68 
Dr. Thomson on Oxalic Acid. 
less than 117 grains of oxalic acid would have been required, 
and at least 145 grains of oxalate of lime would have been ob- 
tained instead of the 119, which was the result of Bergmann’s 
experiment. It is obvious that Bergmann did not precipitate 
all the lime. He added oxalic acid till it ceased to produce 
any effect on the solution from the great excess of nitric acid 
evolved ; and then took it for granted that all the lime was 
separated. But had he added ammonia, he would have got an 
additional quantity of oxalate of lime, and the precipitation 
would have recommenced upon adding more oxalic acid. This 
explanation accounts in a satisfactory manner for the differ- 
ence between Bergmann's statement of the composition of 
oxalate of lime, and mine. 
2. Though the preceding experiment was made with care, 
yet as some of the most important of the following observa- 
tions in some measure rest upon the analysis of oxalate of 
lime, I thought it worth while to verify that analysis in the 
following manner. 
100 grains of crystallized oxalic acid were dissolved in 1000 
grains of water, making a solution which weighed 1100 grains. 
It is obvious that every 100 grains of the above solution 
contained 9 09 grains of crystal of oxalic acid, equivalent, 
according to the preceeding analysis, to 7 grains of real 
acid. 
100 grains of this solution were gradually mixed with lime 
water till the liquid ceased to produce any change on vegeta- 
ble blues. The oxalate of lime thus formed being well dried, 
weighed 11.2 grains. Exposed to a violent heat in a platinum 
crucible, this salt left 4.2 grains of pure lime. Hence it was 
composed of 
