To call the scholars of the world together for concerted action towards the correlation of knowledge meant, of course, first of all, to work out a detailed programme, and to select the best authorities for every special part of the whole scheme. Nothing could be left to chance methods and to casual contributions. The preparation needed the same administrative strictness which would be demanded for an encyclopedia, and the same scholarly thoroughness which would be demanded for the most scientific research. A plan was to be devised in which every possible striving for truth would find its place, and in which every section would have its definite position in the system. And such a ground-plan given, topics were to be assigned to every department and sub-department, the treatment of which would bring out the fundamental principles and the inner relations in such a way that the papers would finally form a close-woven intellectual fabric. There would be plenty of room for a retrospective glance at the historical development of the sciences and plenty of room for emphasis on their practical achievements; but the central place would always belong to the effort towards unity and internal harmonization. We thus divided human knowledge into large parts, and the parts into divisions, and the divisions into departments, and the departments into sections. As the topic of the general divisions--we proposed seven of them--it was decided to discuss the Unity of the whole field. As topic for the departments--we had twenty-four of them--the addresses were to discuss the fundamental Conceptions and Methods and the Progress during the last century; and in the sections, finally--our plan provided for one hundred and twenty-eight of them--the topics were in every one the Relation of the special branch to other branches, and those most important Present Problems which are essential for the deeper principles of the special field. In this way the ground-plan itself suggested the unity of the practically separated sciences; and, moreover, our plan provided from the first that this logical relation should express itself externally in the time order of the work. We were to begin with the meetings of the large divisions, the meetings of the departments were to follow, and the meetings of the sections and their ramifications would follow the departmental gatherings. 3. _The Objections to the Plan_