X-RAY DIFFRACTION 



period of 640 A. along the fiber axis; clam muscle fibrils (22) show 

 indications of a long hber period of 700 A. In the latter two cases, 

 independent observations with the electron microscope led to similar 

 periodicities in the investigated samples. Bear (6) reports a long fiber 

 period of about 600 A. for a large number of collagen specimens; and 



-I - 



o>- 





^r-vMAj 



i 



'*^V>\v 



^VV.^'^^ 



Q 



m 



Fig. 3. — Small and large angle scattering 

 of elongated, parallelized crystallites (16). 



it is interesting to note that synthetic polyamides also show distinct 

 meridional small-angle reflections, which lead to long fiber periods of 

 about 90 A. (16,20). 



Figure 3 shows diagrammatically the small- and large-angle 

 scattering of a highly stretched and subsequently relaxed nylon filament 

 and indicates the relations between the various reflections of the diagram 

 with the corresponding distances in the sample. 



447 



