Franklin planned to have trips of equal speed made between New York and Boston in the spring of 1764, and the time for letter and reply between the two places reduced from a fortnight to four days. When his arrangements were completed a letter and its reply might pass between Boston and Philadelphia in six days, instead of three weeks.

As a result of these arrangements Franklin anticipated that there would be a large increase in the number of letters passing between Boston and Philadelphia and Great Britain by the packets from New York. That the fruits of his outlay answered his expectations is clear from the fact that the revenues, which up to the year 1756 had scarcely exceeded £300 a year, mounted up to £1100[50] in 1757, and that became the normal revenue for some time after.

It was during this period that the British government began to employ packet boats for the conveyance of the mails to the American colonies. Until this time there had been no regular arrangements for the conveyance of the mails between Great Britain and the colonies. There were no vessels under specific engagement to leave either Great Britain or America at any fixed time.

This is not, of course, to say that there were no means of exchanging correspondence between England and America, or even that the post office had no control over the vessels by which letters were carried. Vessels were continually passing between Falmouth or Bristol and New York or Boston in the course of trade; and these were employed for the conveyance of mails. Sometimes the letters were made up in sealed bags by the post office before being handed to the shipmasters; and sometimes they were handed loose to the captains, or picked up from the coffee houses.

The captains were under heavy penalties to hand over to the post office all letters in their possession, when they reached their port of destination, and they were entitled to one penny for each letter so delivered to the local postmasters. By this arrangement, the cost of carrying the letters across the Atlantic fell in no degree upon the post office. Indeed, after the act of 1710, the post office made a very good bargain of the business. The postmasters paid the shipmasters a penny a letter, and the act of 1710 authorized them to collect a shilling for each letter delivered to the public.

A service so irregular had its disadvantages, however. Captains were of all degrees of trustworthiness. Some could be depended upon to deliver the letters at the post office as the law directed; others were careless or unfaithful. These either did not deposit their letters with the postmasters promptly as they should have done, or they had private understandings with friends by which the letters did not go into the post office at all, but were delivered by the captains directly to the persons to whom they were directed.

In 1755 the board of trade called attention to the great "delays, miscarriages and other accidents which have always attended the correspondence between this kingdom and His Majesty's colonies in America, from the very precarious and uncertain method in which it has been usually carried on by merchant ships." The remedy sought was a line of sailing vessels devoted entirely to the conveyance of correspondence. Services of this class were not uncommon, although they were usually confined to a time of war. During the war of Spanish Succession, packet ships ran regularly to Holland and to France.

It was during this war when French and Spanish privateers held the southern seas, that the first line of mail packets was established, which ran to North America. In 1705, the British government contracted for five vessels of one hundred and forty tons each, to carry the mails to and from the West Indies.[51] Each vessel was to carry twenty-six men and ten guns. The contractor was paid £12,500 a year.

A curious feature of the contract was that the contractor was required to enter into a warranty that the receipts from the vessels for mails and passengers would not be less than £8000. If they did not come up to this amount, the contractor had to make up the shortage, up to the sum of £4500 a year. The contract was for three years certain, with an additional two years if the war should last so long.

The postal business of the West Indies was comparatively large at the beginning of the eighteenth century. The receipts for the two years ending January 1706—£10,112[52]—make the American continental business, even under Franklin's capable management, very small by comparison. In 1760 the receipts from the colonial post office of North America were only £1100. This packet service to the West Indies was maintained until the peace of Utrecht in 1713.