62 CARNEGIE INSTITUTION 



heat, the conductivity, viscosity, and other physical constants of 

 the terrestrial components would greatly advance geophysics. Mr. 

 S. Guenther, professor of geograph}' at the Technical High School 

 in Munich, who has done much work in geophysics, might be more 

 familiar with these questions. 



With expressions of sincerest respect, your most obedient, 



Dr. Ernst Mach, 



IF. Becke to E. Suess, June <5, igo2.'\ 



Vienna, Austria, /?^7^^ <5, igo2. 

 My Dear Mr. President : 



In accordance with your wish I take the liberty of communicating 

 to you the following project for experiments bearing upon the de- 

 velopment of slaty structure in crystalline schists. 



According to a law announced by Riecke in Goettingen early in 

 the nineties, the melting point is raised by mechanical deformation, 

 or what is the same thing, the solubility of a body in the surround- 

 ing solution is promoted so that if in a saturated solution two bodies 

 of the same kind as that dissolved exist, of which one is subjected 

 to mechanical pressure (or is stretched or twisted) , while the other 

 remains in a state of ease, the strained body is dissolved, while the 

 unstrained body grows at the expense of the same solution. 



This law may be applied to an aggregate of crystals surrounded 

 by a saturated solution of their substance. If the aggregate is sub- 

 jected to a one-sided pressure, the portions under pressure should 

 grow. The crystals should flatten perpendicularly to the direction 

 of pressure, and a slaty structure should result. 



Thus one might make a cake of salt soluble in water, such as 

 alum, epsom salts, etc., and subject it to a one-sided pressure in 

 such a manner as to permit of lateral yielding, the vessel meantime 

 being filled with a saturated solution of the salt. 



It would be particularly interesting to investigate the influence 

 which especially favorable directions of growth might exert ; how, 

 for example, on the one hand isometric crystals would behave and, 

 on the other hand, such as have a natural tendency to a tabular or 

 prismatic form. 



With the highest respect, your obedient, 



F. Becke. 



