Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society to Sir James Bell, Town Clerk, Guildhall, EC 'Replying to your letter of the 15th instant, the British Vacuum Cleaner Company have recently cleaned a large number of parcels of books in our Library and also each year they have applied their process of cleaning to this building; to the best of my knowledge their work has always been of a satisfactory character. They have never cleaned any documents for us. In case of valuable documents I should be inclined to [?] for a special operator, selected for [?] work.' 16 March 1915