1() ON OXALIC ACID. 



By these means they were rediiced 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. 



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



contain 27 oxalate of lime contain 27 grains of lime. Of consequence, 

 the oxalic acid in this compound must 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 oxalate by 13*3 grains. These 13*3 grains are the 

 amount of the water of crystallization, which either did 

 not unite with the salt, or was driven off by the subsequent 



Crystalsof ox- exposure to heat. Hence crystallized oxalic acid is com- 



alic acid con- g^j of 



tain -2^ water. *^ 



Real acid • • • • 45" 7 • i ^ * f 77 

 ■wr ^ TO o f- equivalent to < ' 



water 13-3 3 ^ [23 



58-3 100 



So that the crystals of oxalic acid contain very nearly the 

 fourth part of their weight of water*. 



II. Alkaline and Earthy Oxalates. 



Oxalate of 1. The preceding experiment gives us likewise the com- 



lime, position of oxalate of lime. This salt, when merely dried 



m'b acid, : , . •,, , • ,• f ^ 1-1 



37 3 base. m the open air, still retains a portion or water, which may 



This propor- * Vauquelin in a late dissertation on cinchona, marked with that pro- 



lion confirnied found skill which characteiizes ail the productions of this illustrious 

 by an experi- chemist, has mentioned incidentally, that the crystals of oxalic acid 

 ^^' contain about half their weight of water. He dissolved 100 parts of 



quelin. 



cinchonate of lime in water, and precipitated by means of oxalic acid ; 22 

 parts of crystallized oxalic acid were necessary ; and the oxalate of lime 

 formed weighed 27 grains. From this experiment he draws the conclu- 

 sion which 1 have stated (See Ann. deChimie, lix, 164 j or our Journal, 

 vol. XIX, p. 213). But this ingenious chemist does not seem to have 

 been aware of the real composition of oxalate of lime. 27 grains of 

 that salt are composed very nearly of 10 grains of lime and 17 grains of 

 aciJ. But the weight of the crystals used by Vauquelin was 22; the 

 difference, 6, is obviously the water of crystallization in 22 grains of 

 the crystals. But if 22 grains contain 5 of water, it is obvious, that IQO 

 contain very nearly 23. So ihat his wxperiDient in reality coincides with 

 mine. 



be 



