The effect of varying the rate of load upon the strength, breaking stretch and load-stretch diagram of viscose yarn is described. Tests were made on an in clined-plane machine, in which the rate of increase of load is constant throughout any one test'.The strength increases as the rate of loading is in creased. S = 2.3R + K where S is the breaking strength at rate of load R, and K is related to the inherent strength of the material. The breaking stretch appears to be unaffected by change in rate of load. The only portion of the load diagram which appears to be definitely affected by the rate of load at which the test is performed is the "elastic limit," which increases with the rate of loading. 1. Bellinson, H. R. Text. Rsch., May, 1940, P. 287-97. 2. Tippett, L. H. C. "The Methods of Statistics," Williams and Norgate (1937), p. 126. 3. Tippett. Ibid., p. 164. 4. Tippett. Ibid., p. 149. 5. Tippett. Ibid., p. 186. 6. Haven, G. B. Proc. Am. Soc. Test. Mats., 23, 653 (1923). 7. Schoffstall, C. W. and Hamm, H. A. N. B. S. J. Rsch., 2, 871 (1929). 8. Hunter, A. S. Rayon Text. Mo., 17, 739, 805 (1936). 9. Steinberger, R. L. Text. Rsch., 4, 229 (1934).