342 ADULTERATION OF LEMON ACID.

a concentrated solution of muriate of potash,taking care that the solution of the acid isin excess. If a precipitate ensues, thefraud is obvious, because citric acid doesnot produce a precipitate with a solution ofmuriate or potash.

Or, by adding to a saturated solution oftartrate of potash, a saturated solution ofthe suspected acid, in excess, which pro-duces with it an almost insoluble precipi-tate in minute granular crystals. Purecitric acid produces no such effect whenadded in excess to tartrate of potash.