[r-t] Re: Decisions
robin at robinw.org.uk
Mon Jan 10 14:21:12 UTC 2005
In reply to Harry Poyner.
Harry does a good job pointing out the problem with describing methods by
the work they do in words. He adds yet another version to the growing list
of definitions of Cromer. All good and none unique. At least we have the
situation where place notation is a unique description of a method. This is
why I can state my belief that "...by all means use the concept of works,
but use formulae first."
In fact, none of the extensions Harry proposes are allowed. In short, since
Cromer has 5ths place at half lead, any extension MUST have either 5ths
place under the treble when it goes up from 6ths to 7ths OR have 7ths at the
half-lead. The candidates I came up with which fit this bill are:
x1x1x2x1x2x7, x1x1x2x5x2x(5 or 7), x1x1x2x1x4x7 or x1x1x2x5x4x7 and only the
second has a plain bob lead end.
Also, the concept of preservation of pivot bell, though appearing in 1953
had been abandoned as a concept by 1971.
I sent Harry, by separate copy, a copy of Roger Bailey's guidance note and
of my own 'aide-memoire' for the decisions.
Briefly, extension is like this:
Split the work into 'above' and 'below' the treble.
Sectionalise each bit of the work according to position, e.g., in Cambridge
x3x (at the start) is the 'B' section, the 3rds place forcing the treble to
5ths is 'E', etc.
Pick a place to start ('up' and 'down' independently), e.g., 'EF'
Write down the p.n. up to & including the start place.
Copy the starting point and write down the rest of the p.n. either
statically (stay same) or expand (add two).
Look at all possible extensions, produce all possible methods and check the
lead-ends - regular methods must be regular, etc.
There are, obviously, detail differences between numbers of bells and
various restrictions on starting points, adjacent places, etc, but that's
all it is! It looks much more interesting, but is more tedious to do, on the
higher numbers of bells. There's not much of a pattern on 6!
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