xm. 



THE PHYSIOLOGY OF DEEP-SEA ' LIFE. 



I HAVE no observations of my own to present in regard to 

 the composition of sea-water. For convenient reference, the 

 interesting results of the chemists of the " Vdringen " and 

 " Challenger " are here given in a condensed form. 



As early as 1872, the chemist of the German expedition to 

 the North Sea and the Baltic, Dr. Jacobsen, successfully .ex- 

 tracted at sea the gaseous elements of sea-water. The appara- 

 tus which he used was subsequently adopted by other expedi- 

 tions, with but little modification. 



On board the Norwegian vessel, the " Voringen," Dr. Tornoe 

 employed a machine modified by Captain C. Wille, consisting of 

 a spiral tube nearly five feet in length, open at both ends, 

 through which water passes freely as the instrument is lowered. 

 When raised the ends are closed by conical valves worked by 

 screw fans, which, as in the case of the Sigsbee cuf), revolve in 

 one direction while going down, and in the opposite while 

 ascending, the valves closing in a short distance. 



The difficulty of making an analysis of gases on board a 

 small vessel is very great, though the separation of the gases 

 from the sea-water is not a hard process, and is accompHshed 

 by an apparatus not materially different from that employed 

 by Bunsen. But the modification made in this apparatus by 

 Dr. Behrens (Fig. 193) is all-important, and renders the opera- 

 tion comparatively easy. The attempt made on the " Blake " 

 with Bunsen's apparatus failed, partly from want of room, and 

 partly from my want of familiarity with the work. 



The apparatus is made up of a flask for the reception of the 

 sea-water to be tested, and of a bulb-tube connecting with the 



