July 26, 1895.] 



SCIENCE. 



97 



but the instrument was little known to 

 physiologists. Since 1890, however, it has 

 in its improved form, with a wax cylinder, 

 engaged the attention of Professor Her- 

 mann, of Konigsberg, and more recently of 

 Dr. Boeke, of Alkmaar, and of Professor 

 M'Kendrick, of Glasgow. By an ingenious 

 method of photographically recording the 

 vibrations of the marker that runs over the 

 impressions produced by sounds on the wax 

 cylinder of the phonograph, and which, by 

 acting on a thin glass plate, reproduces the 

 sounds, Hermann has obtained the curves 

 corresponding to the tones of the vowels, 

 and he has shown that the vowels are true 

 musical tones, each having its own proper 

 pitch, and not, as Von Helmholtz supposed, 

 the pitch of a harmonic tone corresponding 

 to the shape of the oral cavity when the 

 vowel sound is uttered. When one con- 

 siders that the phonograph can faithfully 

 reproduce human speech, the sounds of a 

 musical instrument, of a quartette or chorus 

 of human voices, or the sovmds of an or- 

 chestra, and that all these sounds and tones 

 are imprinted on the wax cylinder of the 

 phonograph in the form of a more or less 

 complicated wave, it is manifestlj^ of great 

 importance to determine the wave form for 

 any particular sound. If this could be 

 done, not onlj' would it be of great scientific 

 interest to svibmit the curve to harmonic 

 analysis (as was done by Jenkiu and Sw- 

 ing), and thus determine the component 

 waves, but it might be possible to cut the 

 curves on the margin of a wheel, or other 

 appropriate device, and thus construct a 

 speaking or singing machine. Sjjeech and 

 song and orchestral effects might be multi- 

 plied mechanically. The grooves on the wax 

 cylinder vai-y in depth fi-om the 1-1 000th to 

 the l-2000th of an inch, and, thus, as the 

 curve is in the bottom of the groove, it is 

 a difficult matter to trace its form. Boeke 

 has measured the transverse diameters of 

 the grooves at diiferent points, and fi-om 



these measurements he has calculated the 

 depths, and thus he has endeavoured, as it 

 were, to construct the curve. M'Kendrick 

 has taken direct photographs of the marks 

 on the M^ax cj'linder, and has thus been able 

 to demonstrate vibrations (or ' dabs ' on the 

 wax cylinder traveling with great velocity) 

 made at the rate of 1,500 to 1,800 per 

 second. He has also shown that there is a 

 definite form of these markings for pure 

 tones, for the simpler chords, and for very 

 complex tones, such as those of the organ, 

 piano, or a quartette or chorus of human 

 voices. By adapting large resonators to 

 the phonograph, M'Kendrick has also made 

 it possible to so increase the volume of tone 

 as to make it audible even in a hall of con- 

 siderable size. Edison and others have fre- 

 quently used large resonators, but M'Ken- 

 drick has gone further in this direction. 

 Recognizing, however, that resonance can- 

 not increase the volume of tone beyond a 

 certain limit, he has made use, with much 

 success, of Mr. Alfred Graham's ingenious 

 loud-speaking telephone, along with a trans- 

 mitter of variable resistance, as supplied by 

 Messrs. Muirhead and Co., of Westminster. 

 In this way the tones of the phonograph 

 are much amplified in volume and improved 

 in quality. To phj^siologists the interest of 

 these researches lies in the mode of action 

 of the vibrating plate of the phonograph. 

 This acts like the drumhead of the ear. 

 Consequently the better the modes of move- 

 ment of such a plate are understood the 

 better can we explain the mechanism of the 

 drumhead of the ear — a drumhead, how- 

 ever, infinitely more sensitive than the 

 phonograph plate. — London Times. 



CURRENT NOTES ON PHYSIOGRAPHY (XIIL). 



THE CATOCTIN BELT OF MARYLAND AND 



VIRGINIA. 



The Blue ridge, dwindling from the Car- 

 olina highlands, extends a few miles north 

 of the Potomac at Harper's Ferry, there 



