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

by Frederick W. Hamilton

My dear Sir:

When the letter is informal use a comma.

Dear John,

6. Between the chapter and verse in scriptural references.

John xix: 22.

7. Between the city of publication and the name of the publisher in literary references.

“The Practice of Typography.” New York: Oswald Publishing Company.

The colon has been similarly employed in the imprints on the title pages of books.

New York: Harper & Brothers, 1880.

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