CONTENTS- 
Transactions : 
“ Aural Perception by the Blind,” 
Drs. S. B. Mezes and H. L. Hilgartner 1 
“The Economics of Concentrated Capital,” 
Maj. C. E. Dutton, U. S. A 7 
“Vertical Curves for Railways,” 
James -C. Nagle 21 
“Experiments With X-Rays Upon the Blind,” 
Drs. H. L. Hilgartner and E. F. Northrup. 29 
“On the Bio-Geographv of Mexico and Southwestern United 
States,” 
C. H. Tyler Townsend 33 
“Some Texas Oil Horizons,” 
E. T. Dumble . 87 
“Texas Permian,” 
W. F. Cummins ' 93 
“Science in the Conduct of Life,” 
Dr. George Bruce Halsted 99 
Proceedings : 
Titles of Papers Read Before the Academy from February 5, 
1897, to November 5, 1897 .105 
New Members Elected 106 
New Fellows Elected 106 
Announcement 107 
