618 wells: solubility of calcite in water 



Calculated Solubility of Calcite in Water at 16°C., in Contact with Air 

 Containing the Partial Pressure, P, of CO2 (Johnston) 



solubility of calcite in natural waters the dependence on tem- 

 perature is barely mentioned. 



Since data at lower temperatures are lacking, and since the 

 variation of the solubihty of calcite with temperature is a mat- 

 ter of great importance in geochemistry, I have carried out some 

 new experiments designed especially to show the effect of tem- 

 perature on the solubility. 



The method of working consisted in agitating the solutions 

 under investigation by a current of outdoor air for long intervals. 

 The Jena flasks employed were kept in a thermostat while air 

 was being passed, and, for the experiments at 1°C., they were 

 immersed in a mixture of ice and water in a refrigerator during 

 the whole continuation of the experiments. 



The outdoor air used for stirring was filtered through cotton 

 and washed by water. Although the carbon dioxide content of 

 the air is known to be slightly variable,^ this procedure must 

 have equalized the small variations to a considerable degree. A 

 number of careful determinations of the carbon dioxide content, 

 made at various times, ranged from 3.02 to 3.27 parts in 10,000, 

 with a mean of 3.18 parts. Apparently, then, equilibrium with 

 a normal atmosphere was more nearly approached than it could 

 be by any other simple procedure. 



The Joplin calcite used had the following composition: Si02 

 0.09, MnO 0.05, FeO 0.19, CaO 55.80, MgO none, CO2 (by dif- 

 ference) 43.87, sum 100.00 per cent. As far as determined calcite 

 was the only solid phase involved, but, if a less soluble phase did 

 in fact exist in the mixtures, the solubilities actually found would 

 of course apply to it. The calcium content of the solutions was 



6 Letts and Blake. Sci. Proc. Roy. Dublin Soc. 9: Pt. 2, 107. 1900. 



