280 



ON EARTH-CURRENTS, AND THE DIURNAL 



The values of the quantity within the brackets, for the same days 

 and hours, are given in the following Table : 



TABLE IV. 



Calculated Values of the Intensity of the Earth- Currents, in the Line connecting 

 Derby and Birmingham. 



9. The mean results corresponding to the several hours, in these 

 four Tables, are projected in curves in Plate I., figs. 1 and 2. 

 As we are concerned only with relative values in both cases, the 

 ranges of the observed and computed results have been previously 



