Duncan MacRae, C. C. Van Voorhis
1921 Journal of the American Chemical Society  
347 mechanical strength must be attributed to solution forces, the system being physically homogeneous down to molecular and submolecular dimensions. -4 more complete survey of the elastic constants, particularly of the time of relaxation, in relation to composition and treatment, is now in progress, both mechanical and optical methods being used. It is believed that the comparison of mechanical and optical methods will permit a inore definite allocation of the respective types of structure.
more » ... es of structure. Summary. 1. ,S?Ieasurements of the rigidity of gelatin jellies are given, shun big that the jellies follow Hooke's lair nearly up to the breaking point. 2 . The relation of the modulus of clasticity to the concentration uf gelatin is discussed; it is found that a function of the type E = kcn is ralid for a certain range, but the constants k and 71 may vary from one grade of gelatin to another. 3. The influence of acidity and alkalinity on the elasticity has been followed quantitatively. PH measurements show that the observed variations of elasticity are not a simple function of the actual hydrogen-ion concentration. 4. The influence of alcohol and glycerin in different concentrations on the coefficient of rigidity has been measured.
doi:10.1021/ja01436a018 fatcat:z2vhhkp3zzgjpm4unaswojji6u