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The Perception Of Binaural Phase Difference Not Caused By An Intensity Effect, G. W. Stewart

Proceedings of the Iowa Academy of Science

It is becoming well known that it is possible to perceive a difference in phase at the ears by a displacement of the phantom image from the median plane. Attempts, have been made to explain this effect by bone conduction and the effect of intensity, for it is also well known that a difference of intensity will also cause a displacement. But the only published explanation of this character has been shown to be not satisfactory. Yet, since a large group of psychologists believe that sensation depends entirely upon the mode of response of the end organ and not upon …

The Frequency Limits Of The Binaural Phase Difference And Intensity Effects, G. W. Stewart

Proceedings of the Iowa Academy of Science

The variation in localization of a phantom source with phase difference only at the ears and the variation with intensity differences only at the ears are here called the binaural phase difference effect and the binaural intensity effect respectively. That these variations follow according to law, the former linearly and the latter logarithmically, is not discussed.

The Relation Of The Smaller Forest Areas In Non-Forested Regions To Evaporation And Movement Of Soil Water, Irwin T. Bode

Proceedings of the Iowa Academy of Science

The importance of the climatic and edaphic relations of forests has been the basis for wide discussion and study. The scope of this field is shown in a condensed way in a report of the Sub-Committee on Forest Investigations to the Fifth National Conservation Congress, which discusses studies undertaken up to the time of the report (1913) and presents in general results obtained. Recently, Zon, in a paper, "Forests and Water in the Light of Scientific Investigation," has presented a much more comprehensive view of the subject and the literature. He has attempted to bring together "all the well-established scientific …

The Use Of The Terms Flint And Chert, Waldo S. Glock

Proceedings of the Iowa Academy of Science

Reference to almost any two text books in geology will show that there are different usages for the terms flint and chert. Perhaps much of the confusion is due to the fact that the origin of these substances is unknown, in which case exact definition at this time would be premature. Whatever the reason it seems advisable to bring out the variability of definition, if for no other purpose than to state a problem without attempting its solution. Blackwelder & Barrows- Elements of Geology, 1911, page 39. Flint is defined as "a very compact, dark grey, siliceous rock." Farther on, …

The Photographic Determination Of The Form Of An Airplane Loop, And The Dynamics Of The Loop, L. P. Sieg

Proceedings of the Iowa Academy of Science

During a greater part of the years 1918 and 1919, the writer was engaged at Langley Field, Virginia, on experimental work connected with the determination of bomb trajectories. The work was under the direction of Dr. A. Wilmer Duff, as Engineer-in-charge, and the writer as assistant engineer. The credit for the development of the photographic method, described below, is due to Doctor Duff. The details connected with this paper, have been worked out by the writer as an interesting and important side issue of the main problem.

On Finding The Equation Of The Characteristic Blackening Curve For A Photographic Plate, P. S. Helmick

Proceedings of the Iowa Academy of Science

In 1890 Hurter and Driffield proposed the following equation for the density "D" of a photographic plate exposed for a time "t" to light of constant intensity: D = 1/a Log_e (b-[b-1] e^-ct) where "a", "b", and "c" are parameters.

Miscellaneous Addresses, 1885-1920, Homer H. Seerley

Faculty Book Gallery

Homer Horatio Seerley was the second chief administrator of UNI. His predecessor was James Cleland Gilchrist. Seerley led the school from 1886 to 1928.

The Alumni News Letter, V3n4, October 1, 1919, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

Summer Term Commencement [Program], August 21, 1919, Iowa State Teachers College

UNI Commencement Programs

The program of the commencement ceremonies, including a list of institutional leadership, a list of the departments by college, awards given at the ceremonies, and a list of undergraduate and graduate degree candidates.

The Alumni News Letter, V3n3, July 1, 1919, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

Iowa State Teachers College Program Of Recitations, Summer 1919, Iowa State Teachers College

UNI Schedule of Classes

A listing and schedule of the courses being taught as well as policies and procedures concerning attending classes at the Iowa State Teachers College.

Spring Term Commencement [Program], June 3, 1919, Iowa State Teachers College

UNI Commencement Programs

The program of the commencement ceremonies, including a list of institutional leadership, a list of the departments by college, awards given at the ceremonies, and a list of undergraduate and graduate degree candidates.

College Catalog And Circular 1919, Iowa State Teachers College

UNI Programs and Courses Catalogs

Table of Contents

Calendar for 1919-1920 ... 5
Officers of Administration ... 6
Officers of Instruction ... 9
General Information ... 36
Residence, Student Health, Assembly ... 40
Expenses and Fees ... 40
Free Scholarships ... 42
Extension Service ... 42
Acceptance of Credits from Other Institutions ... 43
College Organizations ... 43
Training in Actual Teaching ... 44
Public Lectures and Entertainments ... 45
Boarding and Lodging ... 45
Employment of Students ... 46
Normal Training ... 46
School Credits in Lieu of Certificate Examinations ... 46
Examinations for Teachers Certificates ... 47
Department Certificates ... 47
Bureau of …

The Alumni News Letter, V3n2, April 1, 1919, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

Iowa State Teachers College Program Of Recitations, Spring 1919, Iowa State Teachers College

UNI Schedule of Classes

A listing and schedule of the courses being taught as well as policies and procedures concerning attending classes at the Iowa State Teachers College.

