Correspondence with Charles Hitch and Sidney Dell re an article by Hitch, published in 'Review of Economics and Statistics', XL, August 1958, criticising British Naval Operational Research during the Second World War After correspondence with Blackett, a reply to Hitch's article was prepared by Sidney Dell, and a rejoinder by Hitch (copies of both are included) but neither was published. This episode led Blackett to obtain copies of the wartime papers on convoy size (D.81) and refer to the matter in his Royal United Services Institute lecture (D.109) and subsequntly in 'Studies of War' (H.93-H.95) 1959