The various changes and improvements adopted by the Post Office since 1840, in addition to those already named, are so numerous that only the most important can be considered here. Among others the amalgamation of the London District Post with the General Post in 1854 deserves attention. In the following year it was ordered that letters should be sorted in each of the ten postal districts into which London was divided instead of being taken to the General Office at St. Martin's-le-Grand as had been customary, thus materially lessening the expenses of sorting and facilitating their delivery.[290] [290] _Ibid._, 1855, p. 12; 1856, p. 9; 1860, p. 8. In 1840 there were but 4028 post offices in the Kingdom; in 1854, 9973.[291] Road letter boxes were introduced in 1858 and the public receptacles for the receipt of letters numbered 13,370 in 1859 as compared with 4518 before the establishment of penny postage.[292] In 1829 the total number of persons in England employed in Post Office business numbered only 5000. Twenty-five years later for the United Kingdom over 21,000 were so employed; in 1880 over 47,000, of whom, however, more than 11,000 were engaged wholly in telegraph duties. By 1890 these had increased to nearly 118,000 and by 1900 to 173,000 of whom 35,000 were females.[293] [291] _Ibid._, 1855, p. 21. [292] _Ibid._, 1855-59. [293] _Rep. Commrs._, 1829, ii, p. 137; _Rep. P. G._, 1855, p. 20; 1881, app., p. 16; 1891, app., pp. 34-35; 1901, app., p. 50. The money order business which originated as a private speculation in 1791 was the result of an attempt to check the frequent theft of letters containing money. In 1838, shortly after its acquisition from the proprietors, the rates were reduced and the number of money orders transmitted increased from 188,000 in 1839 to 587,000 in 1840 and to 1,500,000 in 1842. From the latter date until 1879 the increase both in the number and in the value of money orders transmitted was steady, aided by the increase in 1862 from £5 to £10 of the maximum transmissible sum and by the reduction in rates in 1871. The penny rate of that year for orders to the value of ten shillings was a mistake, for the actual cost to the state of issuing and paying a money order was about 3_d._ In order to meet this difficulty a simpler form of order was issued in 1881 with an initial rate as low as half a penny, the cost of which to the Post Office was much less than that of the old kind of order. These postal notes, as they were called, were issued for new denominations in 1884 and 1905 and the rates on some of them were diminished. The lowest rate for a money order was for a few months fixed at 3_d._ but, as this aroused considerable opposition, the present rate of 2_d._ was soon after substituted, and in 1903 the maximum sum transmissible was increased to £40 with a few accompanying changes in rates. In 1889 an opportunity was given in the case of a few towns for