the common tempered organ, and the only addition to the play- 
er’s duties, is the management of certain pedals which must occa- 
sionally be pressed, when the music modulates into a different 
key. he object of these pedals is to enable one finger-key to 
open either of two or more valves. For example, if the C# (or 
Db) finger-key be pressed when the music is in the scale of one 
flat, the note wanted is C#' the leading note to D minor, (see 
the table ;) but if the music is in the scale of four flats, a differ- 
ent note, Db?, is wanted and is given by the same finger-key. 
The A finger-key opens, in the scale of C, the valve to A*, and 
the same finger-key opens, in the scale of G, the valve to the pipe 
A*. ‘These pedals are equal in number to the scales or signa- 
tures in which the organ is designed to play—each pedal belongs 
to a certain signature, and they are arranged in their natural or- 
der, as follows: 
MODULATION PEDALS, 
&e., 5b, Ab, 3b, 2b, 1p, 5, 1#, 24, 34, 4#, 5#, &c. 
By pressing any one of these pedals, the action is brought into 
such a position, that the finger-keys will act on those valves (an 
no others,) which are required in the scale to which the pedal be- 
on The act of putting down any pedal will always draw up 
any other which may be down at the time, and will detach from 
the finger-keys every valve not wanted in the scale required. 
5. 'To illustrate the practical operation of the organ, we will 
take a tune, which is entirely in one diatonic scale, as the “ Hun- 
dredth Psalm” in the key of G. On putting down the 1# pedal, 
the organ is in readiness to play. The valves of the pipes be- 
longing to the scale of G, are connected with the proper finger- 
keys, and all others are detached ; consequently, the playing of 
this composition on the euharmonic, will be the same as on the 
common organ. This however isa simple illustration, and before 
we explain a more complicated one, we must speak further of the 
plan of the instrument. 
46. As but seven, of the twelve, finger-keys are employed to 
play the diatonic scale in each key, to the remaining five finger- 
keys are brought on and attached, by the same pedal and at the 
same time, five other notes, which are set down in the table as 
“leading notes of the minor scales” and “ perfect sevenths,” and 
three others which belong to the adjoining scales. In each pedal 
will be found the following chords, viz., the tonic, the dominant, 
and subdominant—the chord of the relative minor (the sixth of 
the scale, )—the chord of the mediant (the third, )—the major chor 
of the dominant of the relative minor—and the chord of the sev- 
