Donovan — On alleged Impevfections of the Tanhicj-fovh. 239 
Whether or not the alleged imperfection of the fork may have 
shaken the confidence of tuners is uncertain ; but it is a fact that the 
instrument called the pitch-pipe" is at present much in use, although 
it is known that its pitch varies a little according to the strength of 
the blast and the temperature, while that of the fork is invariable at 
all ordinary temperatures.^' 
Earl Stanhope adduces the alleged imperfection of the fork as an 
argument against the efficiency of a mode of tuning piano-fortes 
occasionally resorted to, by means of twelve forks, each tuned to one 
particular tempered note of the diatonic scale. An ear capable of 
judging accurately of unisons was then competent to tune any instru- 
ment with twelve fixed tones, without reference to temperament. 
The Earl proceeds to say : ' ' I have contrived a tuning instrument 
which is far superior. It consists of thirteen slips of plate-glass, each 
of which is exactly six inches long by two inches in breadth. They 
are tuned, respectively, one perfect octave higher than the pitch of 
keys in the monochord table ; for by varying the thickness I can 
tune one slip to C, another to G, &c. The thickness of the slip which 
yields the sound of the middle C is about nine hundredths of an inch ; 
and the thickness of the slip which yields the sound of the first treble 
C is about eighteen hundredths. Those two C's are the two extremes. 
Each slip yields a sound which is extremely pure. . . Ey means of 
this tuning apparatus, which is pitched to my new and improved 
temperament, any careful person, with a moderate ear, can tune an 
instrument perfectly." 
The necessity for having recourse to this difficultly obtainable tuning 
apparatus could only arise out of the alleged imperfection of the fork ; 
and, previously to coming to any conclusion on the subject, it is proper 
to inquire whether that imperfection really exist. If there be a beat, 
it must be true that each prong is a separate musical instrument, and 
gives an independent ring at a diff'erent pitch from the other. In 
order to try if I could perceive this duality of pitch, I made the fol- 
lowing experiment. A tuning-fork, with long prongs, being held by 
the shank, was smartly struck, and one of its tops instantly applied to 
a surface of water ; there was ai; instantaneous momentary ring which 
was exactly at the pitch of the whole fork. The trial was then made 
with the other prong, and with precisely the same efi'ect. If these 
trials prove anything, it would be that the prongs were in unison. 
But there may be a further inference. I conceive that if each prong- 
had been in a state of independent vibration the contact with water of 
one prong would silence that one only, but both were silenced at the 
same moment, although the natural sound of the fork would have been 
audible during three or four seconds ; for in order to intensify and 
prolong the sound, after dipping the top of the fork, the shank was 
* Dr. Smith found his organ a quarter tone higher in summer than in winter. 
All wind instruments are much affected by the breath of the performer. 
