105 
of British and Foreign Salt. 
magnitude of the crystals, and their degree of compactness 
and hardness. Quickness of solution, it is well known, is 
pretty nearly proportional, all other circumstances being 
equal to the quantity of surface exposed. And since the sur- 
faces of cubes are as the squares of their sides, it should follow 
that a salt whose crystals are of a given magnitude will dis- 
solve four times more slowly than one whose cubes have only 
half the size. 
That kind of salt, then, which possesses most eminently 
the combined properties of hardness, compactness, and perfec- 
tion of crystals, will be best adapted to the purpose of packing 
fish and other provisions, because it will remain permanently, 
between the different layers, or will be very gradually dis- 
solved by the fluids that exude from the provisions ; thus fur- 
nishing a slow, but constant supply of saturated brine. On 
the other hand, for the purpose of preparing the pickle, or of 
striking the meat, which is done by immersion in a saturated 
solution of salt, the smaller grained varieties answer equally 
well ; or, on account of their greater solubility, even better. 
With the hardness or strong aggregation of the several 
varieties of salt, it seemed to me not improbable that their 
specific gravity might, in some degree, be connected. The 
exact determination of this property in saline substances is, 
however, a problem of considerable difficulty, as will sufficiently 
appear from the various results which have been given, with 
respect to the same salts, by different experimentalists. Thus 
Muschenbroek makes the specific gravity of artificial muriate 
of soda to vary from 1918 to 2148, the mean of which is 2033. 
Sir Isaac Newton states it at 2 1 43, and Hassenfratz at 2200.* 
* Annales de Chimie, Vol. XXVIII. p. 13. 
MDCCCX. P 
