On the basis of the present data it would seem that there is no marked relationship between the surface tension and the degree of polymerization of nitrocellulose solutions of normal butyl acetate as determined by the Du Nouy method. It should be noted that no great precision is present in the recorded data. A slight change in surface tension due to a difference in the degree of polymerization could easily be more than offset by errors in measurement. The solutions become much more viscous with increased concentration. This limited the range over which the surface tension could be measured with any degree of accuracy. For with highly viscous solutions the ring would be pulled slowly from the surface making it extremely difficult to determine the exact force required for the break. A second effect was that with increasing concentration a film of the solution adhered across the ring. The data indicates that there is no great change in the surface tension with varying concentration within the range studied. / M.S.