98 U. S. BUREAU OF FISHERIES. 



a pipe 7, which runs along the underside of the bottom to its center 5, 

 where it connects with an aperture in the bottom 2. A discharge 

 leg 9 is shown passing through the bottom % to the container 10^ 

 terminating in the space beneath the bottom of the container already 

 referred to. At the point in the container at which it is desired to 

 establish the normal water level one or more small holes 11 are 

 drilled through the intake leg 6 of the siphon. 



In use the container 1 is filled with water to the desired level, 

 which corresponds with the small holes 11 in the intake leg 6 of the 

 siphon. Under these conditions the siphon will remain inoperative 

 and the water level constant. If the water level rises, however, be- 

 cause of the melting of ice that may be packed in the neck of the con- 

 tainer, or for any other cause, so that the top 5 of the siphon becomes 

 submerged, the siphon will automatically function and will draw 

 water through the opening 8 in the bottom of the container and dis- 

 charge it through the discharge leg 9 of the siphon. This action will 

 continue until the water level within the container falls sufficiently to 

 uncover the small openings 11 in the intake leg 6 of the siphon, where- 

 upon the air that will pass into the siphon through, the holes 11 Avill 

 immediately stop its action. This arrangement provides a very strong 

 suction at the intake end and will be found sufficient to draw off the 

 greater part of the pollution that has settled at the bottom of the 

 container. 



The siphon may be caused to function regardless of the water level 

 whenever it is desired to remove polluting matter by simply tilting 

 the container so that the siphon is entirely submerged and tilting it 

 back again when the desired result has been accomplished, after 

 which water may be added to reestablish the desired normal level. 

 The siphon arrangement will also make it impossible for the con- 

 tainer to be filled too full, since the siphon will function as soon as 

 its top J becomes submerged and will automatically reduce the water 

 level to the desired normal. 



A modification of the arrangement of the siphon of A (fig. 5) is 

 shown in G (fig. 5), in which the entire siphon with the exception of 

 the end 12 of the discharge leg 9 is located within the container, the 

 extension 7 of the intake leg 6 being shown positioned within the 

 container. This extension 7 may be made of rubber or other flexible 

 material, so that it may be moved or may fall by gravity to the lower- 

 most part of the container or that portion of the container from 

 which it is desired to remove sediment. The intake end of this 

 siphon may be covered with a strainer 13 if desired to prevent small 

 fish or fish eggs from being siphoned out. 



A further modification is shown by Z> (fig. 5). In this instance 

 the siphon is not perforated at the desired water level, the small 

 openings 11 being omitted. The discharge leg 9 of the siphon instead 

 of terminating below the bottom of the container passes through the 

 body of the container, terminating on the outside of the container 

 at a point that corresponds with the desired level of the water within 

 the container. 



A covenient and improved form of receptacle for ice is illustrated 

 by E (fig. 5), wherein a simple perforated pan is shown securely and 

 conveniently mounted in the upper end of an ordinary can. The 

 shape, of course, may be modified to adapt it to any type of container. 



