CONTENTS. 
TITLES OF PAPERS. 
Page 
Aural Perception by the Blind; Drs. S. E. Mezes and H. C. Hilgart- 
ner 1 
The Economics of Concentrated Capital; Major C. E. Dutton 7 
Vertical Curves for Railways; J. C. Nagle. . . ... 21 
Experiments with X-rays Upon the Blind; Drs. H. L. Hilgartner 
and E. F. Nortlirup . . . 29 
On the Bio-Geograpliy of Mexico and the Southwestern United 
States; C. H. Tyler Townsend 33 
Some Texas Oil Horizons; E. T. Dumble 87 
Texas Permian; W. F. Cummins ... 93 
Science on the Conduct of Life; Dr. George Bruce Haslted 99 
Titles of Papers read before the Academy, 1897 105 
List of new Members and new Fellows . 106 
Reprint of an announcement made in the April programme 107 
COMMITTEE ON PUBLICATION. -.P 
W. W. Norman. G. B. Halsted. - E. T. Dumble 
