Copy letter from Robert William Frederick Harrison to M E MacGregor, Trinity College, Cambridge 'In reply to your letter of March 6th, I think I shall be able to supply you with an electro of the illustration you require subject to the formal consent of Council, which, however, may be anticipated. I shall be glad therefore if you will let me have the reference of the paper which you refer to, as I find no mention of it in your letter.' 10 March 1913