Letters Received to H.H. Barker, January 8, 1932

UNIVERSITY OF MISSOURI COLUMBIA san 11 1002 DEPARTMENT OF CHEMISTRY January 8th, 1932. Mr. H. H. Barker United States Radium Corporation 535 Pearl Street New York City My dear Barker: After writing you hastily from Elgin we went on the next day to Chicago. A dense fog and rain prevailed during most of our return trip but we got home safely. While our experiments at Elgin gave us what we consider very reliable and gratifying results, the ex- periments we conducted in Dr. John's office in Chicago, the same place where you and I made our tests, were not very successful, due to a very anomalous behavior of the instru- ments, both gamma and emanation chambers. We discovered these irregularities soon after lunch. The natural drifts of our instruments were fluctuating and gradually increas- ing. We finally decided that these irregularities were due to the presence of radium emanation in the atmosphere of the laboratory. By a experiments we definitely established this fact. Therefore, the results obtained on Dr. John's patients were simply qualitative in character, Upon our return to Columbia we at once set about to improve the natural drift of our instruments and we also calibrated the emanation chambers. These will be ready very shortly for return to Dr. Flinn. I think that both chambers will probably be in better condition as far as insulation is concerned than they were upon their arrival here; at least I hope that Dr. Flinn will think so. The Wulf-Hes: gamma ray instrument, however, has developed an increased natural drift. I have treated the instrument now in various ways, hoping to reduce the natural drift; we have been only partially successful. The natural drift is still about forty to fifty per cent higher than it was at Elgin. It is still quite low nevertheless, .0007 divisions per second; at one time last fall it was down to .00043, and that was the average at Elgin. We asked Dr. Read at Elgin not to supply us with the dosages of radium until we have made a report of our findings. We hope that in this way the element of un- conscious influence on our experiments will be entirely eliminated. We expect to prepare a report very soon, but in order to make the readings with the gamma ray instru- ment quantitative we must do a little work on calibrating the instrument.