Specimens of Rocks. Proof of an Illustration for Wright's 'Globe Prepared for Man'. Math Eitemau Uwchlwytho gan Yale Center for British Art
Sir Wm. Ferguson, Bart. F.R.S Sergeant-Surgeon to the Queen &c Math Eitemau Uwchlwytho gan Llyfrgell Genedlaethol Cymru / The National Library of Wales
John Heaviside, Esqr Surgeon Extraordinary to the King F.R.S. F.A.S. &c Math Eitemau Uwchlwytho gan Llyfrgell Genedlaethol Cymru / The National Library of Wales
