In 1765 the inland rates for short distances were reduced, and a new standard of charge was introduced. Hitherto, all charges had been regulated on a mileage basis. For short distances they were now based on the number of post stages. For one post stage the rate was made 1d. for a single letter, for a double letter 2d., for a treble letter 3d., and for every ounce 4d.; for two post stages, 2d., and in proportion for double, treble, and ounce letters.[54] The financial result of the change was unsatisfactory.[55] Up to this period the mails were carried by postboys riding horse. Notwithstanding that on all the chief roads stage-coaches were running more expeditiously than the post-horses, the Post Office kept to the old way. The superiority of the stage-coaches as means for the conveyance of letters was noticed by Mr. John Palmer, proprietor of the theatre of Bath,[56] who was so greatly impressed with the fact that he devised a complete and definite plan for the establishment of a system of mail conveyance by coach. The cost of the riding post (boy and horse) was 3d. a mile, and Palmer estimated that the change could be carried out without involving any increase of cost, especially if, as he proposed, the coaches carrying the mails should be exempted from toll. The proposal was severely criticized by the district surveyors of the Post Office, who reported on it.[57] At the Treasury, however, the proposal met with a more favourable reception. Pitt called a conference on the 21st June 1784, and after hearing the explanations of Palmer and the criticisms of the representatives of the Post Office, decided that the plan should be given a trial. Accordingly, on the 2nd August 1784 the first mail-coach ran. The experiment, which was conducted on the Bath Road, proved successful, and the plan was rapidly extended throughout the kingdom. The first coach cost 3d. a mile, the same rate as the riding post; but ultimately the coaches proved to be cheaper than the horse posts. In 1797 the rate was no more than a penny a mile.[58] Almost simultaneously with the introduction of mail-coaches there was an increase in the rates of postage, made solely with a view to increased revenue.[59] The alteration was more or less fortuitous. In his Budget of 1784 Pitt had proposed a tax on coals which had not been well received, and the increased postage was substituted. Palmer is said to have claimed the credit of suggesting the substitution.[60] If so, his faith in his plan was abundantly justified. Notwithstanding the handicap of increased rates, it was an unqualified success, and the effect on the revenue was immediate and considerable.