1836.] Method of putting music on organ barrels. 53 



present position would be correct to begin with for marking 

 the barrel with the proper chords according to the music ; 

 then the point,/, being shifted from c, to d, the parallel rule 

 must be raised till it stops against the pin, k, which would 

 aU^ raise the stop, g, a short distance, and prevent it resting 

 as it now does on the rail, a. The point, /, is then to be 

 brought down till it touches the edge of the stop, g, and the 

 note or notes are to be marked on the barrel. The para!! el 

 motion after this, must be depressed and brought to the posi- 

 tion it now is in, and the stop, g, being also depressed till it 

 touches the rail, a, the apparatus would be in the same posi- 

 tion as represented in the sketch, which is the right position 

 for commencing the note, d, i ; to mark which upon the barrel 

 would be a repetition of the process just described. On con- 

 sideration, it will be plain that the effect of the parallel 

 action is to cut off a portion of each note in order to produce 

 space for the point of the key, a, in fig. 6, to fall into, so that 

 distinct sounds may be produced when similar notes follow in 

 succession. This quantity, so cut off, does not diminish the 

 proper value of the notes, although it does the length of the 

 staples ; for the angular figure of the point of the key com- 

 pensates for the diminution of length. The space between 

 the notes being only sufficient to allow the key to fall freely, 

 the succeeding note sounds immediately after the one pre- 

 ceding, the breadth of the key being equivalent or nearly 

 equivalent to the intermediate space between note and note, 

 as seen in fig. 6, 



5th December, 1835. J. B. 



P. S. — From an error in the former manuscript a sentence 

 commencing at the 10th line in page 351, last vol. ought to 

 stand as follows. Now, one piece of mechanism with only 

 one first moving power cannot effect two opposite motions at 

 the same time, namely, a slow movement for the music, and 

 a rapid or slow movement for the bellows, according as the 

 music may require. Slow music generally requires more air, 

 and quick music less air : it would be difficult to provide for 

 these two opposite cases by one piece of mechanism working 

 both the barrel and the bellows, and for the instrument to 

 keep good time. 



