192 Transactions of the American Institute. 



reach the ear. Let me give some experimental examples. I sound 

 this mounted tuning-fork ; it furnishes us with a pure note, and you 

 can observe its quality. This (flute) organ pipe gives the same note, 

 a little mixed with the higher octave ; but this reed-organ pipe, which 

 also gives the same fundamental note, with the other two, has an 

 entirely different sound, and one might imagine its note was an octave 

 higher than those of its companions. But the notes are the same, as 

 is announced by the beats, which I produce by sounding any two of 

 the instruments together, and then lowering the note of one of them 

 slightly by holding my hand near the top of the pipe. 



The reason of the difference in the case of the reed-pipe is simple. 

 It generates not only the four-feet waves of its companion, but many 

 sets which are shorter, waves which give the octave the next higher 

 duodecimo, etc. The fundamental or lowest note of the pipe, being 

 mingled with all these noisy companions, tails, of course, to produce 

 as decided an impression on the ear as otherwise would be the case. 

 Now, these reed-pipes, with their train of multitudinous notes, have 

 for us, as speaking human beings, a particular interest, and we must 

 pause for a minute to examine their construction. They consist of a 

 vibrating tongue down at the base, which lets the current of air from 

 the bellows pass through in puffs, and generates a set of tones after 

 the manner of the syren, except that the tongue remaining of the 

 same length, the set of tones is always the same, whereas the tones 

 of the syren, in my experiment, were always changing. But, you 

 will ask, can single drops of air, as they are admitted by the vibrating 

 tongue, generate several sets of waves ? I have often noticed that the 

 drops of water, as they fall from the blade of an oar in perfectly quiet 

 water, generate several different sets of waves which vary greatly in 

 length,* and it is the same with the waves or tones of our vibrating 

 tongue. They are afterward strengthened or weakened by the pipe. 

 By altering the shape and size of the pipe, you can strengthen or 

 weaken particular notes which are present, and thus give the sound a 

 different quality, without necessarily altering the pitch of the proper 

 or fundamental note. I have here three reed-pipes, constructed for 

 me by the well-known organ builders, Jardine & Son, which give 

 exactly the same fundamental note, but, owing to the variation in 

 the shapes of their pipes, the quality, as you notice, is quite different, 

 one of them giving trumpet-like tones, while the others resemble in 

 sound the hautboy and clarionet. 



*TMs is intended as an illustration, rather than an explanation, of the formation of complex 

 waves.— R. 



