and Soft States in Metals. 269 
the units of which the lamellze are built up, exceedingly thin 
layers of the amorphous phase are formed throu chont the 
whole mass of strained metal. Slipping is easy so long as 
fresh moving surfaces are forthcoming for the supply of the 
mobile phase : but when all the available crystalline phase has 
become encased in the unyielding amorphous phase, plasticity 
under these particular stresses comes to an end. 
48. This encasing of the crystalline elements with films of 
the hardened phase, which occurs whenever movement takes 
place among these elements, seems for the first time to supply 
the needed “explanation of the passage of a metal through a 
highly plastic stage to a state of hardness and tenacity much 
greater than it originally possessed. 
49. One of the most remarkable features in hardening is 
the large effect which is produced even by an apparently very 
incomplete transformation of the C phase. A bar of metal 
which has been ruptured by tensile stress shows a micro- 
structure which consists of comparatively large crystalline 
ageregates, and yet the tenacity has been largely increased 
by the straming. Hyven assuming that these crystalline 
aggregates are very thoroughly interpenetrated by films of the 
amorphous phase, the greater part of the metal is still visible 
in the crystalline phase. 
50. [ have made many attempts to destroy all traces of the 
C phase by thoroughly beating strips of gold- and silver-foil, 
but have not yet succeeded in doing so. The result of beating 
gold-foil 0-42 mm. in thickness till it covered nearly three 
times its original area was to alter the metal into a hard 
springy, tenacious state, the surfaces being thoroughly flowed 
and vitreous looking. Etching with aqua regia disclosed a 
deep granular layer immediately under the vitreous cover ing, 
and by further etching this granular layer was removed, and 
the disarticulated skeleions of crystals were disclosed. The 
strip of foil from which the A phase had been removed 
by etching was soft and pliable, and had completely lost its 
spring. (Figs. 3-8.) 
51. It is well known that as the diameter of a wire is 
reduced by drawing it through a die, the tensile strength 
increases in a very aed degree. In this way the tensile 
strength of Swedish iron may be raised from 20 tons per 
square inch in the bar form, to 80 tons per square inch in a 
wire of 0*1 mm. diameter. In view of the observations in the 
preceding paragraph (50), we may conclude that even ina 
wire of this degree of fineness a considerable amount of the 
erystalline phase remains still untransformed. Even the high 
tensile strength of 80 tons per square inch must therefore fall 
