On the Depth ami Saltness of the Ocean. 27 



All the conclusions we have di'awn from this law of the 

 distribution of the species, and from the other circumstances 

 which, here as elsewhere, accompany the erratic pheno- 

 menon, in speaking of the basin of the Rhone, are applicable to 

 the basin of the Rhine. The identity of the general pheno- 

 mena is complete. Here also it is the law of moraines which 

 can account for this distribution — a distribution which shews 

 itself to be regular, notwithstanding the absolute mixture of 

 species, such as we must expect in a valley so complicated, 

 and subject to so many accidents, as that of the Rhine. 



Oh the Depth and Saltness of the Ocean* 



Captain Wilkes, U. S. N., to whom these subjects were re- 

 ferred at the last meeting of the Association, said, that he 

 found it impossible to make a written report upon subjects of 

 so great interest as were embraced in the inquiry referred to 

 him. From the little attention that had as yet been given to 

 inquiries on these subjects, but few facts had been elicited ; 

 he should therefore content himself by stating to the Associ- 

 ation what had been done, although it was comparatively 

 little, with the hope that the Association would be induced 

 to turn their attention to the subject as one of great interest 

 for future inquiry. He stated, that with the depth of the 

 ocean there were connected many interesting subjects of in- 

 quiry ; among them, its actual depth, its mean temperature 

 and density, the penetration of solar light, submarine cur- 

 rents, and the saltness and specific gravity of sea-water. 



Although experiments to ascertain the depth of the ocean 

 have been frequently made, we are as yet ignorant of its 

 maximum depth, and we continue to be satisfied with the con- 

 jectures and the results obtained from theory. These, as is 

 well known, vary in the limit of depth from five to eight 

 miles. 



The greatest depth to v\ hicli the ocean has been penetrated 



• Prom the Proceedings of the Ninth Annual Meeting of the American As- 

 sociation of Ueologistti and Naturalists, at IJoston, SeptcnibLT It; 17. 



