CREAM OF TARTAR, acid potassium tartrate,or “bitartrate of potash,” HKC 4 O 6 H 4 , is obtained from argol or crude tartar, the crust or deposit formed by wines in bottles and casks in which they are undergoing fermentation. Red are usually richer in argol than white wines. A ton of grapes yields, according to the nature of the fruit, quantities varying between 1 and 2 lb of argol, of which, in good samples, an average of about 83 per cent, is cream of tartar. French red wines examined by Μ. Fauré contained from O6664 to *19728 per cent, by weight of this salt, and white wines from - 09172 to ’ 15208 per cent.; Μ. Jacob found from ’ 7 to l ’ 201 grammes per litre in the wines of Tonnerre. The manufacture of cream of tartar is conducted as follows. Ground granulated argol is wetted and then dissolved in water at a temperature of 100° C.; after two or three days, during which insoluble impurities subside, the clear liquid is drawn off into earthen vessels. The crystals it deposits are re-dissolved in boiling water holding finely comminuted pipe-clay and animal-charcoal in suspension. The solution after standing till a thin film of crystals appears on its surface is run into conical coolers, the sides of which become in eight or nine days coated with fine clear crystals, colouring matters having been precipitated by the clay and charcoal. The crystals are then bleached and dried by exposure to sunlight and air. In Venice tho impurities of the crude tartar are separated by repeated crystallizations, and finally by adding white of egg and wood-ashes to the boiling solution, and removing the scum formed. The name “cream of tartar” was originally given to the crust of minute pure white crystals formed on the surface of cooling solutions. Cream of tartar is a ...