CONTENTS 



Officers and Committees for 1916-1917 7 



Past Officers 8 



Ninth Annual Meeting 



Report of Secretary 9 



Report of Treasurer 13 



Report of Committee on Ecological Survey of State 14 



Addresses 



Address of Welcome, Dr. T. J. Burrill 17 



Life and Work of John Ulric Nef, Julius Stieglitz 18 



Symposium on Astronomy 



Stellar Photometry, Joel Stebbins 23 



The Determination of Stellar Distances, Philip Fox....28 



(jeneral Papers 



Purification of Sewage by Aeration in the Presence of 

 Activated Sludge, Edward Bartow 31 



Tests on the Comparative Friability of Illinois Coals 

 and Their Practical Application, L. A. Mylins 31 



Photographing Flowers and Insects, 



Arthur G. Eldredge 33 



A Laboratory Efficiency Test for Advanced Students 

 in Chemistry, David F. McFarland 36 



Science and Mathematics, James B. Shaw 40 



The Correction of Echoes and Reverberation in the 

 Auditorium at the University of Illinois, F. R. 

 Watson 45 



The Future of Popular Science, John C. Hessler 50 



The Hospital and Its Field of Work for the General 

 Scientist, Walter G. Bain 54 



Discussion of Dr. Bain's Paper, 



Dr. A. R. Trapp 61 



T. J. Burrill 62 



