Her plot has many changes; every day
Speaks a new scene. The last act crowns the play.
3. When each of the members of a compound sentence makes a distinct statement and has some dependence on statements in the other member or members of the sentence.
Wisdom hath builded her house; she hath hewn out her seven pillars; she hath killed her beasts; she hath mingled her wine; she hath furnished her table.
Each member of this sentence is nearly complete. It is not quite a full and definite statement, but it is much more than a mere amplification such as we might get by leaving out she hath every time after the first. In the former case we should use periods. In the latter we should use commas.
4. A comma is ordinarily used between the clauses of a compound sentence that are connected by a simple conjunction, but a semicolon may be used between clauses connected by conjunctive adverbs. Compare the following examples:
The play was neither edifying nor interesting to him, and he decided to change his plans.
The play was neither edifying nor interesting to him; therefore he decided to change his plans.
5. To indicate the chapter references in scriptural citations.
Matt. i: 5, 7, 9; v: 1-10; xiv: 3, 8, 27.