By altering the throw of the piston the amount of supersaturation can be adjusted within very wide limits.
If such air contains no ions, then it requires about an eightfold supersaturation before any water-drops are formed; if, however, ions are present C.
It is, however, a metastable eutectic point, for it lies in the region of supersaturation with respect to the heptahydrate; and it can be realized only because of the fact that the latter hydrate is not readily formed.
The system will therefore pass along the line x'm, until at the point m solid salt separates out (provided supersaturation is excluded).
Thus if its solubility be even moderate, one is likely to attainsupersaturation in the "cake" and consequently a dull product.
If no precipitate results in a short time, the solution is not supersaturated—it may be too dilute and may require further concentration, but the error of supersaturation has been excluded.
X, of the precipitate, then this excess may cause supersaturation of the saturated washing fluid and some of the salt may be precipitated out of the washing fluid.
Moreover, supersaturation (Potilitzin, 1889) only takes place with those substances which are capable of giving several modifications or several crystallohydrates, i.
