1869.] on the Scientific Exploration of the Deep Sea. 413 



a continuous current streams through it ; but so soon as the descent 

 is checked, either by the arrival of the apparatus at the bottom, or by 

 a stop put on the line from above, the valves fall into their places, and 

 thus enclose the water that may fill the bottle at the moment. The ex- 

 Fig. 3. 



Water-Bottle as seen at A externally, and at B in section ; drawn to a scale of one-eighth 



the actual size. 



pansion of this water and of its dissolved gases, as the bottle is brought 

 to the surface, causes a pressure from within, which lifts the upper valve so 

 as to permit the escape of whatever part of the contents of the bottle may be 

 in excess of its capacity. The interior of the bottle was coated with var- 

 nish, to prevent the chemical action of the sea-water upon it. — The work- 

 ing of this very simple apparatus was found to be entirely satisfactory. 

 Abundant evidence was obtained that, when it descended to the bottom, 

 it brought up bottom-water : thus, in the area of the " Globigerina-mud," 

 the water was slightly turbid, and deposited after a time a fine sediment 

 (which might be removed by filtration), that proved to consist almost 

 entirely of extremely minute Glohig evince. And hence it may be fairly in- 

 ferred that when its descent was checked at any intermediate point, the 



VOL. XVIII. 2 K 



