Intelligence and Miscellaneous Articles, 145 



of which is known for every temperature. The vapour which forms 

 in the second apparatus is collected during ten minutes, before the 

 passing of the current ; there is scarcely any ; the circuit is then 

 closed, which determines a rapid boiling. The heat supplied is 

 known ; the vapour which it has formed without change of tempera- 

 ture is weighed, and the latent heat is deduced. 



IV. The two Specific Heats. — A third application of the same prin- 

 ciple can be made. In a large bell-glass rilled with air a metal wire 

 is stretched ; an intense current is passed for a short time through it, 

 which developes a determined quantity of heat ; a fraction of this 

 disappears by radiation; the remainder, which is constant, gives 

 heat to the gas, which can be measured in two ways — either by in- 

 crease of the volume at constant pressure, or by increase of the 

 pressure at constant volume. From these two effects the ratio of 

 the two specific heats can easily be deduced ; and the number found 

 is about 1*42, a number indicated by the velocity of sound. 



These experiments are now in full operation. I wished by this 

 communication to make my own the general method which will be 

 applicable to all questions of calorimetry. I have associated with 

 me in this work four distinguished pupils of the Laboratoire de 

 Recherches de la Sorbonne, MM. Richard, Amaury, Champagneur, 

 and A. Thenard. We shall presently publish the results of our work. 

 — Comptes Bendus, March 28, 1870. 



ON THE FIXED NOTES CHARACTERISTIC OF THE VARIOUS VOWELS. 

 BY M. R. KGENIG. 



According to the researches of MM. Donders and Helmholtz, 

 the mouth, arranged for the emission of a vowel, has a note of 

 stronger resonance, which is fixed for each vowel, whatever may be 

 the fundamental note on which it is given. A slight change in the 

 pronunciation modifies the vocal notes so sensibly that M. Helm- 

 holtz has been able to propose to linguists to define by these 

 notes the vowels belonging to the different idioms and dialects. 

 Hence it is of great interest to know exactly the pitch of these 

 notes for the different vowels. M. Donders sought to arrive at 

 this by observing the rustling or whistling which the current of air 

 produces in the mouth when the different vowels are whispered ; 

 the notes which he has found differ considerably from those given 

 by M. Helmholtz. The latter used a set of tuning-forks, which he 

 made to vibrate in front of the mouth when it was arranged to 

 articulate a vowel. Every time the sound was strengthened by the 

 air enclosed in the cavity of the mouth, this mass of air was evidently 

 in unison with the tuning-fork. By this method, which is more 

 correct than the first, M. Helmholtz found that the vowel A was 

 characterized by the fixed note (sit?) 4 , O by (sib) 3 , E by (sib) 5 ; and 

 these results really appear incontestable. As none of the tuning-forks 

 arranged was sufficiently acute for the vowel I, M. Helmholtz tried 

 to determine the characteristic note by the means already employed 



Phil. Mag. S. 4. Vol. 40. No. 265. Aug. 1870. L 



