The notes and rests above can
be organized in regular groups of two or four beats and divided by “Bar
Lines”. The space between two bar lines is called a “measure”:
The constant number of beats
between two bar lines is indicated at the beginning of each example by
the numerator of a common fraction, (“Time Signature”). The denominator
shows what unit is to be counted as one beat:
The rest for a complete measure is always
, whatever the time signature
may be, and it is always placed in the middle of the measure.
A note filling a complete
measure is also placed in the middle of the measure except when shorter
notes are written above or below it, to be sounded simultaneously with
it. In such cases the long note is placed at the beginning of the
measure.