I must confess, however, my views were not altogether limited to increased speed: I saw that tubular conveyance, if successful, would facilitate frequent despatch; indeed, that a rapid succession of mails would probably be the most economical way of using the apparatus; again, that as the tubes could without inconvenience keep the line of ordinary roads, pass through the heart of towns, and even be carried, when necessary, through the very post offices along the route, I hoped for no small economy, both of time and money, in the disuse of the mail-carts plying between such offices and the various railway stations. I further thought that, if railway companies saw a successful competitor for postal service, they would moderate their demands, or, if remaining unreasonable, would be controlled by arbitrators, who would of course take the new rival into account. Lastly, I hoped that the great acceleration consequent upon the adoption of the new plan would prove highly acceptable to newspaper proprietors, by expediting the distribution of their journals. In due time I received a very able report upon the subject. This was drawn up by Mr. Cowper, but received Mr. Gregory's sanction. The substance is given in the following passage:-- "I find that with pipes of sufficient diameter, and a vacuum of 11 lbs., a speed of 120 to 150 miles an hour might be obtained, but at a very great cost, both in first outlay and in working expenses." I may add that the means recommended was exhaustion of the tube, not the injection of air; that powerful engines would have had to be erected at intervals of only four miles; that the chief weight to be dealt with was not that of the piston and the mail--which really constituted only a small fraction of the whole--but that of the air itself within the tube; that the annual expense, including four per cent. interest on outlay, would be, for a tube ten inches in diameter, about £32,000 the hundred miles, but for a fifteen-inch tube, which I regarded as indispensable, no less than £80,000.