1906.] 



SULPHURIC ACID ON DEPOSITION OF METALS. 



259 



In 2.5 minutes, 0.1157 gram of copper was deposited. 



" 5 " 0.1897 " 



" 7.5 " 0.2385 " 



" 10 " 0.2489 " 



(Figure 2, Curve 2.) 



The presence of three cubic centimeters of acid affects the curve 

 but sHghtly. The departure is noticed in the deposition of the last 

 traces of the metal. The copper was completely removed in twelve 

 minutes. 



In 2.5 minutes, 0.1079 gram of copper was deposited. 



5 



7-5 

 10 

 12 



0.1807 



0.231 1 " " 



0.2450 " 



0.2488 " 



(Figure 2, Curve 3.) 



The effect of a large amount of sulphuric acid was noticed again 

 in the latter part of the decomposition, when four cubic centimeters 

 of acid were added. It was then observed that it took six minutes 

 longer than it did when but three cubic centimeters were present to 

 remove all copper. 



.In 2.5 minutes, 0.1060 gram of copper was deposited. 



" 5 

 " 7.5 

 "10 

 "12 

 "18 



0.1684 

 0.2078 

 0.2402 

 0.2458 

 0.2487 



(Figure 2, Curve 4) 



In the presence of five cubic centimeters of acid, twenty-five 

 minutes were necessary in order that the last traces of copper might 

 be removed. The solution did not become colorless until after eig'h- 

 teen minutes. 



(Figure 2, Curve 5.) 



