Sketch of laboratory apparatus by N E Condon, Materia Medica and Pharmacology Dept., University of Edinburgh, sent to Dr [Leonard George] Goodwin Electrical diagram of 30-60 volts, with two ebonite discs mounted on a spindle. With a detail drawing of the ebonite disc coated with brass foil and a note 'we are driving the spindle at 900 per min.' Signed by N E Condon, with a departmental stamp. 27 July 1943