TIILES OF PAPERS PRESENTED 
The Address of the President : American Science. ............ 33 
Chemistry 
Further Work in the Study of Free Energy of Aqueous Solutions. 
J. N. Pearce and H. B. Hart. 
The Effect of Relative Positions of the Hydroxide and Amino Radicals 
in the Migration of Acyl from Nitrogen and Oxygen. E. Charles 
Raiford and H. A. Iddles. ................. 
A Chemical Study of Dolomites. Nicholas Knight. ............... 37 
Geology 
Three Glacial Tills at Ames, Iowa. John E. Smith... 47 
Eolian Deposits in Webster County, Iowa. John E. Smith ...... 
Discovery of Volcanic Ash in Iowa. Charles Keyes...... 49 
Geological Age of the Terrepleins of Utah's High. Plateaux. Charles 
Keyes ............................... 54 
Batholithic Veinings of the Sierra de los Cucaras in Baja California. 
Charles Keyes 57 
Some Pleistocene Sections at Des Moines. James H. Lees. ........... 59 
Some Carboniferous Protozoa. Eula D. McEwan. 
A Cephalopod from the Coal Measures at Centerville, Iowa. A. O. 
Thomas 
Some Oligocene Brachiopods from the Island of Antigua, A. O. 
Thomas ........ 
Some Proboscidean Remains Found in Henry County. H. E. Jaques. . 65 
The Loess Fossils of Western Tennessee. B. Shimek. 
Physics and Astronomy 
A Laboratory Optical Pyrometer: Notes on its Design and Operation. 
Wm. Schriever ............... 69 
Measurements of the Amplitude of Vibration of the Diaphram of the 
Hewlett Tone Generator. Clarence E. Lane 83 
Determination of the Minimum Audible Intensity of Sound for Tones 
of High Frequency. Clarence E. Lane 89 
A Single Band Acoustic Wave Filter. G. W. Stewart ................ 93 
The Effect of Drawing on the Crystal Structure of Tungsten Wires. 
L. P. Sieg 95 
A Note on Kater’s Reversible Pendulum. L. P. Sieg. 98 
The Coefficient of Simple Rigidity, and Young's Modulus for Hexa- 
gonal Crystals of Selenium. L. P. Sieg and R. F. Miller 103 
The Absorption of Light Passing Through Deep Slits, as a Function of 
the Length and Depth of the Slits and of the Wave Length of the 
Light. L. P. Sieg and A. T. Fant. 112 
