Hi,
I just saw the following item on ebay.
item number 260704191699
link <http://cgi.ebay.co.uk/SCALING-SLIDE-RULE-ORGAN-PIPES-RENSCH-SYSTEM-RARE-/260704191699?pt=UK_MusicalInstr_Keyboard_RL&hash=item3cb32e44d3>
I guess this is used to calculate Pipe Organ scales ?
P.S can anyone recommend any books that help explain about Pipe Organ scales for a beginner ?
regards Peter B