Letters Received to H.H. Barker, June 5, 1930

UNIVERSITY OF MISSOURI COLUMBIA DEPARTMENT OF CHEMISTRY MAY 7 1930 Jun May 5, 1930 Mr. H. H. Barker U. S. Radium Corporation 535 Pearl St. New York City, N.Y. Dear Mr. Barker: With reference to the Welsbach stock of Mesothorium in process, let me say that this is steadily declining and will probably be exhausted within the next year. You may have heard that the Welsbach Company has decided to discontinue the manufacture of Thorium Nitrate. When the present stock of Monazite sand is worked up this division of their work will be discontinued. In fact, it has been closed already. Within another year the accumulated residues and materials in process will doubtless be finished up. Last year we refined about 800 mg. and this year we shall refine by July lst about 600 mg. All of the aged material has been disposed of, but I do not know whether the 800 mg. which we refined last year was also included in the sale. Dr. Breckenridge and an assistant have begun processing the zinc residues. They did not get started as quickly as they had hoped be- cause they made two or three duplicate runs on some batches before undertaking operations on a more extended scale, but they are now operating with a large kettle and the work should go forward quite rapidly from now on. They are not ready as yet to start a crystallizing system. Dr. Breckenridge was pleased to hear however that the next lot of material would be coming along soon.