16. Letter-carriers and rural messengers are prohibited at any time from distributing letters, newspapers, &c., except such as have passed through the Post-Office. They are not allowed to receive any payment beyond the unpaid postage on letters or newspapers delivered.[209] Further, in delivering letters, they are not allowed to deviate from the route laid down for them by the proper authorities. 17. Persons living within the free delivery of any town cannot obtain their letters at the post-office window, unless they rent a private box, in which case they may apply for them as often as a mail arrives. In some cases where there are not frequent deliveries of letters, persons may apply at the post-office for their letters arriving by a particular mail after which there is not an immediate delivery from door to door. 18. Persons having a distinct residence in any town cannot have their letters addressed to the post-office (except a private box be taken), and a postmaster is warranted, when such letters arrive so addressed, to send them out by the first delivery. The "Poste Restante" is meant for commercial travellers, tourists, and persons without any settled residence. Letters so addressed are kept in the office for one month, after which, if they are not called for, they are returned to the writers through the Dead-Letter Office. "Ship-letters" in sea-port towns, or letters addressed to seamen on board ship expected to arrive at these towns, are kept _three_ months before they are thus dealt with. 19. When any letters, &c. remain undelivered, owing to the residences of the persons to whom they are addressed not being known, a list of such addresses is shown in the window of the post-office to which they may have been sent, during the time (only _one week_ in these cases) they are allowed to remain there. 20. Greenwich time is kept at the Post-Office. LONDON DISTRICT POSTS. 1. The London district comprises all places within a circle of twelve miles from St. Martin's-le-Grand, including Cheshunt, Hampton, Hampton Court, Sunbury, and the post towns of Barnet, Waltham Cross, Romford, Bromley, Croydon, Kingston, and Hounslow. 2. There are ten postal districts, each of which is treated in many respects as a separate post town. The names of the districts are as follows, the initial letter or letters of the name forming the necessary abbreviation to each, viz.:--East Central, West Central, Western, South-Western, North-Western, Northern, North-Eastern, Eastern, South-Eastern, and Southern.