FOR PLEASURE AND PROFIT. 107 



yards in depth at deepest part ; and this would mean that, in 

 the case of a pond two yards deep, the dam ought to be six 

 yards, at least, across at foot and one yard at crown. . . . 

 The weakest part of ail ponds is tho foot of the dam, and par- 

 ticularly at the foot of the outlet. The outlet upright " (I 

 have termed this outlet the controlling sluice in the chapter 

 on screens and sluices) " ought, therefore, to be at least two 

 feet loaiger than the depth of the pond, and to be sunk below 

 the level of the foot of the dam. The weak point at the foot 

 of the dam may be overcome by removing (before beginning to 

 build the dam) the turf over the whole width and length of the 

 ground occupied by the dam, the turf to be ladd back and 

 .afterwards to be used for covering the face of the dam. . . . 

 Every barrowful of earth carted must be carefully and tho- 

 roughly stamped down. When the dam is finished water 

 ought not to be turned on for three months, the dam to bb 

 allowed to settle and all damage by moles, rats, etc., to b< 

 made good before water is let in, which even, then has to bfl 

 done very gradually. It will be seen that making even a low 

 retaining dam is not a job to be easily undertaken, and it will 

 pay to call in at the outset professional help from a practical 

 dani-builder." I quite endorse Herr JafiVs opinions, and have 

 nothing to add to them, only that, where possible, a dam built 

 entirely from turfs, as I recommend in another chapter, is to 

 be preferred even to plain earth; but the turfs should be 

 cut with plenty of soil attached to them. 



Before describing Mr. Malloch's designs for fish-passes, it is 

 necessary that I should show you two others of his. These are 

 the important pass on the river Earn (Perthshire), at Dupplin 

 Dyke, and the Luiicarty pass (Perthshire). In ths former case 

 an enormous number of salmon used annually to assemble in 

 the water below the dyke, where it formed an impassable 

 barrier. By-the-bye, this water is well known to at least 

 some of my readers as the famous salmon and sea-trout fish- 

 ery rented by Mr. Wynne Corrie, brother of Mr. E. Valentine 

 Corrie, the fish-culturist of Winchester. By the erection of 

 the pass many miles of additional water on the Earn are now 



