198 Foreign Literature and Science. 



on the natural history of fossil shells, has been published 

 in the present year by those able mineralogists, A. Brog- 

 niart and A. G" Desmarest. It is entitled, " Histoire natu- 

 relle des crustaces fossiles sous les rapports zoologiques et 

 geologiques ; savoir, les Trilobites, par M. A. Brongniart, 

 membre de I'institut, et les crustaces proprement dits, par 

 M. G. A. Desmabest, professeur a 1' Ecole d'A^fort, &c. 



6. ji New Journal of Natural Science has been commenced 

 at Copenhagen, under the editorship of professors OErsted, 

 Horneman, and Rheinhardt, and Dr. Bredsdorf. 



7. Color of Sea Water. — The color of the polar seas pre- 

 sents various tints from intense blue to olive green. These 

 tints do not depend on the state of the air, but solely upon 

 the quantity of water. They are divided into bands of va- 

 rious shades, in which whales are more frequently found 

 than in all other parts of the sea. It has long been thought 

 that those greenish waters take their tint from the depth 

 of the sea. Captain Scoresby however, has discovered in 

 these waters by means of a microscope, a great number of 

 spherical globules, semi-transparent, accompanied by de- 

 tached filaments similar to small locks of very fine hair. 

 These globules are^ — and _! — of an inch in diameter, 



° _ 17 2 1 7 3 _ 



and on this surface are 12 nebulosities, composed of brown- 

 ish points, in 4 or 6 pairs alternately. He considers the 

 globules as animals of the genus Medusa. The filamen- 

 tous substance is composed of parts which in their greatest 

 dimensions, are -^ — of an inch. Examined by the most 



' 1 7 1 • 



powerful lens each filament appears to be a chain of moril- 

 iform articulations, the number of which in the largest fila- 

 ment is about 300. The diameter is not more than — ! — 



17 3 



of an inch. Though these substances appeared to change 

 their aspects, captain Scoresby could not determine wheth- 

 er they were composed of living animals, having the pow- 

 er of locomotion ; but he is convinced that it is to the 

 presence of these microscopic beings that the polar seas 

 owe the various tints of green which are observed in them. 

 He calculates that one cubic foot of this water may con- 

 tain 110,592 globules of these Medusas, and a cubic mile 

 about 23,888,000 hundreds of millions. He supposes that 

 these animalculas furnish nutriment to the Actinia sepia, 



