368 Professors Tyndall and Huxley on the Structure 



the case above mentioned, the melting of the ice around the 

 points of contact leaves the pieces united by slender columns of 

 the substance. 



Acquainted with these facts, the thought arose of examining 

 how far, in virtue of the property referred to, the form of ice 

 could be changed without final prejudice to its continuity. It 

 was supposed that though crushed by great pressure, new attach- 

 ments would be formed by the cementing, through regelation, 

 of the severed surfaces ; and that a resemblance to an eflPect due 

 to viscosity might be produced. To test this conjecture the fol- . 

 lowing experiments were made : — Two pieces of seasoned box- 

 wood, A and B, fig. 2, 4 inches square and 2 deep, had two 

 cavities hollowed out, so that when one was placed upon the 

 other, a lenticular space, shown in section at C, was enclosed 

 Fig. 2. 



between them. A sphere of compact, transparent ice, of a volume 

 rather more than sufficient to fill the cavity, was placed between 

 the pieces of wood, and subjected to the pressure of a small 

 hydraulic press. The ice broke, as was expected, but it soon 

 reattached itself; the pressure was continued, and in a few 

 seconds the sphere ivas reduced to a transparent lens of the shape 

 and size of the mould in ivhich it had been formed. 



This lens was placed in a cylindrical cavity, 2 inches wide and 

 \ an inch deep, hollowed out in a piece of boxwood, C, fig. 3, 

 as before ; a flat plate, D, of the wood being placed over the 

 lens, it was submitted to pressure. The lens broke as the 

 sphere did, but the fragments attached themselves in accordance 

 with their new conditions, and in less than half a minute the mass 

 was taken from the moidd a transparent cake of ice. 



The substance was subjected to a still severer test. A hemi- 

 spherical cavity was hollowed out in a block of boxwood, and a 

 protuberant hemisphere was turned upon a second slab of the 



