14 ANNIVEHSAEY ADDHESS. 



Jackson in shallow water of a temperature below that then sup- 

 posed necessary for such growth, viz., G0° to 70°. 



Mr. Couthouy, of Boston, U.S., states that the Adreas flourish 

 best in water not over 78° F. His companion in the scientific 

 corps of the U.S. Ex. Ex. (Professor J. C. Dana) shows that 

 reef-forming corals range in water between 6<.>° and 85° F. 

 Captain Nares, if I remember rightly, snows that some corals 

 will grow in water at a temperature of less than 30° F. The value 

 of such inquiries, in a geological point of view, has been shown by 

 Dr. Duncan, Q.J.G.S. vol. xxvi, 1870. 



It may not be of much importance now to repeat the soundings 

 given in the Reports, of the various depths at which red clay, grey 

 mud, shells, grey ooze, and Globigerina ooze was found ; but from 

 Captain Wares' s tables I have calculated that the latter has a 

 mean depth in the Atlantic of 1,957 fathoms, or 11,742 feet, at a 

 mean temperature of 35*38 . The occurrence of delicate Penta- 

 crinites and other living beings at great depths refutes, however, 

 the notion that pressure prevents life, for the pressure upon these 

 creatures was so great as to_crush iron. "We may ask whether the 

 cause of resistance to the pressure is the fact that these delicate 

 animals are themselves pervious to water, or, as in the case of 

 Gloligerince, because they are also globular. At a depth of 2,500 

 fathoms the pressure amounts to eight tons to the square inch. 

 Near St. Thomas's Island the sea bottom is 3,875 fathoms below 

 the surface. "We may ask again, how can creatures whose bodily 

 surface has only one inch in extent bear even one-fourth of such 

 pressure unless the pressure from within is equal ? 



I cannot resist the temptation of quoting here a passage or 

 two from another authority on the present topic. Dr. "Wallicli 

 who was naturalist in the Expedition of 1860, under Sir L. 

 M'Clintoch, on board the " Bull Dog," surveying the telegraph 

 route between Great Britain and America, published for private 

 circulation some " Notes on the Presence of Animal Life at 

 vast depths in the Sea," and from them I take the following state- 

 ments : — " On two occasions living specimens of Serpula were 

 obtained. One at a moderate depth, the other at 080 fathoms, 



