Casgliadau Arlein
Amgueddfa Cymru
Chwilio Uwch
Papers re. sparking plug, 1917
Brevet D'Invention. French patent? document No. '485997'. Dated 4th December 1917. Three page document including two diagrams of spark plugs (see original tech. drawing 2001.142/28).
Nid yw sylwadau ar gael ar hyn o bryd. Ymddiheuriadau am yr anghyfleustra.