ON OXALIC ACID. 15 



tiot probable that the whole of this loss is water. To ascer- 

 tain the quantity of water contained in these crystals I had 

 recourse to the following method. 



1. Seventy grains of crystallized oxalic acid were dissolved The acid pre- * 

 in 600 grains of water, constituting a solution which weighed ^urt^te ^f * 

 670 grains. lime. 



Fifty grains of pure carbonate of lime, in the state of cal- 

 careous spar, were dissolved in muriatic acid; this solution 

 was evaporated to dryness, to get rid of the excess of acid, 

 and the residue redissolved in water. 



Into this muriate of lime the solution of oxalic acid was .■^s the muriatic 

 dropped by little and little as long as any precipitate fell, j^^,^^ ^|^^ j^^.. 

 and tiie oxalate of lime thus formed was separated by the portions m su- 

 filter. Pure oxalic acid is not capable of precipitating the " "'"' 

 whole lime from solution of muriate of lime, the muriatic 

 acid evolved being always sufficient to retain the last por- 

 tions in solution. 



It was necessary to get rid of this excess of acid ; the me- this saturated 

 thod which appeared the least exceptionable was to saturate ^ 'i"i"i<^'"*' 

 the muriatic acid with ammonia; accorduigly when the ox- 

 alic acid ceased to occasion any farther precipitate, I cau- 

 tiously added pure ammonia, till the liquid ceased to pro- 

 duce any effect upon vegetable blues. A copious additional 

 precipitate of oxalate of lime was thus obtained. Oxalic 

 acid was now added again as long as it rendered the liquid 

 muddy. By thus alternately having recourse to the acid 

 solution, and to ammonia, and by adding botii with great 

 caution to avoid any excess, I succeeded in separating the 

 whole of the lime, without using any sensible excess of ox- 

 alic acid. 



558 grains of the acid solution were employed, a quan- 

 tity which is equivalent to 58 "3 grains of the crystallized 

 acid. 



2. The oxalate of lime, after being well washed and 

 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 



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