These arrangements are based altogether upon the voluntary principle, but when agreed to, they are necessarily embodied in legal contracts. We have no earlier return of postal railway mileage than 1855; that was at the height of the antagonism with the Post Office. The miles run were then 27,109 per diem, but so rapidly had friendly arrangements been entered into, that in 1862 (the last year for which a mileage return is published) it had risen to 49,782 miles per diem. Had these returns been continued to the present time, they would have exhibited an increase to 60,000 per diem, for in 1863, there were three hundred and ninety-three towns having a night and day mail from London, fifty having 3 mails daily from London, seven having 4, three having 3, and three having 4. But in 1865, the number had increased as follows: four hundred and ten having a night and day mail from London, fifty-seven having 3 daily from London, nine having 4, and six having 5. The gross sum paid by the Post Office to the railways of the United Kingdom in 1866 was £570,500, only £170,500 more than, as Mr. Page states, were paid to railways in 1855; but at that time the Post Office, with only few exceptions, did not run more than one day and one night mail train in each direction on the greater portion of the 8,280 miles which then constituted the railway system of the kingdom; but on the first of January, 1866, the railway system was 13,289 miles, over about 12,000 miles of which, the Post Office was able by its contracts, to send mail bags by whatever trains, whether goods or passenger, they chose to select from. At the present time (as already stated) the railway service of the Post Office cannot be less than 60,000 miles a day[45].