Pag eneee eee oaks Sines fe APPENDIX "D" INCOMING TELETYPE November 13, 1953 FROM: J Division,. LASL, Los Alamos, New Mexico TO: USAEC, Washington, D. C. For Charles Marshall from Graves, Cite J1IG21453. DOE ARCHIVES Confirming our telecon of November 12, this laboratory will interpose no objection to the release of version of IVY film shown here but Commission should understand that release represents a change in philosophy. Major items released are; one, megaton yields, approximately twelve megatons. Elemination of words saying this will not conceal this information from knowledgable observers; two, Mike was a device not deliverable; three, Curtiss is an assembly ship for atomic weapons; four, quick methods of obtaining approximate yields are available, are called Bhangmeters, and depend on measuring some quantity as a function of time; five, methods of measuring various effects are given in much more detail than previously. We recommend that one should not adopt the philosophy that since this has been released one must be more. careful of other information and thereby tighten up security to such an extent that our work becomes more difficult. That philosophy might easily give the Commission a very heavy handicap. Appendix "pb" At