I recently had a chance to browse the 1991 tome by Owen H. Jorgensen
on piano tunings, entitled

   "TUNING -
 Containing The Perfection of Eighteenth-Century Temperament,
 The Lost Art of Nineteenth-Century Temperament
 and the Science of Equal Temperament,
 Complete With Instructions for Aural and Electronic Tuning"

Copyright 1991 by Owen H. Jorgensen, published by Michigan State
University Press, East Lansing, Michigan 48823-5202; ISBN 0-87013-290-3

This remarkable book, comprising 768 pages describing 30 to 40 historic
temperaments, encompasses tunings and commentary from circa 1636 through
circa 1920.  This has to be the ultimate reference for any questions
regarding historic tunings.  (Jorgensen's work is incorporated in the
Sanderson AccuTuner.)  What I enjoyed most was the staff notation for
setting the bearings of each tuning.  These are quite easy to read, and
comprise three or four pages for each tuning.

My impressions were that Jorgensen has captured the technical details
of tuning historic temperaments in an excellent reference book.  His
most important points were:

1.  Composers wrote for the instruments of the day.  So if the tuning
was just, or equal, or something in between, the composers wrote,
voiced, and annotated for *that* instrument/tuning.

2.  If you want accurate reproduction of a composer's intent, you
should play the piece on his instrument, with the proper historic
tuning.

3.  Most fascinating to me was that the musical community generally
realized (though hotly debated) the need for equal temperament circa
1800, but almost a century elapsed before for aural tuning techniques
evolved which could provide reasonable accuracy.

(Note that the evolution of the method for tuning the equal temperament
was coincident with the evolution of the piano itself, especially the
scaling of the strings.  Until evenly drawn high strength wire, both
unwrapped and wrapped, was available in high quality, the inharmonicity
of the notes could not progress smoothly up and down the scale.  This,
in turn, would prevent precise tuning of the beat rates of partials.
The ultimate test of a good temperament on any piano is a smooth change
of the beat rates as progressive thirds are played -- both in the
bearings octave, and outside it.)

Each of the tuning methods in the evolution had faults which tended to
produce deviations from equal temperament.  These deviations were most
pronounced in one or two intervals of the "bearings" octave.  Different
tuning methods would favor/penalize different intervals -- though as
the procedures evolved, the errors were made progressively smaller.

John Rhodes

 [ The table of contents of the book and a sample manuscript for
 [ a specific tuning are at http://mmd.foxtail.com/Tech/  -- Robbie