This article "The History of Musical Tuning and Temperament during the Classical and Romantic Periods" is useful and has a reference section for other articles/books
THanks so much for this and also the reference to a better version of Dr Burney's text.
The paper on classical tuning is particularly interesting on issues of pitch, which clarifies issues of the discrepancies between pitches A415 A425 A432 A435 A440 and A553 or so that one encounters and about which concert pianists argue annoyingly! It also deals with the longevity of Meantone but ignores a Third Way, intentionally or otherwise ducking the issue. This was, commonly now known as "Well Temperament" after the title of the "Wohltemperiert Klavier".
What did this mean? According to the 1950s edition of Grove, in contrast to Meantone in which, as explained by the paper, four major and minor keys were impossible, all keys could be accessed with equal facility and thus giving rise to the concept of Equal Temperament even if some keys were tuned better than others . . .
It's this with which I have had the facility to experiment during the past decade with the assistance of many performers on the piano. Jorgensen is adament that so-called Unequal Temperament was universal up to the death of Chopin in 1849, so making modern performances in equal temperament incomplete of clues to musicianship and performance, and the repertoire performed experimentally from past this time suggests that differences between keys, invisible inaudible in modern equal temperament, were expected to be heard in romantic music well after this time.
For the accompaniment of singers requiring semitonal transpositional shifts for vocal comfort, whether in Church or the drawing room for entertaining songs, the new equal temperament may well have suited the purposes of popular music - but for "high art", it is apparent from the compositions that differences between keys provided expected variation, colour and were expected to be heard.
Certainly Liszt works well with unequal temperament, Schubert too, and Schumann can be heard with http://www.youtube.com/watch?v=Wd0o7qzIGz8http://www.youtube.com/watch?v=c2EtSaqEzI0http://www.youtube.com/watch?v=c8PXv5h1hwI
Brahms may well be on the cusp but moving forward Debussy works curiously well:http://www.youtube.com/watch?v=GdFXGkqE-MMhttp://www.youtube.com/watch?v=SthGamF8qIQhttp://www.youtube.com/watch?v=NXVShKy0LP4
The question is "What temperment". Harpsichord and Fortepiano magazine last year ran an article explaining that Vallotti was extensive through time and place throughout Europe whilst to my ears it's not strong enough. Jorgensen recommended variations of Werkmeister III as does a piano tuner or two in USA. A commentator on http://www.youtube.com/watch?v=dHOcCLvUeH4
suggests 1/6 comma Meantone whilst Villefranche organ http://www.youtube.com/watch?v=UwoglLif3ps
is pleasant and has the characteristics of increasing colour of keys proportional to numbers of sharps or flats that I'd expect . . . but that tuning system is probably neither . . .