ON OXALIC ACID. }g 



of oxalate of ]iine, and likewise to the proportion of water 

 of crystallization in crystallized oxalic acid. 



The lime water necessary to saturate the acid amounted Water dissolve* 

 to 3186 grains. Hence, it contained only ^igth of its ris I'me. 

 weight of lime. 



3. The oxalates of barytes and strontian are white, taste- Oxalates of ba- 

 less powders, which may be obtained by mixing oxalate of ''y^'^^^"'^^^'"®'^* 

 ammonia with the muriates of these alkaline earths. It is 



said, that these earths are capable of forming soluble su- 

 peroxalatPs with this acid ; but I have not tried the experi- 

 ment. These oxalates, as well as oxalate of lime, are par- 

 tially soluble in the strong- acids. 



4. Oxalate of magnesia is a soft white powder, bear- Oxalafe of 

 ing a considerable resemblance to oxalate of lime, It "iag"t;s'a. 

 is tasteless, and not sensibly soluble in water; yet when 

 oxalate of ammonia is mixed with sulphate of magnesia, 



no precipitate falls ; but if the solution be heated and con- 

 centrated sufficiently, or if it be evaporated to dryness, and 

 redissolved in water, in both cases the oxalate of magnesia 

 separates in the state of an insoluble powder. 



5. Oxalate of potash readily crystallizes in flat rhom- Oxalate of 

 boids, commonly terminated by dihedral summits. The la- P^^^*^*^- 

 teral edges of the prism are usually bevilled. The taste of 



this salt is cooling and bitter. At the temperature of 6o° 

 it dissolves in thrice its weight of water. When dried on the 

 sand b?ith, and afterward exposed in a damp place, it ab- 

 sorbs a little moisture from the atmosphere. 



This salt combines with an excess of acid, and forms a Salt of sorrel, 

 superoxalate, long known by the name of suit of sorrel. It 

 is very sparingly soluble in water, though more so than tar- 

 tar. It occurs in commerce in beautiful 4-sided prisms at- 

 tached to each other. The acid contained in this salt is 

 very nearly double of what is contained in oxalate of potash. 

 Suppose 100 parts of potash ; if the weight of acid neces- 

 sary to convert this quantity into oxalate be x, then 2 x will 

 convert it into superoxalate. 



6. Oxalate of soda readily crystallizes. Its taste is nearly Oxalate of 

 the same as that of oxalate of potash. When heated, it '"^^^" 

 falls to powder, and loses the whole of its water of crystal- 

 lization. Soda is said to be capable of combining with an 



C 2 excess 



