h^dro^gen- * 

 of hidrogen ; and we say. Jour, de Phys. Dec. I8O9, that po- 

 tassium sets free all the hidrogen of phosphuretted or arseni- 

 cated hidrogen. In this there is nothing extraordinary. At 

 first we employed an excess of potassium, and an absorption 

 of hidrogen took place. But since, particularly when Mr. not oihen;? Ise. 

 Davy had conchided from his experiments, that sulphfir, 

 phosphorus, and pho&phu retted and sulphuretted hidrogen, 

 contain oxigen, having examined anew the action of potas- 

 sium Oil sulphurette(l, phosphuretted, and arsenicated hidro- 

 gen gas; and for this having necessarily employed an excess 

 of gas; we have seen, that, in this case, no portion of the 

 hidrogen of the phosphuretted or arsenicated hidrogen i» ab- 

 sorbed. Tns it appears, that we are perfectly consistent; 

 Vol, XXIX.— May, 1811. ^ '-F 4. s- gjnce 



