of the Fishery Board for Scotland. 
61 
NOTE X. 
MALLOCH'S PATENT AUTOMATIC FISH PASS. 
' My invention has for its object to make automatic fish passes, to be 
placed or built at dikes, weirs, or natural falls on rivers or streams. 
Figure 1 on the sheet of drawings is a section through the pass when 
the sluice is shut. Figure 2 is an elevation of the lower end of pass. 
Figure 3 is a perspective view of the pass when the sluice is open. 
The pass to be 6 feet wide and 3 feet deep at the lower end, or more 
according to the depth of water in the stream, boarded on the top and 
sides A with planking. 
The sides of pass to be fitted into the dike D and securely fixed, and 
also into the natural bed of the river B. The pass to be strongly bound 
together with angle iron R bolted through the planking, and the pass 
besides being securely fitted into the dike, to be strongly bound with iron 
straps V bolted into the stonework of dike. The lower portion of the 
pass to extend down the stream to the distance shown on drawings or 
further if found necessary. 
A beam C to be placed across the mouth of the pass, fitted into the 
natural bed, but kept sufficiently high that not less than 7 inches of 
water will be kept inside the pass when the sluice is open, where this can- 
not be done the natural bed of the pass to be dug out to a sufficient 
depth. 
A sluice S to be put across the bottom of the pass of the dimensions 
shown, made of planking bolted together with iron rods having screws and 
nuts on ends. The sluice to be let into grooves in two upright posts P, 
which will be firmly fixed into the bed of the stream having cross beam 
at bottom of each and struts from same to posts. 
A cross beam K connecting the two upright posts at top and forming 
rest for three strong iron pulleys L and chains connected to loops at ends 
of iron plates F bolted to the sluice. 
The chains to be passed over the pulleys and attached to iron straps 
binding trough T on opposite side of pulleys from sluice. This trough 
to be made sufficiently heavy to almost lift the sluice when no water is 
pressing against it. 
A 2-inch metal pipe M to be placed at the top of the fall let into the 
water and carried down the pass and up the side of upright post and have 
a spigot at end J turned down over end of trough. The top of trough 
being lower than inlet at top of fall the water will pass through this pipe 
and fill the trough. 
When the trough is about filled it will be sufficiently heavy to raise 
the sluice from the water, and will itself fall down on the top of the pass 
to the position shown on the perspective view. To prevent a too sudden 
fall of the trough on the pass, spiral springs Q, one on each post, are fixed 
in the top of the grooves for the sluice striking against. The water supply 
to trough falling on slanting iron scoop N attached to post, will then be 
thrown over the trough and pass into the stream and the water in the pass 
will have a clear run through it. The water in the trough will gradually 
run out through a small spigot 0 in the end of trough at the bottom of 
same. When the trough is about empty the sluice will again fall down 
and dam back the water in the pass and thus fill it, and all fish that are 
inside will escape over the fall to the upper reaches of the stream or river. 
The supply pipe to trough is much larger than the spigot for emptying 
