Machinery is the most important feature in the modern history of our country. How it has enriched and extended our commerce, and built up the greatness of the nation, is an interesting and instructive reflection. It thus justly claims the important position which it here occupies. The long array of busy engines, which stretches almost as far as the eye can reach, forcibly reminds the visitor of this department in the old Crystal Palace of Hyde Park. Indeed, the most interesting set of machinery, that employed in cotton spinning, which instructed so many thousands in Hyde Park as to the manner in which the huge bale of cotton was transformed into the perfect woven fabric, is now to be seen here in full work. The set includes Beating Frames, Carding Engines, Drawing, Slubbing, and Roving Frames, Throstle Spinning Frames and self-acting Mules. Near at hand to this most perfect and beautiful collection of machinery, which was manufactured by Walker and Hacking, and Harrison & Co., are placed the rude wooden engines invented and used by Arkwright for the same purpose; thus we are enabled to measure at a glance the immense progress we have made in the course of less than a century. Proceeding lower down the gallery, the visitor is struck with astonishment at the massive machinery by which iron is hammered, drilled, punched, and planed as easily as so much deal. Messrs. Whitworth, Muir, and Harrison & Co., are the principal exhibitors of these ponderous engines. Advancing still further, the visitor witnesses a sugar-cane crusher in motion. Centrifugal pumps, Drying Machines, together with Steam Engines of all descriptions in full work form the next most important features, whilst innumerable other inventions and machines of a smaller character make this part of the palace one of the most interesting. The visitor can, if he choose, reach the South Wing through this department, and pass from thence down the Colonnade to the Railway Station; but he will most probably pass from the door under the Central Transept on to the first Terrace, and proceed to the inspection of the Gardens and Park, of which we treat in the next division. PART III. THE EXTERIOR.