APPLICATIONS OF THE MICEOSCOPE. 125 



nent, the great watershed between the Arctic 

 Ocean and the south ; the Asiatic chain of 

 steppes and mountains crossing that continent 

 from west to east, until it disappears on the 

 shores of the Pacific ; the chain of the Aleutian 

 Islands ; and, finally, along America from west 

 to east the watershed between the streams 

 that run to the north and south ! 



5. Along this submarine plateau, the Sound- 

 ing Apparatus of Mr. Brooke brought up " its 

 first trophies" from the bottom of the North 

 Atlantic. They were submitted to an eminent 

 Microscopist of the United States, Professor 

 Bailey of West Point. He at once expressed 

 his surprise arid delight. " The bottom of the 

 ocean," he writes to Mr. Maury, " at the depth 

 of more than two miles, I hardly hoped ever to 

 have a chance of examining ; yet, thanks to 

 Brooke's contrivance, we have it clean and free 

 from grease, so that it can at once be put under 

 the Microscope. I was greatly delighted to find 

 that all these deep soundings are filled with 

 microscopic shells; not a particle of sand or 

 gravel exists in them. . . . The results al- 

 ready obtained are of very great interest, and 



