﻿Calcium Carbonate in Water. 



965 



It will be seen that arragonite is far slower in attaining 

 equilibrium in solution than calcite. Indeed, in order to 

 obtain results in a reasonable time, arragonite was taken not 

 with water but with a saturated calcite solution, carefully 



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filtered free from solid. Thus, the solution being already 

 almost saturated with regard to arragonite, the end point 

 was reached much more quickly. Experiments performed 

 in this manner are distinguished by a star in the table. 

 Where it is evident that the true solubility value has not 

 been reached, the result is placed between brackets and is 

 not used in the calculation of the mean value. 



The comparative slowness with which equilibrium is 

 attained in the case of arragonite is not due to the larger 

 size of the particles, for by observation with the microscope 

 it was found that the two minerals were ground to equal 

 degrees of fineness, but may rather be ascribed to the 



