Sounding of two Notes. 421 



existence by choosing as the fundamental note of the interval 

 a much deeper note than 0, namely double E (80 v. s.). 



The great fork had on one of its prongs a wooden board 

 24 centims. broad and 40 centims. long, and, by means of a 

 powerful electromagnet placed between its prongs, was made 

 to vibrate strongly in a space of from 12 to 15 millims. I 

 held my ear to this board, while I brought more or less close 

 to it a tuning-fork with sliding weights and divisions, which I 

 held loose in my hand. If we experiment in this manner, and 

 raise the note on the latter tuning-fork from 80 v. s. gradually 

 higher and higher, the first single audible beats are again lost 

 in a roll and rattle which continue beyond the fifth (20 beats). 

 At 144 v. s., when 32 lower beats and 8 upper beats are 

 produced, the latter begin to be distinguishable. At 148 v. s. 

 (m=34, m/ = 6) and at 150 v. s. (m = 35, m'=5), beside the 

 rattle of the 34 or 35 lower beats, the 6 and 5 upper beats can 

 be clearly heard. A good idea may be obtained of the sound 

 produced if we curve the tongue as in forming the letter R, 

 while we force the air out of the mouth in short strong puffs, 

 instead of in one continuous stream. 



While on the subject of this experiment with the deep 

 double-E fork, I may remark by the way that it is extremely 

 difficult to produce very deep simple notes of any intensity. 

 As I was anxious to make my experiments upon beats by 

 means of notes which should have the widest possible intervals 

 with the smallest possible difference in the absolute number of 

 vibrations, I constructed for the notes of the double octave 

 (64 — 188 v. s.) two large wooden resonators, one 40 and 

 the other 60 centims. high and wide, and both 2 metres long. 

 Like the before-mentioned brass resonators, they were fitted 

 with clamping-screws, so that they could be tuned with 

 the greatest precision, and the openings could be increased or 

 diminished at pleasure ; but the effect which 1 obtained from 

 them in connexion with the powerful forks was so small that 

 I lost more in intensity by taking one of these deep notes for 

 the fundamental note than I gained by the lesser number of 

 vibrations. 



If we increase the interval of the octave 128 : 256 v. s., at 

 which we have now arrived by retaining the fundamental note 

 C, while we again raise the second note proceeding from the 

 octave higher and higher, we produce again the single audible 

 beats, which, when they have attained the number of 10 to 12 

 at 276 to 280 v. s., change into a simple roll, which at 296 v. s. 

 (20 beats) is transformed into a confused rattle. This rattle 

 soon becomes weaker ; and between e and/, about 332 to 336 

 v. s., the clang of the two notes only allows a mere roughness 



