as an Ingredient oySea' Water. 321 



the waves break, becomes consolidated, converted into sand- 

 stone, by the deposition of carbonate of lime from sea-vpater, 

 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 

 economy of nature, inasmuch as the phenomena alluded to, — 

 the one destructive, the other restorative, — have been ob- 

 served in most parts of our globe where geological inquiry 

 has been instituted. 



Reflecting on the subject, it seemed to me desirable to as- 

 certain 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 Barbadoes, in the West Indies, to Eng- 

 land, in November last (1848), I availed myself of the op- 

 portunity 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 Bar- 

 badoes, tested for carbonate of lime, gave strong indications 

 of its presence ; thus, a well-marked precipitate was produced 

 by ammonia, after the addition of muriate of ammonia in ex- 

 cess, that is, more than was sufficient to prevent the separa- 

 tion of the magnesia, which enters so largely into the compo- 

 sition of sea- water ; and a like eff"ect was produced either by 

 boiling the water, so as to expel the carbonic acid, or by eva- 

 porafion 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' 

 north, and longitude 63" 20' west, more than a hundred miles 

 from any land ; the result was negative. Further trials were 

 made on the 22d 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 



