[r-t] Double Grandsire Doubles

[Don Morrison]

2009/3/25 Simon Humphrey <sh at keystrata.co.uk>:
> An old friend of mine alleges that many years ago I gave him some extents of Double Grandsire Doubles.
>
> Even if this is true, I’ve no record or recollection of what the callings were.
>
> Are there any extant extents in this method, using normal and/or reverse Grandsire bobs and singles?  Or even 240’s?  I’m aware of Don Morrison’s 480’s.

An exhaustive search, which is even feasible by hand, pretty quickly
confirms that a true extent with the usual Grandsire bobs and singles
only at the lead end is not possible. Undoubtedly a less brute force,
clever proof is also possible.

I believe Eddie Martin worked out some clever extents using half-lead
calls, which it appears were published in _The Ringing World_: 1984,
p721; and 1992, p1126. I also appears a pair of 240s, I don't know
using what types of calls, by Albert Pitman, were published in 1958,
p499. I don't have ready access to any of those RWs right now, but I
hope someone who does will post the figures for these callings to this
list.




-- 
Don Morrison <dfm at ringing.org>
"The first of April is the day we remember what we are the other
364 days of the year."                               -- Mark Twain