ORGAN. 
rylindric tube, of a mixture of lead and tin ; 
A B, (fig. 6) open at one end, and nearly 
closed at the other by a lump of the same 
metal, E, which is circular for about two- 
thirds round, and fits the end of the pipe ; 
the other third is a straightedge: the up- 
per edge of the conical pipe, F, is bent to 
be parallel to this, and thus forms a small 
cleft similar to the wooden one for the pas- 
sage of the air, the lower edge of the cylin- 
drical pipe, A B, is bent into the line of the 
cleft and cut sharp, to divide the current of 
air ; these pipes are open at top, and are 
brought to tune by bending the pipe at the 
top, and thus altering its bulk ; a is a piece 
of metal, called the ear, soldered upon the 
pipe at each end of the cleft, to prevent the 
stream of air being dispersed before it 
meets the sharp edge of the pipe, B A ; in 
the small pipes this is not applied. 
The bellows of the organ are double, as 
shewn in fig. 1, Plate I; that is, they are 
two distinct pairs, E,F, connected together 
at their hinge ; so that when one is opening, 
and filling with air, the other is forcing its 
air out into the regulator, D ; the bellows 
receive their motion by a rod, d, from a 
crank, a, on a spindle which comes through 
the box, in which the machine is enclosed, 
and has a handle on it by which it is turn- 
ed. The regulator, D, is exactly similar to 
another pair of bellows, and is filled with 
air from the bellows, E F, below it, through 
two valves in the bottom board over the 
bellows ; from this regulator the air pro- 
ceeds through the passage, bef, (seen bet- 
ter in the section), fig. 2, &c. 
Fig. Plate I, to a long trunk, g, go- 
ing under the pipes called the air-chest, 
which communicates rvith them by a small 
valve, h, under each it is kept shut by a 
small wire spring, and is opened by a wire 
fixed to the end of a rod, G ; above the 
valve, the passage enlarges, and goes under 
two small wooden sliders or stops, nm, 
and from thence in two distinct passages to 
the wooden and metal pipes, N M. 
The air-chest, g, is common to all the 
pipes, and each pair (of wooden and metal 
pipes) has a valve, h, and spring to them- 
selves ; the small passage above each valve 
belongs to each pair of pipes, and has no 
connection with the other ; the two stops 
belong to all the pipes ; »n, to the metal, and 
«, to the wooden ones ; they are long slips 
of wood drilled with so many holes as there 
are pipes, and at the same intervals, (the 
disposition of the pipes is shown in fig. S, 
which is a plan of the whole instrument put 
together) ; so that when the holes are over 
the passages, the air has free conimimica- 
tion from the valve to the pipes ; but when 
the stops are drawn out, the interval be- 
tween each hole applies itself to the holes 
under the pipes, and thus stops the pas- 
sages. 
We now come to describe the apparatus 
which opens the valves, h, at the proper 
time, to perform the note of a piece of mu- 
sic. 
The axle, on which the crank, «, (fig. 1,2, 
and 3) is formed, has an endless screw, o, 
(fig. 3,) cut upon it to turn a wheel, p, by 
the teeth cut in its circumference; this 
wheel is in the same piece with a cylindriC 
barrel, H H, shown separately (in fig. 4, 
Plate II) ; it has a great number of short 
pins stuck in it, which, as it revolves upon 
its pivots, catch the ends of a number of 
small levers called keys, rrr, and raise 
them ; this depresses the other, ttt, ends, 
which are attached to the rods, G, and con- 
sequently open the valves. There are as 
many of the levers, or keys, as there are 
pipes, each answering to a different note of 
the gamut ; the pins in the barrel are so dis- 
posed, as to lift the keys in the same ordet- 
and time as any piece of music for which 
the barrel has been previously made. The 
keys all turn upon one wire, as a centre, 
and to prevent their shifting sideways ; and 
by that means missing the pins in the bar- 
rel intended for them, they move in small 
notches, cut by a saw in two pieces of brass 
plate, which are screwed to the edge of a 
piece of wood, K, and project below it; the 
wire which forms the centre for the keys 
is also fixed to the piece of wood, K, which 
is called the key-frame. A number of small 
pieces of mahogany are fixed to the keys at 
t, and to these the rods, G, are jointed by 
a piece of leather glued to both ; v v, are 
small screws going through the key-frame, 
and touching the piece of wood, t, their use 
is to adjust the levers, so that the ends, r r, 
shall form one straight line. 
The key-frame is not fastened dovrn to 
the frame of the machine, but has a piece, 
of iron plate, »c, fastened to each end, and 
turning upon screws fixed to the frame of 
the instrument upon which the whole key- 
frame can be fitted as a centre ; tw-o screws 
through its ends, resting their points upon 
the frame, support it, and by screwing 
these out, the whole frame can be raised or 
lowered, to adjust the ends of the keys the 
proper distance from the, centre of the bar- 
rel, H. 