Table Of Contents

Proceedings of the Iowa Academy of Science

No abstract provided.

Iowa State Teachers College Program Of Recitations, Winter 1918-19, Iowa State Teachers College

UNI Schedule of Classes

A listing and schedule of the courses being taught as well as policies and procedures concerning attending classes at the Iowa State Teachers College.

1919 Old Gold, Iowa State Teachers College

UNI Yearbooks

The student yearbook of the Iowa State Teachers College, later known as the University of Northern Iowa.

Some Structural Features Of Selenium Deposited By Condensation From The Vapor State In The Neighborhood Of The Melting Point, L. E. Dodd

Proceedings of the Iowa Academy of Science

The primary object of this paper is to record some experimental observations. During work on the vapor tension of the element selenium, above and below the melting point, where the Knudsen method of molecular flow was used, the condensed material deposited itself on the cooling tube of the apparatus in a noteworthy manner. Some numerical data on it in addition to that necessary for the vapor pressure measurements were obtained incidentally at the time of the experiments. A description of the behavior of the deposit, from run to run of the pressure measurements, is here given, partly by means of …

The Alumni News Letter, V3n1, January 1, 1919, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

The Binaural Difference Of Phase Effect, G. W. Stewart

Proceedings of the Iowa Academy of Science

The binaural difference of phase effect has become of increased importance in recent years. The following are the new facts obtained in recent experiments which are still in progress.

An Illustration Of The Wedge-Work Of Roots, A. O. Thomas

Proceedings of the Iowa Academy of Science

The wedge-work of roots is a powerful and effective agent of weathering and performs an important part in breaking up solid rock. Since the indurated rocks, as a rule, are covered by mantle rock of considerable thickness the actual penetration of their seams, joints, and crevices by roots is concealed. In some cases, too, the mantle rock is of so great thickness that even the longest roots fail to reach the solid rock below. On bare rocky cliffs where there is sufficient moisture, trees, in some cases of large size, grow from crevices and joints where their seeds have sprouted. …

Observations Of The Total Solar Eclipse Of June 8, 1918, At Matheson, Colorado, D. W. Morehouse

Proceedings of the Iowa Academy of Science

The Drake University Observatory eclipse expedition occupied a very favorable site at Matheson, Colorado. It was wholly through the courtesy of Dr. Edwin B. Frost, Director of the Yerkes Observatory, who with Prof. E. E. Barnard, had selected this station as one of two very desirable locations, that the expedition was so happily situated.

Officers, Past Presidents, And Members, Iowa Academy Of Science

Proceedings of the Iowa Academy of Science

No abstract provided.

The Correlation Of Art And Science In The Museum, Homer R. Dill

Proceedings of the Iowa Academy of Science

What is it that makes the museum a success? I believe this question may be satisfactorily answered by a careful study of the people who visit museums. Go to some good museum and stroll quietly about among the groups of spectators and listen to their remarks; note carefully the types of exhibits that attract their attention, occasion their comment, and hold their interest. If you are interested and wish to follow up your investigation, go again and as often as you are able. You may thereby get some suggestions for building a museum for the public that never would occur …

Further Notes On Helicina Occulta Say, B. Shimek

Proceedings of the Iowa Academy of Science

Few American mollusks equal Helicina occulta Say in interest. It is an operculate species which has been reported at times as aquatic, though it is strictly terrestrial; its living representatives are distributed over widely separated areas in restricted local colonies, and evidently represent a declining race; and it is a common fossil of the loess of peculiar significance, of much more general distribution in the loess-covered portions of the upper Mississippi- Missouri basin, failing to reach the region of the northernmost living colonies, but extending well beyond them westward.

A Century Of Iowa Geology, Charles Keyes

Proceedings of the Iowa Academy of Science

The first centennary of a science in Iowa is upon us. History of the sciences in the commonwealth now goes back beyond the span of our statehood. It transgresses a date when even a name for our state was yet unknown. In Iowa, by many years, claims to first recognition for geology antedate those of every other natural science. Curiously enough this earliest Iowa episode is also the most important geological event for the entire continent during a hundred years. It is even worldwide in some of its aspects. Nor are these early observations alone in their great significance. During …

The Action Of Conical Horns, G. W. Stewart

Proceedings of the Iowa Academy of Science

Conical horns possess two aspects of considerable importance. In the first place, they are an exceedingly important form of acoustical apparatus. Again, there is no exact theory of the action of conical horns and hence the only recourse for quantitative information is that of experiment.

Proceedings Of The Thirty-Third Annual Session (Of The Iowa Academy Of Science), Held At Cedar Falls, April 25 And 26, 1919: Minutes Of The Meeting; Staff & Committee Reports

Proceedings of the Iowa Academy of Science

No abstract provided.

The Relation Between Voltage And Candle-Power In Modern Incandescent Lamps, William Kunerth

Proceedings of the Iowa Academy of Science

Among the operating characteristics of incandescent lamps, there are certain features which are often overlooked by the man using or dealing with lamps. The voltage is one of the chief factors upon which the behavior of a lamp depends. It is well known that under an excessive voltage, a lamp will not last long, but will last much longer than its normal life if the voltage is below normal. Mathematical formulae have been deduced from experimental results to cover this relation.