In 1858, William "Duff" Armstrong was tried in the Circuit Court of Illinois for the murder of James Metzker on the night of August 29, 1857. The State's star witness was Charles Allen, who testified on direct examination that he had seen Armstrong strike Metzker in the eye with a slingshot. According to one young lawyer present in the courtroom, Lincoln sat with his head thrown back, his steady gaze apparently fixed upon one spot of the blank ceiling, entirely oblivious to what was happening around him, and without a single variation of feature or noticable movement of any muscle of his face. Finally, Lincoln stood and began his cross-examination of Mr. Allen.

By Mr. Allen:  Yes.

Q:  And you stood very near to them?

A:  No, it was one-hundred fifty feet or more.

Q:  In the open field?

A:  No, in the timber.

Q:  What kind of timber?

A:  Beech timber.

Q:  Leaves on it are rather thick in August?

A:  It looks like it.

Q:  What time did all this take place?

A:  Eleven o'clock at night.

Q:  Did you have a candle there?

A:  No, what would I want a candle for?

Q:  How could you see from a distance of one-hundred fifty feet or more, without a candle, at eleven o'clock at night?

A:  The moon was shining real bright.

Q:  Full moon?

A:  Yes, a full moon.

At this point in the trial, Lincoln withdrew a blue-covered almanac from his back pocket, opened it slowly to the astronomy table for the night in question and placed it before the witness. Lincoln then continued with his cross-examination ...

Q:  Does not the almanac say that on August 29th the moon was barely past the first quarter instead of being full?

A:  (No audible answer from the witness)

Q:  Does not the almanac also say that the moon had disappeared by eleven o'clock?

A:  (No audible answer from the witness)

Q:  Is it not a fact that it was too dark to see anything from so far away, let alone one-hundred fifty feet?

A:  (No audible answer from the witness)

The defendant, William "Duff" Armstrong, was thereafter found not guilty!