Trajectories in Logarithmic Potentials

Trajectories in logarithmic potentials are investigated by taking as example the motion of an electron within a cylindrical capacitor. The solution of the equation of motion in plane polar coordinates, (r,{\phi}) is attained by forming a series expansion of r and of 1/r as a function of {\phi}. The terms of the series contain polynomials, the recurrence relation of which is given, together with some further characteristics. By the comparison-theorem of infinite series, the convergence of the solution is demonstraded. The simplest trajectories in logarithmic potentials are represented by rosette type orbits with a period of 4{\pi}/3, and by circular paths.Comment: 17 pages, 5 figure

The peppers

Peppers are native plants of tropical America, one of the few vegetables which still abound in the wild state. The earliest mention of them was in a report of Columbus’ first voyage. The garden peppers are regarded as dwarf, early maturing forms of Capsicum frutescens. They are either annuals or perennials, according to climatic conditions. The peppers are both self and cross-fertilized. The collection of peppers grown in securing the data for this bulletin, included over 200 varieties, a large proportion of which were synonyms, secured from the American and European seed trade

The Botanical Work of Dr. L. H. Pammel at Iowa State College

The task of reciting the history and activities of the work in botany at Iowa State College under the leadership of Dr. L. H. Pammel for the last thirty-five years is no small one and while worthy of an abler pen, is an assignment which I accept with pleasure. A few figures taken from the college catalog the year Dr. Pammel took up his work here, 1889, and for the current year, may be of interest to this end

Bordeaux spray for tip burn and early blight of potatoes

Tip burn and early blight, the two most common foliage troubles of the potato in Iowa, are of enough economic importance in the corn belt to be dealt with profitably thru the use of the bordeaux spray. Five seasons of spraying experiments at the Iowa Agricultural Experiment station point to that conclusion. These tests also suggest that under Iowa conditions five applications of bordeaux mixture per season are likely to be most profitable. That number gave an average annual crop increase of 20 bushels of potatoes per acre and an average annual increased profit of $9.62 per acre. Three applications gave an average annual increase of only 10 bushels per acre and an average annual increased profit of only$2.07 per acre, which seemed too little to be profitable. Seven applications gave an average annual increase of 22 bushels per acre in the yield and of $5.96 in profit representing a diminishing net return

Controlling downy mildew of lettuce

With the rapid development of the greenhouse industry in Iowa in the last decade, lettuce has become the most important vegetable crop grown under glass in this state. In some seasons a disease known as downy mildew is one of the most serious troubles met with in forcing this crop. Competition with garden lettuce from the Pacific Coast and the Gulf States, together with the high cost of production in recent years, makes the control of downy mildew an urgent question with many Iowa growers. The downy mildew of lettuce, long known as a destructive garden and greenhouse disease, is caused by a parasitic fungus. Brenda lactucae, which is widely distributed in both Europe and America. It is somewhat similar to the fungus which causes rose mildew, and develops typical white, downy growths which are readily seen. These are found especially on the lower surface of the leaf. They consist of grayish masses of fungous growth, which produce myriads of spores, conidophores, by which the fungus is propagated

Alegria - A Popping Seed Used in Mexico as a Substitute for Pop Corn

Amaranthus caudatus L., var. leucospermus Th. Observations of the author regarding Alegria, which is used as a substitute for popcorn in the maize region of southern Mexico. Taxonomic characters of plant, popping quality of species of Amaranthus used for this purpose and character of endosperm

Late potato blight in Iowa

Climatic conditions in Iowa are generally unfavorable to the development of the potato disease known as late blight. It is of rare occurence here but in occasional seasons it causes serious losses. The climatic conditions under which late blight occurs in Iowa are a high degree of humidity with heavy dews and midsummer temperatures lower than usual. An excess of rainfall and a predominance of cloudy weather are contributing factors. The practice of shipping in northern grown potatoes for seed is common in Iowa. Such seed is apt to be infected with the late blight fungus