and they support the heel of the 60-feet spans over the aisles, at the height of 20 feet. The outer walls are built of masonry to a height of 5 feet, and above that are composed of glazed sash placed between the columns. Portions of the sash are movable for ventilation. Louvre ventilators are introduced in continuous lengths over both the avenues and the aisles. The building is lit entirely by side light, and stands lengthwise nearly east and west.

Shafting. The building admits of the most complete system of shafting, the facilities in this respect being very superior. Eight main lines may be introduced, extending almost the entire length of the structure, and counter-shafts introduced into the aisles at any point. The hangers will be attached either to the wooden horizontal ties of the 60-feet span roof trusses or to brackets especially designed for the purpose, projecting from the columns, in either case at the height of 20 feet from the floor.

Hydraulic Annex.-The annex for hydraulic machines contains a tank 60 feet by 160 feet, with depth of water of 10 feet. In connection with this it is expected that hydraulic machinery will be exhibited in full operation. At the south end of this tank will be a waterfall 35 feet high by 40 feet wide, supplied from the tank by the pumps on exhibition.

HORTICULTURAL BUILDING.

The liberal appropriations of the city of Philadelphia have provided the horticultural department of the exhibition with an extremely ornate and commodious building, which is to remain in permanence as an ornament of Fairmount Park. It is located on the Lansdowne terrace, a short distance north of the Main Building and Art Gallery, and has a commanding view of the Schuylkill River and the north-western portion of the city. The design is in the Mauresque style of architecture of the twelfth century, the principal materials externally being iron and glass. The length of the building is 383 feet, width 193 feet, and height to the top of the lantern 72 feet. The main floor is occupied by the central conservatory, 230 by 80 feet, and 55 feet high, surmounted by a lantern 170 feet long, 20 feet wide and 14 feet high. Running entirely around this conservatory at a height of 20 feet from the floor is a gallery 5 feet wide. On the north and south sides of this principal room are four forcing houses for the propagation of young plants, each of them 100 by 30 feet, covered with curved roofs of iron and glass. Dividing the two forcing houses in each of these sides is a vestibule 30 feet square. At the centre of the east and west ends are similar vestibules, on either side of which are the restaurants, reception-room, offices, etc. From the vestibules ornamental stairways lead to the internal galleries of the conservatory as well as to the four external galleries, each 100 feet long and 10 feet wide, which

surmount the roofs of the forcing houses. These external galleries are connected with a grand promenade, formed by the roofs of the rooms on the ground floor, which has a superficial area of 1800 square yards. The east and west entrances are approached by flights of blue marble steps from terraces 80 by 20 feet, in the centre of each of which stands an open kiosque 20 feet in diameter. The angles of the main conservatory are adorned with eight ornamental fountains. The corridors which connect the conservatory with the surrounding rooms open fine vistas in every direction. In the basement, which is of fireproof construction, are the kitchen, store-rooms, coal-houses, ash-pits, heating arrangements, etc.

This structure will stand north of the Horticultural Building, and on the eastern side of Belmont avenue. It will illustrate a novel combination of materials, and is capable of erection in a few months. Its materials are wood and glass. It consists of a long nave crossed by three transepts, both nave and transept being composed of Howe truss arches of a Gothic form. The nave is 820 feet in length by 125 feet in width, with a height of 75 feet from the floor to the point of the arch. The central transept is of the same height and a breadth of 100 feet, the two end transepts 70 feet high and 80 feet wide. The four courts enclosed between the nave and transepts, and also the four spaces at the corners of the building, having the nave and end transepts for two of their sides, will be roofed and form valuable spaces for exhibits. Thus the ground plan of the building will be a parallelogram of 540 by 820 feet, covering a space of above ten acres. In its immediate vicinity will be the stock-yards for the exhibition of horses, cattle, sheep, swine, poultry, etc.

This comprehensive system of building-viz., Main Building, covering 21.47 acres; Art Gallery, covering 1.5 acres; Machinery Building, covering 14 acres; Horticultural Building, covering 1.5 acres; Agricultural Building, covering 10.15 acres-provides for the accommodation of the seven departments of the classification.

There will be required, in addition to these buildings, a number of smaller structures for the administration of the exhibition, all of which are now being designed, with a view to their early erection. The preparation of the grounds allotted to the Commission in Fairmount Park and the construc