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Certain Features Of Rheostat Design, H. L. Dodge

Proceedings of the Iowa Academy of Science

Everyone who has used rheostats of the sliding-contact type has experienced inconvenience in obtaining the desired values of current and voltage. If the rheostat is connected in series with the load, small currents cannot be obtained. If the load is shunted across a portion of the rheostat on the potentiometer principle, part of the winding carries a double load and consequently only a fraction of the full current capacity is available. To secure the advantages of both methods of connection there must be a complete rewiring of the circuit. This requires time and attention and especially in the case of …

The Address Of The President, Geo. W. Stewart

Proceedings of the Iowa Academy of Science

As President of the Academy I now have the honor to present an address, thus reestablishing a former custom, but with appropriate regard for the necessity of brevity. Within the time of twelve minutes I propose to glance at recent progress in physics and also to discuss the function and responsibility of this Academy. The notable achievements in that science within the past few years cannot all receive mention hence it is essential that there be pointed out but a few typical eases of progress.

1917 Senior Review, Iowa State Teachers College High School

Malcolm Price Laboratory School Yearbooks

The student yearbook of the Teachers College High School (later the Northern University High School, part of the Malcolm Price Laboratory School of the University of Northern Iowa).

Quarterly News Letter To The Alumni, January 1, 1917, Iowa State Teachers College

Quarterly News Letter to the Alumni

A quarterly publication to keep graduates of the Iowa State Teachers College informed on the happenings on campus and of fellow alumni.

In Memoriam: Arthur G. Smith; Bert H. Bailey, R. P. Baker, S. W. Stookey

Proceedings of the Iowa Academy of Science

No abstract provided.

Continental Perspective Of American Precambrian Stratigraphy, Charles Keyes

Proceedings of the Iowa Academy of Science

To many of the delegates to the Twelfth International Geological Congress who listened to the papers and discussions on Pre-Cambrian problems and who afterwards took part in the Canadian transcontinental excursions into regions where the ancient elastics were displayed in infinite variety, the most valuable feature perhaps, was the field evidences of the amazing taxonomic possibilities which on the American continent the Pre-Cambrian sections were opening up. Few of the travelers had ever seen so deeply into the oldest stratified rocks in so short a time, under such favorable circumstances, or under happier guidance. Some of the participants in the …

An Interesting Case Of Resonance In An Alternating Current Circuit, H. L. Dodge

Proceedings of the Iowa Academy of Science

The phenomena of voltage and current resonance are familiar to all students of alternating currents. The former occurs in series circuits and complete resonance is secured when the condensive reactance is equal to the inductive reactance. The latter occurs in connection with parallel circuits, the necessary condition being that the sum of all the susceptances, both condensive and inductive, equals zero.

The X-Ray K-Radiation Of Tungsten, Elmer Dershem

Proceedings of the Iowa Academy of Science

Metals of the greater atomic weights can be made to emit at least two types of characteristic X radiations, known as the J, or soft and the K or hard radiations. In a previous paper the wave lengths of the known lines in the L region of the tungsten X-ray spectrum were given. The work has since been extended to the characteristic lines of the K region.

On Certain Elastic Properties Of Drawn Tungsten Wires, L. P. Sieg

Proceedings of the Iowa Academy of Science

The wires used in these experiments were furnished through the kindness of Dr. A. G. Worthing of the Nela Laboratory of the General Electric Company, of Cleveland, Ohio. There were five specimens from each of two different sets of wires. Thus each group of five wires was drawn from the same original swaging. The wires range in radius from.002397 cms. To.02584 cms. Tungsten is very hard and brittle, and can be drawn only by experts. The tungsten has previously to be made very free from impurities, and then worked and swaged into a rough wire. This is then drawn down …

The Electrical Capacity Of Similar, Non-Parallel Plane Plates, And Its Application Where The Plates Are Non-Rectangular., L. E. Dodd

Proceedings of the Iowa Academy of Science

An investigation in which it was necessary to find the distance between plane, non-parallel plates in terms of their electrical capacity raised the question of the amount of error in applying the equation for parallel plates. An equation for non-parallel plates was derived.

The Stroboscopic Effect, L. E. Dodd

Proceedings of the Iowa Academy of Science

Consider a straight row of equally spaced white dots on a black belt running at a constant velocity v over two pulleys. Let the dot spacing be D₀. Suppose that the belt is in a darkened room so that even when the belt is at rest the dots are invisible. Let the moving belt be periodically illuminated by some source of intermittent and approximately instantaneous illumination of constant frequency B.

Precontact Conduction Currents, L. E. Dodd

Proceedings of the Iowa Academy of Science

During some work in which capacity measurements were made of plane conducting plates (silver films) in air at very short distances, the writer was able to take some incidental readings of small currents that passed between the plates when they apparently lacked several wave lengths of being in contact. Three sets of measurements were taken in one evening. Figure 1 of figure 38 shows the electrometer deflection plotted with the time. The characteristic shape of the curves suggests an exponential relation.

Table Of Contents

Proceedings of the Iowa Academy of Science

No abstract provided.

