BOOK VIII. XVII. 4-7 



the flow is very abundant, since the quantity of 

 water which hes below the level of the sea is only 

 forced out by the greater violence of the fresh sea 

 water rushing in. Many people think that in the 5 

 sides of ponds of this kind deep recesses and winding 

 caves should be constructed for the fishes, so that 

 there may be shadier places of retreat for them when 

 they feel the heat. But if a change of sea water is 

 not continually passing through the pond, the result 

 is to cause a contrary condition, for lurking-places of 

 this kind do not easily admit a change of water and 

 only with difficulty get rid of the stale water, and 

 more harm results from the putrid water than bene- 

 fit from the shade. There ought, however, to be 6 

 excavated in the sides of the pond what may be de- 

 scribed as a series of similar cells which may serve to 

 protect the fish when they want to avoid the heat of 

 the sun and yet at the same time let the water, which 

 they have received, easily flow out again. It will be 

 well to remember that gratings made of brass with 

 small holes should be fixed in front of the channels 

 through which the fish-pond pours out its waters, to 

 prevent the fish from escaping. If space allows, it 

 will not be amiss to place in various parts of the pond 

 rocks from the sea-shore, especially those which are 

 covered with bunches of sea-weed * and, as far as the 

 wit of man can contrive, to represent the appearance 

 of the sea, so that, though they are prisoners, the fish 

 may feel their captivity as little as possible. 



Having arranged " stalls " for them on this 7 

 principle, we shall introduce our " water flock " into 

 it, and it should be our prime concern to recall also in 

 our dealings with rivers the advice given for our 

 business with dry land : " And consider well what every 



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