The artist who prepared the above cut of the outsido of the Great Cen tral Fuir Buildings in Logan Square, specially for the pages of “Our Daily Farr,” has done his work so well as to leave but little room for de scription or explanation. The thoroughfares which form the extreme foreground of the picture are Nineteenth and Vine Streets. The door of entranco nearest to the person examining the picture is at the northwest eorner of the Square, and the perspective sweeps in a southerly and east wnrdly direction over the roofs and spires of the city. The noble struc ture which looms up in the background, upon the left hand side of the picture, is the Cathedral of Saint Peter and Saint Paul, tho finest speci men of church architecture in the city. On the southern side of the Fair Ground, Wills’ Hospital “ for the Halt and the Blind” will be seen ; while those who nro familiar with our local landmarks will readily recognize in the distance tho spires of Saint Mark’s Church, the West Arch Street Pres byterian Church, and of the Baptist Church on West Chestnut Street. These aro only the most prominent points in the grand panorama which includes within its sweep fully one-half of the city, with nine-tenths of its commerce, trade and wealth. The gothic structure which runs from east to west and intersects the Square is Union Avenue, a noble ball which is worthy of the name it bears; at this writing, it contains more splendid wares, and more magnificent groupings of the emblems of patriotism and loyalty than can be found in any single apartment in the country. From its centre rises a mammoth flag-staff, 2111 feet high, from the summit of which waves a magnificent speoimen of the Stars and Stripes. On the left of Union Avenue is a canopied structure which is also sur mounted with a flag. This is the Horticultural Department, where, amid a world of floral sweets, a fountain is in constant play, rendering the per fumed air delightfully cool and pleasant. Between art and nature, rare plants, and plashing waters, scenic effects, bright lights and brighter eyes, t " o J t,oultur ®l Department becomes mimic fairy-land, and the visitor a most fears to see the bright picture melt away like a pleasant dream that is too delightful for reality. — 1?*!?” opposite side of Union Avenue, is another circular building, 18 .J 8 oC ® u P ,e< i as a.Restaurant. It is light, airy, well ventilated and magnificently decorated, forming agrand dining-room capable of entertain ing fully a thousand guests at the same time. Ihe entire range upon the extreme left-hand side of the picture, extend g trom Eighteenth Street to Nineteenth Street, is occupied by the Art a whioh contains the most magnifioent collection of paintings ever got ogether in the United State,. 8 ground plan of the buildings which we print upon the other sido of zne sneet, gives a foil and aoeurate key to tho arrangements of the sereral buildings, the uses to which they are applied, Ac. * .»> v« ' GREAT CENTRAL PAIR BUILDINGS, Logan Square, Philadelphia, June, 1864. And now for some figures : Union Avenue, which we have already described as llio main structure of the group whicli form the Fair Buddings, is sit) fcot long and 60 feet wide, with en elevation from floor to the point of the arch of 50 feet. The Gothic Arch of this Building is formed with rafters, constructed with tho Howe Truss, each rafter being 2 feet in depth and 6 inches wide, with pannels 2 feet wide, in each of which aro two main braces and one counter brace 2 inches square; tho chords are of 3by G inch scantling. The rafters aro placed at distances of about 19 feet apart, and are footed upon heavy timbers set upon tho ground, properly notched to receive the chords. Tho chord of the arch is about 60 feet, with versed sine of G feet 6 inches. Thcro are four lateral buildings, extending north and south, from Union Avenue, having a width of 26 feet, a height of 18 feet, and a length of 250 feet each way. Upon the north and south, and parallel with Union Avenuo along Race and Vine Streets, are buildings 29 feet wide and 18 feet high, each 500 feet long—that on the north (tho Art Gallery,) being lighted from the roof. From the middle of Union Avenue extends a gallery northward, con necting with the Floral Department, (which, as we havo already stated, is a circular building.) 190 feet in diameter, 100 feet of which is covered with a canvas canopy. In the middle of this department is a lake, with foun tains of great variety of jet, arranged around and in it, in tho centre of which is an island upon which are tastefully arranged an imposing group, of tropieal plants and fruit. Upon tho South of Union Avenue, on the line of the Floral Depart ment, is the Restaurant, which is also circular, with a diameter of 190 feet. Connected with this are a number of buildings arranged for culinary purposes, such as Main Kitchen, Pastry, Mnizena Kitchen, Ico House, Ware Closets, Sculleries, and Servants’ Dining Room. The Pennsylvania Kitchen and the William Penn Parlor, on tho north and South of Union Avenue, are relatively 81 by 34 and 60 by 34 feet. The names of the architect and builders of Union Avenue are Siriokland Kneads, architect, and Burton and Quigley, builders. The remainder of the buildings were put up by B. 11. Shedaker, master builder, under the immediate direction of John Welsh, Esq., Chairman of the Executive Committee, and of the Committee of General Arrangements, of which J. C. Cresson, Esq., was Chairman. Mr. Henry E. Wrigley prepared many of the original drawings. The internal decorations were in charge of the Committee of Internal Arrangements, of which J. 11. Orne, Esq., was Chairman. The aggregate lengih of the Fair Buildings is 6,500 feet, or more than a mile. A million and a half feet of lumber was used in their construction, and the work of building and decoration was completed within forty work ing days.