Copy letter from Robert William Frederick Harrison to The Secretary, Messrs Madderton & Co Ltd, Loughton, Essex 'Dear Sir, In reply to your letter of the 19th instant; the Number of the "Proceedings" of the Royal Society containing Sir William Abney's paper on 'The Action of Ozone on Water-colour pigments' is on sale at the published price of 3/- (three shillings) net. Copies may be purchased from the Society's printers - Messrs Harrison and Sons, 45 St Martin's Lane, London WC. The paper in contained in Proceedings No 536, Vol 80.' 20 August 1909