42. Instead of _-s,_ the ending _-es_ is added--

(1) If a word ends in a letter which cannot add _-s_ and be
pronounced. Such are _box, cross, ditch, glass, lens, quartz_, etc.

[Sidenote: _-Es added in certain cases_.]

If the word ends in a _sound_ which cannot add _-s_, a new syllable is
made; as, _niche--niches, race--races, house--houses, prize--prizes,
chaise--chaises_, etc.

_-Es_ is also added to a few words ending in -o, though this sound
combines readily with _-s_, and does not make an extra syllable:
_cargo--cargoes, negro--negroes, hero--heroes, volcano--volcanoes_,
etc.

Usage differs somewhat in other words of this class, some adding _-s_,
and some _-es_.

(2) If a word ends in _-y_ preceded by a consonant (the _y_ being then
changed to _i_); e.g., _fancies, allies, daisies, fairies_.

[Sidenote: _Words in -ies._]

Formerly, however, these words ended in _-ie_, and the real ending is
therefore _-s_. Notice these from Chaucer (fourteenth century):--

[Sidenote: _Their old form._]

The _lilie_ on hir stalke grene.
Of _maladie_ the which he hadde endured.

And these from Spenser (sixteenth century):--

Be well aware, quoth then that _ladie_ milde.
At last fair Hesperus in highest _skie_
Had spent his lampe.

(3) In the case of some words ending in -_f_ or -_fe_, which have
the plural in _-ves_: _calf_--_calves_, _half_--_halves_,
_knife_--_knives_, _shelf_--_shelves_, etc.

Special Lists.

43. Material nouns and abstract nouns are always singular. When
such words take a plural ending, they lose their identity, and go over
to other classes (Secs. 15 and 17).

44. Proper nouns are regularly singular, but may be made plural
when we wish to speak of several persons or things bearing the same
name; e.g., _the Washingtons_, _the Americas_.

45. Some words are usually singular, though they are plural in
form. Examples of these are, _optics_, _economics_, _physics_,
_mathematics_, _politics_, and many branches of learning; also _news_,
_pains_ (care), _molasses_, _summons_, _means_: as,--

_Politics_, in its widest extent, is both the science and the art
of government.--_Century Dictionary_.

So live, that when thy _summons comes_, etc.--BRYANT.

It served simply as _a means_ of sight.--PROF. DANA.

[Sidenote: Means _plural_.]

Two words, means and politics, _may be plural_ in their
construction with verbs and adjectives:--