248 



EXPERIMENTAL PHONETICS. 



are frco from error, however delicate they may seem to be, owing- 

 to the inertia of the parts, and consequently other arrangements 

 were demanded. In 18(^2" Rudolph Konig introduced hi.s well-known 

 method of showing the movements of membranes by manometric 

 flames. The apparatus is now so well known as to require no detailed 



3L 



Fig. 11.— Appamtus of Hensen. d. Wooden 

 prism; c, glass; </, smoked glass kept in its 

 plane by a screw clamp, c; a, b, supports. 



Fig. 12 — The reconling portion of the Sprachzeichner 

 of Hensen. /, i, frame having a joint, :; h, wooden 

 point; g, smoked glass. 



description. Gas is led l)y a tube into a small capsule of wood, the 

 cavity of which is divided by a thin membrane (tig. 14, a). The 

 gas passes into the right half of the cavity and escapes into a small 

 burner, where it is lit. If sound waves are diverted by a small con- 

 ical resonator into the left half of 

 the capsule, the meml^ranous parti- 

 tion vibrates, there are alternations 

 of compression and of rarefaction 

 in the gas on the right side, and the 

 flame is agitated, moving upward 

 and downward with each vibration. 

 The method of Wheatstone of dis- 

 sociating the flames b}" a rotating 

 mirror is then employed, and a sinu- 

 ous ribbon is seen in the mirror. 

 FIG. i3.-\vriting portion of Hensen's apparatus, xhe ribbon is cut Vertically iuto 



/(, V, weights supporting an a.xis o, carrving " 



markerj;, with a pointr,- (?, adisccommuni- teeth, some larger, some Smaller. 



eating to the marker jj the movements of the 'PJjg larger leSS freouent COITC- 

 mcmbrane; </, smoked glass plate. i / . i i ' 



spond to the fundamental tone of 

 the sound, the smaller to the harmonics that enter into the compo- 

 sition of the compound tone on which the (juality of the vowel 

 depends. 



These flam(> pictures are only seen for an instant, and many efl'orts 

 have been made to tix them by photographic methods. This was first 



«Konig: Quelque.s Experiences d'Acoustique (Paris, 1882). 



