The only existing office, in a sound state, and having any architectural pretensions, which must be removed, is the State Paper Office, which is obviously too much in the way of a good general arrangement of plan to be allowed to remain. The Parade, enclosed by the Public Offices on three sides, and by the open screen to the Park on the fourth, would form a striking feature of the locality, and provide a larger and more conveniently arranged area for inspections than at present; and the advantage which is proposed, of being able to close it at pleasure, might be found to be of important use, in times of public excitement, not only for the inspection of the military but also of the police. THOROUGHFARES AND TRAFFIC. Ample accommodation is provided for the diversion of the eastern and western traffic, through the proposed main north and south thoroughfares of Whitehall and St. James’s Park, by means of two new bridges across the river, and a public thoroughfare through the Mall to the Strand. Westminster Bridge, rebuilt as proposed, should be retained in its present position, as being the natural line of communication with the Birdcage Walk, and the most convenient approach to the three important buildings in Westminster, from the Surrey side of the river. It is of the utmost importance, however, that the level of its roadway, as determined by Parliament, should remain unaltered; otherwise the effect of not only the Palace at Westminster, but also of the proposed Government Offices, will be seriously injured. To obviate in some degree the sunken effect of the New Palace at Westminster, as it will be seen from the bridge, even when lowered to the level determined by Parliament, a raising of the River Terrace of that building might be worthy of consideration upon that as well as other grounds. The plan exhibits two alternative propositions for the bridge at Charing Cross,--one, an entirely new bridge, and the other the present Suspension Bridge, widened for carriages. The former is preferred by the authors of this plan, but, if the latter should be adopted, it is hoped that its principle of suspension may be abolished, so that the present towers and chains may no longer destroy some of the finest effects of London, as seen from various points of view. MISCELLANEOUS IMPROVEMENTS.