52 Method of putting music on organ barrels. [Jan, 



13. — The foregoing process is strictly correct for laying off 

 music on a barrel for a piano forte, but there is a peculiarity in 

 the organ that requires further explanation. The piano 

 strikes a single blow, and a single pin on the barrel effects it, 

 and whether the note be a long one or a short one, a pin, 

 simply, is all that is required; but with the organ it is not 

 so. If a note is a long one it must be kept sounding as long 

 as the proper time of the note lasts : for instance, if 3 long 

 and 3 shorter notes were to be struck by a self performing 

 piano, the pins might be arranged as shown in fig. 5 ; but if 

 they were to be sounded on the organ, they would be shaped 

 as shown in fig. 6, where they are not simply pins, but staples 

 which keep the key «, sustained, and the note sounding as 1 ng 

 as its proper time continues. Now from examining the spaces 

 between the pins in fig. 5, it will be seen that there is ample 

 room for the point of the key, a, fig. 6, to descend between 

 them, and no provision to this end is necessary to be mnde; 

 but as the true distance between note and note is the same 

 on the organ as on the piano, and as the organ notes are con- 

 tinued sounds and not sudden blows struck by a hammer, as 

 in the other instrument, it follows that if the process before 

 described was not to be modified, were a note to be sounded 

 two or more times in succession, there would be only one 

 continued sound (from the preceding staple ending just where 

 the succeeding one commenced) instead of two or more suc- 

 cessive sounds. The key in fact would have no space to fall 

 into, to cut off the sound, and to commence again to produce 

 distinct notes. To hit on some easy practical method to 

 diminish every note* a given space gave me some trouble^ 

 but I effected it by means of a parallel rule, the use of which 

 is as follows. 



14. -— In fig. 4, let a, represent a part of the front rail of 

 the stand x.x fig. 3 : and let b, represent the parallel rule at- 

 tached to it. Suppose that two notes from c, to d, and from 

 d, to i, had to be set off on the barrel, the apparatus in its 



* The longer or staple notes are here alluded to, not notes consisting of a single 

 pin, of which of course there are numbers on organ barrels as well as on barrels for 

 piano fortes. 



