Thornton, William M.D.2018-05-252018-05-251967-02-02http://hdl.handle.net/2152.3/8907Correspondence between Dr. William Thornton and David Langston, a ninth grade student seeking information on the mass measurement device for a science school project.Dr. William ThorntonCorrespondenceDavid LangstonSpace Medicinemass measurement deviceMMD