Still more important was the division of London into ten postal districts, carried out during the year 1856. The immense magnitude of the metropolis necessitated this scheme; it having been found impossible to overcome the obstacles to a more speedy transmission of letters within and around London, or properly to manage without some change, the ever increasing amount of Post-Office business. Under the new arrangements, each district was to be treated in many respects as a separate town, district post-offices to be erected in each of them. Thus, instead of all district post-letters being carried from the receiving houses to the chief office at St. Martin's-le-Grand, there to be sorted and re-distributed, the letters must now be sent to the principal office of the district in which they were posted; sorted there; and distributed from that office according to their address. The time and trouble saved by this arrangement is, as was expected, enormous. Under the old system, a letter from Cavendish Square to Grosvenor Square went to the General Post-Office, was sorted, and then sent back to the latter place, travelling a distance of four or five miles: whereas, at present, with hourly deliveries, it is almost immediately sent from one place to the other.[132] An important part of the new scheme was, that London should be considered in the principal provincial post-offices as ten different towns, each with its own centre of operations, and that the letters should be assorted and despatched on this principle. Country letters would be delivered straightway--without any intermediate sorting--to that particular part of London for which they were destined; whilst the sorters there having the necessary local knowledge, would distribute them immediately into the postmen's walks. With respect to the _smaller_ provincial towns, it was provided that their London correspondence should be sorted into districts on the railway during the journey to the metropolis. Thus, on the arrival of the different mails at the several railway termini, the letters would not be sent as formerly to the General Post-Office, but direct to each district office, in bags prepared in the course of the journey. It was a long time before this new and important plan was thoroughly carried out in all its details; but now that it is in working order, the result is very marked in the earlier delivery of letters, and in the time and labour saved in the various processes. In fact, all the anticipated benefits have flowed from the adoption of the measure.