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The Blackening Of A Photographic Plate As A Function Of Intensity Of Monochromatic Light And Time Of Exposure, P. S. Helmick

Proceedings of the Iowa Academy of Science

By an empirical modification of Hurter and Driffield's and Ross formulae, it has been possible to express the blackening of a photographic plate exposed to monochromatic light as a function of intensity of light and time of exposure with an accuracy within the limits of the experimental data at hand. By means of monographic charts the constants of the equations can be computed by semi-graphical methods.

Alcohols As Factors Altering Fatigue Processes In Frog Muscle, Francis Marsh Baldwin

Proceedings of the Iowa Academy of Science

In a recent paper experiments were cited which indicate that developing sea-urchin eggs when subjected to suitable concentrations of various liquid-soluble substances, i.e., the higher alcohols, show unmistakable rhythms of susceptibility and resistance according to the phase of physiological activity at the specific time of treatment. Such observations constitute additional evidence that a very intimate relation or correlation exists between the general physiological condition of the egg, and the physical state of its plasma-membrane. The present paper is a preliminary report of experiments conducted in the light of recent advances to analyze the effects of various concentrations of the alcohols …

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

Proceedings of the Iowa Academy of Science

No abstract provided.

A Single Band Acoustic Wave Filter, G. W. Stewart

Proceedings of the Iowa Academy of Science

Theoretical considerations lead to the conclusion that a single band acoustic wave filter can be made in a manner analogous to the electric wave filter and also that in the acoustic case there should be a repetition of the band at high frequencies. The accompanying drawing shows the results of experiments with two filters whose dimensions also are indicated.

The Alpha Lines In The "K" Series Tungsten Spectrum, Charles Crofutt

Proceedings of the Iowa Academy of Science

According to Bohr's theory of the atom, radiation takes place only when an electron goes from one orbit to an orbit closer the nucleus. If W represents the energy associated with an orbit, that is, the energy required to remove an electron from the orbit to infinity, the energy radiated when an electron goes from orbit (1) to orbit (2) will be W₂ - W₁ = h, where orbit (2) is closer the nucleus. Assuming that an absorption frequency corresponds to the energy associated with a ring of the Bohr atom, the difference between two absorption frequencies should …

The Alumni News Letter, V4n4, October 1, 1920, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

Summer Term Commencement [Program], August 19, 1920, 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, V4n3, July 1, 1920, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

Spring Term Commencement [Program], June 1, 1920, 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 1920, Iowa State Teachers College

UNI Programs and Courses Catalogs

Table of Contents

Calendar for 1920-1921 ... 3
Officers of Administration and Instruction ... 4
General Information ... 30
Residence, Student Health, Assembly ... 34
Expenses and Fees ... 35
Free Scholarships ... 37
Extension Service ... 37
Acceptance of Credits from Other Institutions ... 37
College Organizations ... 38
Faculty Organizations ... 39
Training in Actual Teaching ... 39
Public Lectures and Entertainments ... 39
Boarding and Lodging ... 40
Employment of Students ... 41
Twelve Weeks Normal Training ... 41
School Credits in Lieu of Certificate Examinations ... 41
Examinations for Teachers Certificates ... 42
Department Certificates ... …

The Alumni News Letter, V4n2, April 1, 1920, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

The Localization Of Sound By Wave Phase In The Open Ear, Henry M. Halverson

Proceedings of the Iowa Academy of Science

Wave phase localization may be studied under normal conditions; ie, without the aid of conductors to the ears. Our apparatus consists of two telephone receivers connected in series from the same source. If the receivers are so energized as to produce a pure tone, the observer, by closing one ear and moving the head carefully from one source to the other, (the side of the head parallel to the axis of the receivers) will experience a series of "highs" and "lows" in intensity. These points of maximum and minimum intensity correspond exactly to the points of reinforcement and interference as …

What Constitutes Voice?, C. I. Erickson

Proceedings of the Iowa Academy of Science

General mechanism of voice production.

Swimming Pool Sanitation, Jack J. Hinman Jr.

Proceedings of the Iowa Academy of Science

The swimming pool, being really a sort of common bath, rapidly departs from a sanitary condition, unless prompt and adequate measures are taken to maintain a reasonable degree of purity in the water. Moreover, since various types of intestinal infections, infections of the respiratory system, eye and ear infections, gonorrheal infections and skin infections have been traced to the waters of swimming pools, the protection of the bathers by means of proper treatment of the water and rigid inspection of all entrants into the pool is essential to safety.

The Alumni News Letter, V3n2 [V4n1], January 1, 1920, Iowa State Teachers College

The Alumni News Letter

Contains news of the College and its alumni.

Comparison Of Absorption Occuring In Corn Stalk Tissue And In Prepared Biocolloids, L. E. Yocum, A. L. Bakke

Proceedings of the Iowa Academy of Science

Growth, an important function of the plant, is characterized by being possible under a wide range of temperature, moisture, available plant food, and other limiting factors. It is a hydration of the colloidal material (protoplasm) of the plant to which, later in the life of the plant, matter is added. This added matter, of course, increases the dry weight. Protoplasm has been found to adhere so closely in its actions to the laws of artificially constructed biocolloids that many attempts are being made to construct a biocolloid whose behavior agrees with the observed behavior of protoplasm and in that way …

1920 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.

