Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons 'Please prepare electros of the blocks illustrating the paper by Dr J T [James Thomson] Bottomley & F A King on "Experiments with vacuum electroscopes" (read March 7, 1907) and send them, with your account, to: - The Editor of "The Philosophical Magazine", c/o [care of] Messrs Taylor & Francis, Printing Office, Red Lion Court, Fleet Street, E.C.'. 10 April 1907