322 Dr Davy on Carbonate of Lime 



from the shore, the water deep blue, as it always is out of 

 soundings ; in all these instances, likewise, the results were 

 negative ; the transparency of the water was nowise impaired 

 by the test applied. The last trial was made on the 3d of 

 December, when in the channel off Portland Head about 

 fifteen miles ; now, slight traces of carbonate of lime were 

 obtained, a just perceptible turbiduess being produced. 



The sea-water from Carlisle Bay, the shore of which and 

 the adjoining coast are calcareous, yielded about 1 per 

 10,000 of carbonate of lime, after evaporation of the water to 

 dryness, and the resolution of the saline matter. A speci- 

 men of water taken up on the voyage off the volcanic island 

 of Fayal, about a mile from land, yielded a residue which 

 consisted chiefly of sulphate of lime, with a very little car- 

 bonate of lime, — a mere trace ; acted on by an acid, it gave 

 off only a very few minute air-bubbles. A specimen taken 

 up off Portland Head about fifteen miles, yielded an evapo- 

 ration and resolution of the saline matter only a very minute 

 residue, about 4 only per 10,000 ; it consisted in part of 

 carbonate, and in part of sulphate of lime. 



What may be inferred from these results 1 Do they not 

 tend to prove that carbonate of lime, except in very minute 

 proportion, does not belong to water of the ocean at any 

 great distance from land ? And, further, do they not favour 

 the inference, that, when in notable proportion, it is in conse- 

 quence of proximity to land, and of land the shores of which 

 are formed chiefly of calcareous rock ? In using the word 

 proximity, I would not limit the distance implied to a few 

 miles, but rather to fifty or a hundred, as I am acquainted 

 with shores consisting of volcanic islands in the Caribbean 

 Sea, destitute of calcareous rock, on which, in certain situa- 

 tions, sandstone is now forming by the deposition from the 

 sea-water of carbonate of lime. 



Should these inferences be confirmed by more extensive 

 inquiry, they will harmonise well with the facts first referred 

 to, the solvent power, on one hand, of sea-water impreg- 

 nated with carbonic acid, on cliffs of calcareous rock, in 

 situations not favourable to the disengagement of carbonic 



