Bartow—A Mechanical Cause of Homogeneity of Crystals. 671 
disturbances be sufficiently consideradle, intercalation will, it is evident, 
take place even where there is very little or no compatibility be- 
tween the assemblages coming together.’ 
The mixture will in the latter case be such as is obtained by 
shaking together different ingredients whose forms are incom- 
patible ; there will be more or less uniformity of distribution but no 
symmetry, and in no such case can there be absolute homogeneity. 
Since the packing is closer when the two kinds of assemblage 
‘do not intermix, the principle of closest-packing will, in the cases 
supposed, be continually to some extent undoing what intermix- 
ture the disturbances have accomplished, and producing here and 
there small patches of each kind unmixed with the other, which 
patches will however speedily be shaken to pieces again while 
fresh ones are formed. 
The amount of fluctuation going on will prevent any appreciable 
uniformity of orientation of the patches being exhibited, but it 
is easy to see that some of the features displayed will be very 
like those above traced in cases of mixtures which solidify. 
Unless some separating influence is at work, intermixture of this 
kind will tend to produce uniformity of distribution of the patches 
of one kind of assemblage throughout patches of the other; in 
other words intermixture in all proportions. Separating influences 
are, however, conceivable, which will remove portions of one or the 
other kind. of assemblage when a certain relative proportion of it 
is exceeded, the result being to limit the proportions in which the two 
assemblages can intermiz. 
Thus, for example, in cases where one kind of assemblage would, 
if found alone, experience a change to the solid state, but is capable 
of remaining liquid when finely divided and distributed through 
the other assemblage, it is clear that intermixtures composed of the 
two kinds in which the predominance of the former is beyond a 
certain limit will contain patches of the latter large enough to be 
unaffected by the proximity of the first-mentioned kind. Where 
this is the case these patches will pass to the solid state, and so the 
proportion of the kind in excess in the liquid mixture will be 
reduced till solidification can no longer occur. 
1 Comp. Lothar Meyer, ‘ Grundziige der theoretischer Chemie,’’ p. 128. 
2 See pp. 657-659. 
SCIEN. PROC. R.D.S., VOL. VIII., PART VI. 3C 
