Copy letter from Robert William Frederick Harrison to S A Crooke, 35 Holland Villas Road, Kensington, W 'Dear Sir, I am directed to acknowledge the receipt of your letter (without date) enclosing a Note on "The relation of specific gravity to the dielectric constant - a capacity of insulating materials", but I am to inform you that it is not in my power to receive any paper or communication intended for consideration by the Society unless itis presented by a Fellow of the Society. Since you have mentioned that you are acquainted with a number of Fellows of the Society you will no doubt have no difficulty in procuring the endorsement of one of them to your Note, which I return to you for that purpose.' 14 July 1910