APPARATUS. 23 



tubing without the teat filling sufficiently to work 

 the shutter. This can be somewhat counteracted 

 by unscrewing the ball and blowing into the tubing 

 as hard as possible, and immediately nipping the 

 end tight and screwing on the ball again. There 

 is then already a small pressure throughout the 

 release, and less air will have to be squeezed 

 from the ball in order to raise the lever of the 

 shutter. To the same end the entire release, ball, 

 tube, and teat may be filled with water, the tube 

 being repleted by suction. This medium admits 

 of no compression, and the release can be made to 

 respond more quickly. Water-filled tubing should 

 never be used in a tree, as the dependent weight 

 would prove too great a strain for the walls of the 

 tube, and it would part. 



If some sixty feet of tubing are purchased, it will 

 be found convenient to cut it into three irregular 

 lengths of about ten, twenty, and thirty feet, 

 having little metal screw-connections to join them 

 together, as thereby any desired length can be 

 coupled up. 



With such a peculiarly suitable release at our 

 command it would serve no good purpose to dwell 

 on others, but mention may be made of the electric 

 method whereby the returning bird may itself be 

 made to operate the shutter, by making a contact 

 between two wires, thus completing a circuit. The 



