Existence of course of business when relevant .—When there is a question whether a particular
act was done, the existence of any course of business, according to which it naturally would have been
done, is a relevant fact.
Illustrations.
(a) The question is, whether a particular letter was dispatched. The facts that it was the ordinary
course of business for all letters put in a certain place to be carried to the post, and that particular letter
was put in that place are relevant.
(b) The question is, whether a particular letter reached A. The facts that it was posted in due course,
and was not returned through the Return Letter Office, are relevant.