Digital Commons Network^™

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 Conservation Of Underground Waters, James H. Lees

Proceedings of the Iowa Academy of Science

Ranking with the soil and the atmosphere, water is recognized as being one of the absolute essentials of existence. We are all familiar with the fact that where water is absent - or unavailable, which is equivalent - life likewise is absent or nearly so. It is difficult, perhaps needless, to decide which is the most necessary, soil, air, or water, all are so intimately interwoven into the complex relationships of life. Not only is that water which is exterior to the organic creation an essential to the continued well-being of that creation but much the greater bulk of animal …

The Taxonomy Of Algebraic Surfaces, R. P. Baker

Proceedings of the Iowa Academy of Science

The problems of taxonomy are problems of order. Any discrete set can be arranged in linear order but it does not follow that any linear order is satisfactory. The separation of natural neighbors may be inevitable. Examples are Linnaeus' botanical classification, or the arrangement of logical classes (abed, abcd, ----) where a natural arrangement applies in general surfaces of connectivity greater than one, or n-dimensional space. Any number of interrelations of a discrete finite set can be indicated by a three dimensional model where the elements are points and the relations say colored lines, as in a Cayley color …

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.

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.

A Table Of The Total Number Of Stroboscopic Velocity Curves For Any Of The Natural Numbers From 1 To 500 Inclusive Taken As A Limiting Value Of N And M, L. E. Dodd

Proceedings of the Iowa Academy of Science

The stroboscopic velocity equation is v₈ = (A - n/m’B)D_o , where n/m is a fraction at lowest terms. Since there are as many stroboscopic velocity curves as there are different values of n/m this fraction may be referred to as the "stroboscopic parameter."

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.

Fall Term Commencement [Program], December 2, 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, 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 …

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.

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

The Alumni News Letter

Contains news of the College and its alumni.

Winter Term Commencement [Program], March 11, 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.

Table Of Contents

Proceedings of the Iowa Academy of Science

No abstract provided.

Notes On The Occurrence Of Warts On Cottontail Rabbits, J. E. Guthrie

Proceedings of the Iowa Academy of Science

About twelve years ago my attention was drawn to some interesting epithelial growths on the head of a cottontail rabbit which was sent to the college by Mr. J. Schuyler Long, who wrote from the Iowa School for the Deaf at Council Bluffs. The head and accompanying letter were referred to Professor H. E. Summers, then head of the Department of Zoology at Iowa State College. The letter reads: "I am sending you a rabbit's head... It has several curious growths which resemble horns. I have killed a great many rabbits but never saw anything like it before. I should …

Hybridization In Iris, M. Louise Sawyer

Proceedings of the Iowa Academy of Science

In the progress of some cytological studies of pollen tube formation, fertilization and related events, I became interested in the cytology of hybrids, and determined to make some crosses for the sake of material for a cytological examination of fertilization between parents of different species. Some experience with hand pollination of Iris suggested the choice of that genus for my experiment. A survey revealed the fact that of species at my command, there was no pair that have been reported to produce hybrids. Iris pseudocorus and Iris versicolor were available. Their near relationship made it seem likely that crossing might …

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.

An Ecological Study Of Dry Run, A Typical Prairie Stream, Laurence Palmer

Proceedings of the Iowa Academy of Science

Dry Run, a tributary of Cedar River in Black Hawk County, Iowa, furnishes an excellent unit for studying the ecology of a prairie stream. It is rather exceptional in that for a greater portion of the year a natural barrier is formed where the stream flows underground for the last two miles of its course. This study is concerned only with the west branch which joins a brook of similar size near the grounds of the Cedar Valley Fair Association. While this paper deals only with a description of the creek and the distribution of its fish inhabitants, it is …

Some Interesting Insect Habitats In The Tropics, Dayton Stoner

Proceedings of the Iowa Academy of Science

The particular habitats to which reference is made in this paper include a few of the most striking and unusual ones observed in the West Indian Islands Barbados and Antigua. Observations were made and collecting was done by the writer at these places in May, June and July, 1918, at which time he was a member of the University of Iowa Barbados —Antigua Expedition.

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.

Variations In The Carotid Arteries Of The Rabbit, Francis Marsh Baldwin

Proceedings of the Iowa Academy of Science

That the blood vessels of any group of mammals in general are subject to great variations is well known. Such minor variations as have been observed within any group have usually been ignored or at most, resolved to conform to the type. Using the rabbit as a basis of study in mammalian anatomy during the past two years the writer has had an opportunity to make some interesting observations on the variations of the carotid arteries. Of one hundred and fourteen specimens dissected in the laboratory, twenty-three, or about twenty per cent were found to differ from the usual condition …

Title Page

Proceedings of the Iowa Academy of Science

No abstract provided.

The Address Of The President - Some Problems In Conservation, Samuel Walker Beyer

Proceedings of the Iowa Academy of Science

The credit for directing the attention of the public to the almost universal waste of the Nation's resources must be accorded to the late President Theodore Roosevelt. The great President was not only the originator of the movement but continued to be its most aggressive and enthusiastic apostle and promoter. The idea first found definite expression in his address before the Society of American Foresters, March 26, 1903, in which he emphasized the necessity of forest preservation and pointed out the close relationship between the forests and stream flow.