1835.] on Eacemic Acid. 107 



brought in contact with a flaming body. It is next to im- 

 possible to burn off the whole of the charcoal, the potash 

 even after fusion retaining a black colour. 



Tartrate of Potash. 

 This salt long known by the name of soluble tartar, forms 

 large crystals as transparent as glass. Their primary form 

 is a right oblique prism, deviating but little from rectangu- 

 lar : the inclination of the faces of the prism being 89° 30' 

 and 90° 30'. The obtuse edges of the prism are usually 

 replaced by tangent planes. 



It has a saline and unpleasantly bitter taste. Its specific 

 gravity is 2*140. If Wentzel's statement that water at 

 50° dissolves its own weight of it be correct, it possesses 

 nearly the solubility of racemate of potash. 



To determine the composition of this salt, 93*75 grains 

 of dry crystals of tartaric acid, were exactly saturated with 

 carbonate of potash, the solution was evaporated to dry- 

 ness and kept in the temperature of 100° till it ceased to 

 lose weight. In this state it had a moist appearance and 

 weighed 171*95 grains. Now, it contained 82*5 of tartaric 

 acid and 60 of potash. Hence,' its constituents were 

 Tartaric acid . . . . 8*25 



Potash 6*00 



Water 2*945 



17*195 

 2*945 of water is very nearly 2 J atoms. Hence, it would 

 appear that this salt when dried at 100° contains 2| atoms 

 of combined water. When kept for three hours in the 

 temperature of about 300°, the weight was reduced to 137*7 

 grains. Thus it had lost all its water and a portion of its 

 acid had been dissipated. 



III. BI-RACEMATE OF POTASH. 



This salt is obtained with great ease if we dissolve 214 

 grains of the crystals of racemic acid in water, and add to 

 the liquid by a little at a time, a concentrated solution of 

 87*5 grains of anhydrous carbonate of potash. After the 

 effervescence is at an end, the bi-racemate is deposited 

 abundantly in flocks, consisting of minute crystals. We 

 may collect it on a filter, wash it and dry it. 



