17. The movable C clef
or
, formerly in very common use, is now utilized for only two purposes, viz., (1) in music written for certain orchestral instruments (cello, viola, etc.) of extended range, in order to avoid having to use too many leger lines; and (2) for indicating the tenor part in vocal music. This latter usage seems also to be disappearing however, and the tenor part is commonly written on the treble staff, it being understood that the tones are to be sung an octave lower than the notes would indicate.
The C clef as used in its various positions is shown in Figs. 7, 8, and 9. It will be noted that in each case the line on which the clef is placed represents "middle C."
[18.] A sharp is a character which causes the degree of the staff with which it is associated to represent a pitch one half-step higher than it otherwise would.
Thus in Fig. 10 (a) the fifth line and first space represent the pitch F, but in Fig. 10 (b) these same staff degrees represent an entirely different tone—F♯. The student should note that the sharp does not then raise anything; it merely causes a staff degree to represent a higher tone than it otherwise would. There is just as much difference between F and F♯ as between B and C, and yet one would never think of referring to C as "B raised"!
