CHEMISTRY AND THE FARM 877

g. Definitions based on a sequence or upon a Dedekind cut.

A mere glance at the list makes it obvious that depending uponthe definitions used, complex numbers may or may not be classi-fied as irrational.

It was pointed out previously that there is no uniformity re-garding the classification of zero as an integer. Without detailedanalysis of the number of books giving each definition, it may bestated that many texts are not clear as to whether zero shouldbe included in the group of integers. For example one text usesa definition which specifically includes zero and another spe-cifically excludes zero, others are indefinite.As an example of another inconsistency, some books specify

that a+bi is a pure imaginary when a==0 and 6=0. Others spe-cifically point out that zero is a pure imaginary, at least oneauthor calls attention to the fact that zero is the only numberwhich is common to the real system and the system of pureimaginaries.

Granted that some of these distinctions are technical and per-haps trivial, they still bring out the fact that even in mathe-matics which is supposed to be the exact science, we are not inagreement as to the definition of the terms employed. It wouldseem that we could agree on definitions for the elements of ournumber system, at least on definitions that are to be used in be-ginning texts. The facts are that writers of elementary textsfail to agree on the system of classification of numbers, neitherdo they call attention to this disagreement.

CHEMISTRY AND THE FARM FOLK SCHOOL

RALPH E. DUNBARNorth Dakota Agricultural College, Fargo. North Dakota

The recently organized farm folk school at the North DakotaAgricultural College offers a unique educational opportunity foryoung men. The school offers not only courses in technical agri-culture but also courses which deal with the social, cultural, andeconomic relationships of rural life. North Dakota is essentiallyan agricultural state. Such manufacturing industries as are foundin the state are primarily concerned with processing agriculturalproducts. The farm folk school is dedicated to helping youngmen solve the problems of production and distribution, and to

878 SCHOOL SCIENCE AND MATHEMATICS

the problem of living a wholesome life on the land. The onlyentrance requirement is an interest in agriculture. The farm folkschool is a short course. Its enrollees vary in age, educationaltraining, background and experience. The courses are taught onan adult level.The farm folk school course of study covers two winter periods

of fifteen weeks each, divided equally into three terms of fiveweeks. A total of fifty-one subjects are offered of which thirty-six must be completed for final certification. Students select sixsubjects per term. The present program includes eight distinctcourses in Agricultural Economics, eight in Agricultural Engi-neering, two in Agricultural Entomology, five in Agronomy,seven in Animal Husbandry, one in Animal Pathology, one inBacteriology, two in Dairy Husbandry, one in English, three inHistory and Sociology, four in Home Economics, three in Horti-culture and Forestry, one in Plant Pathology, three in PoultryHusbandry, one in Physical Education, and one in Chemistry.An additional total of six group participation courses are offeredin the evenings and include Club Organization and Parliamen-tary Practice, Public Speaking, Personal and Social Develop-ment and Family Relations, Community Music, Plays andPrograms, and Public Discussions.The course in chemistry, specifically referred to as "Farm

Chemistry," includes a brief study of the chemistry of thoseelements which affect our daily life. How to read and understandthe labels on a sack of commercial livestock feed, a can of paint,a sack of commercial fertilizer, chemical tests on the value ofinsecticides and fungicides, using farm raw materials in chemicalprocesses, the chemist in control of purity of food and fabrics,paints and varnishes, and water are considered in turn. Thestudents enrolled in this course in Farm Chemistry are pre-dominately high-school graduates. They differ greatly, however,in the type and extent of their science training. Few, if any, ofthe group contemplate continuing their studies in college. Thecourse is consequentlytaught as a service course with no thoughtof producing efficient chemists. The basic idea has been to makethese young men, not active producers, but intelligent and ap-preciative consumers in a world of chemistry and science.The class meets daily, five times a week, for six weeks. A total

of twenty-six major topics, each directly correlated to the stu-dent’s daily experience, are discussed. Periodic examinationsare used to check the efficiency of lecture and reading assign-

PLASTER OF PARIS MOLDS 879

ments. The following topics have been included in the course asoffered during the past two years.1. The Inevitable Presence and Influence of Chemistry.2. The Foundations of Chemistry.3. Chemistry in the Home.4. Chemistry of the Automobile.5. The Chemical Composition and Nature of Water.6. The Chemical Analysis and Use of Water.7. Care and Chemical Treatment of Water.8. The Clothes We Wear.9. Synthetic Fabrics.

10. Plant Growth and Food.11. Insecticides and Fungicides.12. The Chemical Nature of Foods.13. Food Fads, Poisons and Adulterants.14. Nutritional Requirements for Livestock.15. By-products from Farm Animals.16. Products from Wheat.17. Products from Flax.18. Products from Corn and Power Alcohol.19. Miscellaneous Farm By-products.20. Commercial Livestock Feeds.21. The Chemical Nature of Commercial Fertilizers.22. Results of Applied Fertilizers.23. Paints for Protection and Permanence.24. Varnishes for Variety.25. Lacquers and Synthetic Finishes.26. Paint Labels and Lies.

PLASTER OF PARIS MOLDS IN ELEMENTARYSCIENCE

CHARLES H. STONEOrlando, Florida

1. Preparation of a plain mold. Procure at the ten-centstore an assortment of small jelly molds made of aluminum;these can be bought two for a nickel for the smaller ones and soon for the larger ones. Grease the inside of a small mold with avery thin layer of vaseline, not enough to be visible to the eye.Mix up in another dish some plaster of Paris to a thick cream,fluid enough, however, to pour well. Pour this into your greasedmold and jar the dish on the desk to cause the thick substanceto settle and drive out air bubbles. Let stand for some time; thetime required will depend largely upon the quality of the plasterused and also upon the amount of water which must be evapo-rated before the process is complete and the plaster has "set"or become hard. Do not be in too much of a hurry to remove the