128 BULLETIN OF THE 



The following are the principal experiments which have been recorded 

 regarding the solvent action of sea-water on corals. According to Mr. 

 Robert Irwine,^ dead or rotten coral of several species of Porites, exposed 

 to sea-water of 1.0265 specific gravity, and of a temperature of from 

 70® to 80° Fahrenheit, was found to be soluble to the extent of 5 to 20 

 ounces to the ton. We have no data to show how far this capacity of 

 solution is in excess of the deposition of limestone due to the corals 

 themselves, or to the sand and debris carried into the lagoons or the 

 inner part of the reefs. No observations have been made regarding the 

 amount of carbonate of lime existing in lagoons, and in the sea-water on 

 the sea face of a reef. 



Mr. W. G. Reid, in a paper read before the Royal Society of Edin- 

 burgh, February 6, 1888, observed that the solubility of carbonate of 

 lime increased with pressure. 



Mr. James G. Ross ^ detailed in " Nature " other experiments show- 

 ing a considerable amount of solution. In a species of Oculina 0.0748 

 gramme was lost, from a specimen weighing 16.3164 grammes, in twenty 

 days. In another case, 0.1497 gramme was lost in thirty days by a 

 mass of Madrepora weighing 15.334 grammes. The above experi- 

 ments would both indicate the possibility of a very material deepening 

 of a lagoon by the solution of the coral. At such a rate of solution, 

 a lagoon four miles in diameter might be deepened one fathom in a 

 century. 



The rotten condition of the old shore reef of Havana,^ completely 

 honeycombed as it is, shows how rapidly limestone is acted upon by 

 sea-water. The rotten reef rock of the Everglades, soaked by brackish 

 water, which is often accumulated in large bodies behind the old reef 

 ranges, has been described by Professor Agassiz. This water, saturated 

 with carbonate of lime, often rushes out with considerable volume after 

 a storm, and produces great havoc with the shore fishes of the adjoining 

 reef. Their dead bodies often line the shores of the Florida reefs for 

 miles, when there has been such an outburst of water saturated with 

 carbonic acid. The existence off shore of bands of sea-water similarly 

 saturated with carbonic acid may explain the great destruction of fishes 

 which so often takes place in fishing vessels carrying their catch from 

 the Florida Reef to Havana. It will have been noticed by all who have 

 ever seen a coral sand beach, or a breccia beach, or a beach composed 



1 Nature, March 15, 1888, p. 461. 



2 Nature, March 15, 1888, p. 462. 



8 See Three Cruises of the Blake, Fig. B, p. xii. 



