The rates established under this law have remained in operation substantially unchanged up to the present time. The most important modification was made in 1900, when the maximum limit of weight of the single letter was raised from 15 to 20 grammes. Under these rates the letter post has developed continuously. In 1872 the total number of letters passing by post within the territory of the Imperial Post Office was 422 millions, and in 1910 the number had increased to 2,026 millions. As in other countries, the letter rate has proved extremely profitable. The net revenue of the Imperial Post Office in 1872 amounted to 4·7 million Marks, and in 1910 to 88 million Marks. In Germany, however, the railways are State-owned, and the Imperial Post Office is not required to pay to the railways a full equivalent for the services performed. The value of the service performed by the railways on behalf of the Post Office for which no charge is made against the Post Office is not definitely known.[250] The newspaper traffic, the parcel post, and the Imperial Telegraph Service are carried on at heavy loss. The Post Office also performs numerous services, such as those in connection with the National Insurance schemes, for which it receives no monetary credit; and there is no doubt that taken by itself the letter traffic is largely profitable at the existing rates, even when full allowance has been made for all legitimate charges against the service. NOTE ON RURAL DELIVERY Until the eighteen-thirties there was no State provision for the letter traffic in country districts. Residents in the country must deliver all their letters at, or fetch them from, the nearest post office, which was done on market-day or by messengers. In 1824 a beginning was made in Prussia by the introduction experimentally of a delivery service at certain post offices. In the following years the number of rural deliverers and the number of posting-boxes in the villages were increased, and a uniform delivery fee (_Landbestellgeld_) of 1 silver groschen instituted. The delivery fee was abolished on the 1st January 1872 (law of 28th October, 1871). This meant the abandonment of a yearly revenue of 1-1/2 million Marks. In spite of the increase in the number of post offices there were still in 1880 as many as 19 million people, the greater half of the whole nation, and 17,000 localities, outside the limits of the postal service.[251] In 1880 a great step forward was taken. The number of rural deliverers was largely increased, and also the number of postal stations in the country (_Posthülfstellen_).[252] A daily delivery was extended to the greater number of places, the rural routes in most cases being so arranged that the deliverer returned by the same route, thereby enabling an answer to be sent the same day to letters received on the outward journey.[253] * * * * * II THE RATE FOR NEWSPAPERS NEWSPAPER POST IN ENGLAND