702 THE POPULAR SCIENCE MONTHLY. 



echinoderms, moUusks, and crustaceans. The observations of these 

 educated naturalists are familiar to the readers of the " Transactions " 

 of the German zoological societies. For a long time the discoveries 

 of this large party of expert collectors were thus freely contributed to 

 the various scientific publications of Germany and Great Britain, But 

 in 1873 Herr GodefFroy commenced the Journal of the Museum Godef- 

 froy, a thick quarto issued in four yearly parts. This journal contains 

 the elaborate report of distinguished naturalists on the series of speci- 

 mens submitted to them. Thus Milne Edwards, of the Garden of Plants 

 at Paris, has described the crustaceans ; and Liitken, of Copenhagen 

 University, the echinoderms ; and Dr. Giinther, the celebrated ichthy- 

 ologist of the British Museum, the fishes. The Journal is profusely 

 illustrated with colored cuts, and takes high rank for its beauty and 

 scientific value. 



Such is the remarkable Museum Godeffroy. As a storehouse of 

 material for the benefit of working naturalists it stands unique ; and 

 as an auxiliary to the purest, highest research, it is one of the signs of 

 the times that wealth is not absorbed in material interests ; that com- 

 merce counts it an honor to contribute to original investigation. May 

 the number of such men increase, and such institutions multiply ! 



-- 



THE POLAE GLACIEES. 



By C. C. MEEEIMAN. 



THE centre of gravity of the earth is the centre of the sphere formed 

 by the surface of the oceans ; or rather, owing to the flattening 

 of the earth at the poles, it is a point equally distant, in opposite 

 directions, from the level of the sea. The waters, being free to move, 

 must of necessity conform themselves to this equidistance from the 

 gravitating centre of the whole mass. Inasmuch, then, as any plane 

 which cuts the earth into two parts through its centre of gravity must 

 equally divide the weight of the whole earth, it follows also that the 

 same plane would exactly bisect the great sphei-oid of the oceans. In 

 each hemisphere the sea-level in all corresponding parts would be at 

 the same distance from this centre ; and whatever land and mountains 

 there might be above the ocean in one half would have to be counter- 

 balanced by land, or an excess of weight of some sort, in the other 

 half. And this counterpoising weight must itself rise above the level 

 of the sea, unless we say that one side of the world is composed of 

 heavier materials than tlie other, of which there is not the least evi- 

 dence or probability. 



If the plane thus dividing the earth be that of its equator, there 

 will be found in the northern hemisphere about 44,000,000 square miles 



