Growth^ and Habits of Coral Zoophytes. 49 



in other animals belong to polyps ; for this function, as we 

 have remarked, is the lowest attribute of vitality. 



Neither is it at all necessary to inquire whether the lime 

 in sea-water exists as carbonate or sulphate, or whether 

 chloride of calcium takes the place of these. The powers of 

 life may make from the elements present whatever results 

 the functions of the animal require.* 



Various waters were collected in the vicinity of the coral 

 islands, and at different distances from them, for the purpose 

 of analysis, in order to compare the constitution of the sea 

 in different parts ; but they were lost with the Peacock on 

 the bar of the Columbia river. The proportion of lime salts 

 which occurs in the water of the ocean is about ^ to gV ^^ 

 all the ingi'edients in solution. Professor Forchammer has 

 ascertained that around the West Indian seas, where corals 

 abound, lime is not as abundant as elsewhere in the ocean, 

 the proportion, according to five analyses, being 247 to 

 10,000 ; while in the Kattegat, where the rivers of the Baltic 

 carry it in considerable quantities, the proportion, from four 

 analyses, is 371 to 10,000. t Schweitzer obtained the follow- 

 ing results in water taken from the British Channel \% — 

 Water 964-74 grains ; chloride of sodium, 2706 ; chloride of 

 potassium, 0*77 ; chloride of magnesium, 3*67 ; bromide of 

 magnesium, 003 ; sulphate of magnesia, 2*29 ; sulphate of 

 lime, 1-41; carbonate of lime, 0-03=1000-00. 



Recently Dr G. Wilson has detected fluorine in sea- water, 



• If a 4rop of sea-water be slowly evaporated under a microscope of high power, 

 crystals of selenite (sulphate of lime) are produced, having the most common 

 forma presented by native crystals of this mineral, as stated in works on minera- 

 logy. On adding more water, they are again dissolved; and this may be 

 repeated indefinitely. These results would seem to indicate that the lime was 

 mostly in the state of a sulphate. Mr Darwin states the remarkable fact, de- 

 scribed by Mr Webster (Voyage of the Chanticleer, ii., 319), that a deposit of 

 salt and gypsum two feet thick occurs on the shores of Ascension, which was 

 formed by the dash of the waves. Beautiful crystals of selenite were obtained 

 by the writer in logs of half decomposed wood in the shore cliffs near Callao, 

 which were of similar origin. 



t On Comparative Analytical Researches on Sea-Water, by Prof. Forcham- 

 mer, Rep. Brit. Assoc, for 1846, p. 90. 



X Lond. and Ed. Phil. Mag. for July -1839, xv., 61 j Amer. Jour. Sci.^ 

 xxxviii., 12. 



VOL. LII. NO. cm. — JANUARY 1852. D 



