the character of the proposition, but it may be laid down as a
general principle that the prospect must be made to understand
thoroughly just what the article is for, how it is made, how it
looks, how it is used, and what its points of superiority are.
Whenever possible, the description and explanation in the letter
should be reinforced by samples or illustrations that will give a
more graphic idea of the product.

The prospect may be sufficiently familiar with the thing you are
selling to relieve you of the necessity of describing and
explaining, although usually these supports are necessary for a
selling campaign. But it must be remembered that description and
explanation alone do not make a strong appeal to the will. They may
arouse interest and excite desire but they do not carry conviction
as argument does. Some letters are full of explanation and
description but lack argument. The repair man from the factory may
give a good explanation of how a machine works, but the chances are
he would fall down in trying to sell the machine, unless he
understood how to reinforce his explanations with a salesman's
ability to use argument and persuasion.

And so you must look well to your arguments, and the arguments that
actually pull the most orders consist of proofs--cold, hard logic
and facts that cannot be questioned. As you hope for the verdict of
the jury you must prove your case. It is amazing how many
correspondents fail to appreciate the necessity for arguments. Pages
will be filled with assertions, superlative adjectives, boastful
claims of superiority, but not one sentence that offers proof of any
statement, not one logical reason why the reader should be
interested.