CHANGE OF VOLUME AND OF LENGTH. 



67 



Kirchhoff's Constants /' and /.". 

 lo. »^üirtiiii'- from the formuUe 



and T^ =]-/.-' + 



00 L/.. , -(A--^-') jy' 



II- 



"4 4 j A'(l + 3^)' 



wliicli give the change of volume and of length of ferroiiuigLietio 

 ovoids in terms of Kirchhofes constants // and //', ayc obtain the 

 following expressions for these two constants : 



and ]:" = 



2(1 + 3^) 

 37 -jj 



2{l + 'Sd)' 



1 4/i:(i+3ö) _^,_7..^o/ 



where p= — -fri ^ + ^~'' + ■^'•^ 



H' 



„„a ,=--Mi+ML;+^?^a+,o+Ä-. 



M' o 



These constants, as calculated from the change of dimensions 

 of ovoids, are given in the following table, and gra])hieally drawn 

 in Fig. o : 



