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[Page 37]

37

are connected together by leather joints that
suffer the upper one to move with facility: as
the under board is fixt or stationary, a
supply & discharge of air depends wholy
upon the action of the upper part, on which is
place such a quantity of weight as is
necessary to give a due force to the air that
supplies the Pipes; this supply is however, very
unequally dealt out, for this weight acting
some times with a greater, & sometimes with a
lesser power; pruduces an inequality in its
air strength of the air, that causes the difference
of perhaps a quarter of a tone in the same
pipe, which must necessary heppen; for the
upper board is in every respect a perfect
lever, the centre of motion being at the end
where thenose is fixed, the hither end or that
part where the handle is, must move in a
circular direction & therefor the weight cannot
act with an equal power; but further to
illustrate that matter; supppose a Lever in
length 4 yards from the fulcrum or centre
of motion, with a pound weight appended
to the hither end; when the lever is in an exact
horizontal direction, it will press in the
middle at the rate of 12 pounds; if the lever
be elevated above the horizontal direction
to 45 degrees, the weight will then lose one
half of its power, & that will also be the
case if the it be depressed as much below
the horizontal position

The imperfections of the Bellows to chamber
organs use is still greater, for they always deliver
the air in violent Puffs, which do not only prevent
clear tuning, but even destroys whatever is
performed on the Keys

Having thus freely condemned the usual
method observed in making organ Bellows, it
may be expected that I propose something
to