462 



NATURE 



\_March 15, 1888 



animals living in it, or by coral sand carried into it by wind and 

 waves from the outer edge in the same space of time, and there- 

 fore I think the balance of evidence is in favour of Mr. Murray's 

 explanation of lagoon formation. 



Could the experiment be made, it would be a matter of 

 extreme interest to know if, and in what proportion, carbonate, 

 of lime really exists in lagoon waters, as also the proportion- 

 in the waters outside the reef, where new coral formation is 

 actively at work. 



It is quite reasonable to suppose that the dead coral so 

 dissolved in the formation of lagoons is carried out as material 

 for fresh coral growths. Robert Irvine. 



Royston, Edinburgh, March 6. 



In reference to the interesting discussion on coral formations 

 which has recently appeared in Nature, a few words from the 

 chemist's point of view may not be out of place. 



For some time past I have been endeavouring to satisfy myself 

 regarding the solubility of calcium carbonate in sea-water, and 

 with this end in view I immersed weighed pieces of dead coral 

 (dried at 212° F. till constant) in sea-water. These were pro- 

 tected by suspending them under glass bells floated in about 

 18 inches of water, and allowed to remain at rest for a known 

 length of time. The following are the results obtained : — 



First Experiment. — Oculina varicosa, from St. Thomas, West 

 Indies, weight i6*3i64 grammes, with a surface of, roughly, 

 8 square inches, lost by solution in twenty days, 0*0748 gramme. 

 Second Experiment, — Madrepora scabrosa, from Levuka, Fiji, 

 weight 21 "8540 grammes, surface of 16 square inches, lost OT497 

 gramme in thirty days. 



Third Experiment. — Montipora foliosa, ■ Amboyna, weight 

 1 5 '3334 grammes, surface of 15 square inches, lost 0*1223 

 gramme in forty-six days. 



Every care was taken that the corals should not be subjected 

 to the action of other than convection currents. The tempera- 

 ture ranged between 30° and 40° F. Specific gravity of the 

 water found less than i •026. 



Mr. W. G. Reid, in a paper communicated to the Royal 

 Society of Edinburgh, showed that the solubility of carbonate 

 of calcium increased with pressure ; and when determining the 

 percentage of CaCOs in certain soundings I found that the 

 greater the depth the less carbonate derived from surface shells 

 was present, while it is a well-known fact that in the red clay 

 or other deep-sea deposits, CaCOj almost completely, if not 

 entirely disappears, as has frequently been pointed out by Mr. 

 Murray. 



From the above considerations there can be little doubt that 

 there is considerable action going on in the waters of the ocean. 

 Take, for instance, a circular lagoon four miles in diameter ; 

 this would give a superficial area of 12J square miles. Taking 

 the results obtained in Experiment I, and applying them to this 

 imaginary case, ihen in twenty days, in absolutely still water, 

 there would be dissolved 464 tons of CaCOg, equal to 8472 tons 

 in a year. If the specific gravity of carbonate of calcium be 

 taken at 2*65, this amount would give a thickness of half an 

 inch covering the whole area of the lagoon. In other words, 

 at the same rate it would require about a century to deepen the 

 lagoon one fathom. 



These results must be, however, very much under-stated, as 

 the temperature in the coral regions is about twice what I could 

 obtain ; the sea-water is denser ; there is the action of carbonic 

 acid ga=:, COo, which is constantly being generated by decom- 

 posing organic matters, especially in these warm area=, and all 

 which would increase materially the solubility. Moreover, there 

 are the tides and currents continually replacing, or rather 

 mixing with, the denser waters. 



The coral animals in the lagoon aiv, however, constantly 

 laying down new material in the shape of CaCO^, assimilated 

 either directly from the sea or through the medium of other 

 organisms upon which they feed, or both combined. Now it 

 depends upon the excess of the one process over the other 

 whether there be an increase or decrease in the depth of the 

 lagoon. 



Growth is restricted mainly in reefs to the outer periphery, 

 leaving large spaces of coral sand in the interior to be freely 

 acted upon. In this way the coral formation increases outwards, 

 while there is a deepening of the interior, albeit this deepening 

 is very small. James G. Ross. 



