Tartaric acid is largely made from wine lees, i.e. the deposit formed when wine is kept in casks. Tamarinds may be extracted with boiling water, the liquid being mixed with a little pipeclay and filtered through animal charcoal to decolourise it. Powdered chalk should he added to the liquid until it ceases to effervesce; the precipitate should he collected on a filter cloth, and a solution of calcium chloride added to the filtrate until it ceases to give a precipitate; the precipitate is tartrate of lime, and should be collected along with the first precipitate. The precipitate should he mixed with a little water and dilute sulphuric acid added in very slight excess. The liquid should then he filtered, evaporated gently to a syrup, and left to crystallise. The crystals may be washed two or three times with cold water, which may he added to the next lot of acid required, and the crystals of tartaric acid should be dissolved in the least possible quantity of hot water, and the solution evaporated and allowed to crystallise again to get rid of the sulphuric acid.