The Conference was not empowered to enter into any definite arrangement for the amelioration of the system of international postal traffic. Its function was simply to discuss and proclaim general principles applicable to the conduct of the traffic, with a view to their ultimate adoption by the nations of the world. The discussions centred on the three fundamental questions of uniformity of weights, uniformity of rate, and simplification of accounting.[576] Thirty-one articles of agreement were adopted.[577] These articles recommended, _inter alia_, the adoption for ordinary letters of a unit of weight and a progression of weight of 15 grammes; and for corrected proofs, samples, and documents not in the nature of a letter, a unit and progression of 40 grammes. The Conference was convinced that transit charges were often an invincible obstacle to the establishment of a really advantageous international system, and recommended that the transit rate for each country should never exceed half the postage reckoned at the inland rate of the country traversed, and that for small countries it should be even less. For sea transit the Conference recommended that in no case should the charge against an administration in respect of such transport be greater than the actual charge made on the country of destination by the shipping agency by whom the mails were conveyed. Although its conclusions were without the sanction of authority, the Conference was nevertheless of great assistance to the development of an international system. It brought into prominence the obstacles in the way of international postal intercourse, and the difficulties which must be removed before a common system could be founded. And it formulated general principles which might with advantage be observed in the making of fresh agreements between individual countries, and might serve as a basis for a common agreement. Its conclusions were, as a matter of fact, so used in numerous instances. Towards the end of 1868 Dr. von Stephan, of the postal administration of the North German Union, published in the official journal of the Union a definite project for a postal union between all civilized nations, and proposed a discussion of the project at a universal Congress. The proposal was taken up by the administration of the North German Union. The diplomatic arrangements for calling a Conference were, however, interrupted by the Franco-German War of 1870. After the conclusion of peace, the proposal was again taken up, and the Swiss Government undertook the task of inviting the administrations of the chief countries to send representatives to a Congress at Berne. The invitation was readily accepted, and the Congress met in 1874. The proposal submitted to the Conference was that the Union should cover the following categories of postal traffic:-- (1) Letters. (2) Postcards. (3) Newspapers and other printed matter. (4) Samples. (5) Commercial papers.