(Continued from page 3 of cover 



VOLUME 58. 



Ames, A. Jr., Proctor, C. A., and Ames^ Blanche. — ■'. Vision and the Technique of Art. 

 pp. 1-47. 28 pis. In press. 



Birkhoff, George D. and Langer, Rudolph E. — The Boundary Problems Associated 

 with a System of Ordinary Xifiear JJitlererftial Equations of "the First Order, pp. 49- 

 128. In press. 



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

 pp. 129-147. January, 1923. $1.60. 



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

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



