Re, at the end of some words derived from the Latin or French, is
pronounced like a weak er, as theatre, sepulchre.

S.

S has a hissing sound, as sibilation, sister.

A single s seldom ends any word, except in the third person of verbs,
as loves, grows; and the plurals of nouns, as trees, bushes,
distresses; the pronouns this, his, ours, yours, us; the adverb thus;
and words derived from Latin, as rebus, surplus; the close being always
either in se, as house, horse, or in ss, as grass, dress, bliss, less,
anciently grasse, dresse.

S, single at the end of words, has a grosser sound, like that of z, as
trees, eyes, except this, thus, us, rebus, surplus.

It sounds like z before ion, if a vowel goes before it, as intrusion; and
like s, if it follows a consonant, as conversion.

It sounds like z before e mute, as refuse, and before y final, as rosy; and
in those words, bosom, desire, wisdom, prison, prisoner, present, present,
damsel, casement.

It is the peculiar quality of s, that it may be sounded before all
consonants, except x and z, in which s is comprised, x being only ks,
and z a hard or gross s. This s is therefore termed by grammarians suæ
potestatis litera; the reason of which the learned Dr. Clarke
erroneously supposed to be, that in some words it might be doubled at
pleasure. Thus we find in several languages.