1905-6.] Electric Oscillations amcl Magnetic Properties of Iron. 47 
loss per cycle, it is evident that any apparatus which measures 
the drag between rotating field and core, or in any other way 
integrates the B - H cycle with respect to value and sign, will 
measure increase of energy loss for low fields, and decrease of 
energy loss for high fields ; and this irrespective of whether the 
oscillations are co-directional or transverse. Between these 
extremes, giving definite and opposite readings, uncertain results, 
or no results at all, may be anticipated from magnetic detectors 
of this kind. 
I acknowledge my indebtedness to the Royal Society of London 
for placing at my disposal a Government grant for the purposes of 
this investigation. The work is being continued. 
( Issued separately February 8, 1906.) 
