ORGAN. 
bend them fideways. T’o avoid this danger, the fame lever, 15, 
which communicates motion to the wheel to fhift the barrel, 
has a detent, 17, jointed to it - one end; it paffes through 
the frame of the organ reftin ona roller 18; the extre- 
mity of it is fituated beneath a Graal roller 19, which is at- 
tached to the front plate of the key-frame at its end : the ope- 
ration of this is, that when the knob, 15, is drawn forwards 
to fhift the barrel, the detent, 17, alfo advances, and an in 
on or thicker part coming upon t aie ow as Sea the 
high, 
{prings on purpofe, permits 
all is rea y for the next tune, whic 
downwards, to permit the efcape, but pre- 
vent the re-entrance of the air. The operation of this is, 
that when the key-frame is lifted up for the purpofe of fhift- 
ing the barrel, the bellows clofe, and the air included in 
them paffes out beneath the upper valve ; but on the frame 
being fuffered to defcend, the air cannot fpeedily obtain ad- 
miffion into the bellows, as there is no other paflage than 
from leakage, and this regulates its fall. wear thefe pro- 
vifions for fhifting the barrel, be pinion, 4, (fig. 8.) is like- 
wife detached from the wheel a moment of its {hifing, 
that it may have no capediaient to its motion from friGtion. 
To explain this, we muft obferve that the : = {pin- 
dle, 3, is fupported by a crooked lever, 22, (jig. 10.) moving 
on a fulcrum in the framing ; the o oppofite end mee preffed 
down by a {pring 23, fixed on the top of the frame s, always 
keeps the teeth of the pinion, 4, and wheel, 5, in clofe con- 
tact with each other. The lever 1, cached to the key-frame, 
to connect with a fecond 
n 
ver, Ty 
fore, ‘ depreflin ng this, the fame effect is Peedi as aol 
be by draw ing out t the knob 
improvement in this organ is the circumftance of 
ade to operate upon the ftops, as well as 
the keys, by which means it performs any full piece of mufic 
ect. The mec ie by which the motion is 
e ftop equires particular 
figures For its eee anie "he upper fet of fliders e, (figs. 1 
and 2 re appropriated folely for the barrel ; ie 
dend (fig. 2.) by being attached to 
lower ends of thefe are conneCted b 
s, X, X, extending beneath the wind cheft, 
to {mall levers 4, ( rg. 1.)3 thefe are affixed to fhort fpindles, 
whofe fituation is marked by 2, in fg. ow itis evident, 
by that partially turning the fpindle a, the lever, #, will draw 
the connefting rod X, and by the lever, W, a&tuate the 
are moped: at the I lefteban 
i he 
flider, ee, of the flap. The : figure alfo fhews that the ee 
tremities of the fpiadles ve 
of the keys 4. It is in the oe between thefe that the 
ingenious contrivance is fhewn. Fig. g is a {mall detent or 
three-armed lever, in fhape ay the letter T, called the tumbler, 
fixed on the projecting extremity of the fpindle v ; from each 
of its two arms, 26, 27,a pin projects: 28, (figs. 12 and 13.) is 
a detent of brat, congected at its lower end with the end of 
one of the 
the oppofite eng of the key is lifted up by the pins of 
‘ ; 
tumbler has a proje c 
of a light {pring, 30, "8 fixe o ] part of the de- 
tent 28, and when at liberty eared ee in the direc- 
27, of the 
tumbler: in this ttate, if the ie is drawn Boar by - 
key, it depreffes the arm 27, and throws the arm, 29, over t 
the oppofite fide, as fhewn in fig. 12, carrying the en'd of thé 
{pring, 30, with it, and bending it. Now the inftant the pref- 
fure of the key is relieved, the {pring throws the detent over 
to ne other arm, 26, of the tumbler, and it is ready the next 
time it is acted upon by the key, to return the ftop to ita 
cael pofition 
$ it is neceflary, w 
mufic, that uae w 
t once. 
which are exclu- 
‘op pees 
fits of fmall eons pipes; as ar 
flageolet ftop ; laftly, the trumpet ftop, ay confifts of 
i & 
Our readers will now 
in the wind cheft, and the remaining 14 for 
are all fituated towards the left-hand end, becaufe, as ean in 
. 2, the wires for the valves are there at fo great a diftance 
alunder, as to admit the ftop-keys to be placed in the {paces , 
between the valve-keys. The barrcl has 102 igi of pins 
in action at the fame time, and eight times as many, viz. 816, 
upon its circumference, containing eight different ee as 
before defcribed ; any one of which can be played by fhifting 
the {nail-wheel 10. There is a {mall dial in front of the 
organ, with an index, which fhews what tune the barrel is 
fet for: it ison the oppofite fide to the wind-dial y (fig. 1.), 
and its motion iscommunicated from the wheel 41, by a lever 
and detent. On turning the taal w, the endlefs fcrew, 2, 
gives motion to the fpindle 4, and that turns the barrel with 
a very regular motion, becaufe of the fly-wheel v (jg. 1. i 
