22 A. 31. Mayer — Researches in Acoustics. 



(5) Intervalle avec la note fondamentale SOL 2 = 192 v. d. 



Diapasons employes avec branches de 10 mm sur 17 mm . 



SOL 2 : LA 2 Roulement simple assez fort. 

 " : 244 v. d. Raucite prononce. 

 " : SI 2 Raucite i'aible. 



La consonance commence encore avant SOL 2 : UT S . 



II resulte de l'ensemble de ces observations, que pour les 

 intervalles des notes tres graves les faits ne s'accordent pas du 

 tout avec votre loi, mais aussi que pour les intervalles des notes 

 de plus en plus aigues, l'accord entre les faits et la loi devient 

 toujours meilleur et Unit par etre presque parfait quand la note 

 fondamentale atteint SOL 2 ." 



I experimented on the hearing of twelve persons with all 

 the forks at my command among which I could obtain conso- 

 nant intervals. It is true that the number of intervals thus 

 furnished, by 80 forks, did not amount to many. Many such 

 intervals can only be obtained in the laboratory of Dr. Koenig 

 where is his "grand tonometre" giving the frequency of all 

 sounds from 16 to 21845 complete vibrations per second. 

 However, 1 secured, between UT 3 and SOL 6 enough intervals 

 among the forks to establish the law and the facts given in 

 Table II. 



All the persons experimented on, except myself and one 

 other observer, were accomplished musicians, several of them 

 violinists of more than exceptional ability. Three were gradu- 

 ates of the Conservatory of Music of Leipzig. 



These experiments were all made in the same manner, viz : 

 by taking a fork giving the lower tone and sounding it suc- 

 cessively with others which gave more and more beats per 

 second, till these beats blended into a continuous smooth sen- 

 sation, forming the smallest consonant interval. As musicians 

 rather avoid than dwell on dissonant intervals I educated each 

 one in the special subject of the roughness of the sensation 

 given by beats, by making the beats more and more frequent 

 till near consonance, then giving an interval which is admitted 

 by every one to be consonant. In this way their hearing was 

 trained in what I wished them to discern, viz : that separa- 

 tion in the pitch of two forks which just gives a consonant 

 interval. 



The variation among the decisions of these different ob- 

 servers never equalled two vibrations, generally they agreed 

 exactly. This agreement among observers in the judgment of 

 a consonant interval is remarkable. I give the mean of these 