The Personal Equation In Motor Ability, Martin L. Reymert

Proceedings of the Iowa Academy of Science

In order to try out experimentally the common notion, that an individual will show a constant behaviour as to speed and accuracy in all kinds of motor performance - within his group - a series of reaction and motor tests were given to sophomores. The tests were: (1) Tapping in group (with pencil). (2) Individual tapping (on telegraph key). (3) Counting numbers orally. (4) Writing numbers. (5) Counting and writing as one combined activity. Simple bodily reactions of (6) the lips, (7) the jaws, (8) the index finger, (9) the head, (10) the elbow, (11) the thumb, (12) the foot. …

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

Proceedings of the Iowa Academy of Science

No abstract provided.

Proceedings Of The Thirty-Fourth Annual Session (Of The Iowa Academy Of Science), Held At Iowa City, April 23 And 24, 1920: Minutes Of The Meeting; Staff & Committee Reports

Proceedings of the Iowa Academy of Science

No abstract provided.

Presentation Of The Calvin Memorial Portrait; Addresses Pertaining To The Presentation Of The Calvin Memorial Portrait, Thomas H. Macbride, L. H. Pammel, M. F. Arey, B. Shimek, A. O. Thomas, Edgar R. Harlan

Proceedings of the Iowa Academy of Science

No abstract provided.

The Hall Effect And The Specific Resistance Of Thin Silver Films, G. R. Wait

Proceedings of the Iowa Academy of Science

The Hall Effect of ordinary metals may be expressed by the equation E=HIa/e where E = the Hall Effect, I= the primary current, e= the thickness of the conductor and a= a constant whose value in silver lies between.00083 to.00090. In the present investigation the above equation was found to hold in thin silver films, and that has a value of.00084.

Table Of Contents

Proceedings of the Iowa Academy of Science

No abstract provided.

A New High Frequency Tone Generator, C. W. Hewlett

Proceedings of the Iowa Academy of Science

Ordinary telephone receivers will respond satisfactorily to alternating currents at frequencies as high as ten thousand vibrations per second, but above this frequency so much of the electrical energy is absorbed in hysteresis and eddy current loss that it becomes impracticable to supply enough energy to the receiver to enable it to serve as a satisfactory source of sound waves.

The Measurement Of Motility In Children, Lillian Tow

Proceedings of the Iowa Academy of Science

What we expect and demand in discipline and performance at each age should depend upon a child's development, mental, physical, and functional. In this laboratory the evaluation for scientific and diagnostic purposes of motor rather than mental capacities is being stressed. The object of this investigation is to find what the motor equipment of children is on entering school. The discovery of the basic motor tests which applied at five and six years of age will give results which are reliable and significant in that they throw light on motor ability. Previous investigations on young children have had for their …

Serial Action As A Basic Measure Of Motor Capacity, C. Frederick Hansen

Proceedings of the Iowa Academy of Science

Motor tests involving "continuous discriminative reactions" or "serial action" are being standardized by the psychologist with the end in view of reproducing, in dealing with his practical problems, the actual conditions of simple daily motor activities more closely than obtained in the traditional reaction time tests. These newer measures of motor capacity recognize the essentially fluid character of stimuli and reactions - their fundamentally continuous interplay, which is apparent not only in simple motor achievements like walking or handling tools, but also in the complex activities of the musician, the telegrapher, the typist, or the expert mechanician. In the analysis, …

A Standardized Measure Of Motility, Merrill J. Ream

Proceedings of the Iowa Academy of Science

In any survey of the fundamental capacities of motor control the factor of speed of simple movement is obvious as one of the basic essentials which underlie all the developed complexities of movement. This fundamental capacity for speed in a simple repeated movement we call motility, and the motion selected is an easy movement of the forearm in which the finger taps a telegraph key. This type of movement is selected because it is one of the most rapid of the voluntary movements; it is clearly developed, is very simple, and requires no learning. It is assumed that the ability …

Susceptible And Resistant Phases Of The Dividing Sea-Urchin Egg When Subjected To Various Concentrations Of Lipoid-Soluble Substances, Especially The Higher Alcohols, Francis Marsh Baldwin

Proceedings of the Iowa Academy of Science

That dividing Arbacia eggs show periods of varying susceptibility and resistance when exposed to chemical substances and to various physical conditions has been proved by numerous investigations. When eggs from a single fertilized lot were placed at regular successive intervals after fertilization in cyanide containing sea-water (m/100 to m/200), Lyon found that they were highly resistant to poisoning fifteen or twenty minutes after fertilization, while eggs exposed to the same solution at the time of cytoplasmic division were promptly killed. Later, after the first division had been completed, the resistance to poisoning again returned, followed by a second susceptible period …

A Biological Reconnaissance Of The Okefinokee Swamp In Georgia: The Fishes, E. L. Palmer, A. H. Wright

Proceedings of the Iowa Academy of Science

From the earliest days of North American ichthyology to the present the fishes of South Carolina and North Carolina have received particular attention and in more recent times according to one author Florida fishes have attracted more general interest than those of any other state in the Union. Georgia forms by contrast have received scant attention and often have come into ichthyologic literature by inclusion in the range of northern species known from Florida or of southern species known from South Carolina and northward.

The Mechanical Penetration Of The Sweet Corn Pericarp, R. A. Rudnick, A. L. Bakke

Proceedings of the Iowa Academy of Science

Hawkins and Harvey, Rosenbaum and Sando, and Hawkins and Sando have used a modified Joly balance fitted with a puncturing needle to determine the force necessary to puncture the cells of the potato tuber, tomato, and certain smaller fruits. For the penetration of these tissues a relatively small force is necessary.