REPORT OF THE PRESIDENT, 1923. 11 



logical, and other physical conditions determining the development 

 of the plants and animals upon which the inhabitants were dependent. 

 The studies proposed will naturally require the assistance of a con- 

 siderable group of specialists and it is hoped that through coopera- 

 tion of other agencies and institutions interested in this work a 

 thoroughly fundamental investigation may be carried out. 



In planning the proposed researches on early American civilizations 

 the effort has been made so to organize our studies that the informa- 

 tion obtained may have the maximum value for interpretation of 

 present and future problems concerning the people of Middle America. 

 Through all of the stages of preparation for this work it has been most 

 gratifying to have the hearty cooperation and support of the govern- 

 ments of the Middle America region and also of all institutions and 

 individuals of these countries in any way concerned with this research. 



The series of lectures on results of recent researches, which was 



initiated in 1921, was continued in the winter and spring of 1922-23. 



It is considered an important personal means of 



Lectures. interpreting to the scientific public some of the 



results of current investigations. The following titles 



represent the lectures given during the past year : 



November 7, 1922. The heat of the sun and other stars. C. G. Abbot. 



November 21, 1922. The greater problems of the earth's magnetism and their bearing on 

 astronomy, geology, and physics. L. A. Bauer. 



November 28, 1922. The constitution of the hereditary material and its relation to develop- 

 ment. T. H. Morgan. 



December 5, 1922. The properties of matter as illustrated in the stars. H. N. Russell. 



December 12, 1922. The motions of the stars. W. S. Adams. 



April 19, 1923. Present problems in the field of atomic structure and their bearing upon 

 the nature of ethereal radiations. R. A. Millikan. 



April 25, 1923. Application of interference methods to astronomical problems. A. A. 

 Michelson. 



It is interesting to note that the lectures by Dr. Abbot on the 

 heat of the sun and other stars, by Dr. Russell on the properties of 

 matter as illustrated in the stars, by Dr. Adams on the motions of the 

 stars, by Dr. Millikan on atomic structure, and by Dr. Michelson on 

 the application of interference methods, all relate to the extraordinarily 

 interesting program of cooperative research involving the staff of 

 Mount Wilson Observatory and a considerable group of associate 

 investigators closely related to and cooperating with the Institution 

 in its studies in the field of astrophysics. 



In the same way the lecture on the greater problems of the earth's 

 magnetism has brought out the intimate relation between problems 

 of the physics of the earth and many of the fundamental questions of 

 astronomy and geology. The lecture by Dr. Morgan, on the hereditary 

 material and its relation to development, set forth in an extraordinarily 



