Part 4 (1/2)

DeVinne remarks upon this use of the colon that it is traditional and can not be explained.

The colon is sometimes used between the hours and minutes in indicating time, like: 11:42 a.m.

DeVinne does not approve of this, though other authorities give it as the rule. It is probably better to use the period in spite of its use as a decimal point, which use was probably the motive for seeking something else to use in writing time indications. In railroad printing the hour is often separated from the minutes by a simple s.p.a.ce without any punctuation.

THE PERIOD

The period, or full stop, marks the end of a declarative sentence. As a sign it has several other uses which will appear in the paragraphs following.

_Rules for the Use of the Period_

1. At the end of every sentence unless interrogative or exclamatory.

2. After abbreviations.

Nicknames, _Sam_, _Tom_, etc., are not regarded as abbreviations.

The metric symbols are treated as abbreviations but the chemical symbols are not. M. (metre) and mg. (milligram) but H_{2} O and Na Cl.

Per cent is not regarded as an abbreviation.

The names of book sizes (12mo 16mo) are not regarded as abbreviations.

The period is now generally omitted in display matter after

Running heads, Cut-in side-notes, Central head-lines, Box heads in tables, Signatures at the end of letters.

The period is omitted

After Roman numerals, even though they have the value of ordinals.

After MS and similar symbols.

In technical matter, after the recognized abbreviations for linguistic epochs. IE (Indo-European), MHG (Middle High German)

and after t.i.tles of well-known publications indicated by initials such as AAAPS (Annals of the American Academy of Political Science).

When a parenthesis forms the end of a declarative sentence the period is placed outside the parenthesis, as in the preceding example. A period is placed inside a parenthesis only in two cases.

1. After an abbreviation.

This was 50 years ago (i.e. 1860 A.D.)

2. At the end of an independent sentence lying entirely within the parenthesis.

Lincoln was at the height of his powers in 1860 (He was elected to the presidency at this time.)