( Continued, from page 3 of cover. ) 



VOLUME 58. 



1. Ames, A. Jr., Proctor, 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, Rudolph E. — The Boundary Problems Associated 



with a System of Ordinary Linear Differential Equations of the First Order, pp. 49- 

 128. In press. 



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



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



4. Bhidgman, P. W. — The Effect of Pressure on the Electrical Resistance 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 



Revision 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. 



