A VALUABLE addition to the administration building of the Carnegie Institution of Washington has for some time been under construction and will probably be completed in time for the usual Institution lectures in late October or early November. The new structure has been designed primarily to facilitate development of the public relations programme of the Institution by improving conditions for handling its publications, and for more direct contacts with the public through lectures, conferences and exhibitions. The principal room in the addition is an auditorium, designed to seat about five hundred, which, under the name of Elihu Root Hall, is being dedicated to the memory of Mr. Root. Up to the present time the facilities for lecture programmes have been limited to a room seating comfortably about half that number, and it has been necessary in most cases to limit invitations to those who have something more than a general interest in the subjects presented. With the accommodation now in preparation it will be possible to include a larger invitation list with freedom to invite men of science and laymen representing all fields of interest. Committee and conference rooms have been designed for the special purpose of arranging for discussions with a limited group of special students of subjects under consideration, and thus promote inquiries and research into the particular field of natural knowledge in which they are engaged.