264 ALEXANDER AGASSIZ 



given depth. With this instrument he had been unable 

 to get life at one hundred and fifty fathoms. He brought 

 on board the Albatross a net similar to that used by Dr. 

 Chun, made for the expedition by Ballauf of Washing- 

 ton. This was not found to work satisfactorily and was 

 discarded after a first attempt. But, " thanks to the in- 

 genuity of Captain Tanner," he and Agassiz between 

 them devised an arrangement known as the " Tanner " 

 net. This was so weighted that it went down bottom 

 first, thus preventing anything from getting into the 

 net on the way. It was then towed for a time at any 

 desired depth, and before being hauled to the surface a 

 messenger was sent down that released two weights 

 which tightly closed the lower part of the net, leaving 

 the upper part open, to catch specimens on the way to 

 the surface. On account of the simplicity of its construc- 

 tion and the accuracy of its action, Agassiz always con- 

 sidered this closing net far more reliable than any other 

 similar contrivance. 



The results of a very considerable use of the Tanner 

 net on this expedition led him to believe that in the open 

 ocean there is a very marked falling-off in animal life 

 below two hundred fathoms. Later experiences, though 

 they did not alter his general conclusions, would seem 

 to have somewhat extended the depth to which he be- 

 lieved life to extend. 



During his last expedition in 1907, Agassiz said, in 

 conversation, that from the results of his own investi- 

 gations he was of the opinion that in the open ocean 

 there was a great intermediate belt between the pelagic 

 fauna and the species living at or near the bottom, where 

 there was practically no life, nothing but the falling 

 bodies of dead animals. Where the results of other ob- 



