Thus in Demonstrations III and IV notice how the subordinate clauses are for the most part enclosed in commas.
+10. Help through Scansion and Metre.+--A knowledge of this is indispensable in translating verse. To scan the lines will help you to determine the grammatical force of a word, and a knowledge of metre will enable you to grasp the poet’s meaning as conveyed by the position which he assigns to the various words, and the varying emphasis which results from variation of metre. For example:--
(1) _A grammatical help._--You know that final +-a+ is _short_ in nom. and voc. sing. 1st Decl., and in neut. plural, and is _long_ in abl. sing. 1st Decl. and 2nd Imperat. 1st Conj.
Thus in Demonstration II (p. 24) you can easily determine the grammatical form of finals in +-a+.
In Sentence IV +agnă+, in VI +cervă+, in VIII +iunctă columbă+, in IX +Cynthiă+ are all short and nom. sing.
In Sentence V +umbrā unā+ are long and abl. sing. in agreement.
(2) _A help to the poet’s meaning._--The more you know of the principles of scansion, the better able you will be to understand and appreciate the skill with which a great poet varies his metre and chooses his words.
+11. Help through a Study of the Period in Latin.+--One great difference between English and Latin Prose is that, while modern English is to a great extent a language of short, detached sentences, Latin +expresses the sense by the passage as a whole+, and holds the climax in suspense until the delivery of the last word. ‘This mode of expression is called a +PERIOD+ (a +circuĭtus+ or +ambĭtus verborum+), because the reader, in order to collect together the words of the Principal Sentence, must make a _circuit_, so to say, round the inserted clauses,’[2] ‘Latin possesses what English does not, a mode of expression by means of which, +round one main idea are grouped all its accessory ideas+, and there is thus formed a single harmonious whole, called the +PERIOD+.’[3]
[Footnote 3: Postgate, _Sermo Latinus_, p. 45.]
A +PERIOD+ then is a sentence containing only one main idea (the Principal Sentence) and several Subordinate Clauses. The Periodic style is generally used for History and Description, and is best seen in Cicero and Livy.