502 



Johnston, Merwin; and Williamson 



Table III. 



Summary statement of experiments on the transformation of aragonite to calcite 

 in presence of water (liquid or vapor). 



Amt. of 

 water 



grams. 



10 



10 

 10 



1 

 1 



10 

 10 

 10 



10 



10 



1 



10 



Temp. 

 C. 



190 

 270 

 280 

 300 

 300 

 337 

 340 

 345 



345 



350 



400 

 400 



410 



Duration 



of heating 



hours* 



24 



24 

 48 

 24 

 48 

 24 

 24 

 24 



24 



24 



24 

 24 



24 



State of 

 water 



Eemarks 



No change. 



liquid 



liquid 



liquid 



vapor 



vapor 



liquid Changed to calcite rhombs. 



liquid i No change. 



liquid | Changed to calcite rhombs. 



vapor (?) 



vapor 



vapor 

 vapor 



vapor 



f Changed to calcite paramorphs; 

 J we had reason to believe that 

 ] the bomb had leaked slightly 

 |^ in this experiment. 



j Changed in part to calcite 

 I paramorphs. 



Changed to calcite paramorphs. 



* Of this time from 3 to 4 hours would be required for the attainment of the final 

 temperature ; the cooling took place always in less than 5 minutes. 



