Lee marched over the mountain wall,—­ Over the mountains winding down, Horse and foot, into Frederick town.  —­WHITTIER.

III.  Plurals formed by Adding -s or -es.

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.