Casgliadau Arlein
Amgueddfa Cymru
Chwilio Uwch
The Efficient Combustion of Coal (booklet)
Full title - ''The Efficient Combustion of Coal. A Simplified Method of Ascertaining Heat Loss'' 57 page booklet.
Nid yw sylwadau ar gael ar hyn o bryd. Ymddiheuriadau am yr anghyfleustra.