( 544 ) 



2. PüPPER 'j, under vo.n Pebals guidaiice lia^ tried to make a 

 determination of tlie atomic weight by an eleetrieal method. 



He connected in tlie same circuit a silver couiometer and a cell 

 containing a hydi'ochloric acid solution of antimony trichloride. A 

 rod of pure antimony (wrapped in linen) suspended iji the li(piid 

 constituted tlie positi\'e electrode, whilst the negative electrode con- 

 sisted of a weighed platinum wire. 



During the electrolysis the electrolyte was kept in continual motion 

 by means of a stirrer so as to exclude local changes in the concen- 

 tration of the li(piid. 



Under these circumstances explosive antimony is deposited on the 

 negative electrode^). Poppkr fused the substance formed in a tube 

 made of hard glass in an atmosphere of nitrogen; iji this way 

 the antimony trichloride present in the metallic mass Avas expelled. 

 As soon as all the cidoi-ide had \()huiH/.ed the antimony regulus was 

 washed first \vith solution of tartaric acid, then with watei-, dried 

 at 120'^ and weighed. Additional experiments had proved that the 

 glass tube did not sulfer any alteration in weight on heating and 

 melting the metal contained therein. 



The silver electrode in the coidctiuelcr was wrai)ped in a piece 

 of linen. After the electrolysis was completed, the silver which had 

 deposited in the platiimm dishes employed was l)oiled and washed 

 with Avater until this no longer gave a reaction with hydrochloric 

 acid and it was then dried at 120^ 



Popper's results obtained in the electi'olysis of solutifms contaijiing 

 respectively 7 and 22 ]>er cent of SbCI., are given in the subjoined 

 table. We have, however, i-ecalcnlated the data as Popper still uses 

 the atomic weight JOT. (it) for silviM- w heivas more accurate ijivestiga- 

 tions have shown this to l>e J07.i>.'). 



In a second series of experiments in which a few more improve- 

 ments had been made as regards the insulation of the silver couio- 

 meter, Popper found for 7 })er cent solutions as equivalent weight 

 the value 40.33, therefore as atomic weight the value 120.99. 



As he could not discover any sources of error in his process and 

 still believed in the accuracy of the results obtained by Cooke, who, 

 by purely chemical means, had found the atomic weight of antimojiy 

 to be 119.9 he concludes his paper with the words: "Sollte nicht 

 die Entdeckung des Elements "Germaninm" durch Winkler den 



1) Compare 1. 



') Such was the case with solulious coulainiug 22 per cent of Sb GI3. In solu- 

 tions containing 7 per cent. Popper obtained civslalline «oj^-explosive antimony. 

 I will fully refer to this particularity later on in my paper with Dr. Ri.nger. (Gohe.n.) 



