CORAL REEFS. APPENDIX. 205 



accumulation taking place over the floor of the lagoon, I am 

 positive that it does not by a long way meet the case of these 

 islands. The height of the shores in the Bermudas, doubtless, 

 permits of vastly excessive destruction, and the conditions, 

 possibly, cannot be absolutely compared with what we find in 

 other coral islands. Nevertheless, I am inclined to believe 

 that the organic accumulation (sea-urchins, shells, corals, For- 

 aminifera) alone over the floor of the lagoons fully covers the 

 quantity demanded in the computation. Bourne and Wharton 

 are likewise of the opinion that the amount of accumulation is 

 in excess of that of solution ; the observations of these investi- 

 gators were made on low-land reefs, in which the special con- 

 ditions of the Bermudas were wanting. 



J. G. Ross. "Coral Formations." Nature, Mch. 15, 1888. 



Also an attempt to determine the solubility of calcium car- 

 bonate in sea-water. Mr. Ross finds that a specimen of Oculina 

 varicosa, one of the hard West Indian corals, measuring about 

 8 square inches of surface (with a weight of 16*3164 grammes) 

 lost by solution in 20 days 0'0748 gramme; and, similarly, a 

 specimen of the porous Madrepora scabrosa, from the Feejee 

 Islands, with a surface of 16 square inches, and a weight of 

 21 '8540 grammes, lost in a period of 30 days 0*1497 gramme. 

 From a circular lagoon, four miles in diameter (or with a super- 

 ficial area of some 12 J miles), it is concluded that at this 

 rate of solution there would be removed within a year 8472 

 tons. This if evenly distributed "would give a thickness of 

 half an inch covering the whole area of the lagoon." 



T. Mel lard Reade has pointed out the error in this calcula- 

 tion (Nature, Apl. 5, 1888), which assumes for the quantity of 

 lime-carbonate removed by solution 125 times that which is 

 carried by the proposition. In other words, the removal of 

 8472 tons from the floor of the lagoon in question would only 

 increase its depth (per annum) by the ?lv inch instead of one- 

 half inch. At this rate, as Mr. Reade points out, it would re- 

 quire a period of a million years to hollow out a lagoon of 60 



