THE HALL OF MINES AND MINING.

LOCATED at the southern extremity of the western lagoon or lake, and between the ELECTRICITY and TRANSPORTATION BUILDINGS, is the MINES AND MINING BUILDING. The architect of this building, which is 700 feet long by 350 wide, is S. S. BEMAN, of Chicago. Its architecture has its inspiration in early Italian renaissance, with which sufficient liberty is taken to invest the building with the animation that should characterize a great general Exposition. There is a decided French spirit pervading the exterior design, but it is kept well subordinated. In plan it is simple and straightforward, embracing on the ground floor spacious vestibules, restaurants, toilet rooms, etc. On each of the four sides of the building are placed the entrances, those of the north and south fronts being the most spacious and prominent. To the right and left of each entrance, inside, start broad flights of easy stairs leading to the galleries. The galleries are 60 feet wide and 25 feet high from the ground floor, and are lighted on the sides by large windows and from above by a high clearstory extending around the building.

The main fronts look southward on the great Central Court and northward on the western and middle lakes and a beautiful thickly wooded island. These principal fronts display enormous arched entrances, richly embellished with sculptural decorations, emblematic of Mining and its allied industries. At each end of these fronts are large square pavilions surmounted by low domes which mark the four corners of the building and are lighted by large arched windows extending through the galleries.

Between the main entrance and the pavilions are richly decorated arcades forming an open loggia on the ground floor and a deeply recessed promenade on the gallery floor level, which commands a fine view of the lakes and islands to the northward and the great Central Court on the south. These covered promenades are each 25 feet wide and 230 feet long, and from them is had access to the building at numerous points. These loggias on the first floor are faced with marbles of different kinds and hues, which will be considered part of the Mining Exhibit, and so utilized as to have marketable value at the close of the Exposition. The loggia ceilings will be heavily coffered and richly decorated in plaster and color. The ornamentation is massed at the prominent points of the facade. The exterior presents a massive, though graceful appearance.

The main fronts are 65 feet high from ground to top of cornice, and the main central entrances are 90 feet to apex of pediment. The long sides of the building are treated in a simpler manner than the main fronts; large segmental windows extend through the galleries and are placed between the broad piers, affording an abundance of light to the space beneath the galleries. The two-storied portion of the building, of which the gallery forms the upper part, extends entirely around the structure and is 60 feet wide. This portion is built of wood and iron combined.

The great interior space thus enclosed is one story high, 630 feet long and 230 feet wide, with an extreme height of 100 feet at center and 47 feet at sides, and is spanned by steel cantilever roof trusses supported on steel columns placed 65 feet apart longitudinally, and 115 feet and 57 feet 6 inches transversely, thus leaving clear space in center of building 630 feet long, and 115 feet wide, with two side divisions, each 57 feet 6 inches wide and 630 feet long, leaving the central space encumbered with only 16 supporting steel posts. The cantilevers are of pin connection to facilitate erection. The inner and higher ends of the cantilevers are 46 feet apart and the space between them is spanned by riveted steel trusses with an elliptical chord.

These trusses are designed so as to form a clearstory 12 feet high, with vertical sash extending the entire length of central spaceó630 feet; said space terminating at each end with a great glass gable setting back 60 feet from front ends of building. The wide spacings of the cantilever necessitated an extensive system of longitudinal perlines of the riveted lattice type.

A great portion of the roof is covered with glass. It may be of interest to state that the cantilever system as applied to roofs has not been used heretofore on so large a scale and that the MINES BUILDING is the only one of the Exposition group, excepting the large domes, that has steel roof trusses.

The exterior of this building, like that of all the others, will be made of staff, similar to that used in facing the recent Paris Exposition buildings. The cost of the MINES BUILDING is $250,000.