IOWA ACADEMY OF SCIENCE ,259 
INDEX 
Page 
American Lepidostrobus, The First Reported Petrified, is from Warren 
County, Iowa 163 
Anniversary Address 17 
Anomalous Ovary Ill 
Apparatus for Measuring 'Small (Intervals of Time, New Laboi^tatof-y, 
Independent of Clock or Chronograph : 185 
Arid Plateau-Plains as Features of Eolic Erosion 157 
Blight of Rarley-Helminthosporium Teres Sacc 
Botany in Iowa, Twenty-five years of 43 
Broad Winged Hawks, Remarkable Flight of ..195 
Carbonic Rocks, Nether Delimitation of 153 
Charter Members of the Iowa Academy of Science 27 
Chromaffine cells of the Adrenals of the Pig, Source of .215 
Constitution of Academy 6 
Dye-Plants, Native, and Tan-Plants of Iowa .’ 113 
Early Iowa Locality Records 26-3 
Effect of Rupture by Abrasion on the Electrical Conductivity of Selenium. . .179 
Ferns and Liverworts of Grinnell and Vicinity 105 
Food Habits of Red Tailed Hawk, Cooper’s Hawk, and Sparrow Hawk.... 199 
Food of the Black Crowned Night Heron In Captivity 193 
General Geologic Section of Iowa, Sundry Provincial and Local Phases of.. 147 
Geodes of the Keokuk Beds, Origin of 169 
Geology, History of in Iowa for the Last Twenty-five Years 65 
Greetings from Visiting Academies 86 
Herpetology of Iowa, II. Contributions to ......207 
Heteranthera Dubia, Notes on ..131 
Insect Parasitism, A Study in.... ....209 
Mammals from Northwestern Iowa, Notes on a Collection of 203 
Melanism, Occurrence of, in the Broad Winged Hawk 191 
Method of Determining Whether the Restoring Torque is Proportional to 
the Tor,sional Strain During the Vibration of a Torsional Pendulum. . . .189 
Osage Series of the Mississippian System, Study in the Cherts of , 173 
Physics, The Progress of, in Iowa in the Quarter Century ......* 73 
Pollen Tubes, Behavior of in Richardia Africana 109 
President’s Address 11 
Program 8 
Radioactive Disintegration of Sodium as an Element, Evidence Favoring. . . .175 
