Letter from [Percy Alexander] MacMahon, Old Palace Yard, Westminster, to the Assistant Secretary of the Royal Society, Burlington House 'Dear Sir, I should be glad if any communications for me which may relate to the business of the Standards Department might be sent to the above address. In order that there may be no delay such communications should, in the usual course be addressed to me under the title of Deputy Warden of the Standards. Yours faithfully, P A MacMahon'. 25 June 1907