When the mail-bag containing it was put into the Travelling Post-Office van, Mr Bright passed in after it. Our energetic sorter was in charge of the van that night, and went to work at once. The letters to be dropped at the early stages of the journey had to be commenced even before the starting of the train. The letter did not turn up at first. The officials, of whom there were six in the van, had littered their sorting-table and arranged many of the letters, and the limited mail was flying north at full speed before the Bones epistle found its appropriate pigeon-hole--for it must be understood that the vans of the Travelling Post-Office--the T.P.O., as it is familiarly called by its friends--are fitted up on one side with a long narrow table, above which are numerous pigeon-holes, arranged somewhat like those of the sorting-tables in the non-travelling Post-Offices. There is a suggestive difference, however, in the former. Their edges are padded to prevent the sorters' knuckles and noses from being damaged in the event of violent jolting. The sides and ends of the vans are padded all round to minimise their injuries in the event of an accident. Beyond this padding, however, there are no luxuries--no couches or chairs; only a few things like bicycle saddles attached to the tables, astride which the sorters sit in front of their respective pigeon-holes. On the other side of the van are the pegs on which to hang the mail-bags, a lamp and wax for sealing the same, and the apparatus for lowering and lifting the net which catches the bags. Everything connected with railways must needs be uncommonly strong, as the weight of materials, coupled with high speed, subjects all the parts of a carriage to extremely violent shocks. Hence the bag-catching affair is a powerful iron frame with rope netting, the moving of which, although aided by a pulley and heavy weight, tries the strength of a strong man. Nimbly worked the sorters, as they swept by town and field, village, tunnel, bridge, and meadow,--for time may not be wasted when space between towns is being diminished at the rate of forty or fifty miles an hour, and chaos has to be reduced to order. The registered-letter clerk sat in one corner in front of a set of special pigeon-holes, with a sliding cover, which could be pulled over all like a blind and locked if the clerk should have occasion to quit his post for a moment. While some were sorting, others were bagging and sealing the letters. Presently the junior sorter, whose special duty it is to manipulate the net, became aware that a bag-exchanging station drew near. His eyes might have assured him of this, but officers of the Travelling Post-Office become so expert with their ears as to know stations by the peculiarity of the respective sounds connected with them--caused, it might be, by the noise of tunnels, cuttings, bridges, or even slighter influences.