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Calibration Of A Gold Leaf Electrometer For Ionization Work, Leroy D. Weld
Calibration Of A Gold Leaf Electrometer For Ionization Work, Leroy D. Weld
Proceedings of the Iowa Academy of Science
The ordinary type of ionization electroscope having a straight, horizontal scale of 100 divisions in the focal plane of its microscope, over which the image of the gold leaf is seen to move obliquely, is subject to well-marked variations which, for certain kinds of work, necessitate its calibration.
The Natural Ultra-Violet Frequency Of Silver Bromide, P. S. Helmick
The Natural Ultra-Violet Frequency Of Silver Bromide, P. S. Helmick
Proceedings of the Iowa Academy of Science
The ultra-violet maximum of the selective photo-electric effect can he calculated by expressions given by the following authorities: Lubben, v ion = v undissolved salt + 2 Q/N h; Haber and Lewis, Q = N h (Σ v resultants - v reactants); Haber, vv/ v r = √M/m; Lindeman, Vv = √ n e2/m r3/π; where v =critical frequency in ultra-violet (v) or infra-red (r), N=Avogadro's constant, h =Planck's element of action, M=molecular weight of the substance, n =valency of atom to which electron belongs, e =charge on an electron, and …
The Genus Empoasca In North America, Albert Hartzell
The Genus Empoasca In North America, Albert Hartzell
Proceedings of the Iowa Academy of Science
While the writer was connected with the Iowa Agricultural Experiment Station the potato leafhopper (Empoasca mali) appeared in immense numbers in the Upper Mississippi Valley. Investigations were carried on during the summers of 1919, 1920 and 1921 at Ames, Iowa, to establish definitely the relation of this insect to the disease it transmits, commonly called tipburn or hopperburn of potatoes, which was causing severe damage to the potato crop, and if possible devise means for its control. The difficulty experienced in separating closely related species of Empoasca, which had been confused by former investigators, led to the desire to trace …
On Super-Regeneration, E. O. Hulburt
On Super-Regeneration, E. O. Hulburt
Proceedings of the Iowa Academy of Science
A simple mathematical analysis of super-regeneration yielded conclusions, in accordance with observation, that the super-regenerative system amplifies without distortion and that the amplification increases with increase of signal frequency and with decrease of variation frequency. Two single tube super-regenerative circuits, interesting because of their simplicity, are described.
A Zoological Park In New Zealand, Dayton Stoner
A Zoological Park In New Zealand, Dayton Stoner
Proceedings of the Iowa Academy of Science
The University of Iowa Expedition to the South Seas participated in by six persons from that institution between May 14 and September 4, 1922, was undertaken largely for the purpose of making biological and geological collections and field observations. More than 17,000 miles were traversed of which something over 12,000 were by water. Of the total elapsed time-approximately 112 days-forty-five were spent in travel, after leaving the American continent, for the purpose of arriving at and returning from our objectives, Viti Levu of the Fiji Islands, where four weeks were spent, and the Dominion of New Zealand, where about …
The Torques And Forces Between Short Cylindrical Coils Carrying Undamped Alternating Currents Of Radio Frequency, W. A. Parlin
The Torques And Forces Between Short Cylindrical Coils Carrying Undamped Alternating Currents Of Radio Frequency, W. A. Parlin
Proceedings of the Iowa Academy of Science
Measurements of the torques and forces between two short single layer cylindrical coils carrying undamped currents alternating at radio frequencies showed variations with the frequency of the current oscillation not predicted from the classical formulas of Maxwell and others. When the current in the coils and the angle between the planes of the coils were maintained constant, the torque between the two coils connected in series, with the currents in the same sense, was found to remain approximately constant as the frequency of the current increased from 60 to 0.3x101 cycles per second, but when the frequency increased from …
Food Of The Short-Nosed Gar-Pike (Lepidosteus Platystomus) In Lake Okoboji, Iowa, George E. Potter
Food Of The Short-Nosed Gar-Pike (Lepidosteus Platystomus) In Lake Okoboji, Iowa, George E. Potter
Proceedings of the Iowa Academy of Science
The food habits of any animal have a distinct bearing upon its life and so it is with the Gar-pike. In order to ascertain the kind and amount of food taken by this fish, many collections were made, stomachs dissected, the contents carefully examined and preserved.
