Royal Society. 233 



the 3rd of December, when in the Channel oHPortland Head, about 

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

 a just perceptible turbidness being produced. 



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

 joining 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 specimen 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 

 carbonate 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 Port- 

 land Head, about fifteen miles, yielded on evaporation and resolu- 

 tion of the saline matter only a very minute residue, about '4 only 

 per 1 0,000; it consisted in part of carbonate and in part of sulphate 

 of lime. 



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 impregni»ted with carbonic acid 

 on cliffs 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 the oeconomy 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 

 suffer 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 



