172 



Messrs. Mills and Bicket's Researches 



The washing of the precipitate took a long time ( a maximum 

 of two days), especially when the nickelous salt was in excess 

 of the manganous. After the precipitate had been washed, it 

 was dissolved in dilute hydric chloride, and the manganese 

 and nickel separated and estimated by the method given 

 above. 



In the course of these experiments we noticed that, (1) if 

 we kept the clear filtrate in a glass-stoppered bottle for some 

 time, or boiled it, a further precipitate appeared; and (2) that 

 the clear nitrate was alkaline to test-paper, turning red litmus 

 blue. 



The results obtained in these experiments are comprised in 

 the following table ("temperature" meaning temperature of 

 the reagents after mixture): — 



Table I. 



Nickelous 



salt taken. 



n. 



Manganous 



salt taken. 



m. 



Nickelous 



salt preci- 



pil ated. 



v. 



Manganous 

 salt preci- 

 pitated. 



Temperature. 



grm. 



grin. 



grm. 



grm. 



o 



•1000 



•9000 



•0953 



•5850 



12-9 C. 



•2000 



•8000 



•1852 



•4616 



136 



•3000 



•7000 



•2799 



•3766 



12-5 



•4000 



•6000 



•3588 



•2976 



130 



•5000 



•5000 



•4305 



■2450 



13-6 



•6000 



•4000 



•4788 



'1536 



128 



■7000 



•3000 



•4991 



•1089 



17-0 



•8000 



•2000 



•5584 



•0722 



170 



•9000 



•1000 



•5841 



•0363 



15-2 



III. B. Separate Precipitab'dity. 



We next tried the following experiments to determine the 

 precipitability of manganous and nickelous sulphates when 

 separate. Tour series were undertaken, viz. (1) when the 

 nickelous salt varied and the sodic carbonate was constant, 



(2) nickelous salt constant and sodic carbonate varying, 



(3) manganous salt varying and sodic carbonate constant, 



(4) manganous salt constant and sodic carbonate varying. 

 (1) Nickelous Scdt varies, Sodic Carbonate constant. — The 



bottles containing the solutions were brought to a constant 

 temperature by immersion in a tank of running water. After 

 the solution of nickelous sulphate had been measured out, it 

 was made up to 100 cub. cent, with distilled water that had 

 been cooled to the same temperature, and then 10 cub. cent, 

 of the sodic carbonate solution was added, the mixture stirred, 



