Martin L referred to : > on an early canal dating from > before engineers figured out the importance of keeping water > use down by evening-up the lock heights
and > the various replacements of two > shallow locks with one deep one An example of the former, which is the opposite of the latter, is the original bottom lock at Wolverhampton This was twice the fall of the rest of the locks in the flight, and was reduced to conventional rise, with a new lock built above it, early in its life. I suspect the original lock would have been a contender for Martin C's list. David Mack
