Many descriptions have been given by visitors of the spectacle presented in this long and deep gash through the mountains during the progress of the excavations. From these and the numerous photographs taken at that stage the traveller will be able to reconstruct the scene--the two hundred miles of railroad construction track, laid down tier above tier at different levels; the thousands of men busily at work; the roar and smoke of the dynamite tearing the rock into fragments; the mighty steam-shovels like great dragons burying their iron teeth in the surface of the bank, engulfing a huge mouthful, then swinging round and belching it all into the dirt trucks, to be carried off to the dumping-ground at Gatun near the Atlantic or Balboa at the Pacific end of the canal. At Culebra, Colonel Goethals made the "dirt fly" to the full satisfaction of public opinion in the United States. All sorts of devices and machinery were employed to hasten and economize the process. For example, there was the Ledgerwood Unloader. Railway trucks provided with flaps were used, these flaps making a single platform of the whole train. At the rear of the train was a plough which could be drawn by a wire rope attached to a drum carried on a special car in the fore part of the train. When the train arrived at the dumping-ground the drum was started, and the plough, advancing from the rear, swept the 320 cubic yards and rock from the sixteen cars in seven minutes. Then there was a "track-shifter," invented by an employee on the isthmus, which lifted and relaid the railway lines as the spoil-tracks had to be shifted. This powerful engine raised the track and ties clear of the ground and deposited them from three to nine feet sideways. The "spoil trains" were treated with all the respect which is accorded to the fastest mail trains of the day on an English main line. They followed one another from the cutting at intervals of three minutes, and any delay, of course, balked the mammoth steam-shovel of its gluttonous meal on the stones and rubble of the mountain-side. Any cause of delay was at once reported by telephone to the superintendent of transportation at Empire, and the obstruction was immediately dealt with. By this persistent concentration on the main object the dirt has been made to fly not only more speedily but more cheaply.