Observations On Sphenodon Punctatum In Captivity, Wendell Krull
Observations On Sphenodon Punctatum In Captivity, Wendell Krull
Proceedings of the Iowa Academy of Science
Sphenodon punctatum, known as the tuatara lizard by the natives of New Zealand, is the only living species of reptile included in the order Rhynchocephalia and is considered by scientists to be the most ancient representative of reptile-like animals now living. All the other representatives of the order are known only as fossils. The rhychocephalians possess so called "abdominal ribs" which foreshadow the plastron of the chelonians.
The Flora Of The Olympic Peninsula, Washington, Albert B. Reagan
The Flora Of The Olympic Peninsula, Washington, Albert B. Reagan
Proceedings of the Iowa Academy of Science
No list of the plants of the Olympic Peninsula has ever been published so far as the writer can learn. This paper covers observations ranging over a period of five years while the writer had charge of the Quillayute and Hoh Indians of that peninsula. His observations, here recorded, also give the uses to which the Indians of the coast apply the plants
Studies Of The Cytology Of Melilotus Alba, E. F. Castetter
Studies Of The Cytology Of Melilotus Alba, E. F. Castetter
Proceedings of the Iowa Academy of Science
There are two varieties of Melilotus alba (Desr.), namely, the annual and the biennial. Rogers made some observations on the anatomy and cytology of the biennial variety. The present paper covers the cytology of the annual variety.
Plants And The Surface Film Of Water, Robert B. Wylie
Plants And The Surface Film Of Water, Robert B. Wylie
Proceedings of the Iowa Academy of Science
The plant's uses of water are many. As a solvent water permits the absorption of raw materials of all kinds taken in by the plant. Within the plant body water performs many functions, some of it even entering into the constitution of the protoplasm itself. In leaving the plant in the form of vapor its evaporation cools the tissues when otherwise they might at times be injured by the radiant energy of the sun to which extensive portions of the plant must he exposed for photosynthesis. The familiar root-shoot type of land vegetation is the form-response of plants to the …
Apparent Fossil Fruits From The Fort Union Beds Of North Dakota, Merrill A. Stainbrook
Apparent Fossil Fruits From The Fort Union Beds Of North Dakota, Merrill A. Stainbrook
Proceedings of the Iowa Academy of Science
In the summer of 1920 the writer visited the Eocene Badlands of western North Dakota, going there on the completion of a field course in geology in the Northern Black Hills. These badlands are situated in several counties bordering on the Little Missouri River. A thick series of sandstone, shale and lignite is exposed in the nearly barren and partly denuded hills. The beds have characteristic topographic expressions and can be traced long distances by these alone; the sandstones form benches and the shales gentle slopes. In one of these sandstone benches a number of small spheroidal bodies were noted. …
Extracts Form The Experiences Of A Well Digger, J. M. Lindly
Extracts Form The Experiences Of A Well Digger, J. M. Lindly
Proceedings of the Iowa Academy of Science
Nature seems to hold her secrets for those who seek them. An investigation of the earth's surface oft-times reveals the unexpected. Even the experiences of the man who penetrates the earth by digging, by boring, or by drilling, whose object is to find a supply of water, may include incidents worthy of more than a mere passing notice.
