XCVI 



details of which will be given in another connection. 



5, indicates a frame, enclosing the end of the dis- 

 charge pipe leading from the pond ; and provided with 

 screens, s. s. 5., the purpose of which will be indicated 

 hereafter. 



C, is the "collector," into which the fish are drawn by 

 the lowering of the water in the pond ; and c a valve, 

 which controls the flow of the water through the dis- 

 charge pipe, m. 



Z>, indicates the position and direction of a wide, shal- 

 low drain at the bottom of the pond ; having smaller 

 drains, d. d. d. d., by means of which all of the water is- 

 led into the collector when the pond is being emptied. 



£!, represents the embankments ; which are about six 

 feet in height at the angle of the pond, the lowest part 

 of the meadow gradually lessening with the ascent of 

 the land until they are lost in the higher ground. 



In the next plate the upper portion presents a longitu- 

 dinal section of the pond. The lower part of the plate 

 shows a portion of the same section enlarged, so that 

 with the horizontal projections the position and detail 

 arrangements of the pond are clearly illustrated. The 

 fish are readily drawn into the collector 0. A long han- 

 dle hook for removing the planks ^, g, g, is shown at h. 



As already stated, the "overflow," indicated at 0, 

 is perhaps the most important point to be considered, 

 and especial attention is therefore directed to its con- 

 struction. By way of precaution this outlet is loca- 

 ted in the solid ground at the side of the pond, rather 

 than in any part of the embankment, which might be 

 weakened by its presence ; and is protected by three wire- 

 cloth screens of varying texture, the coarser mesh being 

 placed farthest in the pond in order to collect all drift, and 

 thus prevent the clogging of the second and third screens, 

 the meshes of which should be fine enough to preclude the 

 escape of the smallest fish. It will also be observed that 

 the screens are so placed as to present a considerable 



