TARTAKIC ACID. 113 



a way not liable to any such suspicions. I shall 

 now relate the results of my new experiments on 

 this subject. 



2. Tartrate of potash is a salt which crystal- 

 lizes in large transparent four-sided right prisms p tash 

 with rectangular bases. They contain two atoms 

 of water of crystallization, but are easily ren- 

 dered anhydrous by heat. A quantity of these 

 crystals was left upon the sand bath for twenty- 

 four hours in a covered glass capsule in a heat 

 amounting for several hours to about 240 ; 

 14-25 grains of the salt, thus rendered anhydrous, 

 were dissolved in distilled water ; 2O75 grains 

 of dry nitrate of lead were dissolved in another 

 portion of distilled water, and the two liquids 

 were mixed together : a double decomposition 

 took place, and the tartrate of lead precipitated 

 with such rapidity that in about an hour it left 

 the mothe,r water quite transparent and colour- 

 less. This mother water was tested with nitrate 

 of lead and tartrate of potash, without being in 

 the least affected by either. Hence, it contained 

 no sensible quantity either of tartaric acid or of 

 lead. The whole of these two bodies was con- 

 tained in the precipitate which had fallen. 



From this experiment we see that 14-25 grains 

 of anhydrous tartrate of potash contain just the 

 quantity of acid necessary to saturate- 14 grains 

 of protoxide of lead, which are contained in the 

 20-75 grains of nitrate of lead. The tartrate of 



Vor, II. H 



