Agenda for the Twenty-First Meeting of the Underwater Physiology Sub-Committee Agenda for the twenty-first meeting of the Underwater Physiology Sub-Committee to be held on 9 May 1945, enclosing: an addendum to U.P.S. 43 "Submarine Air Purification Trial Carried out in H M Submarine Thule on 4 - 7 July, 1944" by G P B Boissard and H L Bolton; further comments on report U.P.S. 54 "Effect on Personnel of HIgh Carbon Dioxide - Low Oxygen Percentages During Prolonged Submergence Tests in Submarines"; and report U.P.S. 57 titled "Carbon Dioxide in Magazines of H M Ships" by J A B Gray. 2 May 1945