SALMON AND TROUT CULTURE. 465 



A grating fine enough to keep the young fish within bounds 

 chokes up with rubbish in a few minutes, and is carried away 

 bodily or the water is forced into another channel ; in either 

 case the fish are liable to pass out of bounds, and they are 

 virtually lost to the original owner. The safest plan to adopt 

 in the construction of ponds is to excavate rather than to dam 

 up ; it is very much more expensive, costing as a rule between 

 eightpence and a shilling per cubic yard; but this is much more 

 than balanced by the security against unsound heads of dammed- 

 up ponds. If the soil is suitable, however, a thoroughly sound 

 * head ' is easily made, the thickness of which must depend on 

 the weight of water behind it ; but the head should in no case 

 be less than eight or ten feet through, and it is sometimes 

 necessary to make it as thick as thirty feet. The inside of 

 pond-heads should shelve off towards the centre of the pond at 

 a considerable angle, but as much depends on local circum- 

 stances, no hard and fast rule can be laid down. Camp- 

 sheathing, or planking, is necessary in some places, and brick 

 heads may have to be formed where space is limited, and where 

 a perpendicular head is required. If ponds are well made in the 

 first instance, there need be no danger of the head breaking away. 



In making ponds, it is most desirable to have the ' outlets ' 

 very capacious, so as to take off any extra water in a very wet 

 season. Ponds for business purposes should also be constructed 

 within easy distance of a railway station, and where good fresh 

 water can be obtained on the road and added at the last 

 moment. The cost and risk of removing yearling and older 

 fish are very much lessened in such a case. Per contra^ very 

 many fish are killed by the addition of unsuitable water on the 

 journey, and except in well known localities, I never allow 

 water to be added after the consignment has been sent off, pre- 

 ferring to send fewer fish in one vessel, or, which amounts to 

 the same thing, a sufficient quantity of water to last out, ?nd 

 keep the fish alive ; it is the rarest thing for any of my fish 

 to be lost on the road. 



A fish-breeder, who looks for some return for the money 

 laid out on his ' fishery,' must be able to put his hand on any 



