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The third, or last pond from forty square rods to ten or more 

 acres, and from eight to twenty feet deep. The water in the 

 last pond must be deep if large trout would be grown. From 

 8,000 to 10,000 trout may be grown in the smallest pond, 

 and from 300,000 upward to 2,000,000 in the largest pond. 

 The dams for these ponds should be buUt of stone or earth, 

 to be lasting. Earth is much the cheapest. Clay will hold 

 all the water and make a permanent dam. If built of stone, 

 the cheaper way is to build a double wall, laid in quick lime, 

 with two inch space between, and fill the space with water- 

 lime grouting, which will hold the water through all time. 

 This waU should be in thickness in proportion to its height, 

 say..from four to ten feet. These dams can be built partly 

 of stone and partly of earth, as may be desired. At the 

 bottom of each of these dams there should be a flume from 

 six inches to four feet square, according to volume of water, 

 to draw off the water and fish when desired, from one pond 

 to the other ; also, to catch and assort the fish for use in the 

 lower pond, and to clear the ponds of grass and filth when 

 necessary — perhaps in from four to eight years. There must 

 also be a flume for waste water on top, with a wire screen to 

 prevent the trout from running out, or they would soon leave 

 the pond. To hold the young fry, the meshes in the screen 

 must be little larger than the head of a pin, as these young 

 trout are very tiny when the egg is absorbed, not more than 

 one to one and one-fourth inch long. The first dam must 

 be tight to keep them. The dams will cost from $50 to 

 $4000, depending upon size and quality. 



SPAWNING BEDS. 



There must be a race leading into each of the two lower 

 ponds from two to ten feet wide, and two to six rods long, 

 with descent enough to produce a gentle, rippling current. 

 The bottom must be covered two or three inches deep with 

 well washed gravel, with a nice screen at each end, to be 

 raised or closed at pleasure. These races should be so con- 



