If one were to sing a perfectly rigid tone, its photographic record would be a horizontal straight line. Such a thing is very rare, however, in any type of singing, for most sustained tones photograph as more or less irregular wavy lines. Indeed, a voice whose sustained tones photographed as a straight line would not produce as good tones as one with rapid and regular variations of the vocal cords. A good singing voice possesses what is called the _vibrato_. In terms of the photographic records, the pitch vibrato consists of a rise and fall of pitch of about half a tone about six times a second. In Figure I are given samples of tones photographed by Seashore and Metfessel from the singing of _Annie Laurie_ by Lowell Welles. The first represents the singing of the word “dew” in the line, “Where early fa’s the dew.” The second is the word “and” from the line, “And for bonnie Annie Laurie.” The vibrato is present in both tones. Note how the voice line varies above or below the note E on “dew” and F-sharp on “and,” sometimes as much as a quarter of a tone. Note also the smoothness and regularity of the pitch fluctuations. It is this smoothness of the vibrato which characterizes good singing. [Illustration: “AND” F♯ “DEW” E FIG. I] To illustrate their scope, methods, and possibilities three specimens of photographic records of Negro voices are presented: a song, _I Got a Muley_,[99] by Odell Walker; a yodel or “holler,” as it is commonly called, by Cleve Atwater; and Cleve’s “1926 Model Laugh.” [99] The tune is slightly different from the music of the song of the same name given in Chapter XIV. It is variously called _I Got a Mule on the Mountain_, _I Got Mule Named Jerry_, _I Got a Muley_, _Jerry on Mountain_. Figure II is the photographic notation of _I Got a Muley_. The music of the song as best it can be represented in ordinary notation is given below. Several interesting things are revealed by the song picture in Figure II.[100] For one thing, we have here a picture of some of those elusive slurs which are so common among Negro singers. Take the words “muley on a mount’n” in Figure II-A, for example. [Music: I GOT A MULEY, MULEY ON A MOUNT’N CALL ’IM JERRY; I GOT A MULEY, MULEY ON A MOUNT’N CALL’IM JERRY. I CAN RIDE HIM, RIDE’IM ANY TIME I WAN’ UH; I CAN RIDE HIM RIDE’IM ANY TIME I WAN’UH, LAWD, LAWD, ALL DAY LONG.]