104 ^^ Oxalic Acid. 



acid solution, and to ammonia, and by adding both wi^l^ 

 crreat caution to. avoid any excess, I succeeded in separating 

 the whole of the lime without using any sensible excess of 

 oxalic acid. 



558 grains of the acid solution were employed, a quantity 

 which is equivalent to 58'3 grains of the crystallized acid. 



2. The oxalate of lime, after being well washed a^id 

 drained, and exposed for a week to the open air, at a tem- 

 perature of about 60% weighed 76 grains; but upon being 

 left on the sand bath for some hours in a temperature be- 

 tween 200^ and 300% its weight was reduced to 72 grains. 



3. These 72 grains of dry oxalate of lime were put into an 

 open platinum crucible, and gradually heated to redness. 

 By these means they were reduced to 49-5 grains, which 

 proved to be carbonate of lime. The crucible was now ex- 

 posed to a violent heat in a forge. Nothing remained but a 

 quantity of pure lime weighing 27 grains. 



4. From this experiment we learn, that 72 grains of dry 

 oxalate of lime contain 2/ grains of lime. Of consequence, 

 the oxalic acid in this con)pound nuist be 45 grains. But 

 the weight of crystallized oxalic acid actually used was 58-3 

 grains, a quantity which exceeds the whole acid in the ox- 

 alate by 1 3*3 grains. 'I'hese 13*3 grains are the amount of 

 the water of crystallization, which either did not uniie with 

 the salt, or was driven off by the subsequent exposure to 

 heat. Hence crystallized oxalic acid is composed of 



Real acid - - 45- 

 Water - - 13-3 



58-3 



Now this is equivalent to • 



Kcal acid - - 77 

 Water - - 23 



100 



So that the crystals of oxalic acid contain very nearly the 

 fourth part of their weight of water*. 



II. .Alkaline 



* Vauqiielin in a lite dissertation on cinchona, irarked with that profound 

 ikiU wliich characterizes all the productions of this illustrious chemist, has 



mentioned 



