A quantity of felt, of weight similar to that of the cap, was procured and the revolver discharged at it from varying distances.

A microscopic examination showed that certain discolorations around the bullet-hole (claimed by the defence to be burns made by the powder) were, in fact, grease marks, and that the shot must have been fired from a distance of about fifteen feet.

The defendant was convicted on his own story, supplemented by the evidence of the witness who made the tests.
The most obvious and first requirement is, as has been said, to find the direct witnesses to the facts surrounding the crime, commit their statements under oath to writing, so that they cannot later be denied or evaded, and make sure that these witnesses will not only hold no intercourse with the other side, but will be on hand when wanted.

This last is not always an easy task, and various expedients often have to be resorted to, such as placing hostile witnesses under police surveillance, or in some cases in "houses of detention," and hiding others in out-of-the-way places, or supplying them with a bodyguard if violence is to be anticipated.

When the proper time comes the favorable witnesses must be duly drilled or coached, which does not imply anything improper, but means merely that they must be instructed how to deliver their testimony, what answers are expected to certain questions, and what facts it is intended to elicit from them.