(Continued from page 3 of cover.) 



VOLUME 58. 



1. Ames, A. Jr., Phoctor, C. A., and Ames, Blanche. — Vision and the Technique of Art 



pp. 1-47 28 pis. February, 1923. $3.75. 



2. Birkhoff, George D. and Langer, Budolph E. — The Boundary Problems and Develop- 



ments Associated with a System of Ordinary Linear Differential Equations of the First 

 Order, pp. 49-128. April, 1923. $3.15. 



3. Vainio, Edward A. — Lichenes in Insula Trinidad a Professore B. Thaxter Collecti. 



pp. 129-147. January, 1923. $1.00. 



4. Bridgman, P. W. — The Effect of Pressure on the Electrical Besistance of Cobalt, Alumi- 



num, Nickel, Uranium, and Caesium, pp. 149-161. January, 1923. $.75. 



5. Bridgman, P. W. — The Compressibility of Thirty Metals as a Function of Pressure and 



Temperature, pp. 163-242. January, 1923. $1.70. 



6. Baxter, Gregory P., Weatherill, Philip F. and Scripture, Edward W., Jr. — A 



Bevision of the Atomic Weight of Silicon. The Analysis of Silicon Tetrachloride and 

 Tetrabromide. pp. 243-268. February. 1923. $.75. 



7. Evans, Alexander W . — The Chilean Species of Metzgeria. pp. 269-324. March, 



1923. $1.25. 



8. Brues, Charles T. — Some New Fossil Parasitic Hymenoptera from Baltic Amher. 



pp. 325-346. March, 1923. $.65. 



9. Kennelly, A. E. ■ — Text of the Charter of the Academic Boyale de Belgique, Trans- 



lated from the Original in the Archives of the Academie at Brussels, pp. 347-351. 

 April, 1923. $.40. 



