In a previous paper5 describing an X-ray method for quantitative comparison of crystalline orientation in cellulose fibres, data were presented which suggested a relationship between orientation and the tensile strength of three commercial samples of cotton cord. Through informal co-operation with Dr. C. M. Conrad2, it was possible to further establish this relationship on ten specially selected samples of raw cotton varying widely in tensile strength.3 A brief summary of the results, and a detailed description of the technique employed in obtaining the results are given in the present paper.