the trace drawn by the stylus must be perpendicular to the average circumference (in the case of record sheets in disc form) or to the axis (in the case of record sheets in strip form) of the area reserved for speed recording,
ní mór don rian a tharraingíonn an stíleas bheith ingearach leis an meánimlíne (i gcás leathán taifid i bhfoirm diosca) nó leis an ais (i gcás leathán taifid i bhfoirm stéille) den limistéar a choimeádtear i gcomhair an luas a thaifeadadh,