Differing methods of pointing have been called 'rhetorical punctuation and grammatical punctua tion, with the supposition that in the former case, for guidance in reading, each place of natu ral pause should be indicated by a dis tinctive point. It was probably this rhetorical or elocutionary consideration that led to the as signment of time values to the marks. The comma was said to indicate a pause long enough to count one, the semicolon two, the colon three, and the period four. But good reading or speak ing does not justify this notion of counting, pauses being made where even a rhetorical punc tuator would not indicate them, and the time of the pause being often shortened or lengthened in a way that cannot be recognized 'iyithout the addition of other distinctive marks not yet in vented. In any case the reader's individuality may ignore punctuation. Consequently. punctua tion governed by purely grammatical circum stance seems likely to prevail increasingly, al though it has not yet entirely superseded the other method. Another classification has been made, including, besides rhetorical and gram matical, etymological and reference punctuation; but. although the marks for the last two pur poses are used in positions similar to those of real punctuation, their nature more nearly ap proaches that of diacritics.
The comma is used to mark the slightest ac tual turn or jointure in grammatical construc tion, and thus occurs much more frequently than any other point. Very often it is placed after a long nominative without an actual break in sense, but no one has ever prescribed an exact or even approximate length of the subject after which the comma is to be used.
The semicolon is used after a clause when the turn in sense is too distinct to use merely a comma, and not sufficient for a period ; most fre quently between clauses all or some of which con tain commas. Often a semicolon is placed be tween \\dint might be made separate sentences; this is done, as it is in this instance, because of a closer connection of sense than where the sen tence form is used. Discriminative use of the semicolon is often considered a test of punctua tion.
The colon is now generally confined to an in troductory function, being comparatively seldom used as a mark of ordinary grammatical punctua tion.
The period is used at the end of every sentence that is not a question or an exclamation, an interrogatory or exclamatory sentence being prop erly ended with its own appropriate mark.
The dash is used to denote a sudden change in the construction, a suspension of sense. an unex pected transition in the sentiment, a sudden in terruption, or hesitation.
:Marks of parenthesis are used to inclose a word, phrase, clause, or sentence inserted inde pendently, as for explanation or any similar pur pose. Square brackets inclose aim insertion not merely disconnected, but having no effect on the meaning of the context, an editorial explanatory word or phrase, or an independent direction. as in dramatic composition. An apostrophe is the sign or part of a sign of the possessive: it takes the place of letters omitted in contracting a word: and it is used to mark the end of a quotation whose beginning is marked by inverted commas. The use of various other marks is commonly ex plained in treatises on punctuation, including, marks of reference, elision, emphasis, connection, and diacritics.
Some difference in punctuation is generally considered necessary according to differe net', in composition. Thus, a succession of short Sen tences may need very little pointing within any sentence, while even the same thoughts might be expressed by the use of one long, complex sen tence that demands, for unmistakable division into parts not liable to confusion in reading, cor respondingly complex punctuation. Accordingly, authors must determine this matter without strict reference to any formulated set of rules, as occasional demands for special pointing cannot all be comprehended in any system. As a rule, for instance, the frequent use of dashes has been stigmatized as a mark of ignorance; but, not withstanding, it may be—but not often—truly artistic. Again, while it has been said that the colon has practically gone out of use as a purely grammatical point, it also may be used freely by a master hand with so good effect as to be beyond criticism. Among the fullest and most noted of the older treatises are: Brown. Grammar of Eng lish Grammars (1851 and many later editions) ; Wilson, Treatise on Punctuation, ( 1850 and many later editions). Recent special works are: Bige low. Handbook of Punctuation (Boston, 1885) ; Teall, Punctuation (New York, 1807).