Great organ , including pipes of powerful tone. (5.) Choir organ , of soft, mellow stops, often enclosed in a swell-box. We may add to these the pedal organ , which can be coupled to any but the echo manual.
VARIETIES OF STOPS.
We have already remarked that the quality of a stop depends on the shape and construction of the pipe. Some pipes are of wood, others of metal. Some are rectangular, others circular. Some have parallel sides, others taper or expand towards the top. Some are open, others stopped.
The two main classes into which organ pipes may be divided are:—(1.) Flue pipes, in which the wind is directed against a lip, as in Fig. 138. (2.) Reed pipes—that is, pipes used in combination with a simple device for admitting air into the bottom of the pipe in a series of gusts. Fig. 144 shows a striking