peesident's address. 203 



siliceous deposits of organic origin are the result of Silica-secret- 

 ing creatures, which abound on the surface waters, and also ap- 

 parently in the deepest waters, of all the oceans and seas visited 

 by the "Challenger." About half way between Japan and New 

 Guinea there is a depth of 4,575 fathoms, the deepest "Chal- 

 lenger" sounding, with a bottom of Ooze, containing chiefly the 

 remains of Eadiolarians and Diatoms, and other deep sea Rhizo- 

 pods. In this sounding there was a very small amount of amor- 

 phous clayey matter, and no Carbonate of Lime organisms are 

 expressly mentioned. 



As to the E.ed-Clay deposit, conspicuously ^Ae deep-sea deposit, 

 the following analysis of a sample dried at 110°, from a sounding 

 in 3,150 fathoms, will throw much light upon it. 



Water and Organic Matter 10'40 



Silica 53-30 



Alumina 1 7 '40 



Fen-ide Oxide 11'70 



Lime ) 



,, . r in combination \yith Silica 1'35 



Magnesia J 



Carbonate of Lime 3"10 



Magnesia 1*90 



Sulphate of Lime 0"85 



100-00 



As to animal life in the deep sea, the most important question 

 is, To what depths do living creatures descend? This is not 

 capable of so simple an answer as might at first seem possible. 

 Only a net which can be sent down securely closed, and then 

 opened and towed along, and then closed again before being 

 hauled up, can give any definite and sure information on the 

 matter. Such a net is both difficult to construct and to use. 

 Mr. Alexander Agassiz has, ., however, made a few experiments 

 with such an instrument, and found, when he tried it off the 

 American coast, that the animals extended down to about 50 

 fathoms' depth, but not at all. below 100 fathoms. The problem 

 as to how far this result is one which applies generally, is the 

 most important with regard to deep-sea science now awaiting 

 solution. It is still an open question whether any of the well 



