n convenient
reach of the performer's hands. One stop is in, the other drawn out.

[Illustration: FIG. 140.]

In Fig. 141 we see the table, etc., in cross section, with a slider out,
putting the pipes of its rank in communication with the grooves. The
same diagram shows us in section the little triangular _pallets_ which
admit air from the _wind-chest_ to the grooves; and Fig. 142 gives us an
end section of table, sliders, and wind-chest, together with the rods,
etc., connecting the key to its pallet. When the key is depressed, the
_sticker_ (a slight wooden rod) is pushed up. This rocks a _backfall_,
or pivoted lever, to which is attached the _pulldown_, a wire
penetrating the bottom of the wind-chest to the pallet. As soon as the
pallet opens, wind rushes into the groove above through the aperture in
the leather bottom, and thence to any one of the pipes of which the
slider has been drawn out. (The sliders in Fig. 142 are solid black.) It
is evident that if the sound-board is sufficiently deep from back to
front, any number of rows of pipes may be placed on it.

[Illustration: FIG. 141.]

PEDALS.

The organ pedals are connected to the pallets by an action similar to
that of the keys. The pedal stops are generally of deep tone, 32-foot
and 16-foot, as they have to sustain the bass part of the musical
harmonies. By means of _couplers_ one or more of the keyboard stops may
be linked to the pedals.

SEPARATE SOUND-BOARDS.

The keyboard of a very large organ has as many as five _manuals_, or
rows of keys. Each manual operates what is practically a separate organ
mounted on its own sound-board.

[Illustration: FIG. 142.]

[Illustration: FIG. 143.--General section of a two-manual organ.]

The manuals are arranged in steps, each slightly overhanging that
below. Taken in order from the top, they are:--(1.) _Echo organ_, of
stops of small scale and very soft tone, enclosed in a "swell-box." (2.)
_Solo organ_, of stops imitating orchestral instruments. The wonderful
"vox humana" stop also belongs to this manual. (3.) _Swell organ_,
contained in a swell-box, the front and sides of which have shutters
which can be opened and closed by the pressure of the foot on a lever,
so as to regulate the amount of sound proceeding from the pipes inside.
(4.) _Great organ_, including pipes of powerful tone. (5.) _Choir
organ_, of soft, mellow stops, often enclosed in a swell-box. We may add
to these the _pedal organ_, which ca