FISH COMMISSION OF THE UNITED STATES. 2G1 



drawn to the surface the temperature at the part reached can be 

 read off. 



Several methods have been devised for effecting this reversal. 

 Commander Magnagni, of the Italian Navy, and Mr. W. L. Bailey, 

 of the United States Navy, have each applied a principle which has 

 been used for various purposes in deep sea work. 



Above the case enclosing the thermometer is placed a miniature 

 propeller. As the apparatus descends this propeller does not revolve, 

 but when the apparatus is drawn up the propeller makes a certain 

 number of revolutions, and then unlocks the thermometer, which, 

 being top-heavy, turns over. 



By attaching a number of thermometers at definite points on a 

 line they may be sunk and then read off as they are again hauled 

 on board. 



Another plan of inverting the thermometers was devised inde- 

 pendently by Captain Rung, of Denmark, and by Mr. Bailey. This 

 was to send a weight or messenger down the line after the thermo- 

 meters have reached their places. When this weight reached the first 

 thermometer it caused it to turn over, and at the same time released 

 a second weight, which ran down the line and inverted the next 

 instrument, and so on throughout the series. 



For collecting samples of water for analysis the latest device is 

 Captain Sigsbee's water bottle, which has been used with perfect 

 success for several years. It consists of a brass cylinder about 1 5 

 inches long by nearly three inches in diameter, with poppet valves 

 at top and bottom, opening upwards, and connected by a central rod. 

 As the apparatus sinks the water freely enters at the bottom and 

 flows out at the top. On ascending, however, the valves close, and 

 a propeller wheel above comes into action, and soon engages with a 

 screw, which runs down upon the upper valve, seating it firmly, and 

 preventing any possibility of opening by accident during ascent. 



