English in Use/Other Common Punctuation Marks
The semicolon is used to separate those parts of a compound sentence, which are neither so closely connected as those which are distinguished by the comma, nor so little dependent as those which require the colon.
Complex members 
When two or more complex members, or such clauses as require the comma in themselves, are constructed into a period, they are generally separated by the semicolon: as,
- "In the regions inhabited by angelic natures, unmingled felicity forever blooms; joy flows there with a perpetual and abundant stream, nor needs any mound to check its course."—Carter.
- "When the voice rises, the gesture naturally ascends; and when the voice makes the falling inflection, or lowers its pitch, the gesture follows it by a corresponding descent; and, in the level and monotonous pronunciation of the voice, the gesture seems to observe a similar limitation, by moving rather in the horizontal direction, without much varying its elevation."—Comstock's Elocution, p. 107.
- "The wide, the unbounded prospect lies before me; but shadows, clouds, and darkness, rest upon it."—Addison.
Simple members 
When two or more simple members, or such clauses as complete their sense without subdivision, are constructed into a period; if they require a pause greater than that of the comma, they are usually separated by the semicolon: as,
- "Straws swim on the surface; but pearls lie at the bottom."—Murray's Gram., p. 276.
- "Everything grows old; everything passes away; everything disappears."—Hiley's Gram., p. 115.
- "Alexander asked them the distance of the Persian capital; what forces the king of Persia could bring into the field; what the Persian government was; what was the character of the king; how he treated his enemies; what were the most direct ways into Persia."—Whelpley's Lectures, p. 175.
- "A longer care man's helpless kind demands; that longer care contracts more lasting bands."—Pope.
Words in apposition, in disjunct pairs, or in any other construction, if they require a pause greater than that of the comma, and less than that of the colon, may be separated by the semicolon: as,
- "Pronouns have three cases; the nominative, the possessive, and the objective."—Murray's Gram., p. 51.
- "Judge, judgement; lodge, lodgement; acknowledge, acknowledgement."—Butler's Gram., p. 11.
- "Do not the eyes discover humility, pride; cruelty, compassion; reflection, dissipation; kindness, resentment?"—Sheridan's Elocution, p. 159.
- "This rule forbids parents to lie to children, and children to parents; instructors to pupils, and pupils to instructors; the old to the young, and the young to the old; attorneys to jurors, and jurors to attorneys; buyers to sellers, and sellers to buyers."—Wayland's Moral Science, p. 304.
- "Make, made; have, had; pay, paid; say, said; leave, left; dream, dreamt; mean, meant; reave and bereave have reft." —Ward's Gr., p. 66.
The colon is used to separate those parts of a compound sentence, which are neither so closely connected as those which are distinguished by the semicolon, nor so little dependent as those which require the period.
Additional remarks 
When the preceding clause is complete in itself, but is followed by some additional remark or illustration, especially if no conjunction is used, the colon is generally and properly inserted: as,
- "Avoid evil doers: in such society, an honest man may become ashamed of himself."
- "See that moth fluttering incessantly round the candle: man of pleasure, behold your image!"—Art of Thinking, p. 94.
- "Some things we can, and others we cannot do: we can walk, but we cannot fly."—Beanie's Moral Science, p. 112.
- "Remember heaven has an avenging rod: to smite the poor, is treason against God."—Cowper.
Greater pauses 
When the semicolon has been introduced, or when it must be used in a subsequent member, and a still greater pause is required within the period, the colon should be employed: as,
- "Princes have courtiers, and merchants have partners; the voluptuous have companions, and the wicked have accomplices: none but the virtuous can have friends."
- "Unless the truth of our religion be granted, a christian must be the greatest monster in nature: he must at the same time be eminently wise, and notoriously foolish; a wise man in his practice, and a fool in his belief: his reasoning powers must be deranged by a constant delirium, while his conduct never swerves from the path of propriety."—Principles of Eloquence, p. 80
- "A decent competence we fully taste; it strikes our sense, and gives a constant feast: more we perceive by dint of thought alone; the rich must labour to possess their own."—Young.
