Читать книгу A Treatise on Mechanics онлайн

20 страница из 91

If one of them be detached from the others, and the progress of its formation observed, it will be found gradually to increase, always preserving its original figure. Since its increase must be caused by the continued accession of saline molecules, disengaged by the evaporation of the water, it follows that these molecules must be so formed, that by attaching themselves successively to the crystal, they maintain the regularity of its bounding planes, and preserve their mutual inclinations unvaried.

Suppose a crystal to be taken from the liquid during the process of crystallisation, and a piece broken from it so as to destroy the regularity of its form: if the crystal thus broken be restored to the liquid, it will be observed gradually to resume its regular form, the atoms of salt successively dismissed by the vaporising water filling up the irregular cavities produced by the fracture. Hence it follows, that the saline particles which compose the surface of the crystal, and those which form the interior of its mass, are similar, and exert similar attractions on the atoms disengaged by the water.