Existence of course of business when relevant.-When there is a question whether a particular act was done, the existence of anycourse of business, according to which it naturally would have beendone, is a relevant fact.
Illustrations
(a) The question is, whether a particular letter was despatched.The facts that it was the ordinary course of business for allletters put in a certain place to be carried to the post, and thatparticular letter was put in that place are relevant.
(b) The question is, whether a particular letter reached A. Thefacts that it was posted in due course, and was not returned throughthe Dead Letter Office, are relevant.