for the Determination of the Alkali Metals. 385 



Table IV. 

 The Determination of Caesium as the Perchlorate. 



CsCl 

 taken 

 grm. 



CSCIO4 Theory Error HCIO4 Filtrate 

 found for grm. (70^) (Approx.) 

 grm. CSCIO4 cm-^ cm^ 

 grm. 



A 



The transfer made with the washing solution. 



0-1000 0-1365 0-1380 

 0-1000 0-1368 0-1380 



0-1000 0-1378 0138( 



0-1000 0-1372 0-1380 — O'OOO 



0-1000 0-1376 0-1380 



0-0015 



0-1 



60 



1 





0-0012 



0-1 



60 



1 

 I 



One evaporation 



0-0002 



02 



45 



i 



in glass. 



0-0008 



0-2 



45 



1 





0-0004 



0-2 



20 



J 





B 



The transfer made with the use of the filtrate. 



1 



0-1000 0-1376 0-1380 —0-0004 O'l 20 + 5 



0-1000 0-1378 0-1380 —0-0002 0-1 20 + 5 



0-1000 0-1378 0-1380 —0-0002 0-1 20 + 5 f 



0-1000 0-1377 0-1380 —0-0003 0-1 20 + 5 J 



0-1000 0-1379 0-1380 — O'OOOl 3X0-1 20 + 5 



0-1023 0-1411 0-1412 -O'OOOl 3X0-1 20 + 5 



One evaporation 

 in glass. 



Three evaporations 

 in platinum. 



Table V. 



KCl RbCl 

 taken taken 

 grm. grm. 



CsCl 

 taken 

 grm. 



Per- 

 • chlo- 

 rate 

 found 

 grm. 



Theory 



for 



perchlo- 



rates 



grm. 



Error 

 grm. 



HCIO4 

 (70^) Filtrate 



One evaporation in glass ; transfer with the use of filtrate. 



0-1004 0-1000 0-1004 0-4633* 

 0-1011 0-1000 0-1005 0-4605* 



0-1014 0-1000 0-0807 0-4562t 

 0-1019 0-1000 0-0843 0-4586} 



0-4781 -0-0148* 0-3 20 + 20 



0-4795 -0-0190* 0-3 20 + 20 



0-4527 +0-0035t 5 20+20 



0-4558 +0-0072} 5 20 + 20 



* After dissolving in water and again evaporating with 0-3 cm^ of the per- 

 chloric acid the recovered residues showed error of +0-0006 grm. and + 

 00012 grm. respectively — showing the imperfect conversion of large amounts 

 of chloride in a single evaporation with a moderate amount of perchloric acid. 



f These residues, obtained by evaporating with a large amount of perchlo- 

 ric acid in glass, contained silica. After dissolving, filtering, and reprecipi- 

 tating the errors were reduced to +0-0009 grm. and +0 '0015 grm. respect- 

 ively. 



