NARRATIVE OF THE CRUISE. 



Ill 



ordinary way in a bucket. Water from the bottom was collected in an instrument 

 specially constructed for the purpose. 



The Slip Water-Bottle consists essentially of 

 a brass cylinder A (fig. 39), which slides up and 

 down a metal shank B, of at least twice its length. 

 When the water-bottle is sent down, the cylinder 

 is fixed in the upper part of the shank ; and 

 when it arrives at the bottom it is released and 

 falls down to the lower part, where it rests on the 

 lower of two accurately ground valves C and D, 

 which fit into two conical surfaces on the inside 

 of its upper and under edges. Thus the water 

 which surrounds the shank at the moment of slip- 

 ping is securely enclosed. The proper working 

 of the instrument is dependent on the shank 

 remaining straight ; any bend in it would cause 

 the valves to leak. In the instrument used in 

 the German North Sea Expedition 1 this was pro- 

 vided for by the two valves being connected by 

 a short iron rod, and the upper valve with the 

 slipping arrangement by means of four slighter 

 ones. But for deep soundings, where it is attached 

 to a line along with a weight of three and often 



lir 



four hundredweight, greater strength is necessary 

 to enable it to withstand the knocks to which, 

 even with the utmost care, it is exposed, in being 

 hoisted over the ship's side in a sea-way. Mr. 

 Milne of Edinburgh, into whose hands the con- 

 struction of the instrument was put, secured 

 this end in a way which adds equally to the 

 elegance and to the strength of the instrument. 

 The shank and valves are one solid brass casting 

 of the shape shown in the figure, the cylinder is 

 another, and the slipping arrangement E, fixed to the end of a rod F of suitable length 

 and great stoutness, is screwed into the top of the shank, the screw being secured by a 

 rivet. The water enclosed is removed by means of a tap G, passing through the lower 



Fig. 39.— The Slip Water-Bottle. 



1 Die Expedition zur physicalisch-chemischen und biologischen Untersuchung der Nordsee im Sommer 1872, 

 Berlin, 1875. 



