4. "Another misconception, which occasionally causes trouble and disappointment, consists in assuming that a discretionary power can be intrusted to subordinate officers to remit penalties or overcharges under special circumstances. Cases will occur in which strict observance of a general rule may inflict more or less injustice upon individuals, and where a dispensing power immediately at hand might furnish a remedy. In an establishment as large and as widely spread as the Post-Office, however, there will always be many subordinate officers, some of them carrying on their duties beyond the easy reach of any supervising authority, who are not fit depositaries of such a power, affecting, as it would to a great degree, the public revenue. It therefore becomes necessary to lay down definite and precise rules, from which no departure can be allowed, except under sanction of the Postmaster-General; and in the few instances in which these rules press hardly, appeal must be made to the General Post-Office. It must be added, that in many instances even such appeal is necessarily fruitless, the Postmaster-General being bound to a particular course by positive law." 5. "In regard to the expense of railway conveyance, the public naturally supposes, that as such conveyance is cheapest for ordinary purposes, and as the charges made for the carriage of mails are subject to arbitration, that it must be cheapest for postal purposes also; and, indeed, so cheap, as to warrant the free use of the railways, either as substitutes for other conveyance, or for the multiplication of mails. The fact, however, is very different. Except in certain instances, where companies have entered into arrangements, securing to the Post-Office the use of their trains on moderate, though still highly remunerative terms, railway conveyance, with all its acknowledged advantages, has proved much more expensive than that which it has superseded." We have already spoken at length of railways in relation to the Post-Office, and will not here add any further remark. 6. The English Postmaster-General is frequently supposed to have some control over colonial post-offices, and even those of foreign countries. Except at Gibraltar and Malta, however, he is quite powerless out of the United Kingdom.