THE CARP AND ITS CULTURE. 879 



in summer and winter. This cavity is sometimes called a " kettle," 

 though the appellation varies in different localities. 



From the entrance of the pond to the other end, where the "collector" 

 and the outlet sluice are situated, two or three ditches of 2 feet in depth 

 and 4 feet in length must be made, which cut the deeper "kettles" 

 transversely as far as the collector. These ditches are intended to carry 

 all the fishes into the collector when the pond is being drained. The 

 collector is nothing but a place of Irom 20 to 40 feet in length and 

 breadth near the outlet- si nice, 1 foot deeper than the remaining bottom 

 of the pond. In ponds of superior construction it has generally a wood 

 flooring, and must be cleaned of the mud every year, so that the fishes 

 may not become too much soiled by the mud. 



In speaking of the erection of a breeding-establishment for carp I 

 have in view a water extent of at least 35 to 70 acres area, which in 

 Central Europe would be considered an establishment of about one-third 

 magnitude. 



The inflow of water into the pond should never be allowed to be di- 

 rect; as, for instance, a brook falling into it. This often causes the 

 water to rise at an inopportune time, carrying into the pond other fishes, 

 especially the rapacious pike. The carp also has the disposition to swim 

 toward the inflowing water, by which means it is drawn away from its 

 proper feeding-places. The water should be conducted into the pond 

 sideways from the stream ; and if it should be a small brook only, it may 

 be turned off entirely and carried alongside the pond, from which point 

 the latter can be easily supplied with water. 



The inlet-sluices from the stream must of course be of a strong and 

 practical construction, so that an overflow is impossible, and they ought 

 to be provided with gratings to prevent other fishes from intruding. 



It is an indispensable condition for the culture in ponds, according to 

 established rules, that they be so constructed as to allow of being thor- 

 oughly drained, so that the fishes may be taken out without any diffi- 

 culty. The bottom of ponds should be of such a description as to permit 

 their being dried up for agricultural purposes if necessary. 



In Europe ponds of from 10 to 2,000 acres extent are frequently to be 

 found, which, after having been used for fish-culture for a time, are 

 dried up, and sometimes grass, oats, wheat, i&c, are planted on the 

 ground. This improves the soil exceedingly for fish-culture. I men- 

 tion this simply in order to show that the soil gains by this manipulation 

 not only for fish-culture but also for agriculture. If the soil at the bot- 

 tom of ponds has been freed from the humic acid by vegetation, after 

 being plowed and exposed to the air thoroughly, fishes will thrive in- 

 credibly well in them. This I intend as a suggestion particularly for 

 farmers, who would wish to establish a small pond of perhaps 5 or 6 

 acres size, to show that the soil of their land would not lose, but rather 

 gaiu by doing so. Agriculture and carp-culture go hand in hand in some 

 Central European countries and form a kind of complement to one an- 



