Casgliadau Arlein
Amgueddfa Cymru
Chwilio Uwch
The Change to Metric Pipes, Pipe Flanges and Flanged Valves for General Use (booklet)
43 page booklet in red and white covers, stapled at centre. Notes of guidance for colliery engineers.
Nid yw sylwadau ar gael ar hyn o bryd. Ymddiheuriadau am yr anghyfleustra.