We will now look at the other side of the carriage--or that nearest the platform. Along the whole length of that side, strong iron pegs are fixed about an inch apart, and on these pegs the bags to be made up and despatched on the way are hung. Most of the bags used in the Travelling Post-office are of one size--three feet six inches long, and two feet four inches wide; but for the large towns, bags of greater dimensions are required. Each bag is distinctly marked on both sides with the name of the town to which it is to be forwarded, the letters forming the name being an inch and a quarter in length. The name is also stencilled inside the mouth of the bag, so that the sorter has it immediately before his eyes when putting the letters, &c., away. On reaching its destination the bag is emptied of its contents, is turned inside out, and then the name of the Travelling Post-office from which it was received appears in view. The bag is then folded up and kept ready for the return despatch on the following night. In this way it passes and repasses until it is worn out, when it is withdrawn, and a new one takes its place. We will now assume the train is fairly on its way, and that we are approaching Harrow, the first station at which the mail-bags are received by means of the apparatus. As the machinery constituting the apparatus is of great importance in the system of working, we shall here endeavour to describe it. We may say that the apparatus in the Special Mail is worked in a separate carriage which runs immediately behind the one to which we have referred in the preceding details. A large and very strong net is firmly fixed on the side of the carriage on the near end, and the woodwork being cut away, an aperture is formed through which the pouches containing the bags are taken into the carriage. The net is raised or lowered by pressing down a lever very similar in structure and appearance to the levers which are seen in a signalman's cabin. When the net is lowered, a strong rope is seen to stretch across from the fore-part, and this rope, being held in position by a chain attached to the back-part of the net, forms what is called a detaching line in the shape of the letter V placed thus, <; and as the carriage travels along, the rope at the point forming the angle strikes the suspended pouch, and detaches it from the standard, when it falls into the net, and is removed by the officer attending to the apparatus. The machinery is also arranged so that a bag can be despatched as well as received. A man doing this work should possess keen eyes, steady nerves, and a full average amount of strength. On a dark or foggy night it is difficult to see the objects which serve as guides to the whereabouts of the train, and which are technically known in the office as 'marks.'