GEOPHYSICAL INVESTIGATIONS SUGGESTED 1 97 



3. The rate of molecular diffusion in liquid rocks by os- 



motic pressure. The solution and diffusion of mole- 

 cules of one kind of mineral in liquid rocks or minerals 

 of other kinds. 

 This has a direct bearing on the solution and diffusion of 

 rocks in molten magmas, and on the theory of rock 

 synthesis, and on that of magmatic intrusion by solu- 

 tion of the surrounding rocks. 



4. The recognition of possible colloids in liquid rocks, which 



may form in the presence of gases, such as water gas, 

 under pressure ; the colloidal condition of silicon hy- 

 droxide, aluminum hydroxide, and ferric hydroxide 

 being easily conceivable. It is also possible that more 

 complex, alumino-silicate molecules may become col- 

 loidal. This might be detected electrolitically in mol- 

 ten magmas in the presence of water under pressure. 

 The bearing of this on the problem of differential diffu- 

 sion and differentiation is important on account of its 

 bearing on the question of the origin of different kinds 

 of igneous rocks. 



B. With high press7cre i?i closed vessels. 



1 . The effect of increasing pressure on heat conductivity in 



solid and liquid rocks. 



2. The effect of increasing pressure on the diffusion of gases 



in liquid rocks. 



3. The effect of increasing pressure on molecular diffusion 



by osmotic pressure. 



4. The rate of molecular diffusivity at high temperatures 



and high pressures in liquid rocks containing various 

 amounts of gases. 

 This has an important bearing on the probably high rate 

 of differentiation in the more liquid molten magmas. 



IV. Crystallization from Liquid Rocks with Temperature 

 Determinations and Observation of the Time Ele- 

 ment. 



A. With normal atmospheric pressure. 



1 . The determination of the temperature of saturation and 

 the rate of crystallization of simple minerals in cooling 

 liquids of the same composition. 



