THE INTERNATIONAL POSTAL SERVICE The importance of the international service is evident from the earliest days of post office history; but the working of the service is somewhat obscure. In the i6th century, a regular service seems to have been provided between London and Calais, which was the port on which foreign communications mainly centred. The outward letters seem to have been carried to their destination by English post office messengers, while inward letters were brought by foreign messengers as far as Calais. Many of these couriers appear to have paid but scant attention to their duties, for early in the 17th century the delay in the arrival of important foreign mails was put down to the fact that the messengers minded "their own peddling traffic more than the service of the State or the merchants," and were often found "lying in tippling houses." Witherings, as mentioned above, reorganized the foreign service; and shortly after his time (167o) a regular postal treaty was con cluded between England and France. This was renewed in 1698 after the conclusion of the Peace of Ryswick. The treaty pro vided that the mail from London for Paris and from Paris for London was to leave twice a week, and was to be conveyed throughout with the utmost possible speed. Between Dover and Calais the English Post Office provided the mail packets in both directions; the service beyond Calais was provided by France. Letters could only be prepaid to a limited number of destinations —Paris, Rouen or Lyons; any charges for further transmission were collected from the addressee. In view apparently of the longer distances provided for by the French post office a fixed annual payment of 36,000 livres, to cover everything except these addi tional charges, was made by England.
This treaty, soon interrupted by further hostilities, was again renewed in 1713. The new version is interesting as containing the germ of the international system of accounting for transit mails which lasted with but slight alteration until the latter part of the 19th century. On letters for Italy, which could be franked to Turin, France was to be paid at the rate of 21 sols per single letter ; on letters for Spain franked to Bayonne the payment was 19 sols, on letters for Turkey franked to Marseilles, 17 sols.
Double letters were charged approximately twice, and letters weighing one ounce four times the single rate. The accounting between the two offices was based on the sum of the amounts due on the separate letters, mail by mail. The principles adopted in the 17th century show little change in the i8th, and a treaty con cluded with France in 1802 shows comparatively little variation from its predecessors of over a century before.
As time went on the postal treaties required for the establish ment of a gradually expanding foreign service became more and more numerous. The effect on the public of their varying and complicated provisions can in these days of simplicity scarcely be imagined ; but until well into the second half of the 19th century they presented a bewildering complexity, which made it impossi ble for any one but an expert to be certain that the rate of postage to a particular destination was correct and that the postal regula tions had been complied with. The postage depended on the sums payable to the various post offices concerned in the transit of the letters, and these were often based on their own internal rates and units of weight. The result was an extraordinary variety of rates—often differing materially for the same destination accord ing to the route employed—and a considerable variety in the weight covered by the initial postage rate. Moreover, prepayment was in some cases compulsory, in some cases optional; but com pulsory prepayment only covered conveyance up to a certain point, all charges beyond that point being collected from the ad dressee. The unit of weight was in a large number of cases oz., any letter above that weight being charged "pro rata." The lowest postage in force was that to France, which was 4d. per oz. A letter from England to Belgrade via France, weighing one ounce, cost 5s. ; a half ounce letter to California via Panama cost 4s. 8d., in addition to a further charge on delivery. Even to Spain the postage was 2s. 2d. per half ounce plus a charge on delivery.