1887.] 431 [Smith. 



Taking 10 c.c. of the borax solution as equivalent to 3.5 c.c. of the 

 uranium solution, we Iiave the 250 c.c. of the borax solution equal to 85 

 c.c. of the uranium solution ; but the 85 c.c. represent 85 x .004917 grms. 

 B^O., = .43023 grms. B.A or 36.57%. The theoretical amount of boric 

 acid in 1.1767 grms. borax is .48114 grs. BjOg or 36.64%. 



Free acid very materially affects the results. Extremes of dilution also 

 influenced the same to a certain degree. 



I next endeavored to ascertain how ferric salts would act upon 

 borax. At first, potassium ferrocyanide was employed as an indicator, 

 but was later rejected. On substituting potassium sulphocyanide for it, a 

 few drops of the same were placed in the vessel containing the borax. 

 The first decided "blush" which came over the solution was counted as 

 the end of the reaction. I standardized a definite amount of ferric ammo- 

 nium sulphate with a definite quantity of borax, finding that one c.c. of 

 the iron solution was equivalent to .004479 grams B.fi^. I then dissolved 

 1.2651 grms. of borax in 250 c.c. of water, and titrated a number of por- 

 tions with the standardized iron solution. The results were 36.73% B^Oj, 

 instead of 36.64% bj- theory. 



Upon standardizing a new quantity of iron salt, instead of adding the 

 sulphocyanide solution directly to the borax solution, a few drops of it 

 were placed upon a porcelain plate, and as the end reaction was approached, 

 portions of the liquid were brought in contact with the sulphocyanide 

 by means of a glass rod. In this way the following numbers were ob- 

 tained ; 



1. 10 c.c. borax solution required 1.05 c.c. iron solution. 



3. 5 c.c. " " 0.5 " 



4. 10 " " " " " 



5. 5 " " " 0.5 " 



6. 10 •" " " 1.05 " 



7. " •' " " " " 



8. 20 " - " 2.10 " 



9. " " " " " " " 

 10. 40 •' " '• 4.20 " 



Thus, I found that one c.c. of the iron solution was equal to. 00967 

 grms. B2O3. 



The following tests were then made with the iron solution : 



1. 2.2741 grms. borax were dissolved in 250 c.c. of water, and portions 

 of it titrated : 



10 c.c. borax required 3.40 c.c. iron solution. 



20 " " " " 



This gave 36.14% BA ; theory 36.64%. 



