In the next place we must consider what is added to the affair, that is to say, what is greater, what is less, what is equally great, what is similar.  And from these topics some conjecture is derived, if proper consideration is given to the question how affairs of greater importance, or of less, or of equal magnitude, or of similar character, are usually transacted.  And in this class of subjects the result also ought to be examined into; that is to say, what usually ensues as the consequence of every action must be carefully considered; as, for instance, fear, joy, trepidation.

But the fourth part was a necessary consequence from those circumstances which we said were attendant on affairs.  In it those things are examined which follow the accomplishment of an affair, either immediately or after an interval.  And in this examination we shall see whether there is any custom, any action, any system, or practice, or habit, any general approval or disapproval on the part of mankind in general, from which circumstance some suspicion at times arises.

XIII.  But there are some suspicions which are derived from the circumstances which are attributed to persons and things taken together.  For many circumstances arising from fortune, and from nature, and from the way of a man’s life, and from his pursuits and actions, and from chance, or from speeches, or from a person’s designs, or from his usual habit of mind or body, have reference to the same things which render a statement credible or incredible, and which are combined with a suspicion of the fact.

For it is above all things desirable that inquiry should be made in this way, of stating the case first of all, whether anything could be done; in the next place, whether it could have been done by any one else; then we consider the opportunity, on which we have spoken before; then whether what has been done is a crime which one is bound to repent of; we must inquire too whether he had any hope of concealing it; then whether there was any necessity for his doing so; and as to this we must inquire both whether it was necessary that the thing should be done at all, or that it should be done in that manner.  And some portion of these considerations refer to the design, which has been already spoken of as what is attributed to persons; as in the instance of that cause which we have mentioned.  These circumstances will be spoken of as before the affair,—­the facts, I mean, of his having joined himself to him so intimately on the march, of his having sought occasion to speak with him, of his having lodged with him, and supped with him.  These circumstances were a part of the affair,—­night, and sleep.  These came after the affair,—­the fact of his having departed by himself; of his having left his intimate companion with such indifference; of his having a bloody sword.