On Spec

A couple of days ago I wrote that, based on the serial number, the date of this instrument was probably very early in the Trayser firm's output, e.g. in the 1850's.  This evening I looked much more closely at the paper label which identifies the builder.  The label contains facsimiles of medals from various trade shows.  The right-most medal reads "Exposition Universelle de MCCCLXVII à Paris," so the harmonium could not have been built before 1867.

Onto another topic. There was a bit of discussion about this instrument on the Harmonium Lovers group page on Facebook as I was still considering buying it.  Some of the "harmonium lovers" had requested photos from the previous owner (as had I) and had concluded that the stop pull faces were not original.  I have come to the same conclusion.

The stop pulls, from left to right are:

1. Bass coupler
2. Dulciana
3. Aeoline
4. Melodia
5. Diapason
6. Principal
7. Forte
8. Viola
9. Dolce
10. Celeste
11. Vox Humana
12. Treble coupler

There are 3 ranks of reeds, each breaking between middle e and f:

1. A 16' set, which appears to be continuous from bass through treble
2. A 4' set mounted horizontally on the bass side; then, a 4' set mounted flush on the right side
3. An 8' set, continuous from bass through treble

The stop knobs appear to be associated with the reeds in this fashion:

2. Dulciana:  opens the sourdine winding on the bass half of the 8' rank
3. Aeoline: the bass half of the 4' rank
4. Melodia: the bass half of the 16' rank
5. Diapason: full winding on the bass half of the 8' rank
6. Principal: operates a roller which activates all the stops except the "dulciana" and the "vox humana," in other words, this is a standard "grand jeu"
7. Forte: does not activate anything in the stop channels but clearly activates something below them, in the winding system. Could it be an expression mechanism?
8. Viola: full winding on the treble half of the 8' rank
9. Dolce: the treble half of the 16' rank
10. Celeste: the treble half of the 4' rank
11. Vox Humana: opens the sourdine winding on the treble half of the 8' rank; this channel also has a beater tremulant which I assume this stop also engages.

Although these instruments weren't completely standardized, my understanding is that the first four stops, moving from the center outwards, and numbered ① ② ③ ④, were standard.  These four stops were (per my understanding):

On the bass side:

④ Basson 8’
③ Clairon 4’
② Bourdon 16’
① Cor Anglais 8’

On the treble side:

① Flûte 8’

② Clarinette 16’

③ Fifre 4’

④ Hautbois 8’

And between these two outwardly radiating sets of stops, a stop labeled Ⓖ (grand jeu) and one labeled Ⓔ (Expression).

Referring to the pitches that each of the existing stop knobs activates, it's very possible that this Trayser has exactly this specification.  The twelve stop knobs, in order from left to right, could then read something like:

Bass coupler

④ 8' 

③ 4'

② 16'

① 8'

Ⓖ Grand jeu

Ⓔ Expression

① 8'

② 16'

③ 4'

④ 8'

Treble coupler

If this is so, this means I will be able to use the registrations as printed in so much harmonium music. Very exciting news!  But the question arises: do I leave the existing labels on the stop pulls? I am assuming I will not be able to find documentation on the original specification of this particular instrument.  Should I, nonetheless, have new stop labels made that reflect the above (actual) spec? What would be the impact on this instrument as an antique and a historical artifact?  Comments, please!