Independent quotations 
A quotation introduced without a close dependence on a verb or a conjunction, is generally preceded by the colon: as,
- "In his last moments, he uttered these words: 'I fall a sacrifice to sloth and luxury.'"
- "At this the king hastily retorted: 'No put-offs, my lord; answer me presently.'"—Churchill's Gram., p. 367.
- "The father addressed himself to them to this effect: 'O my sons, behold the power of unity!'"— Rippingham's Art of Speaking, p. 85.
The dash is mostly used to denote an unexpected or emphatic pause, of variable length; but sometimes it is a sign of faltering, or of the irregular stops of one who hesitates in speaking: as,
- "Then, after many pauses, and inarticulate sounds, he said: 'He was very sorry for it, was extremely concerned it should happen so—but—a—it was necessary—a—' Here lord E— stopped him short, and bluntly demanded, if his post were destined for another."—Churchill's Gram., p. 170.
Abrupt pauses 
A sudden interruption, break, or transition, should be marked with the dash: as,
- "'I must inquire into the affair; and if'—'And if!' interrupted the farmer."
- "Whom I—But first it is fit the billows to restrain."—Dryd. Virg. 3.
- "Here lies the great—False marble! where? Nothing but sordid dust lies here."—Young.
Emphatic pauses 
To mark a considerable pause, greater than the structure or the sentence or the points inserted would seem to require, the dash may be employed: as,
- "I pause for a reply.—None?—Then none have I offended.—I have done no more to Caesar, than you should do to Brutus."—Shakspeare: Enfields Speaker, p. 182.
- "Tarry a little. There is something else.—This bond—doesn't give you here—no jot of blood." —ID.: Burgh's Sp., p. 167.
- "It thunders;—but it thunders to preserve."—Young.
- "Behold the picture!—Is it like?—Like whom?"—Cowper.
Faulty dashes 
Dashes needlessly inserted, or substituted for other stops more definite, are in general to be treated as errors in punctuation: as,
- "Here Greece stands by itself as opposed to the other nations of antiquity—She was none of the other nations—She was more polished than they."—Lennie's Gram., p. 78.
- "Here Greece stands by herself, as opposed to the other nations of antiquity. She was none of the other nations: she was more polished than they."—Bullions, E. Gram., p. 114.
If this colon is sufficient, the capital after it is needless: a period would, perhaps, be better.
The curves, or marks of parenthesis, are used to distinguish a clause or hint that is hastily thrown in between the parts of a sentence to which it does not properly belong: as,
- "Their enemies (and enemies they will always have) would have a handle for exposing their measures."—Walpole.
- "To others do (the law is not severe) what to yourself you wish to be done."—Beattie.
The incidental clause should be uttered in a lower tone, and faster than the principal sentence. It always requires a pause as great as that of a comma, or greater.
A clause that breaks the unity of a sentence or passage too much to be incorporated with it, and only such, should be inclosed within curves, as a parenthesis: as,
- "For I know that in me, (that is, in my flesh,) dwells no good thing."—Rom., vii, 18.
- "Know then this truth, (enough for man to know,) virtue alone is happiness below."—Pope.
Included points 
The curves do not supersede other stops; and, as the parenthesis terminates with a pause equal to that which precedes it, the same point should be included, except when the sentences differ in form: as,
- "Now for a recompense in the same, (I speak as to my children,) be you also enlarged."—2 Cor., vi, 13.
- "Man's thirst of happiness declares it is: (for nature never gravitates to nought:) that thirst unquenched, declares it is not here."—Young.
- "Night visions may befriend: (as sung above:) our waking dreams are fatal. How I dreamt of things impossible! (could sleep do more?) of joys perpetual in perpetual change!"—Young.
The hyphen connects the parts of many compound words, especially such as have two accents: as, ever-living. It is also frequently inserted where a word is divided into syllables: as, con-tem-plate. Placed at the end of a line, it shows that one or more syllables of a word are can led forward to the next line.
- A part of the text in this article, was taken from the public domain English grammar "The Grammar of English Grammars" by Goold Brown, 1851.