Letter from J M B Butt [War Cabinet Office] to John Peck [Assistant Private Secretary to WSC] on inventions sent to WSC by an E Yeoman Robinson; refers to letter [carbon enclosed] from F A Lindemann [later 1st Lord Cherwell] to Brigadier [?] Arthur Harker of MI5 asking him to look into Robinson's activities as "he describes in considerable detail methods of the highest secrecy which have been used or are about to be used".