830 



What may be inferred from these results ? 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 nota- 

 ble proportion, it is in consequence 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 de- 

 stitute of calcareous rock, on which, in certain situations, sandstone 

 is now forming by the deposition from sea-water of carbonate of lime. 



Should these inferences be confirmed by more extensive inquiry, 

 they will harmonize well with the facts first referred to, the solvent 

 power, on one hand, of sea-water impregnated with carbonic acid 

 on cliff's of calcareous rock in situations not favourable to the dis- 

 engagement of carbonic acid gas; and the deposition, on the other 

 hand, of carbonate of lime to perform the part of a cement on sand, 

 converting it into sandstone, in warm shallows, where the waves 

 break under circumstances, such as these are, favourable to the dis- 

 engagement of this gas ; and, I hardly need add, that the same in- 

 ferences will accord well with what may be supposed to be the re- 

 quirements of organization, in the instances of all those living things 

 inhabiting the sea, into the hard parts of which carbonate of lime 

 enters as an element. 



Apart from theoeconomy of nature, the subject under considera- 

 tion is not without interest in another relation, — I allude to steam 

 navigation. The boilers of sea-going steam-vessels are liable to 

 suff'er from an incrustation of solid matter firmly adhering and with 

 difficulty detached, liable to be formed on their inside, owing to a 

 deposition which takes place from the salt water used for the pro- 

 duction of steam. On one occasion that I examined a portion of 

 such an incrustation taken from the boiler of the "'Conway," a ves- 

 sel belonging to the West Indian Steam Packet Company, I found 

 it to consist principally of sulphate of lime, and to contain a small 

 proportion only of carbonate of lime. This vessel had been em- 

 ployed previously in transatlantic voyages, and also in intercolonial 

 ones, plying between Bermudas and the Island of St. Thomas, and 

 in the Caribbean sea and the Gulf of Mexico. 



The composition of this incrustation, like the preceding results 

 would seem to denote, if any satisfactory inference may be drawn 

 from it, that carbonate of lime is in small proportion in deep water 

 distant from land, and that sulphate of lime is commonly more 

 abundant. The results of a few trials I have made, whilst rather 

 confirmatory of this conclusion, showed marked differences as to the 

 proportion of sulphate of lime in sea-water in diff'erent situations. 

 That from Carlisle Bay was found to contain ll'S per 10,000. A 

 specimen taken up in lat. 29° 19' and long. 50" 45', yielded about 

 2 per 10,000, with a trace of carbonate of lime. A specimen taken 

 up off Fayal yielded about 9 per 10,000, also with a trace of car- 

 bonate of lime. One taken up off Portland Head, about fifteen miles 



