330 On the recent Improvements 
Fig. 7, isa pipe with two shades at the top or open end, 
the one being close applied, and the other removed. 
Fig. 8, is a bird’s-eye view of the same, The references 
in these figures will be understood, from what has been 
already said. The use of these moveable shades is, that by 
means of them organs can’be constructed with more com- 
plete scales than those in ordinary use, without so great a 
multiplication of pipes, as without this invention would be 
necessary. And whereas, from the ordinary construction 
of the bellows. those at least which rise on four ribs of 
equal breadth at each side, and each end, they do not blow 
with an uniform force, but with less force when full, and 
with a continually increasing force as the top sinks, and 
vice verst. : 
We, the said Henry Liston and Charles Broughton, 
declare, that our invention consists, secondly, in a regulator 
which renders the blast of the bellows perfectly equable. 
This regulator isshown, No. II. fig. 1.it consists of a spiral 
piece of wood (or other proper material)@,1,2,3, of about half 
an inch in thickness, more or less according to the size of 
the machine, and of a pulley 0, 1,2, 3, of similar thickness 
fastened to the spiral. This machine turns on a pin at the 
common centre of the spiral and pulley C. The strin 
d,d,d, is fastened to the pulley 2, 1, 2,3, at c, and being 
wound round it, passes under a small pulley at f, and is 
fastened to the top-board of the bellows at g, at about an 
equal distance from citherend. Another string &, A, fast- 
ened to the string d,d,d, passes under a pulley at 7, goes 
under the bellows, and a simlar pulley on the other side, 
and is fastened to the opposite side of the top-board; that 
when these strings, act on it, they may pull both sides 
equally. These three small pulleys may run in one piece 
of wood, as shown, fig. 2, which being placed under the 
bellows, may be fastened to the frame of the organ; the 
weight or counterpoise / is suspended by a string m, at the 
centre of the spiral, when the bellows are quite empty, 
When, therefore, the bellows begin to tise, the strings 
d,d,d,h,h, are drawn so as to turn the pulley, and conse- 
quently the spiral in the direction b, 1, 2,3, and then the 
string mm is taken upon the edge of the spiral which is 
rooved to receive it: thus as the bellows are gradually 
losing force, the counterpoise J is gradually gaining power, 
by the increasing radius of the spiral on which it acts. | If 
the bellows rise so much as to cause the pulley and spiral 
to make an entire revolution, the weight / will be in the 
position 
