407 



the fact is however tliat the contact between tlie magnesinni and 

 the electrolyte is so good that niercniy is separated over the whole 

 sni'face in a finely divided state, even whilst hydrogen is being 

 given off. 



At the same time it is clear, lliat if we wish to get a magnesiniu 

 into as highly an active state as possible, it is desirable to make 

 its surface as poor as possible in i\lg(ÜH), by first immersing it in 

 an acid solnlion and then amalgamating it. 



Magnesium, activated in tiiis way, contains more dissolved mercury 

 and even remains active in normal KOH, giving the high negative 

 potential of — 1.97 volts in relation to the hydrogen electrode on 

 account of the low iVlg-iouic concentration. 



In a solution containing 1 gr. mol. i\JgSO, per liter this electrode 

 gave a potential of — 1.85 V^ in relation to the hydrogen eleclrode. 



Amalgamation experiments have also been studied in detail for 

 Al and will be the subject of a next paper. 



Amsterdam, Febr. 1923. 



Laboratory for General and anorgnnic 

 Chemistry of the University. 



