Page:The American Cyclopædia (1879) Volume XIV.djvu/596

572 impurities. All the varieties of salt occasionally contain minute quantities of bromides and

iodides. The following table exhibits the composition of salt from various sources:

An examination of this table will show that the impurities differ both in kind and in quality. More or less sulphate of lime and chloride of magnesium are found in salt from whatever

locality or source it may be derived. The purest rock salt is the best of all; next to that is sea salt, and then the average quality from brine springs; but the table shows that the