The preamble recites that posts had at great charges been established on the mainland of North America through most of her Majesty's plantations and colonies, and the Postmasters-General were authorized to establish a "Chief Letter Office" in New York, and other chief offices at some convenient place or places in each of the colonies in America, and to appoint deputies for the "better managing, ordering, collecting, and improving the Revenue" granted by the Act. Rates for the transmission of letters between England and America were fixed, and detailed rates for transmission between specific towns within the North American colonies. The rates between London and America were 1s. for a single letter, 2s. for a double letter, and so on. For transmission within the colonies the rates were, broadly, for distances under 60 miles, 4d. the single letter, 8d. the double letter, and so on; distances under 100 miles, for a single letter 6d., and so in proportion for double and treble and ounce letters. These rates were, in general, higher than those which had been fixed by the colonies under the Neale patent, but for several years they did not produce sufficient revenue to meet expenses. In 1722 the Postmasters-General were for the first time able to say that in the future the Post Office in North America, even if it yielded no net revenue, would no longer involve a charge, and there was a good prospect of a profit. The Act of 1765 provided rates for the longer distances and made a general reduction of nearly 30 per cent. The rates now became, for a single letter, for conveyance for any distance not exceeding 60 miles, 4d.; from 60 to 100 miles, 6d.; from 100 to 200 miles, 8d.; for each additional 100 miles, 2d.[143] In the intervening period the chief events had been the appointment of Benjamin Franklin, in 1737, to be Postmaster of Philadelphia, and in 1753, to be joint Postmaster-General for British North America, and the acquisition of Canada in 1763. The latter event had, indeed, been one of the reasons assigned for the passing of the Act of 1765.[144] Under Andrew Hamilton the posts had run only along the coast, the great main route extending from Portsmouth, N.H., through Boston and New York to Maryland and Virginia. Under his son, John Hamilton, who succeeded him in the office, the posts were pushed inland as occasion offered or circumstances demanded, and for these extensions John Hamilton adopted the principle of establishing routes in those cases where the postage was sufficient to maintain them. On such a basis the system could not, however, be very largely developed. The circumstances of the country made any great extension impossible, and in 1766 the posts still went mainly along the sea coasts.[145]