small space. In case the place of residence or business is not written
in the address, then the complimentary address of _Dear Sir_ or
_Gentlemen_ will be placed on the next line under the name, or fourth
line from the top of the sheet, and the letter will begin on the fifth
line from the top, thus:

[Illustration:

Mr. Henry L. Dunham,
Dear Sir:
In answer to your esteemed favor]

Sometimes for the sake of convenience, and the saving of time and
labor, the letter head has printed in the left corner, above the
address, a blank form of memorandum as follows:

[Illustration:

Referring to
yours of...

OR,

In reply to
your favor of...,]

and after this introduction the writer is able speedily to get at the
marrow of his letter, without acknowledging the receipt of a former
communication.