[Illustration: MR. KING'S LETTER BALANCE HAD A TRIPOD BASE, AS IN THE UPPERMOST FIGURE, THUS AFFORDING THREE TABLETS, ON WHICH THE ASSOCIATIONS OF J. PALMER, ROWLAND HILL, AND QUEEN VICTORIA WITH POSTAL REFORM ARE RECORDED.] But the one factor which to us is the most notable contribution to the success of the Penny Postage plan, was the square inch of paper with its backing of glutinous wash. This enabled the authorities to effect the introduction of prepayment, and save the long delays formerly occasioned by the postman having to await payment for each letter on delivery. It saved the complicated system by which the Post Office had to ensure that the postman did get paid, and in his turn accounted for the money to his office. It was to this simple contrivance of a small label, issued by authority, to indicate the prepayment of postage that the practical success of Hill's plan was greatly due. The little stamps are the royal _diplomata_ which enable us all, at a modest fee, to use His Majesty's mails, a privilege enjoyed by great and small, by rich and poor. So stamp-collectors deem the objects of their interest to have achieved a vast reform in internal and universal communications, giving a powerful impetus to social progress, international commerce, and the world's peace. The year before the introduction of Uniform Penny Postage there were 75,907,572 letters dealt with by the Post Office. The number was more than doubled in the first year of the new system, and the subsequent growth of correspondence is outlined in the figures (letters only) for the following years:-- 1840 168,768,344 1850 347,069,071 1860 564,002,000 1870 862,722,000 1880 1,176,423,600 1890 1,705,800,000 1900 2,323,600,000 1910 2,947,100,000 II THE DEVELOPMENT OF AN IDEA CHAPTER II THE DEVELOPMENT OF AN IDEA Early instances of contrivances to denote prepayment of postage--The "Two _Sous_" Post--_Billets de port payé_--A passage of wit between the French Sappho and M. Pellisson--Dockwra's letter-marks--Some fabulous stamped wrappers of the Dutch Indies--Letter-sheets used in Sardinia--Lieut. Treffenberg's proposals for "Postage Charts" in Sweden--The postage-stamp idea "in the air"--Early British reformers and their proposals--The Lords of the Treasury start a competition--Mr. Cheverton's prize plan--A find of papers relating to the contest--A square inch of gummed paper--The Sydney embossed envelopes--The Mulready envelope--The Parliamentary envelopes--The adhesive stamp popularly preferred to the Mulready envelope. The simplest inventions are usually apt adaptations. The postage-stamp, as we know it to-day, can scarcely be said to have been invented, though much wild controversy has raged about the identity of its "inventor." The historian must prefer to regard the postage-stamp of to-day as the development of an idea.