234 



DEPTHS OF THE OCEAN 



are absolutely correct, the cooling of the 

 solid parts of the apparatus accounts for 

 the difference of two -hundredths of a 

 degree, which is a very probable value. 

 This is an instance chosen at random 

 from a vast number of observations, and 

 proves how accurately deep-sea tem- 

 peratures can now be determined. 



V. W. Ekman has constructed an 

 apparatus to serve as a reversing 

 mechanism and a water-bottle at the 

 same time. The apparatus is made of 

 brass, and consists of a frame carrying 

 inside a cylinder pivoted on an axle at 

 the middle of the frame (see Fig. 163). 

 At either end of the cylinder there is a 

 lid, to which are attached two pairs of 

 levers fastened to the frame near the 

 axle of the cylinder. The cylinder can 

 be placed in such a position that both 

 lids are open, and it is kept in this 

 position by means of a small pin, seen 

 at the top of the frame on the right. 

 Thus adjusted the water-bottle is let 

 down into the sea. A messenger is 

 sent down after it and knocks out the 

 pin ; the cylinder is poised in such a 

 way that it turns over in the frame. 

 The levers gradually draw the lids 

 closer, and when the cylinder is wholly 

 reversed it is held fast by a catch and 

 encloses the water-sample hermetically. 

 To the side of the cylinder is attached 

 a metal sheath for holding a reversing 

 thermometer, which is consequently 

 reversed along with the water - bottle. 

 This apparatus may be fastened any- 

 where on the line, and a number of 

 them may be used at the same time, in 

 which case the messenger - release is 

 arranged in the following manner : In 

 the figure a messenger is seen hooked 

 on to a small bar underneath the water- 



' 



1 



Fig. 163. — Ekman's Reversing 

 Water-Bottle in process 

 OF being reversed, and 



SHORTLY after BEING RE- 

 LEASED. 



