CONDITIONS OF SEDIMENTARY DEPOSITION. 503 



entering into the reaction, then the quantities of carbonic acid 

 and of lime were determined in the filtered solution. 



"Then to run through the scale of pressures of the car- 

 bonic acid from the most feeble to the strongest- that could be 

 obtained. 



" Then to change the temperature and re-commence anew 

 the series of experiments in order to eliminate the influence of 

 heat. 



"The experiments establish the fact that pure water in the 

 presence of carbonate of lime, and of an atmosphere containing a 

 determined proportion of carbonic acid, dissolves simultaneously 

 free carbonic acid according to the law of absorption of gases, 

 neutral carbonate according to the solubility of this salt in water 

 free from carbonic acid, and bicarbonate of lime." 



The relation found between the tension of the carbonic acid 

 and the proportion of bicarbonate formed is such that : "Equil- 

 ibrium being established in the solution, the slightest diminution 

 of the tension of the carbonic acid in the atmosphere determined 

 the decomposition of a corresponding quantity of bicarbonate, 

 with precipitation of the neutral carbonate and the emission of 

 carbonic acid gas." 



The veteran chemist Dumas, in an article on the normal car- 

 bonic acid of the atmosphere, says: 1 



"In recent times, by a happy application of the principle of 

 dissociation, M. Schloesing has shown that the proportion 4 of 

 carbonic acid contained in the air was in relation with that of 

 bicarbonate of lime held in solution in the waters of the sea. 

 When the amount of carbonic acid ( in the air ) is diminished the 

 bicarbonate of the lime in the sea is dissociated, the half of its 

 carbonic acid passes into the air, and the neutral carbonate of lime 

 is precipitated from solution" ("depose"). 



Another condition which may decompose bicarbonate of 

 lime is simple mechanical agitation of the water holding it in 

 solution. Dittmar in examining samples of ocean water for car- 



I Comptes Rendus, Vol. 94, 1882, p. 70. 



