Section 16 of the Indian Evidence Act, 1872 – “Course of Business”
(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 the 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 Dead Letter Office, are relevant: S. 16.
Letters Sent By Post:
The posting of a letter may be proved by the person who posted it or by showing facts from which the posting may be presumed. For instance, evidence of posting may be given by proving that the letter was delivered to a clerk whose duty it was, in the ordinary course of business, to post it, or that it was put into a post-box which is cleared everyday by the postman.
Proof of posting letters raises a presumption that it reached its destination in due course. The post-mark on the envelope is prima facie evidence of the date, time and place of posting. Further, when the acknowledgment of a registered letter comes back (to the sender) with a signature purporting to be that of the addressee, there is a presumption of the fact of service.