in size to a
half-step. It should be noted that this change in the seventh tone of
the scale caused an interval of a step-and-a-half between the sixth and
seventh tones of the scale.

1 whole 2 half 3 whole 4 whole 5 half 6 step and 7 half 8
step step step step step a half step

87. _The melodic minor scale_ substitutes a tone one half-step higher
than six as well as one a half-step higher than seven, but this change
is made in the ascending scale only, the descending scale being like the
primitive form. The higher sixth (commonly referred to as the "raised
sixth") was used to get rid of the unmelodic interval of a
step-and-a-half[15] (augmented second), while the return to the
primitive form in descending is made because the ascending form is too
much like the tonic major scale.

[Footnote 15: The step-and-a-half (augmented second) is "unmelodic"
because it is the same size as a _minor third_ and the mind finds it
difficult to take in as a _second_ (notes representing it being on
adjacent staff-degrees) an interval of the same size as a third.]

1 whole 2 half 3 whole 4 whole 5 whole 6 whole 7 half 8
step step step step step step step

7 whole 6 half 5 whole 4 whole 3 half 2 whole 1
step step step step step step

This form is used only to a very limited extent, and then principally in
vocal music, the harmonic form being in almost universal use in spite of
the augmented second.

88. The minor scale in its various positions (up to five sharps and five
flats) and in all three forms follows: a composition based on any one of
these forms (or upon a mixture of them, which often occurs) is said to
be _in the minor mode_. It will be noted that the first four tones are
alike in all three forms; _i.e._, the lower tetrachord in the minor
scale is invariable no matter, what may happen to the upper tetrachord.
The sign + marks the step-and-a-half.

[Illustration]

_Note._--The student is advised to recite the _harmonic form_
of the minor scale as was suggested in the case of the major
scale, noting that the "raised seventh" does not affect the
key-signature. _E.g._,--E--F[sharp]--G--A--B--C--D[sharp]--E;
signature, one sharp, F.

89. A minor scale having the same signature as a major scale is said to
be its _relative minor_. _E.g._,--e is the rela