Copy letter from Robert William Frederick Harrison to The Secretary, The Imperial Merchant Service Guild, The Arcade, Lord Street, Liverpool 'Dear Sir, The paper by Sir William Abney about which you enquire is not yet published. It was read only last week. It is entitled "Colour-blindness and the trichromatic theory of colour vision". It will be published in a week on two in the Proceedings of the [Royal] Society, but will not then be on [ale] separately, but only in the No. in which it appears with other papers. I might perhaps suggest that if you desire separate copies your best plan would be to apply to the author direct, as he will be furnished with a considerable number of copies for private distribution.' 4 March 1909