made in musical keyed Instruments. 329 
half of the open end of the pipe; and the second shade is 
made to cover the remainder of the mouth or open end: or 
in the case of an open pipe, one shade may be applied to 
the mouth to alter its pitch comma, and another shade may 
be applied to the open end to alter it another comma, For 
the convenience of being removed from or brought to the 
pipe, the shades are fixed on rollers or cylinders of wood, 
or other proper materials moving on pivots. For the pur- 
pose of attaching the shades’ to the rollers, each shade may 
be soldered to a piece of tinned wire, or brass-wire; which 
piece of wire may be screwed into the roller, or the shade 
may be attached to the roller in any other convenient way. 
When two shades are applied to the mouth or open end of 
one pipe, or when in a range of pipes the shades of some 
are upon different rollers trom those of others, then the 
rollers may be arranged one above another; the wire or 
stalk by which the shade is attached on the lower roller, 
bending round the other roller or rollers, so as to apply the 
shade close enough to the mouth or open end of the pipe 
to which it belongs; or when convenient, one or more 
rollers may be placed on one side, and the others on the 
other side of a range of pipes. 
This description is illustrated in the following figures: 
(see PlateIX.) No. I. figure 1, shows two pipes shaded at the 
mouth, each with the single shade, to alter the pitch by 
diesis: a,a,a,a, ibe mouths of the pipes; 4,2, 0,0, the 
shades represented transparent, that the mouths may be 
seen; ¢, c, the wire or sticks by which the shades are at- 
tached to the rollers dd; the stalk attached to the lower 
roller, bending round the roller above it; e, e, supports for 
the pivots of the rollers, one at cach end of the range of 
pipes. 
Fig. 2 and 3 are side-views of a pipe shaded at the mouth, 
to show the positions of the shades when close applied, and 
when removed; the reference being the same as in fig. 1. 
Fig. 4, shows two pipes shaded at the open end; a@,a,a,a, 
the open ends; l,b, the shades; c, c, the stalks which at- 
tach the shades to the rollers d,d@; which are represented 
sloping, to correspond with the tops of the pipes. The 
shade attached to the upper roller is represented as close 
applied to the open end of the pipe, and that on the lower 
roller as removed from the pipe, to which it belongs. 
Fig. 5, is a bird’s-eye view of the same. 
Fig. 6, is a pipe having two shades at the mouth, each 
to alter the pitch comma. . 
Fig. 
