BIRTH AND AFFINITIES OF CRYSTALS 133 



of the new material. This happens with the alums, as mentioned 

 above. 



The researches which I have described in this paper give us, 

 I think, some insight into the invisible structure of the crystal 

 edifice and its manner of growth ; they also lead to one other 

 inquiry which has not yet been carried out. Parallel growths 

 take place upon crystals of the same substance ; they also take 

 place upon crystals of another substance having the same 

 structure and molecular volume. A crystal of the dissolved 

 substance dropped into a metastable solution at once relieves 

 the supersaturation and continues to grow. Is it the case 

 that the supersaturation can also be relieved by a crystal of some 

 other substance, provided that it has the same structure and 

 molecular volume ? I think that this will probably be estab- 

 lished by future experiments, for I have found that the super- 

 saturation of a metastable solution of sodium nitrate appears 

 to be relieved by calcite, but not by the other members of the 

 calcite group. 



If this be so, the relief of -supersaturation and the parallel 

 growth are two occurrences which can hardly be referred 

 merely to the geometrical fitting together of two structures, 

 for this could scarcely force the dissolved substance out of 

 solution. I would rather think of a crystal as an assemblage 

 of vibrating particles, and of the geometrical structure as the 

 expression of some rhythmical motion with which they are 

 endued, so that two crystals which have similar structures are 

 in tune with each other, and respond each to the other's palpi- 

 tations. Is it not possible that the irregular motions of the 

 liquid substance in solution may respond to the rhythmical 

 motion of the crystal particles of a kindred substance in tune 

 with it introduced into the solution, just as one violin responds 

 to another, and so may be transformed into the regular pulsa- 

 tions which perhaps accompany the building up of a crystalline 

 structure ? 



Bibliography 



Miers, H. A., Address to the Geological Section of the British Association, 1905, 



Report, p. 388. 

 Macallum, A. B., and Menten, Miss M. L., On the Distribution of Chlorides in 



Nerve Cells and Fibres, Proc. Roy. Soc, 1906, 77B, p. 165. 

 Miers, H. A., and Isaac, Florence, The Refractive Indices of Crystallising 



Solutions, with especial reference to the Passage from the Metastable to the 



Labile Condition, Jonrn. Chetn. Soc, 1906, 89, p. 413. 



