3. Expressions like in eō tempore, in summa senectūte, take the preposition because they denote situation rather than time.
B. Time within which.
[231]. Time within which is denoted by the Ablative either with or without a preposition; as,—
stella Sāturnī trīgintā annīs cursum cōnficit, the planet Saturn completes its orbit within thirty years;
ter in annō, thrice in the course of the year.
1. Occasionally the Ablative denotes duration of time; as,—
bienniō prōsperās rēs habuit, for two years he had a prosperous administration.
THE LOCATIVE.
[232]. The Locative case occurs chiefly in the following words:—
1. Regularly in the Singular of names of towns and small islands of the first and second declensions, to denote the place in which; as,—