The above examples would be termed perfect trills because they close with a turn. By inference, an imperfect trill is one closing without a turn.
66. The mordent
consists of three tones; first the one represented by the printed note; second the one next below it in the diatonic scale; third the one represented by the printed note again.
67. The double (or long) mordent has five tones (sometimes seven) instead of three, the first two of the three tones of the regular mordent being repeated once or more. (See Fig. 43.)
In the case of both mordent and double-mordent the tones are sounded as quickly as possible, the time taken by the embellishment being subtracted from the value of the principal note as printed.
