The fourth of d is g and has two flats (b and e):—
g a bb c d eb f# g
1 2∼3 4 5∼6∪7∼8
The fourth of g is c and has three flats (b, e and a):—
c d eb f g ab b⊄ c
1 2∼3 4 5∼6∪7∼8
The student will notice a contradiction in the above scale; it is stated that c has three flats and in the example, b is cancelled. This cancel, however, appears as accidental (the raised seventh) and must be a flat in the signature.
The fourth of c is f and has four flats (b, e, a and d):—
f g ab bb c db e⊄ f
1 2∼3 4 5∼6∪7∼8
The fourth of f is bb and has five flats (b, e, a, d and g):—
bb c db eb f gb a⊄ bb
1 2∼3 4 5∼ 6∪7∼8