14 Argyle Place, Edinburgh, March 10. 



Captain Wharton in his interesting paper satisfactorily 

 explains a condition of reef-growth previously little known and 

 but imperfectly understood. I was pleased to learn that Mr. 

 Bourne's long-expected account of Diego Garcia will soon be 

 published. His remarks concerning the directing influence of 

 currents agree closely with those of Semper ("Animal Life," 

 vol. xxxi. Internal. Sci. Ser. p. 228). Of the importance of 

 this agency there can, I think, be no doubt ; but solution is also 

 an important agency within the lagoon, and one more capable 

 of actual demonstration than the directing force of the currents. 

 But amongst the supporters of the anti-subsidence theory of 

 Murray there is a difi'erencc of opinion as to the relative im- 

 portance to be attached to solution ; and we cannot accept the 

 name of "theory of solution" for the new view if it is in- 

 tended to exclude the other agencies that previously cause the 

 death of the coral, such as the repressive influence of sand, the 

 diminished food-supply, the tidal scour, &c. W^ith this exclusive 

 meaning, the name "theory of solution" would contradict 

 itself, and we should be regarding the problem in much the same 

 light as if we were solely to contemplate the mystery of our own 

 existence from the point of view of the undertaker. 



The development of the new theory should be borne in mind. 

 Chamisso, seventy years ago, advanced the view that an atoll 

 owes its form to the growth of the corals at the margin and to 

 the repressive influence of the reef-debris in the interior ; but 

 this view gave no satisfactory explanation of the foundation of 

 such a coral reef, and Darwin was driven to his theory of sub- 

 sidence. The great defect in the view of Chamisso wcs, how- 

 ever, removed by Murray, who supplied the foundation of an 

 atoll without employing subsidence ; and investigations in the 

 Florida Sea and in the Western Pacific have confirmed his 

 conclusions. The forms of reefs he attributed to well-known 

 physical causes ; but Semper and Agassiz have dwelt upon the 

 importance of other agencies, ard in our present state of know- 

 ledge it will be wisest to combine in one view the several 

 ageucies enumerated by these three naturalists as producing the 

 difterent forms of c.ral reefs. On the outer side of a reef we 

 have the directing influence of the currents, the increased food- 

 supply, the action of the breakers. Sec. In the interior of a reef 

 we have the repressive influence of sand and sediment, the 

 boring of the numerous organisms that find a home on each coral 

 block, the solvent agency of the carbonic acid in the sea-water, 

 and the tidal scour. These are all real agencies, and we only 

 differ as to the relative importance we attach to each. Future 

 investigations will probably add others to the list, besides ascer- 

 taining the mode and degree of action of each cause. 



March 10. II. B. GUPPY. 



Reason and Language. 



The kindness of Prof. Max Miiller's reply I recognize with 

 pleasure but without surprise, since those who know him know 

 him to be as remarkable for his courtesy as his great learning. 



In answer to his first question, I must say that I made a point 

 of attending his Royal Institution lecture on the day his 

 "Science and Thought" was published, and was greatly dis- 

 appointed that illness hindered my attending the others. But I 

 immediately obtained his book, and applied myself to understand 

 what seemed to me its essence, though I have not read it from 

 cover to cover. Should I have to review it, of course I shall 

 conscientiously peruse the whole of it. 



Before replying further, it may be well to restate my position 

 as follows, 



Man is an intellectual being able to apprehend certain things 

 directly and others indirectly. Normally, his conceptions clothe 

 themselves in vocal sounds, and get so intimately connected 

 therewith, that the " word " becomes practically a single thing 

 composed of a mental and an oral element. But these elements 

 are not id-ntical, and the verbiim men tale is anterior and 

 superior to the verbum oris which it should govern and direct. 

 Abnormally, conceptions do not clothe themselves in oral ex- 

 pressions at all, but only in manual or other bodily signs, and 

 this shows that concepts may be expressed (however imperfectly), 

 in the language of gesture without speech. One consequence 

 of these relations is that neither the utterance of sounds (articu- 

 late or inarticulate) nor bodily movements could have generated 

 the intellect and reason of man, and Noire's hypothesis falls to 

 the ground. On the other hand, beings essentially intellectual, 

 but as yet without language, would immediately clothe their 



