This section presents formats for memos and letters. Because electronic mail usually has a built-in format, no format is assigned here for it. In your correspondence, you should concentrate on being clear and precise. Because audiences tend to read letters and memos quickly, opt for shorter sentences and paragraphs than you would use in a formal report or journal article. Also, in correspondence, you should consider carefully the tone .
Tone is difficult to control in correspondence.
The answers are not simple. Often, engineers and scientists lose control of tone by avoiding simple straightforward wording. When some people sit down to write a business letter or memo, they change their entire personality. Because these phrases are not natural or straightforward, they inject an undesired attitude, usually arrogance, into the writing. For more information about the style of correspondence, see Chapter 12 of The Craft of Scientific Writing.