The New Hampshire Gazette And General Advertiser

FOR the information of those who put up Butter and Beef for exportation, and of those who wish to have their family salt rendered as pure as possible, I beg the favor of a place in your paper for the following receipt, from the Columbian Magazine, for April, 1789.

Yours, A. B.

A NEW METHOD OF PURIFYING COMMON SALT. By the Earl of Dundonald.

COMMON Salt usually contains an admixture of magnesian and vitriolic Salts, which diminish its good qualities both as a seasoner and preserver of food. These cannot be removed by the common process, without more expence and difficulty than economical purposes will allow. But his Lordship's invention possesses a wonderful degree of facility and accuracy. It is simply this:--Let any quantity of Salt be put into a conical vessel with a small hole at the bottom and placed in a moderate heat; pour a saturated solution of salt, boiling hot, into the vessel, and it will gradually pass through the hole, without dissolving any of the common Salt, though it will carry off a large proportion of the other salts with which it is usually contaminated: Make a brine with some of the purified salt, and repeat the process a second time: This may be again repeated at pleasure, until the required degree of purity is obtained. Each washing carries off nine tenths of the salts which render the mass impure: So that after one washing, the impurity is one tenth; after the second, one hundredth; after the third, one thousandth part of its original quality.