|.K. S. CHAPMAN ON THE DIURNAL VARIATIONS OF THE 



Diagram illustrating the assumed form for the atmospheric conductivity 

 P = po (1 + 3 cos <o + j cos 2 <o). 



25. Substituting the values 



in the expressions for pf in Table II. (the table which relates to the lunar variation), 

 we get the following values for p Caep n . The terms for which o- = are omitted, as 

 they merely produce a monthly change in the mean magnetic elements. 



