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

by Frederick W. Hamilton

When the salutation is formal a colon should be used.

My dear Mr. Smith:

20. To separate the closing salutation of a formal letter from the rest of the sentence of which it forms a part.

Soliciting your continued patronage, I am,
Very sincerely yours,
John W. Smith.

21. To separate two numbers.

January 31, 1915.

By the end of 1914, 7062 had been built.

22. To indicate an ellipsis.

Subscription for the course, one dollar.

Exceptions to this rule are made in very brief sentences, especially in advertisements: Tickets 25 cents. Price one dollar.