Physical and Chemical Behavior of Solids. 223 



(on the assumption that the pressure acts equally on both the 

 ice and the water produced by the melting), and presents 

 indisputable evidence that the ice in these circumstances had 

 actually melted. 



The foregoing discussion of the general effects of compres- 

 sion on crystalline aggregates accentuates the importance of the 

 distinction which must be made between two types of com- 

 pression, viz., according as the pressure is uniform in charac- 

 ter or otherwise; if the compression is not uniform, there is 

 more or less deformation — which, on the views here advocated, 

 is conditioned by an actual melting of a part (and probably 

 only a very small fraction) of the material — and the magnitude 

 of the effects produced is many times greater than when we 

 are dealing with uniform pressure. 



The Effect of Compression of One-Component Solid 



Systems. 



A. — The Flow of Solids under Compression. 



Spring, in an early paper* entitled " Researches on the pro- 

 perty which solid bodies possess of welding (de se souder) 

 under pressure," describes in detail work with a large number 

 of substances of varied character, many of which he was able 

 to cause to flow.f This expression was understood by W. 

 HallockJ — and since then by others — to signify a fusion, or 

 true melting, of the whole mass of the solid ; and accordingly 

 he performed experiments to disprove what he conceived to be 

 Spring's claim. For instance : Spring states that at 700 atm. 

 beeswax flowed out of his apparatus like water, and at 2000 

 atrn. paraffin flowed very easily. Hallock took cylinders of w T ax 

 and paraffin, in which were imbedded pieces of lead and other 

 metals, and subjected them to a pressure of 6000 atm.; but he 

 found that everything came out just as it went in. " Nowhere 

 was there a sign of true liquefaction. The wax and paraffin 

 had acted only as viscous solids, and flowed only to All the 

 available openings." 



Shortly afterwards Spring§ published a note, in which he 

 pointed out that his language had been misinterpreted by 

 Hallock, whereupon the latter admitted the justice of this 

 protest.|| But this contributed nothing towards reconciling the 



* Bull. Acad. Roy. Belg. (2), xlix, 323-79, 1880 ; Ann. chim. phys. (5), 

 xxii, 170, 1881. 



f These observations, together with others, are tabulated in summary form 

 below (p. 225). 



fW. Hallock, this Journal, xxxiv, 277-81, 1887; U. S. Geol. Survey, 

 Bull. 55, 67-75, 1888. 



§Bull. Acad. Roy. Belg., xiv, 585, 1887; this Journal, xxxv. 78-9, 1888. 



i| This Journal, xxxvi, 59-60, 1888; U. S. Geol. Survey, Bull 64, 38-9, 

 1890. 



