For all letters for or from Europe by packet or despatch vessels, the charge was 4 dwt. The rates were doubled for double letters; trebled for treble letters; and a packet weighing an ounce was charged equal to four single letters, and in that proportion if a greater weight. In the event of a surplus of Post Office revenue over expenses, the Postmaster-General was required to pay the amount to the Treasurer of the United States "until the sums of money heretofore advanced by the United States for the support of the General Post Office, with the interest thereon at 6 per cent. per annum," should be repaid, after which any such surplus was to be devoted to the establishment of new post offices or other improvements of the service. If the necessary expenses were found to exceed the revenue, the excess was to be paid to the Postmaster-General by the Treasurer of the United States.[155] Cross posts were farmed in much the same way as the cross posts and bye posts had been farmed in England,[156] and the farmers were bound by contract not to charge rates in excess of those fixed by the ordinance.[157] After the adoption of the Constitution an Act of the Constitutional Congress became necessary. The President, in recommending to Congress the provision of the Post Office and post roads on a liberal and comprehensive scale, referred to the political importance of such a service as aiding the diffusion of a knowledge of the laws and proceedings of the Government,[158] a consideration which was paramount in determining the attitude of the United States Government towards the posts. It was held to be a first duty of the Government to afford every possible means for the dissemination of intelligence--general intelligence for the information and education of the people, and more especially political intelligence for the education of the people as citizens of the Republic. They were making, it was their legitimate boast, a tremendous experiment in politics. They were essaying to demonstrate to the world whether a people had the genius to govern itself, whether democracy and the republic were abstract political ideas only, or whether they could be made actual living things. The English Commonwealth had failed. The French Revolution had come after their own and was still in doubtful case. They could therefore neglect no means likely to strengthen the foundation of their own Republic, and in this view must consider seriously the question of providing effective means for the enlightenment of the sovereign people on all matters pertaining to the executive Government and the Legislature.[159] In order to secure the dissemination of such intelligence members of Congress were given extensive powers of franking both letters and newspapers.