ATOMIC WEIGHTS 



159 



Hence the subjoined percentages: 



Water at 250°. Cuin Cryst. Salt. CuinCuSO^. 



1 25.462 



2 25.452 



3 35.958 25.454 39.745 



Mean, 25.456 



In the second series of analyses, wliich are stated with much detail, 

 several refinements were introduced, in order to estimate also the sul- 

 phuric acid. These will be considered later. The results, given below, 

 are numbered consecutively with the former series : 



CuSOi. 5 aq. 

 3.06006 



2.81840 

 7.50490 



CuSO, at 260°. 

 1.9597 

 1.8048 

 4.8064 



CtiSO, at 360°. 

 1.95637 



4.79826 



Cu. 



.77886 



.71740 



1.90973 



Hence percentages as follows: 



Water,260°. Water, 360°. Cuin Cryst. Salt. CuinCuSOi,260' 



4 35.959 36.068 25.452 39.744 



5 35.964 25.454 39.750 



6 35.957 36.065 25.446 39.733 



Mean, 35.960 



36.067 



25.450 



39.742 



Ditto, 360" 

 39.811 



39.799 



39.805 



Hampe worked with a sulphate dried at 250°, but these data show that 

 a little water is retained at that temperature, and consequently that his 

 results must have been too low. The third of Eichards' series resembles 

 the second, but extra precautions were taken to avoid conceivable errors. 



CuSO^. 5 aq. CuSO, at i 



7 2.88307 



8 3.62913 2.32373 



9 5.81352 



And the percentages are: 



Water at 260°. At 310°. 



35.970 



36.067 



25.448 



