J. H. Long — Polarization of Tartoate Solutions. 277 



tartrate taken, 0*7982 grm. of the carbonate should be required 

 for complete precipitation. Analysis of the supernatant liquid 

 showed in all cases much of the antimony in solution. 



It was noticed that a slight elevation of temperature pro- 

 duced a copious precipitation with escape of C0 2 , in cases, and 

 to test fully the action of heat, solutions were made and mixed 

 hot. The mixture was kept one hour on the water bath and 

 then filtered, the cool filtrate being made up finally to 100 c.c. 

 at 20°. The results found in these tests are given below 

 opposite numbers 12 to 18 inclusive. 













a D for com- 





No. Na 



2 C0 3 



a-o 



KSbOT 



in 



ff-D for 



KSbOT + 



KNaT. 



plete pre- 

 cipitation 











100 c.c. 



by Na 2 C0 3 . 





1 



1 grm. 



25°-170 



4-496grm. 



27°-941 



25°-132 





2 



3 



20-690 



4-226 ■ 



24-417 









3 



5 



16-628 



3-482 



20-764 



12-853 





4 



7 



13 535 



2-838 



17-624 



.... 





5 



9 



10-250 



2-023 



13-607 



3 



767 





6 1 



2 



6-136 



1-458 



10-870 



3 



767 





7 1 



5 



3-510 



•689 



7-094 



3 



767 





8 2 







3-301 



•219 



4-824 



3 



767 





9 



1 



25-582 



5-000 



28-207 



25 



132 



5 minutes. 



9 



1 



25-580 



5-000 



28-207 



25 



132 



30 



9 



1 



24-480 



5-000 



28-207 



25 



132 



12 hours. 



10 



5 



18-620 



5-000 



28-207 



12 



853 



5 minutes. 



10 



5 



17-930 



5-000 



28-207 



12 



853 



30 " 



10 



5 



16-670 



4-716 



26-814 



12 



853 



40 hours. 



11 



9 



11-570 



5-000 



28-207 







767 



5 minutes. 



11 



9 



11-500 



5-000 



28207 







767 



10 



11 



9 



11-132 



5-000 



28-207 



3 



767 



25 " 



11 



9 



10-550 



5-000 



28-207 



3 



767 



65 " 



11 



9 



10-339 



3-569 



21-188 



3 



767 



12 hours. 



12 



1 



24-185 



4-442 



25-473 



25 



132 





13 



5 



10-500 



2-360 



15-245 



12 



853 





14 



8 



4-580 



1-057 



8-908 



3 



767 





15 1 







3-568 



•634 



6-828 



3 



767 





16 1 



5 



3-495 



'317 



5-297 







767 





17 2 







3495 













767 



, 



18 ! 5 







3-380 















767 





From the table, and more readily from the curve marked A, 

 in which the ordinates represent rotations and the abscissas 

 amount dissolved, it will be seen that with the increase in the 

 amount of carbonate added there is a decrease in the rotation. 

 At first the decrease is nearly directly proportional to the 

 amount of carbonate, but later, after the addition of enough to 

 produce precipitation, the change in the rotation is less rapid. 

 If we consider the first tests made with solutions 9, 10 and 11 

 it will be seen, as shown by. curve B, that the decrease in the 