An Unusual Well Record In Northwestern Iowa, James H. Lees
An Unusual Well Record In Northwestern Iowa, James H. Lees
Proceedings of the Iowa Academy of Science
In the autumn of 1920 the town of Holstein, in Ida County, began the drilling of a second deep well for its public water supply, the work being done by Thorpe Brothers of Des Moines. On March 29 of the present year (1923) Mr. George Thorpe called the office of the Geological Survey by phone from Holstein and told me that they were "up against a hard proposition," that they were able to drill only a few inches a day, and he asked me to go up there and advise them what to do. I went to Holstein the next …
Fossil Annelid Jaws From The Iowa Devonian, Walter V. Searight
Fossil Annelid Jaws From The Iowa Devonian, Walter V. Searight
Proceedings of the Iowa Academy of Science
Recently in the process of experiment on limestones from the Cedar Valley formation near Iowa City, Iowa, 0.5 n. hydrochloric acid was used to decompose the carbonates present. In the residues obtained by filtration and washing of the resulting product there were discovered some organic remains almost microscopic in size which were very similar in appearance to those of the jaws of certain groups of recent marine annelids. Further investigations revealed several complete specimens and a number of fragments which show that these remains probably are distributed quite generally through the Cedar Valley limestones. They are now known to occur …
The Trace Left By A Helical Beam Of Electrons On A Plane Perpendicular To Its Axis, C. J. Lapp
The Trace Left By A Helical Beam Of Electrons On A Plane Perpendicular To Its Axis, C. J. Lapp
Proceedings of the Iowa Academy of Science
Experimental work has been done by the writer in which a fine beam of electrons was caught in a magnetic field and turned into a spiral. A photographic plate placed across the path was marked by a trace which at first appeared to be a circle. A close examination however showed that the trace was unsymmetrical and that its curvature appeared to change with the length of Arc.
Electrometric Titration Of Iodate, Bromate, Chlorate And Ferricyanide With Titanous Sulfate, W. S. Hendrixson
Electrometric Titration Of Iodate, Bromate, Chlorate And Ferricyanide With Titanous Sulfate, W. S. Hendrixson
Proceedings of the Iowa Academy of Science
Iodate, bromate, chlorate may be titrated electrometrically with titanous sulfate at the ordinary temperature to an accurate endpoint. There is no necessity to titrate back an excess of the reducing agent. The iodate is titrated best in sulfuric acid solution. There is a rise in potential at the beginning of about 0.25 volt, after which the voltage remains steady till the end-point is reached, when the voltage drops sharply to about 0.3 volt.
The Terrestrial Isopods Of Iowa, Mayne Longnecker
The Terrestrial Isopods Of Iowa, Mayne Longnecker
Proceedings of the Iowa Academy of Science
A careful study of Miss Harriet Richardson's Monograph on the Isopods of North America (Bulletin 54, United States National Museum) shows only eleven species of what are commonly called sowbugs and pillbugs that might reasonably be expected to live in this region, judging from the latitude and climate in which they have previously been found.
The Effect Of Impurities On The Physical Properties Of Oxychloride Cements, H. L. Olin, Ben H. Peterson
The Effect Of Impurities On The Physical Properties Of Oxychloride Cements, H. L. Olin, Ben H. Peterson
Proceedings of the Iowa Academy of Science
The rapidly increasing use of Stucco, a cement made by mixing magnesite with a solution of magnesium chloride, as an exterior for dwelling houses has given rise to an interesting study of its chemical and physical properties. As usually applied, the stucco is made according to the specifications of the Committee on Specifications for Plastic Magnesite, which recommended the following mixture to be standard: One part by weight of plastic calcined Magnesite; Two parts by weight of Standard Ground Silica; Five parts by weight of Standard Ottawa Sand. This is then mixed with a 22 degree Baume solution of magnesium …
1923 Old Gold, Iowa State Teachers College
1923 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.
Title Page - Front Matter
Proceedings of the Iowa Academy of Science
No abstract provided.
Officers, Past Presidents, And Members, Iowa Academy Of Science
Officers, Past Presidents, And Members, Iowa Academy Of Science
Proceedings of the Iowa Academy of Science
No abstract provided.
Proceedings Of The Thirty-Seventh Annual Meeting Of The Iowa Academy Of Science, Held At Mount Vernon, April 27 And 28, 1923: Minutes Of The Meeting; Staff & Committee Reports
Proceedings of the Iowa Academy of Science
No abstract provided.
