5] 8 Prof. A. M. Mayer's Researches in Acoustics. 



preciable change in their intensity. For example, I connected 

 the Ut 3 fork (the second in the harmonic series of Ut 2 ) to the 

 membrane on the Ut 2 reed, and sounded the latter during a 

 few seconds. After the reed was silent, I heard the fork 

 sounding with intensity*. But on loading the fork with a 

 piece of wax, so that it gave five beats per second with the 

 note of the fork when unloaded, I could not, by any variation 

 in the tension of the fibre or of any other circumstances of the 

 experiment, set in vibration the fork by means of the pulse* 

 sent from the reed through the fibre ; yet on placing the nipple 

 of an Vt 3 resonator in my ear, I perceived that this flattened 

 note of the fork produced a decided resonance — thus showing 

 that although the fork could not respond to its own note 

 flattened five beats per second, yet the resonator, under the 

 same circumstances, did enter into sympathetic vibration. When 

 the fork gave/owr beats per second it responded to the reed ; but 

 this response was only audible on placing the ear close to the 

 mouth of the fork's resonant box. With three beats per second 

 the sound of the fork was readily perceptible, while the resonator 

 reinforced it very decidedly. When the fork was out of unison 

 two beats per second^ its sound was slightly increased ; and 

 with a departure of one beat per second the response of the 

 fork was yet stronger, but greatly inferior in intensity to that 

 produced when the fork was in unison with its proper sound 

 (the second harmonic of the reed) > yet the resonator reinforces* 

 this flattened sound as forcibly as it does that which emanates 

 from the unloaded fork. These facts concerning the want of 

 sharpness in the detection of pitch by means of resonators are 

 not in accordance with the statements made in recent popular 

 works on sound, where the resonator is described as remaining: 

 dumb until the exact pitch to which it is tuned is reached, when 

 it responds with a suddenness which has been compared to an 

 explosion ! 



The fork, the stretched fibre, and the intensity of the sound 

 of the reed remaining in the same conditions as in the above 

 experiments, I gradually unloaded the fork until it made only 

 one beat in eight seconds ; and yet even this slight departure from 

 unison with the second harmonic of the reed was evident in the 

 difference in the intensities of the fork's responses when thus 



* It is perhaps hardly necessary to state that in all these experiments 

 I first ascertained that when the fibre was detached from the fork, the 

 latter did not emit a sound caused by the action of the intervening vibra- 

 ting air. This condition is readily attained by screening the mouths of the 

 resonant boxes, or by turning these mouths away from the sounding reed, 

 Also I should here state that the reed was tuned to the fork after the fibre 

 was stretched between the latter and the membrane on the reed-pipe. 



