Calcareous and siliceous

Manley HopkinsHawaii: The Past, Present, and Future of its Island-Lingdom, Londres, Longmans, 1866, p. 515.

As an auxiliary Mr. Williams argument Mr Cheever quotes the opinion of another missionary in the South sea, Mr. Williams, who puts forward a theory that the calcareous covering of marine molluscs are not necessarily secreted by the animal themselves, but suggests that they only secrete a sort of gluten, to which calcareous particles in the water adhere, and form a shell. Mr Williams had probably in his thoughts the common caddis worms found in fresh water. Mr. Cheever goes on to say :- ‘Let there be a chemical precipitation of the minute calcareous particles floating in sea-water, by any means, and there might be formed a reef-agreably to the experiment in which the passing of a stream of electric fluid through water having calcareous and siliceous particles in solution produces stone.