The scientific attitude of mind is necessarily critical, but never sceptical without proper investigation and knowledge. The Translator hopes, therefore, that English-speaking men of science will not judge the question of international language before they have quietly and dispassionately examined the arguments so ably set forth in the following pages. It is not a question of "another language"; it is a question of the final solution by the methods of science of one of the greatest of scientific problems.

Internationalisation of thought is the motto of the twentieth century, the device on the banner of progress. Science, the Super-Nation of the world, must lead the way in this as in all other things. Amidst the clangour and the clamour of political and commercial strife, the quiet empire of knowledge grows, noiseless and unseen. Let all those who believe that this peaceful empire is destined to become the controlling force of the world assist in the attunement of its common language.

The Translator wishes to thank his friend and colleague, Professor J. P. Postgate, for having very kindly revised the translation of Chapters III. and IV.

F. G. Donnan.

University of Liverpool,

March, 1910.