From 1808 to 1840 the rural districts as a rule obtained their postal matter by a special payment on their part to messengers for its conveyance from the nearest town, sometimes aided by a bonus from the revenue, or by means of the "fifth-clause" posts,[272] or by the penny posts which were constantly increasing in number and were occasionally established under guarantee. In 1838 there were fifty-two "fifth-clause" posts in England and Wales, and 1922 villages in the United Kingdom were served by penny posts. In 1843 the government of Sir Robert Peel laid down the following principle: "All places the letters for which exceed one hundred per week should be entitled to a receiving office and a free delivery of letters." A "delivery" here meant a daily delivery, and the boundary of the free delivery was to be determined by the Postmaster-General. The principle enunciated above was followed until 1850, and during that period the increase in the number of free and guaranteed rural deliveries was very great. At the close of this period it was decided that in future the determining rule should be based upon the probability of financial success. A post was held to pay its way whenever its cost was covered by a halfpenny on each letter delivered, but, since it was held that the number of letters would be doubled by free delivery, double the number arriving before its establishment might be assumed to arrive afterward. The post might be bi-weekly, tri-weekly, or weekly. This rule was to a certain extent made retroactive, but no post established under the rule of 1843 was stopped so long as the cost was covered by calculating delivered letters at a penny each. It was decided in 1853 that a post less frequent than once a day might be increased in frequency whenever the cost would be covered by a revenue estimated on the basis of three farthings for each letter, and in treating an application for a second daily post this amount was to be reduced to one farthing. The experiment was tried of delivering letters at every house in a few selected places but did not prove a success. It was stated that at the end of this revision, 93 per cent of all postal packets were delivered. In 1860 the rule was laid down that new posts should be set up only when the cost would be covered by half a penny on each letter actually arriving, the old rule having been found to be too liberal. Two years later it was stated by the Post Office that only 6 per cent of the total postal packages were undelivered. In 1882 the question of extending the rural posts was considered by Mr. Fawcett, the then Postmaster-General, who decided that credit should be given for revenue by increasing the halfpenny to 6/10_d._ for each letter, and in the next year the existing rule as to a second daily delivery was made more liberal. In 1890, for places hitherto unserved, the rate per letter for estimating revenue was increased to three farthings, for each parcel