3H 



GEORGE F. BECKER AND ARTHUR L. DAY 



dust. The original drawing of the experimental arrangements is 

 reproduced here for the sake of defmiteness (Fig. i). Saturated 

 solution was added from time to time if needed, so that throughout 

 the experiment the crystal remained submerged in its saturated 

 solution. The thickness of the crystal was measured at intervals 

 with an appropriate instrument. 



The experiment was repeated many times with a single crystal 

 of alum and various weights, and also with a crystal of copper 

 sulphate, of potassium ferrocyanide, and of lead nitrate, in appro- 

 priate solutions. In no single 

 instance during this series of 

 observations did the crystal fail 

 to lift (i) its own weight; (2) the 

 weight of the superimposed 

 glass plate; (3) the weight of 

 the load upon the glass plate. 

 The distance through which 

 the load was lifted varied in 

 different experiments from a 

 few hundredths to 0.5 mm. 1 



In 1 91 3 Bruhns and Meck- 

 lenburg 2 published a series of 

 experiments upon the same sub- 

 ject which purported to repeat 

 those which we had made and to disprove them. They announced 

 their inability to obtain the experimental results which we have de- 

 scribed, and categorically denied, in the face of much corroborative 

 evidence contained in their own paper, the existence of such a 

 linear force exerted during the growth of crystals. 



To this paper we did not at once reply because it seemed impos- 

 sible that other investigators would long allow the crucial experi- 



1 The data upon which this preliminary account is based were obtained during 

 the winter of 1902-3, but the records were burned in the Geological Survey fire in the 

 following year, which may serve to explain the absence of complete data in the publi- 

 cation of 1905. 



3 W. Bruhns and Werner Mecklenburg (Clausthal), "Uber die sogennante Kris- 

 talhsationskraft," Jahresbericht des Niedersachsischen geologischen Vereinszu Hannover, 



VI O913), 92. 



Fig. 1. — A crystal shown growing 

 between two glass plates and lifting a 

 heavy load. Reprinted from the paper 

 of 1905 (op. tit.). 



