386 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



were found for all voltages, and this set of curves may therefore be con- 

 sidered characteristic. 



7. Three Dimensional Diagrams. — In the five succeeding figures 

 some of the factors so far studied are plotted in groups of three. It 

 would require a great deal of space and many figures to represent all 

 our data in the usual way, and the conclusions which can be drawn are 

 so far not of a sufficiently quantitative nature to demand great accur- 



.026 



.02 



O 



o 



'.016 



t .01 



o 



a. 



< 

 o 



.006 



100 



200 



300 



VOLTAGE 



Figure 15. 

 Same as Figure 14 for higher range of Woltages. 



acy in the presentation of data. It is easier to grasp the meaning of 

 the data when it is arranged as compactly as possible. We have there- 

 fore made use of curves in place of tables of data, and it is hoped that 

 the three-dimensional diagrams will take the place of the large number 

 of curves which they represent. 



Figure 18 is a composite figure in which apparent capacity, charging 

 time, and forming voltage are plotted together, the charge being given 

 at the forming voltage. 



The diagrams represent the results which we obtained with an alu- 

 minium anode which was rather hastily formed for part of the measure- 

 ments and very carefully and slowly formed later in the series. The 

 low voltage curves therefore show no maximum of charge for a short 



