ADELBERT VON CHAMISSO AS A NATURALIST. 259 



Another important subject, with the discussion of which Cha- 

 misso was associated, likewise relates to the pelagic fauna, but also 

 belongs as much to geology and physical geography as to biology. 

 It is that of the origin of the co-called sunken islands or atolls of 

 the south seas and the Indian Ocean. It has been recognized 

 from the first that these islands are the work of organic architects, 

 the coral polyps, which absorb lime from the sea-water and build 

 their oceanic castles with it. 



After Johann Reinhold's theory that the ring-walls were built 

 by the polyps from the depths of the ocean, and Henrik Steff ens's 

 hypothesis of submarine craters, came Darwin's celebrated theory, 

 which supposed that the corals were built upon a substructure 

 already existing in the ocean-bottom which gradually subsided 

 under a continuous volcanic action so as to keep the rising struct- 

 ure at about the same level ; and after that the contradiction of it 

 by Murray and Wyville Thomson, on the basis of observations 

 made during the Challenger Expedition, which pointed to a rise 

 of the substructure. Here comes in a fundamental observation 

 with which Chamisso's name has been associated, to the effect that 

 the coral animals, never moving away from the one spot to which 

 they attach themselves, need a stirring sea to bring them food, 

 oxygen, and lime. Hence an atoll will rise wherever there is a 

 suitable foundation, at not too great depth, on which the polyps 

 can fix themselves ; and as they thrive better on the edge of their 

 ring, where they are favored by wave-beats and currents than in 

 the middle, a ring- wall will rise, which should be higher, as is 

 the case, on the windward side, where the wave-motion is strong- 

 est. These facts have been put prominently forward in all the 

 discussions that have been had on the subject ; and Chamisso has 

 been credited with having been the first person who observed and 

 mentioned them. I am obliged to disclaim Chamisso's title to 

 this honor. The observation was first ascribed to Chamisso by 

 Darwin, who says, in his Coral Reefs, " The larger kinds of corals, 

 ' which form rocks measuring several fathoms in thickness,' pre- 

 fer, according to Chamisso, the most violent surfs"; and from 

 Darwin's it has passed into other works. A study of Chamisso's 

 writings will show that, while he acccurately examined and de- 

 scribed the atolls petrographically, geognostically, and zoologi- 

 cally, he never made that remark. Darwin's mistake originated 

 in his attributing to Chamisso a remark which appears at the end 

 of the third volume of Kotzebue's First Voyage (containing also 

 Chamisso's Remarks and Observations), in an Appendix from 

 other Authors, which, there is abundant evidence to show, was 

 made not by him but by Eschscholtz. 



" The coral reefs and islands of the great ocean," says Chamisso 

 in Ansichten von der Pflanzenkunde und dem Pflanzenreiche, 



