ACCORDING to an article by W. O. Baker (Bell f Lab. Ree.,20, No. 6, Feb., 1942) the toughness, strength and flexibility of plastics are influenced by the arrangement as well as the composition of their giant molecules. In an endeavour to discover the fundamental properties of certain compounds such as cellulose acetate and cellulose butyrate, which make these materials resistant to shock, bending, twisting and dimensional change, studies were undertaken on a molecular scale, the high magnification necessary being obtained by photographing X-ray beams after passage through selected samples of the plastics. These photographs give patterns which can be measured to show molecular distances as small as a billionth of an inch, and they also indicate how the molecules are placed with respect to each other.