While doing some research on D.M. Cook's invention, in particular the "missing" circuit "D", I came across this item for sale on Ebay < http://cgi.ebay.com/1892-QUACK-MEDICINE-AD-FOR-ELECTRO-MAGNETIC-BATTERY_W0QQitemZ140042808371QQcmdZViewItem > and wondered if this might have been the commercial adaptation of his invention?
-Don