150 PHILOSOPHICAL TRANSACTIONS. [aNNO 1771.- 



plain, surrounded by the finest pastures and corn fields of a rich black mould, 

 having either mild or soft springs on tlie spot, or a rivulet that runs through the 

 plain ; the water ought to be mild and soft, by no means too cold, or impreg- 

 nated with acid, calcareous, selenitic, or other mineral particles. The exposure 

 must be sheltered against the cold blasting easterly or northern winds, by a ridge 

 of hills, situated at some distance from the pond, enjoying fully the benign in- 

 fluence of the sun, far from any thick shady wood, that might intercept the 

 beams of the sun, or where the leaves of trees might cause a putrefaction, or 

 impregnate the water with astringent particles. 



Such ponds as are surrounded by poor, cold, and stiff soils, or are open to 

 the east and north winds, or have a wood on one or two sides, and hard or cold 

 water, or such as issues from mines, moors, or mosses, are inferior in goodness. 

 Ponds in a poor, dry, or sandy soil, surrounded by pines or firs, with the just- 

 mentioned inconveniencies, are considered as the worst of all. The ground to- 

 wards the pond ought to have a gentle slope: for deep valleys are subject to 

 great floods, and will then endanger the dykes in a wet rainy season, and often 

 the expectations of many years are carried away. The soil cannot be altered: it 

 is therefore a chief qualification of a pond, to be contrived in a good soil. The 

 sun is a less material article: provided therefore a pond can enjoy the morning 

 and noon-tide sun, it matters not much if the wood be on one or two of its 

 sides. The water is a material point; but in case the springs that supply the 

 ponds are very cold and hard, it may be softened and tempered by exposing it to 

 the sun and air in a large reservoir above the pond, or by leading it for a long 

 way in an open exposure, before it enters the pond. The quantity of water to 

 supply the pond with, is another requisite; too much water makes too great a 

 canal necessary for carrying its superfluity off; and this is very expensive: too 

 little water has another inconvenience, viz. that of keeping the water too long 

 ill the pond, and to cause a stagnation, without any sufiicient fresh supplies; 

 and often, in a dry season, the scantiness of fresh water distresses the lish, and 

 causes diseases and mortality among them. 



The above remarks are general, and must be applied to all kinds of ponds. 

 It is found by experience most convenient, to have 3 kinds of ponds for carp. 

 The first is called the spawning pond: the nursery is the second; and the main 

 pond is the third and largest. There are two methods for stocking the ponds 

 with carp; either to buy a few old fish, and to put them into a spawning pond; 

 or to purchase a good quantity of one year's old fry, for the nursery. A pond 

 intended for spawning, must be well cleaned of all other kinds of fish, especially 

 such as are of a rapacious nature, viz. pike, perch, eel, and trout; and also of 

 all the newts or larvae of lizards, and the dytisci or water-beetles, which fre- 

 quently destroy quantities of the fry, to the great loss of the owner. A pond 



