The amount and extent of the registered letter business may be judged when it is stated that during the month of January, 1874, at the post office in New York over sixty thousand registered letters were received, nearly thirty thousand of which were for delivery in the city, and the rest for other places, New York being a distributing office. DEAD LETTERS. About all that people know or understand of the workings of the Dead Letter bureau of the Post Office Department is that if a letter is not delivered in due time it is sent to the Dead Letter Office, and there opened and returned to the writer. When, each year, they see the report of the Postmaster General, the amount of money and number of letters that are returned to the senders seems enormous, but when it is considered that millions of letters and thousands of dollars are carried and safely delivered correctly each year in the United States, the number that fails of delivery, by contrast, does not seem so great. During the month of November, 1873, nearly ten millions of letters were received and dispatched in New York City. Every effort is always made to return money or any articles of value which may be found in dead letters. It is required that everything valuable shall be registered free when returned to the owners; but if for any reason it cannot be delivered to the rightful owner, it is held in the Department subject to the owners control for four years, and after that time it is conveyed to the Treasury, and goes towards decreasing the annual deficit in the Post Office Department. All letters which are properly stamped and addressed, and go to their destination, but are not delivered at the end of one week, by reason of the person addressed not being found, are advertised, either by publishing once in a daily or weekly paper, or by posting the list in a conspicuous place in the office. At the end of four weeks all then undelivered are sent to the dead letter office. The matter of advertising in newspapers is left to the discretion of the Postmaster General, and it is but few of the larger offices that are allowed to do so. The compensation is fixed by law at one cent for each letter, which is to be paid by the person receiving the letter; but by reason of the fact that by far the larger portion of those advertised are not delivered, the expense is so great that but few offices can be allowed to advertise. All letters which are dropped into an office without stamps or only part paid, or the address is not readable, are sent at once to the Dead Letter office, except in some few offices where a bulletin board is provided for the purpose of displaying to the public letters of this character. When a letter which is wholly or in part unpaid, and upon which the address is legible, is found to contain a valuable enclosure a printed circular is sent to the party addressed requesting that the requisite amount of postage be forwarded in