1867.] Mr. Warington on Alteration of Carbonate-of-Lime Waters. 1 89 



December 5, 1867. 



Dr. WILLIAM ALLEN MILLER, Treasurer arid Vice-President, 



in the Chair. 



It was announced from the Chair that the President had appointed the 

 following Members of Council to be Vice-Presidents : — 



The Treasurer, 

 Dr. Carpenter, 

 Mr. Gassiot. 



In accordance with the notice given at the last Meeting, the question of 

 Col. Le Couteur's readmission into the Society was put to the ballot, and, 

 the ballot having been taken, Col. Le Couteur was declared to be re- 

 admitted. 



The following communications were read : — 



I. On some Alterations in the Composition of Carbonate-of- 

 Lime Waters, depending on the influence of Vegetation, Animal 

 Life, and Season.^' By Robert Warington, F.R.S., F.C.S. 

 Received October 19, 1867. 



In carrying out through a series of years the principles of the aquarium 

 for sustaining animal life in a confined and limited portion of water through 

 the medium of growing vegetation *, I had observed that, during the sum- 

 mer months of the year, a considerable deposit made its appearance on the 

 leaves of the plants and the glass front of the containing vessel, which was 

 found to consist of carbonate of lime in a crystalline condition. This de- 

 posit formed a nidus for the growth of confervoid vegetation, which, at cer- 

 tain seasons of the year, increased very rapidly. These observations were 

 alluded to at one of the Friday- evening meetings of the Royal Institution, 

 March 27, 1857, when portions of the deposit were exhibited, and its com- 

 position demonstrated by experiment. 



The formation of this deposit was then explained as arising from the fact 

 that, as the summer season advances, and we have a longer continuance and 

 also a greater intensity of the light of the sun, the absorption and conse- 

 quent decomposition of carbonic acid by the plants is carried to a much 

 greater extent, while the quantity of carbonic acid produced by the fish re- 

 mains unchanged. The solvent of the carbonate of lime contained in the 

 water being thus withdrawn, a deposit slowly takes place, incrusting the 

 sides of the tank, particularly towards the light, where the confervoid 

 growth, consequent upon it, accumulates in large quantities. 



In continuing these observations, my attention was particularly arrested 

 by the steady increase of deposition, attendant upon the renewed activity of 

 the leaves, during the spring ; and this determined me to ascertain by expe- 

 riment the quantity of carbonate of Ume existent in the water at fixed 

 * Quarterly Journal of the Chemical Society, vol. iii. p. 52. 



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