(a) Two contiguous weak vowels with the accent on the first form an
indissoluble diphthong, e.g. _mu^y_.

(b) Two contiguous weak vowels with the accent on the second may or
may not form a diphthong.

Ex. _Si antes no juras que por ru^in falsía_. Hermosilla.
[Diphthong.]

Ex. _Con sus mil rü|idos_, p. 188, LXXIII, l. 19, [No diphthong.]

c. Two contiguous vowels after the accented syllable.

(1) Two contiguous strong vowels after the accented syllable naturally
form a diphthong.

Ex. _Tú, sombra aére^a que, cuantas veces_, p. 170, XV, l. 7.

Diaeresis may be employed to dissolve the diphthong.

(2) If a strong vowel is followed by a weak vowel after the accented
syllable, they form a diphthong, e.g. _hablaba^is, amara^is_.

This diphthong is easily dissolved.

(3) If a weak vowel is followed by a strong vowel after the accented
syllable, they form a diphthong, e.g. _histor^i^a, ans^i^a_.

Ex. _De la brisa nocturna al tenu^e soplo_, p. 192, LXXV, l. 6.