[1107.] Names of countries are sometimes used in the plural when the country consists of several parts which are called by the same name as the whole country: as, Galliae, the Gauls; Germāniae, the Germanies.
[1108.] Material substantives are often used in the plural to denote different sorts of the substance designated, its constituent parts, or objects made of it: as,
aera, lumps of bronze, bronzes, coppers. aquae, water in different places, medicinal springs. cērae, pieces of wax, tablets, wax masks, waxworks. marmora, kinds of marble, blocks of marble, works of marble. nivēs, snowflakes, snowdrifts, snowstorms, repeated snows. spūmae, masses of foam. sulpura, lumps of sulphur. vīna, wines, different kinds of wine.
[1109.] Abstract substantives are often used in the plural to denote different kinds or instances of the abstract idea, or an abstract idea pertaining to several persons or things: as,
sunt domesticae fortitūdinēs nōn īnferiōrēs mīlitāribus, Off. 1, 78, there are cases of heroism in civil life fully equal to those in war. tē cōnscientiae stimulant maleficiōrum tuōrum, Par. 18, you are tormented by pricks of conscience for your sins. propter siccitātēs palūdum, 4, 38, 2, because the swamps were dry everywhere.
[1110.] The plural is sometimes used in generalizations, and in poetry to magnify a single thing, to give mystery to the statement, or often merely for metrical convenience: as, advēnisse familiārēs dīcitō, Pl. Am. 353, say that the people of the house are come, the plural familiārēs denoting one person. Priamī dum rēgna manēbant, V. 2, 22, while Priam’s realms still stood. externōs optāte ducēs, V. 8, 503, choose captains from a foreign strand, i.e. Aeneas.
[CASE.]
[1111.] There are two groups of cases, the principal and the secondary.
[1112.] The principal cases are the nominative and the accusative. The principal cases, which have more complete inflections than the secondary, express the two chief relations of the noun in the sentence, those of the subject and of the object. The secondary cases are used to express subordinate or supplementary relations.