PLAYFAIR, Lyon, first Baron Playfair (1818–1898), politician and chemist, autograph letter signed to Mr Kitson Esq, 8vo, 2 sides of a bifolium, 25th September 1846, with the stamp of the Museum of Economic Geology, saying that he has “forwarded to Mr Lucas Sir John Guests proposals & I have no doubt you will receive an answer from him”.
Playfair moved to London in 1845 on becoming chemist to the Geological Survey, where a small teaching laboratory had been created for him. Playfair's researches for the Geological Survey mostly concerned coal gases, colliery explosions, and an analysis of the coal best suited to the navy's steamships. He was elected as a fellow of the Royal Society of London in 1848.
Sir John Guest (1785–1852), ironmaster, followed his father into management of the Dowlais Iron Company in 1807. From the mid-1830s to the late 1840s the Dowlais works were in their heyday, and by 1845 they boasted eighteen blast furnaces each producing over a hundred tons weekly. As the railway network expanded at home and abroad so the Dowlais Iron Company seized opportunities for new contracts both within Britain and further afield, notably in Germany, Russia, and America. (ODNB)