Thanks for the info, Miles and Ron.

My rule does have the "traditional" scales on the lower stator, which
seems like a waste, the space could have been used for a couple more log
log scales.

This rule seems like a bit of an oddity, being simplex but having *some*
log log scales. Who was it marketed for?

By the way, I haven't been able to track down the book by Peter Hopps
that was mentioned, could someone please let my know the title and
publisher?

Thanks,
Keith