On A Supposed Fruit Or Nut From The Tertiary Of Alaska, A. O. Thomas

Proceedings of the Iowa Academy of Science

In the summer of 1910, Dr. George F. Kay, while engaged in a study of the Bering River Coal Field of southeastern Alaska, discovered some subspherical, concretion-like bodies in the ''shales of the Tokun formation.'' Three specimens were brought back by Professor Kay and these through his kindness have been submitted to the writer for study. The largest is a smooth oval body with long and short diameters of 8.6 and 7.6 centimeters; the smallest is likewise smooth, irregularly oval, and with diameters of 4.3 and 3.8 centimeters. All three are dark-colored, compact, close-grained stone, brittle under the hammer, and …

The Effect Of Hydrogen-Sulphide On The Unilateral Conductivity Of Zincite-Copper Contacts, R. B. Dodson

Proceedings of the Iowa Academy of Science

Of the many experiments concerned with the unilateral conductivity of the so-called crystal rectifiers very few have had to do with the effect of gases. The experiments described in this paper show that an artificial rectifier can be produced through the action of hydrogen-sulphide upon zincite-copper contacts. Such contacts show little or no unilateral conductivity in vacuo but possess the property to a considerable degree in an atmosphere of hydrogen-sulphide.

Report Of The Inside Survey [Of The Iowa State Teachers College], State College Of Iowa

History of Education Book Gallery

No abstract provided.

Quarterly News Letter To The Alumni, September 1, 1916, Iowa State Teachers College

Quarterly News Letter to the Alumni

A quarterly publication to keep graduates of the Iowa State Teachers College informed on the happenings on campus and of fellow alumni.

Quarterly News Letter To The Alumni, July 1, 1916, Iowa State Teachers College

Quarterly News Letter to the Alumni

A quarterly publication to keep graduates of the Iowa State Teachers College informed on the happenings on campus and of fellow alumni.

Spring Term Commencement [Program], June 6, 1916, 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 1916, Iowa State Teachers College

UNI Programs and Courses Catalogs

Table of Contents:

Calendar for 1916-1917 ... 5
Officers of Administration ... 6
Officers of Instruction ... 7
Faculty Committees 1916-1917 ... 18
Plan of Organization ... 19
General Regulations ... 19
Faculty Regulations ... 22
Order and Deportment ... 22
Credits and Scheduling ... 22
Extension Service ... 23
Exchange of Students ... 23
Expenses and Fees ... 23
College Organizations ... 25
Training in Actual Teaching ... 26
Public Lectures and Entertainments ... 28
Boarding and Lodging ... 28
Employment of Students ... 29
The College Degree Division ... 31
Requirements for Admission ... 32
Definitions of College …

Quarterly News Letter To The Alumni, April 1, 1916, Iowa State Teachers College

Quarterly News Letter to the Alumni

A quarterly publication to keep graduates of the Iowa State Teachers College informed on the happenings on campus and of fellow alumni.

Summer Term, Twentieth Annual Session, 1916, 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.

A Physical Representation Of The Summation Of Certain Types Of Series, L. P. Sieg

Proceedings of the Iowa Academy of Science

Most of us are on the lookout for concrete illustrations of abstract ideas. To be able to visualize a mathematical process is to many of us a step toward the better understanding of that process. The following brief discussion, although having no pretentious to absolute originality, is offered as a physical illustration of the summation of certain simple geometric series.

1916 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.

Table Of Contents

Proceedings of the Iowa Academy of Science

No abstract provided.

A Modern School, Abraham Flexner

History of Education Book Gallery

A Modern School is a 23-page occasional paper, written by Abraham Flexner and published in 1916 by The General Education Board. Flexner (1866-1959) was an American educator and education reformer. The occasional paper presented here addresses many of the perceived failings of the public school system circa 1916 and suggests several reforms. The General Education Board was established by John D. Rockefeller in 1903. According to the Rockefeller Foundation, the board was established to aid education in the U.S. without distinction of race, sex or creed, and was active in promoting the public school movement in the early part of …

An Electrical Device For Securing And Maintaining Constant High Temperatures, W. E. Tisdale

Proceedings of the Iowa Academy of Science

In a paper read before this Academy last year, a device for controlling comparatively high temperatures (up to about 600" C) was explained, together with the necessary auxiliary apparatus, an ordinary electro-magnet circuit breaker, and the source of constant potential necessary to operate this magnet. The oven described in that paper consisted of a properly insulated porcelain tube 30 cm. long and 5 cm. in diameter. It required 10 amperes to heat it to 450° C. The dimensions of the oven limited the size of the tubes in which the crystals were to be produced to not more than 3 …

A New Tonoscope, L. E. Dodd

Proceedings of the Iowa Academy of Science

While undergoing a series of voice pitch tests some three years ago in the Psychological Laboratory of the State University of Iowa, the author learned that in his own individual case, as in some others, there existed, according to the statement of the investigator, Mr. C. J. Knock, a consistent as well as persistent tendency to miss in a definite direction certain intervals of the musical scale. The instrument used in these tests was the Seashore tonoscope, an indicator of absolute pitch developed in some of its later stages at this University.

Notes On The Flora Of Sitka, Alaska, Jacob Peter Anderson

Proceedings of the Iowa Academy of Science

On February 1, 1914, the writer began his duties in connection with the United States Agricultural Experiment Station at Sitka, Alaska. This made necessary a change in thesis subject and at the suggestion of Dr. Pammel, in whose department the major work was taken, the above subject was chosen.

Electromotive Forces And Electrode Potentials In Pyride And Its Binary Mixtures With Water, Methyl Alcohol And Ethyl Alcohol, F. S. Moretimer, J. N. Pearce

Proceedings of the Iowa Academy of Science

The systematic study of the electromotive forces in non-aqueous solvents was begun by Jones. By using cells of the type: Ag-AgNO₃aq , — AgNO₃non-aq. -Ag with the same concentration of the salt in each solvent, he hoped to be able to calculate the degree of dissociation in the nonaqueous solutions. It soon became apparent, however, that the solution pressure of a metal varies from solvent to solvent. Substituting the values found by Völlmer for the degree of dissociation of silver nitrate in ethyl alcohol, he calculated the ratio of the solution pressure of silver in alcohol …