The Progress Of Research In The Coe College Radiological Laboratory, Scott W. Smith Jr.
The Progress Of Research In The Coe College Radiological Laboratory, Scott W. Smith Jr.
Proceedings of the Iowa Academy of Science
Ever since the discovery of x-rays by Prof. W. K. Röntgen in 1895, the physicist has played an important part in the advancement of knowledge leading to the use of x-rays in therapy. Doctor Coolidge with his high voltage tube made it possible to produce very penetrating x-rays; while Professor Dessauer of Germany in his study of the distribution of x-rays, Professor Duane of Harvard, and many other physicists, have aided materially in the harnessing of this potent form of radiation for use in therapy. Therefore in the establishment of the Radiological Research Bureau of Coe College, the primary aim …
The Distribution Of Intensity In The Broadened Balmer Lines Of Hydrogen, E. O. Hulburt
The Distribution Of Intensity In The Broadened Balmer Lines Of Hydrogen, E. O. Hulburt
Proceedings of the Iowa Academy of Science
The intensity distribution across the broadened Balmer lines of hydrogen Hß, Hγ and Hδ excited by condensed discharges for a pressure range from 48 to 250 mm. of mercury was determined by photographing the spectra through a neutral wedge. The broadening was symmetrical and the general form of the intensity curve was convex to the axis of wave-lengths; the curves for each line gave evidences of structure characteristic of the line.
Magnetic And Natural Rotatory Dispersion In Absorbing Media, E. O. Hulburt
Magnetic And Natural Rotatory Dispersion In Absorbing Media, E. O. Hulburt
Proceedings of the Iowa Academy of Science
A theoretical discussion based on the electron theory of H. A. Lorentz yielded formulas for the magnetic rotatory dispersion in isotropic absorbing media and for the natural rotatory dispersion in optically active absorbing media. In a few instances where sufficient data enabled calculation, the new magnetic rotation formula has given accurate agreement with experimental values, thereby accounting for the discrepancy previously noted between the observed Verdet angles and those calculated from a theory which neglected absorption.
The Deflection Of A Stream Of Electrons By Electromagnetic Radiation, E. O. Hulburt
The Deflection Of A Stream Of Electrons By Electromagnetic Radiation, E. O. Hulburt
Proceedings of the Iowa Academy of Science
A theoretical calculation, based on classical electrodynamics, gives for the maximum angular deflection, when certain approximations are made, He/mφ, where ω/2π is the frequency of the radiation, and H is the field due to it. For sunlight (H=.04) the value is only 4 X 10-10, far too small to detect experimentally, while for intense x-rays, the value is of the order of 10-13. Recently C. J. Lapp reported having obtained an observable deflection with x-rays. If further research should confirm this result, it would appear to be in direct conflict with the classical …
Standards Of Capacity, J. B. Dempster, E. G. Linder, E. O. Hulburt
Standards Of Capacity, J. B. Dempster, E. G. Linder, E. O. Hulburt
Proceedings of the Iowa Academy of Science
In order to calibrate with precision condensers for use in radio frequency measurements, three standard condensers of coaxial cylindrical plates were made after the manner described by the former Lord Rayleigh. The three condensers were of capacities 25, 50, and 100 micro-micro-farads. By means of continuous wave radio frequency currents from an electron tube generator a variable air condenser with a vernier was calibrated by a step by step method. This was used as a secondary standard. The measurements were accurate to less than one-half micro-micro-farad, and the calibration was correct to considerably less than one per cent, for capacities …
A Summary Of Recent Experiments On The Relation Between Direct And Calculated Refecting Powers Of Crystals Of Tellurium, L. P. Sieg
Proceedings of the Iowa Academy of Science
By the employment of a micro-spectrophotometer it has been shown that Van Dyke's results, obtained by the indirect method of elliptical analysis, are substantiated. The region of the spectrum covered in this determination of the principal reflecting powers of tellurium extends from 4400 A°. u. to 6600 A°. u. The writer has described elsewhere the apparatus and method used.