698 T. C. CHAMBERLIN 
The detached molecules of this first action, responding to such 
stress as was then felt by them in their relatively free state, took 
the lines of least resistance until they reached some point where 
the organizing force of some crystal, so situated as to be able to 
grow, brought them under control and reattached them with due 
orientation. Such reattachments were obviously conditioned by 
the balance of strength between the crystalline force and the weakest 
phase of the general pressure. As a result the growing crystal 
extended itself most in the line of least resistance and co-operated 
with other crystals of like situation in developing parallelism of 
structure. 
It is obvious that such individual actions on the part of single 
molecules acting by themselves, and acted upon by special stresses, 
could take place while as yet the general strain was far below the 
strain limit and general detachment could not take place. If the 
pressure came on slowly enough, the whole crystal or fragment 
might be broken down in this piecemeal way while the general 
strain was below the mean strain-limit. As only a few molecules 
were in transit at any given time, the mass as a whole would remain 
solid throughout the process. 
The action was thus the special work of individual molecules, 
each suffering its own strain and playing its own part in its own 
way, ie., it was zdiomolecular. ‘The process is sharply distin- 
guishable from the common movement of all molecules, such as 
usually takes place when liquids flow. The process may be studied 
to advantage in the granulation of snow at temperatures that 
inhibit liquefaction.* 
So long as the stress and strain were mild, the foregoing action 
was obviously slow and had rather narrow limitations. But with 
notable increase of stress, giving rise to increase of strain, and 
increase of heat, the process appears to have been hastened and 
given a tendency to collective action in parallel lines, planes, or 
belts, doubtless because resistance was less effective against such 
tC. S. Peet and E. C. Perisho, working with the writer in the winter of 1894, found 
by daily micrometric measurements of many granules, that the larger ones grew 
every day whether the temperature was at, above, or below o° C., the growth appar- 
ently taking place at the expense of the smaller, more sharply curved granules. 
