23-2 Royal Society. 



tlie same high place in the science and literature of the world, is I 

 ara sure the anxious desire of the Royal Society. 



I have the honour to be, 

 My dear Sir, 

 Your most obedient humble Servant, 



RossE, P.R.S. 



" On Carbonate of Lime as an ingredient of Sea-water." By 

 John Davy, M.D., F.R.S. Lond. & Ed., Inspector-General of Army 

 Hospitals, &c. 



The manner in which limestone cliffs rising above deep water are 

 worn by the action of the sea, as it were by a weak acid, such as we 

 know it contains, viz. the carbonic — the manner, further, in which 

 the sand on low shores where the waves break, becomes consolidated, 

 converted into sandstone, by the deposition of carbonate of lime 

 from sea- water owing to the escape of carbonic acid gas, — are facts 

 clearly proving that carbonate of lime is as a constituent of sea- water 

 neither rare of occurrence, nor unimportant in the ceconomy of na- 

 ture, inasmuch as the phaenomena alluded to, — the one destructive, 

 the other restorative, — have been observed in most parts of our 

 globe where geological inquiry has been instituted. 



Reflecting on the subject, it seemed to me desirable to ascertain 

 whether carbonate of lime as an ingredient of sea-water is chiefly 

 confined to the proximity of coasts, or not so limited enters into 

 the composition of the ocean in its widest expanse. 



On a voyage from Barbados in the West Indies to England in 

 November last (1848), I availed myself of the opportunity to make 

 some trials to endeavour to determine this, the results of which I 

 shall now briefly relate. 



First, I may mention that water from Carlisle Bay in Barbados, 

 tested for carbonate of lime, gave strong indications of its presence ; 

 thus a well-marked piecipitate was produced by ammonia, after the 

 addition of muriate of ammonia in excess, that is, more than was 

 suflficient to prevent the separation of the magnesia which enters so 

 largely into the composition of sea-water ; and a like eff'ect was pro- 

 duced either by boiling the water so as to expel the carbonic acid, 

 or by evaporation to dryness and resolution of the soluble salts. 



On the voyage across the Atlantic, the test by means of ammonia 

 and muriate of ammonia was employed, acting on about a pint of 

 water taken from the surface. The first trial was made on the 15th 

 of November, when in latitude 20° 30' N., and longitude 63° 20' W., 

 more than a hundred miles from any land ; the result was negative. 

 Further trials were made on the 22nd of the same month in lat. 

 32° 53', long. 45° 10' ; on the 24th, in lat. 36° 23', long. 37° 21' ; on 

 the 25th, in lat. 37° 21', long. 33° 34'; on the 26th, in lat. 38° 28', 

 long. 30° 2' ; on the 27th, when off Funchal of the Western Islands, in 

 lat. 38° 32', long. 28° 40', about a mile and a half 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 



