MUSICAL INSTRUMENTS— THE ORGAN. 



641 



pneumatic bellows (N), which, being pressed down by the force 

 of compressed air from the wind-chest, opens the large valve (O). 

 This supplies all the pipes in that chest with wind. The swell 

 (B) and solo (D) key-boards also operate their respective wind- 

 chests on the same principle. 



The couplers are operated 

 through the medium of lever 

 (P), which is controlled through 

 a block glued on the tracker (J). 

 When the performer desires to 

 couple the choir to the great 

 organ, the draw-stop pulled out 

 has the effect of pushing the 

 square (G) up against the track- 

 er (K), when the desired result 

 is attained. Again, when he 

 wishes to couple the swell to 

 the great, the pulling out of Ihe 

 draw-stop brings up the lever 

 (R) against the block on the 

 tracker in that connection. 

 The coupling of the swell oc- 

 tave is attained by the levers 

 (S), which are placed at an an- 

 gle so as to pull the tracker of 

 the swell one octave higher, by 

 an ingenious movement. In 

 coupling the solo organ to the 

 great, the lever (T) is moved up 

 to the block on the tracker of 

 that manual. A little study of 

 the plan, and the points given, 

 will explain the general system 

 of action very clearly. In this 

 instrument a set of bells of 

 three octaves (U) are operated 

 from the great-organ key-board 

 by a mechanism of the square 

 piano order ; pneumatic agency 

 is also used here, as the press- 

 ure of the key will not of itself 



furnish the dynamic impulse necessary to put them in vibration. 

 This is attained by a draw-stop, which puts lever (V) and tracker 

 (J) in connection by pushing the former up against the latter. To 

 play any of the key-boards by pedals, a " cam " serves to raise the 

 levers (W) to the tail of the keys, thus establishing a connection. 



VOL. XL. 44 



Fig. 24. — General View of Interior oe Par- 

 lor Organ (Estey system). — Case (^4), lid 

 to key-board {A")^ bellows reservoir (B), es- 

 capement (6), treadle (Z*), tape connecting D 

 with C (d), wind-chest (E), reed-socket (e), 

 reeds (r r), dampers (e), swells (s), octave- 

 coupler levers (-fT), tracker-pin (A), key (F), 

 name-board ((?), stop-knob (/), stop-rod (i), 

 lever and link for swells (./), slide for open- 

 ing dampers (M), grand-organ roll (n), vox 

 humana tremolo ( T), float-wheel of tremolo 

 (t), fan (/), music-support (m), lamp-stool 

 (Z), and knee-swell lever (S). 



