The horizon lines of the upper park are bold and sweeping and the slopes have great breadth in almost every aspect in which they may be contemplated. As this character is the highest ideal that can be aimed at for a park under any circumstances, and as it is in most decided contrast to the confined and formal lines of the city, it is desirable to interfere with it, by cross-roads and other constructions, as little as possible. Formal planting and architectural effects, unless on a very grand scale, must be avoided; and as nearly all the ground between the Reservoir and 106th Street (west of the Boston road) is seen in connection, from any point within itself, a unity of character should be studiously preserved in all the gardening details. [Sidenote: The lower park.] The lower park is far more heterogeneous in its character and will require a much more varied treatment. The most important feature in its landscape is the long rocky and wooded hill-side lying immediately south of the Reservoir. Inasmuch as beyond this point there do not appear to be any leading natural characteristics of similar consequence in the scenery, it will be important to draw as much attention as possible to this hill-side, to afford facilities for rest and leisurely contemplation upon the rising ground opposite, and to render the lateral boundaries of the park in its vicinity as inconspicuous as possible. The central and western portion of the lower park is an irregular table-land; the eastern is composed of a series of graceful undulations, suggesting lawn or gardenesque treatment. In the extreme south we find some flat alluvial meadow; but the general character of the ground is rugged and there are several bold, rocky bluffs, that help to give individuality to this part of the composition. * * * * * Such being the general suggestions that our survey has afforded, it becomes necessary to consider how the requirements of the Commissioners, as given in their instructions, may be met with the least sacrifice of the characteristic excellencies of the ground. * * * * * [Sidenote: Preliminary considerations.] Up to this time, in planning public works for the city of New York, in no instance has adequate allowance been made for its increasing population and business; not even in the case of the Croton Aqueduct, otherwise so well considered. The City-Hall, the best architectural work in the State, and built to last for centuries, does not at this time afford facilities for one-third the business for which it was intended. The present Post-Office, expensively fitted up some ten years ago, no longer answers its purpose, and a new one of twice its capacity is imperatively demanded. The Custom-House, expressly designed for permanence and constructed to that end at enormous expense less than twenty years ago, is not half large enough to accommodate the present commerce of the city.