CLARK: RKDUCTION POTENTIALS 



269 



Probable value of E^ + 0.007. 



TABLE 12 



Reduction of Methylene Blue by Titanium at Ph 8.58 



Buffer Solution: M/10 Borate, M/40 Citrate with HCl 



+0.0018 

 — 0.0136 

 — 0.0190 



—0.0244 

 —0.0278 



— o . 0300 



—0.0315 



—0.0322 

 — 0.0322 



Methylene white precipitate separates. 



Potentials unsteady. End point by color about 23.0 cc. Ti. 



Probable value of E — 0.050. 



TABLE 13 

 Comparison op Characteristic Data of Indigo with That of Methylene Blue 



Indigo 



Ph 



1-55 

 2-45 

 2.87 



4-55 

 6.69 

 8.58 



H electrode 

 potential 



>.0936 

 ).i47i 

 ).I727 

 ).2737 

 ) . 402 1 

 >-5i55 



Reduction 

 potential 



+0.2076 

 +0.1504 

 +0. 1246 

 +0.0205 

 O. lOIO 



— o. 1609 



Difference 



0.3012 

 0.2975 



0.3073 

 0.2942 

 0.301 1 

 0.3546 



loj 1/Hj 



10.0 



9 9 



9-9 



9.8 



10. o 



II. 8 



