162 AXNUAL OP SCIENTIFIC DISCOVERY. 



MUSICAL ACOUSTICS. 



Prof. Helmholtz, in a recent lecture before the Royal Institution on 

 Musical Acoustics, by means of Prof. Wheatstone's wave apparatus, 

 illustrated bis views of the simple aerial waves which produce simple 

 and compound musical sounds, and also explained and illustrated what 

 arc called harmonics. If a musical note be produced from a bell, an 

 open string, or from almost every instrument, a practised ear can de- 

 tect, in addition to its proper note (say C), its octave, 12th, etc. Every 

 tone thus contains its own harmony. To facilitate the preception of 

 these harmonies, the Professor had arranged a series of eight tuning- 

 forks, each fastened to the ends of horse-shoe electric-magnets and 

 joined to resonant glass tubes tuned to a precise note of the fork. 

 The mouths of the tubes were provided with movable covers, which 

 might be removed by means of threads, whose ends were fastened to 

 a set of piano-forte keys. The tuning-forks were rntdc to vibrate by 

 means of intermittent electric currents, and the intensity of each 

 note could be regulated by opening the tube more or less completely. 

 By means of this apparatus many interesting points connected with the 

 subject were illustrated, and by combining the various sounds the 

 Professor succeeded in producing a remarkable imitation of the vowel 

 sounds (u, o, ah, a, e, etc.) The lecture was concluded with remarks 

 on the physiology of the subject and on its psychology, i. e., the effect 

 which musical combinations of sound have on the soul. 



PHOXAUTOGBAPHY. 



For several years past a French physicist, M. Scott, has been en- 

 gaged in experiments on the fixation of sound upon a prepared tab- 

 let, in the same way as photography fixes luminous images ; and has 

 met with considerable success in this new art, which he has named 

 Phonautography. At a recent meeting of the French Academy a short 

 communication was made by the discoverer, in consequence of the 

 publication of some experiments in the same direction made by other 

 gentlemen. This communication was devoted chiefly to a description 

 of certain illustrations laid before the members, and would be unintel- 

 ligible to the general reader without the diagrams. The subject, how- 

 ever, being of immense importance, and likely now to attract great 

 attention, a short account of what has already been done by M. Scott 

 will perhaps be considered of interest. 



The problem which first required solution was the artificial con- 

 struction of an ear, by means of tubes and diaphragms, so as to imi- 

 tate, as nearly as possible, the human ear in its power of collecting 

 sounds of every degree of intensity, and transmitting them to a deli- 

 cate membrane placed at the extremity. After numerous essays, an 

 apparatus was constructed which possessed the above qualifications ; 

 the membrane was seen to vibrate visibly, and in a different manner, 

 with each audible sound or note ; and if a pen or style were fastened 

 to this membrane, its point would trace the wonderfully beautiful and 

 complicated curves and circles appertaining to the elements of sound. 

 The next difficulty consisted in finding a sensitive surface upon which 

 this style could mark the imprint of its movements ; for the vibra- 



