As you requested some notes on interesting subjects on this side the water, I do not think I can better comply with your request than by sending you a few remarks on the present crystal palace at Sydenham as a horticultural structure, and the somewhat novel style of landscape gardening adopted in the grounds around it To enable your readers, however, to form an adequate idea of this extraordinary place, it will be necessary to give a brief sketch of the building itself and the spot on which it stands. The building stands on an irregular parallelogram of ground, containing nearly 300 acres. The most northern portion of this ground rises to the height of some 200 to 300 feet above the level of the surrounding country, and on this elevated ground the palace is erected. This hill is undoubtedly a splendid site for such a building - commanding on the one side a prospect of the counties of Kent and Surrey, and on the other, of the great metropolis, which it overlooks. The approach by railway is up a steep incline, which carries the visitor to the very corridor of the palace.

The building consists of a grand central nave, as it is called, which forms the middle and largest as well as highest portion of the building; two side aisles, which constitute that part of the building right and left of the nave; the transepts, or projecting portions of the building; two main galleries and two wings; beside the colonnade, 720 feet in length, which leads from the railroad terminus to the south wing of the palace. The effect and general beauty of the building is very much increased by several changes that have been introduced since its erection at Sydenham. Those who saw it at Hyde Park must have been struck with the monotonous effect which it had upon the observer, by the great length and sameness of every part of the structure, and also by the continuous rows of columns and girders which succeeded each other so rapidly that the eye felt fatigued and the perceptions deadened very speedily by the contemplation of them, so as to render it impossible to form a true conception of the extent and capacity of the building.

As the palace is now erected, we find pairs of columns and girders advanced into the nave eight or ten feet beyond the continuous line that supports the roof at distances of seventy-two feet, and thereby very much improving the interior effect, and enabling the observer much more easily to measure and to appreciate the extent of the building. I would here remark, that in the French crystal palace, now being erected at Paris, this fault is even more striking than in that at London, although the Paris building has a very different effect upon the mind - probably from its more permanent and substantial appearance, being built of the white sandstone of the Paris basin, which, when first hewn and polished, has the appearance, at a short distance, of white marble; but the interior of the building has a very deadening and monotonous effect But as the interior of the French palace is yet unfinished, and also unfurnished, it is hardly fair to pronounce upon the effect of the whole. It is a splendid structure, and by many will be considered superior to anything that has yet been produced.

The general appearance exteriorly, of the Sydenham palace, is not very unlike that erected at New York, except in the greater extent of the former. For beauty of design, we think the New York palace far before it, as also in the proportion of its parts and in the architectural as well as the mechanical arrangement of its details. The great defect of all glass structures, whether large or small, is a want of harmony, both with the things within and the things without There is unity, but there is no harmony; and what is unity without harmony ? A building may be architecturally and mechanically perfect in all its parts, yet be in harmony with nothing about it; and whether these structures be termed the "Early English" or the "Modern English" style, we are very much of the opinion that the French palace, which is very different from either the London or New York ones, will, with its opaque walls and massive entablatures, be much nearer the mark of architectural harmony than either of its predecessors.

The Sydenham building, like its New York namesake, is entirely of iron above the ground floor, with the exception, we believe, of a very small portion of the north front, which is paneled with wood. The whole of the main building is 1,608 feet in length, and the wings or L at each end are each of them 574 feet, making a continuous length of 2,756 feet, which, with the colonnade 720 feet, leading from the south wing to the railroad station, and which is to form a grand promenade conservatory, with plants and statuary on each side of the path, will form a straight walk, without diverging to the right or left, of 3,476 feet, or nearly three-quarters of a mile. The length of the Hyde Park building was only 1,848 feet; so that, including the wings and colonnade, the present structure is larger than its predecessor 1,628 feet The superficial area of the ground, including the wings, is 598,396 feet; the area of the gallery flooring and wings, 245,260; altogether amounting to 843,656 superficial feet The width of the nave, or main avenue of the building, is 72 feet, which is also the width of the north and south transepts; and the heighth of all three, from the floor to the springing of the arch, is 68 feet The height from the flooring to the crown or top of the arch is 104 feet The length of the north and south transepts is 336 feet respectively.

The length of the central transept is 384 feet; its width, 120 feet; its height, from the floor to the top of the louver, or ventilator, is 168 feet; from the garden front to the top of the louver, 208 feet.

The Sydenham palace is doubtless greatly improved in its exterior effect from the old one in Hyde Park, as very many modifications have been properly introduced - such as the arched roof which covers the nave, raising it 44 feet higher than the nave as it existed in Hyde Park; the three transepts which are now introduced into the structure, instead of one; and the center transept towering into the air, and forming at once a center-piece pleasing in its outlines, and also a grand hall to the palace, of surpassing magnitude and brilliancy. A great improvement, also, is the formation of recesses twenty-four feet deep in the garden fronts of all the transepts. These throw fine shadows on the perspective of the building, and relieve the continuous surface of plain glass, which is the grand source of that unity without harmony that is so justly complained of in all glass buildings of large size, and which gave the New York building, with its Elizabethan turrets, a decided advantage over its predecessor.