IOWA ACADEMY OF SCIENCE 
9 
The Solubility of Lead Sulphate in Aqueous Solutions of Sulphuric Acid.. 
P. A. Jans and J. N. Pearce 
The First Reported Petrified American Lepidostrobus is from Warren county, 
Iowa John L. Tilton 
Nether Delimitation of our Carbonic Rocks Charles R. Keyes 
Arid Plateau Plains as Features of Eolic Erosion Charles R. Keyes 
Sundry Provincial and Local Phases of the General Geologic Section of 
Iowa Charles R. Keyes 
The Salem Limestone and Its Stratigraphic Relations in Southeastern 
Iowa Francis M. Van Tuyl 
The Origin of the Geodes of the Keokuk Beds Francis M. Van Tuyl 
A Study in the Cherts of the Osage Series of the Mississippian System. . . . 
Francis M. Van Tuyl 
A Method of Teaching Elementary Mineralogy G. F. Kay 
On the Dissimilarity of Light and Heat Action in a Certain Variety of 
Selenium • E. O. Dieterich 
A Survey of the Water-Bearing Gravels at Estherville, Emmet County, 
Iowa G. G. Wheat 
Additional Evidence of Unconformity Between the Cedar Valley and Lime 
Creek Stages of the Devonian of Iowa A. O. Thomas 
Some Notes on the Aftonian Mammals A. O. Thomas 
Early Iowa Locality Records B. Shimek 
The Phase Difference at the Ears Produced by a Simple Source of Sound 
G. W. Stewart 
A New Apparatus for Measuring Small Intervals of Time, Independent of 
Clock or Chronograph F. C. Brown 
Evidence Favoring the Radioactive Disintegration of Sodium as an Element 
F. C. Brown 
The Effect of Rupture by Abrasion on the Electrical Conductivity of 
Selenium F, C. Brown 
A Method of Determining Whether the Restoring Torque is Proportional to 
the Torsional Strain During the Vibration of a Torsional Pendulum 
L. P. Sieg 
The Influence of an Electric Current upon the Elasticity of Wires. .H. L. Dodge 
A Simple Laboratory Equipment for the Elementary Study of Alternating 
Currents H. L. Dodge 
Mollusca of Iowa T. Van Hyning 
A Study in Insect Parasitism R. L. Webster 
Systematic Outline of the Reduviidae of N. America S. B. Fracker 
Notes on a Collection nf Mammals from Northwestern Iowa 
Alexander G. Ruthven and Norman A. Wood 
Contribution to the Herpetology of Iowa, II Alexander G. Ruthven 
Food Habits of Red Tailed Hawk, Cooper’s Hawk and Sparrow Hawk 
.F. C. Pellett 
The Harvest Mouse in Iowa F. C. Pellett 
The Interpretation of the Cardio-sphygmogram and the Electro-cardiogram, 
Normal and Pathological W. E. Sanders 
The Source of the Chromaffine Cells of the Adrenals of the Pig. .Mildred R. Yule 
Notes on the Food of the Black Crowned Night Heron in Captivity. .B. H. Bailey 
The Occurrence of Melanism in the Broad Winged Hawk B. H. Bailey 
A Remarkable Flight of Broad Winged Hawks B. H. Bailey 
