562 VOICE AND SPEECH. 



yellow and blue we produce white. Tims also may elementary sounds be blended so as 

 to produce all possible varieties of clang-tint. After having resolved the human voice 

 into its constituent tones, Helmholtz was able to imitate these tones by tuning-forks, and, 

 by combining them appropriately together, to produce the clang-tints of all the vowels." 



Consonants. Some of the consonants have no sound in themselves and serve merely to 

 modify vowel-sounds. These are called mutes. They are 5, d, &, p, t, and c and g hard. 

 Their office in the formation of syllables is sufficiently apparent. 



The consonants known as semivowels are,/, , m, n, r, s, and c and g soft. These 

 have an imperfect sound of themselves, approaching in character the true vowel-sounds. 

 Some of these, Z, m, n, and r, from the facility with which they flow into other sounds, 

 are called liquids. Orthoepists have farther divided the consonants with reference to the 

 mechanism of their pronunciation : d, j, , t, z, and g soft, being pronounced with the 

 tongue against the teeth, are called dentals; d, g, j, &, Z, ??, and q are called palatals; &, 

 j,/, 0, and m are called labials ; m, 72, and ng are called nasals; and &, -, and c and g 

 hard are called gutturals. After the description we have given of the voice, it is not 

 necessary to discuss farther the mechanism of these simple acts of articulation. 



For the easy and proper production of articulate sounds, absolute integrity of the 

 mouth, teeth, lips, tongue, and palate is required. We are all acquainted with the modi- 

 fications in articulation, in persons in whom the nasal cavities resound unnaturally, from 

 imperfection of the palate ; and the slight peculiarities observed after loss of the teeth 

 and in hare-lip are sufficiently familiar. The tongue is generally regarded, also, as an 

 important organ of speech, and this is the fact in the great majority of cases ; but 

 instances are on record in which distinct articulation has been preserved after complete 

 destruction of this organ. These cases, however, are unusual, and they do not invalidate 

 the great importance of the tongue in ordinary speech. 



It is thus seen that speech consists essentially in a modification of the vocal sounds 

 by the accessory organs, or by parts situated above the larynx ; the latter being the true 

 vocal instrument. While the peculiarities of pronunciation in different persons and the 

 difficulty of acquiring foreign languages after the habits of speech have been formed show 

 that the organs of articulation must perform their function with great accuracy, their 

 movements are simple, and they vary with the peculiarities of different languages. 



The Phonograph. In 1877, a remarkable invention was made in this country by Mr. 

 Thomas A. Edison, which possesses considerable physiological interest. Mr. Edison con- 

 structed a very simple instrument, called the phonograph, which will repeat, with a cer- 

 tain degree of accuracy, the peculiar characters of the human voice both in speaking and 

 singing, as well as the pitch and quality of musical instruments. This demonstrates con- 

 clusively the fact that the qualities of vocal sounds depend upon the form of the sono- 

 rous vibrations. The following are the main features in the construction of this remark- 

 able and almost miraculous instrument: It consists of a cylinder of iron provided with 

 very fine, shallow grooves in the form of an exceedingly close spiral. Upon this cylin- 

 der, a sheet of tin-foil is accurately fitted. Bearing upon the tin-foil, is a steel-point 

 connected with a vibrating plate of mica or of thin iron. The vibrating plate is 

 connected with a mo.uth-piece which receives the vibrations of the voice or of a 

 musical instrument. The cylinder is turned with a crank, and, at the same time, the 

 plate is thrown into vibration by speaking into the mouth-piece. As the disk vibrates in 

 consonance with the voice, the vibrations are marked by little indentations upon the tin- 

 foil. When this has been done, the cylinder is moved back to the starting point and is 

 turned again at the same rate as before. As the steel point passes over the indentations 

 in the tin-foil, the plate is thrown into vibration, and the sound of the voice is actually 

 repeated, although much diminished in intensity and distinctness. 



