316 



GEORGE F. BECKER AND ARTHUR L. DAY 



This is not a simple repetition of our experiment, although it 

 has been made to appear so. Bruhns and Mecklenburg have 

 placed in the same vessel a loaded crystal and an unloaded crystal, 

 and have observed, as might have been anticipated, that the 

 unloaded crystal increased in thickness while the loaded crystal 

 did not. This result was confirmed in other measurements of the 

 same kind which need not be reprinted here. 



TABLE I* 



Conditions as Above Described; Room Temperature 



about 20°; Load 95 Gm. No Other Crystal 



Present 



A Very Small Crystal, Conditions as Before, 

 Load 0.7 Gm. 



*The experimental results contained in the present paper were 

 courteously placed at our disposal by Mr. J. C. Hostetter, of the 

 Geophysical Laboratory, who will report in greater detail upon this 

 problem in the near future. 



Let us consider for a moment the conditions of crystal growth 

 in a saturated solution. Suppose a single isometric crystal to be 

 immersed in a solution saturated with respect to it; and suppose 

 further that the water is gradually removed from the solution by 

 evaporation, thus inducing potential supersaturation and the con- 

 tinued growth of the crystal in consequence. If the supersatura- 

 tion is greater than can be balanced by the growth of this crystal 

 under the prevailing conditions, other nuclei will tend to form upon 

 which deposition may take place. Now, what will happen when 

 two crystals of the same substance are present, one of them being 



