154 Dr. S. Tolver Preston on some 



vertical. Have, however, sufficiently delicate experiments 

 been made on this point? 



A contribution published by me in the Philosophical 

 Magazine for April 1880 on crystalline structure might be 

 mentioned here. 



I have tried to define further this open structure, so that it 

 appears to be well adapted for the explanation of cohesion, 

 adhesion, and chemical affinity. 



One knows how the cells of bees are formed by pressure, 

 and how by pressure elastic spheres may be converted into 

 angular, such as hexagonal-shaped, bodies. 



As remarked, the gravitation theory (and many independent 

 facts) demand that the molecules of bodies shall possess an 

 open structure ; which also satisfies the conditions of lightness 

 and economy of material. As crystals exist, it is sometimes 

 supposed that the molecules of bodies (whose open structure is 

 often illustrated by cubes and other figures formed of wire) 

 themselves represent the shapes of the crystals. 



We do not, however, need to assume that the molecules 

 possess exactly such shapes, because if the separate molecules 

 themselves possessed even a rounded structure, they must be 

 pressed into angular forms as soon as two or more of them 

 were pressed together by impacts of the aether atoms. Let us 

 take for illustration the simplest open structure, viz. rings ; 

 although it is not thereby implied that this is the sole ground- 

 form of the molecules. Elastic molecules of any very open 

 structure of three dimensions would probably give a greater 

 stability to the crystal mass formed out of them. 



Simple elastic rings can then by pressure of their boundaries 

 against each other (as caused by the flying of very minute 



Fiar. 1. 



sether atoms through the structure) conceivably be changed 

 into hexagonal, square figures, (fee. Fig. 1 may serve to 



