This is the first report in an investigation of the effects of testing conditions on the load-stretch properties of viscose rayon. This report discusses the effect of chang ing specimen length.It is found that increase in length results in a de crease in the breaking strength. The magnitude of the decrease is in good agreement with Peirce's theory of the Weakest Link.Increase in specimen length also produces an apparent decrease in the per cent breaking stretch. This is prob ably the result of a jaw effect, in that some extension of the portion of yarn gripped by the jaws may occur.