of the Fishery Board for Scotland. 
59 
most liberal manner done away with the cruive, and has incurred con- 
siderable expense in putting a fish-pass on the dike. Unfortunately, the 
fish-pass has been very badly constructed, with far too steep a gradient, so 
that, instead of facilitating the ascent of salmon over the high and steep 
dike on which it has been placed, it is really about the worst place in the 
whole extent of the dike for fish to surmount. This dike is in a curved 
form, and probably the best way to assist the ascent of salmon would be 
to build a short subsidiary dam, about 4 feet high, below the main dam 
across the curve, which is on the right bank of the river. 
'Between Dornoch dike and Strathallan there are mill-dams at 
Colquhalzie and Millearn, neither of which have fish-passes. But they 
are not very serious obstructions when the river is in such a state as to 
induce salmon to run. Still the fact remains that in about fifteen miles 
of river there are three cruise dikes — all of them steep and lofty — and 
two mill-dams. 
I have the honour to be, 
Your obedient Servant, 
ARCHd. young. 
The Fishery Board for Scotland. 
NOTE VIII. 
THE M 'DONALD FISH WAY UNSUITABLE FOR SCOTCH 
RIVERS. 
The McDonald Fishways at Ashbank and Westfield Dam Dykes, on 
the River Ericht, give ample proof that until some plan be devised for 
keeping sand and gravel from entering the tubes, they are totally 
unsuited for the mountain streams of Scotland. The construction of the 
M'Donald Fishway is a long square-made spout, made of strong planking 
with two floors or decks. The under floor or deck being filled with 
square wooden tubes running from the left side of the spout to the right 
side in a direction slanting downwards, so that the lower end of the tubes 
strike the right side of the spout several feet lower down. The lower 
end of the tube then turns upwards, and the water which has acquired 
considerable force by this time is delivered in an upward direction on to 
the top floor or upper deck (which is the deck the salmon pass over), 
where it strikes against the water coming down the upper deck, the meeting 
of the opposing currents causing the water to remain slack, thus allowing 
the salmon to pass up. Four or five of the tubes at the top of the 
fishway are filled directly from the river, and the remaining tubes all 
the way down are filled by the water from the upper deck, the water 
being caught by a sort of flange at the top of each tube. The w T ater 
thus caught runs down the tube in the lower deck, and is again thrown in an 
upward direction on to the upper deck, and this is repeated all the way down. 
Now what inevitably happens in these tubes is this. Whenever a spate 
comes, be it large or small, a lot of sand and gravel is hurled down the 
streams into and over the fishway, finding its way into these tubes, passing 
along them right enough until it reaches the lower end of the tube at the 
elbow or upward turn. Layer after layer of sand and gravel whirl about 
in the corner (the strength of the water although considerable, being 
unable to throw the sand and gravel on to the upper deck) until it 
ultimately gets filled up, and the tube gradually gets filled up. The How of 
