15*^ «K Potassium and sodium. "* 



Hisnasomfor M\\ DirHoii jJreR^Ts the idea of potassium htuv^r a comH 

 t^tessu"n"as a PO«»**^' ''^^^^'<-'^'^^^f«^ ^* s»5tnp'e substance, because, when potash, 

 comiJouaU. wliicli has been previously fused (in which case, he sftys, it 

 ccmsists of I atom t>f water and 1 of potash) is suhniitted to the 

 a</fion of the Galvanic battery, it gives out uo hidroj^en : the 

 eifecl bfthe electricity is to evolve oxigen at the positive pole, 

 and this arises from the water of the hydrate — but the hi- 

 dro^€«H -(dtTn-^G of coutse tVom the same source) draws 

 with it an atoai of |>otash to the negative pole, and they 

 loi^e^her constittile the compound atom potassium, consist- 

 k\g of potash 42 + hidrogen 1 r: 43, and the residuui 

 pota<ih is unaltered. In the French method, by the girn* 

 barrel experiment, a quantity of hidrogeu is evolved, and 

 the results are, potas^'mm, oxidated iron, and part oT the 

 potash emplojed. In this case, Mr. Dalton supposes (aU , 

 lowing however that the constitution of pota>.sinra here '^ 

 not so obvious as when produced by electricity) tliat the 

 hjdiate is decomposed partly into potash and water, and 

 partly into potassiurn and oxigen. 

 Remarks on I" regard to the first conclnsion, that no hidrogen is 



ihitirst. evolved, when Jiisefl potash is made the subject of experi- 



ment with the Voltaic battery, where is the cerfaiuti/ of 

 the fact? At the higli temperature requisite for the fusion 

 of tlie potash, the potassium burns as soon as it is produced, 

 and why not the hidrogen too? Atmospheric air is pre- 

 sent, and we might almost as well itiier^ that no potussiftm , 

 ' is ibrme<l, as no hidrogen; if the proof is to rest pn oqr , 



iaability, under the^e circumstances, of preserving it. ^!<9r,^ 

 may, to be sure, catch, though with diiBculty, a mouientarj 

 glimpse of thfe oiie, which the nature of the other forbids. 

 Could the decomposition of potash iu fusion* be conductec! 

 in close vessels, so as to coUcct the gaseous products (and p*;r-^ 

 haps it might be done), the probability is, that IiidroL;cn would 

 be collected at the negative pole; and if so, all question as to 

 tlie compound nature of potassium' (at least as to its b^jing 



*, The author here appears to b.^-vc fulk'ti jmo a mistake. Mr. JJai- 

 ton i« notftpcaiyinji of tlicjd'vCaiiiposition of j otash while m a staie of 

 tWian-j but /:)(,jwf ash; thai haalifen |)r;;yiov.s!/ Iciscd, ibr ii?t; purpose of 



, , . ,1.; . fonaejdl 



