328 On the recent Improvements 
Specification of the Patent granted to Henry Liston, of Ec- 
clesmacham, in the County of Linlithgow, Clerk, and 
Charles Broughton, of the City of Edinburgh, Writer to 
the Signet, for Improvements in the Construction of Or- 
gans. Dated July 3, 18i0. 
To all men to whom these presents shall come, &c.— 
Know ye, that in compliance with the said proviso, we the 
said Henry Liston and Charles Broughton do hereby de- 
clare, that our invention consists: first, in causing each 
organ-pipe to afford several tones differing from each other 
in acuteness or gravity, by applying to the mouth of a pipe 
or to the open end of an open pipe, one or more moveable 
shades, which are performed by means of a pedal or pe- 
dals, or by a stop or stops for the hand, or in any other 
way, may be enabled to remove from, or bring to the 
mouth or open end of the pipe at his pleasure. These 
shades are made of thin plates of lead or pipe-metal, such 
as is used in the manufacture of metal pipes (thicker or 
thinner according to the size of the shade) or of other con- 
‘venient materials. The shades bear a different proportion 
to the mouths or open ends of the pipes to which they be- 
long, according to the degree of alteration intended to be 
produced on the pitch of the pipes. When it is intended 
to alter the pitch of a pipe, by what is called the enharmonic 
fourth of a tone or the diesis in a tempered system, then 
the shade is of such size, as to cover the whole Jength of 
the mouth (across the pipe) rising about as much above the 
upper-lip, or of such size as to cover the whole open end 
of the pipe, and one such shade only is applied to each 
pipe; or the pitch of an open pipe may be altered, the 
diesis, by means of one shade at the mouth to alter it in 
part, and another shade at the open end, to alter the pitch 
as much more as requisite. This is chiefly useful, when, 
as sometimes happens, the pipe cannot well bear to be al- 
tered the whole diesis at the mouth or open end, or in the 
ease of open wooden pipes, which are tuned by means of a 
fixed shade at’ the open end. When it is intended that 
each shade should alter the pitch by what 1s called comma, 
being the difference between the major and minor tones in 
a system of perfect intonation, then there may be two 
shades to the mouth or open end of each pipe, and the 
one shade is made to cover a little more than the half of the 
mouth across the pipe, but rising as much as the formerly 
described shade above the upper-lip, or a little more nah ee 
3. 
