Seventeen letters, 1912-14, from the architect Clough Williams-Ellis (1883-1978), mainly addressed to Charles Edward Breese (1867-1922), Porthmadog, secretary of the Ffestiniog Slate Quarry Owners Association, chiefly relating to the former's pamphlet, Roofs and their coverings. In praise of slates (London, [1913]), and his standard plans for cottages roofed with 'Portmadoc' slates from the Ffestiniog quarries; together with some sixty letters, 1913, to Charles Edward Breese, mostly from surveyors, architects, builders and local government officers in response to their receipt of copies of the pamphlet.