Punctuation / A Primer of Information about the Marks of Punctuation and their Use Both Grammatically and Typographically

by Frederick W. Hamilton

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 space without any punctuation.

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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.