Correspondence with Lawrence M. Donley, Owens-Illinois Inc., regarding the CER-VIT mirror blank, including queries from Redman concerning properties, mirror surface distortion and mirror systems. There are also copies of correspondence between H.E. Bennett, Michelson Laboratory, California, and Dr G.A. Simmons, Owens-Illinois Inc., including a paper by R.W. Dietz and J.M. Bennett entitled 'Smoothness and Thermal Stability of CER-VIT, a New Optical Material'; O.C. Mohler and L.M. Donley on the performance of blanks at the McMath-Hulbert Observatory; L.M. Donley and M. Carpenter, Science Research Council, on plans for a meeting; and Owens-Illinois Inc. and C. Fehrenbach, Marseilles Observatory, including specifications and a guarantee for a CER-VIT 101 blank.