some of these repeated a number of times in pipes of different shape and construction.
THE ARRANGEMENT OF THE PIPES.
We will now study briefly the mechanism of a very simple single-keyboard organ, with five ranks of pipes, or stops.
It is necessary to arrange matters so that the pressing down of one key may make all five of the pipes belonging to it speak, or only four, three, two, or one, as we may desire. The pipes are mounted in rows on a sound-board, which is built up in several layers. At the top is the upper board; below it come the sliders, one for each stop; and underneath that the table. In Fig. 139 we see part of the table from below. Across the under side are fastened parallel bars with spaces (shown black) left between them. Two other bars are fastened across