Letter from William Ellis, 78 Coleraine Road, Blackheath, London, to [Robert William Frederick] Harrison 'Dear Sir, I do not receive copies of the [Philosophical Transactions] but there are papers at times of which I should like to procure a copy. One such is that by Arthur Schuster "on the periodications of sun spots". If I can be favoured with a copy thereof. Yours faithfully, William Ellis'. 31 July 1906