The Educational screen (c1922-c1956])

realization of the fact that their use is not limited to the field cf mathematics. The situation is natural and allows the presentation of varied material without seeming forced. The film should be useful on the junor and senior high school levels with groups interested in mathematics, reading skills, >ocial studies, journalism, or any other subject in which <lata are presented. Facts About Film (International Film Bureau, 6 Xortli Michigan Avenue. Chicago 2, Illinois) 10 minutes, 16mni, sound, black and white. 1948. Produced by Phototronics. Inc. $50.00. Description of Contents: This film describes many of the characteristics of both 16mm and 3Smm motion picture film and explains the correct ways to handle 16mm film for best results. A man and a small boy find out that although 16mm film is small and easily projected, it is less durable than the 3Smm film used in theaters and must be handled accordingly. They also learn that 16mm film, made of acetate cellulose, is noninflammable, while cellulose nitrate 3Smm film necessitates specially-constructed fireproof projection booths. The narrator next explains how friction anywhere along the film's path through a projector will cause annoying scratches, which are shown to project as heavy lines. The man points out on a projector the features of construction which minimize friction, and the narrator warns against careless threading. Correct procedures for cleaning the aperture plate and sprockets and checking the guide rollers are also demonstrated. When the boy tries to tighten a film too loosely wound on a reel by pulling the end of the film, or "cinching" it, the narrator stops him. The footage containing the resultant black lines, or cinch marks, is then projected. The last part of the film shows how a film moves through a projector by means of the projector's sprockets and intermittent claws and the perforations on the edge of the film. It shows why footage which has torn sprocket holes will not project satisfactorily and illustrates the results as they appear on the screen when the film loop is lost. It suggests stopping the projector immediately and re-threading the film, as well as always checking the threading by means of the manual knob. After a brief suggestion that splicing a broken film is sometimes necessary, the film closes on the note that a clean, well-adjusted projector and a film in good repair will make a good showing possible. Committee Appraisal: A great deal of useful information about motion picture film is presented in an interesting and sometimes humorous manner in this film. Many types of projectors are shown in use in a simple room setting. The approach throughout the film is that while there are precautions to be observed, the care and projection of 16mm film is really very simple and can be mastered by anyone above the primary grade level. The atmosphere is completely non-academic, and the film should be equally useful with both school and non-school groups interested in projection. Its careful study by groups inexperienced in projection is especially recommended, although it has suggestions equally useful to the seasoned projectionist. The Living Earth Series (Encyclopaedia Britannica Films, Inc., 1150 Wilmette Avenue, Wilmette, Illinois) 4 ten-minute reels, 16mm, sound, color. 1948. Produced by the Conservation Foundation in association with the New York Zoological Society. $400 less 10% educational discount. Description of Contents: This scries of four films shows, by means of regular photography, speed-up photography, and animation, in color, the formation of soil, the balance of plant and animal life, the importance of forests and rivers, and the destruction Epcyclopaedia Britannica Films Unusual photographic techniques and a skillful presentation of concepts make the "Living Earth" series a forceful argument for immediate soil conservation measures. The Birth of the Soil emphasizes the importance of topsoil and shows how rock is gradually broken down to sand and gravel, how lichens grow and die on rocks, creating seed-beds, how water dissolves the minerals from rocks, how plant life transfers the sun's energy to the ground, how bacteria, worms, and insects improve the soil, and how a spongy humus is finally established. The function of humus in holding moisture is illustrated by means of an experiment, and plants growing in top-soil and sub-soil are compared. The summary shows the place of top-soil in the "chain of life," which also includes nature's raw materials, the sun's energy, and plant chlorophyll. This Vital Earth shows the complete interdependence of plant and animal life and what happens when man upsets the balance through the mis-use of natural resources. It also describes an experiment hi which rabbits were fed several kinds of hay having different mineral content. The effect on their rate of growth is shown to have direct implications in regard to human growth. The summary adds another link, "organization," to the "chain of life." Arteries of Life shows in detail the functions of plant life in catching and storing water and in maintaining a humus layer. The problem of the dwindling water table and the increasing necessity for artificial reservoirs and irrigation systems is next discussed. The film suggests that the answer lies with the man who uses the forests, drains the marshes, and tills the soil. It asks whether the fate of the soil should rest with the individual man or the people of the nation. Seeds of Destruction pictures the results of breaking any one link in the "chain of life." Soil erosion is shown in many forms, and the effects on plant and animal life are pictured and discussed. As the various links of the "chain of life" break, dust storms, floods, drouth, and muddy streams are shown. The solution to the problem is presented as over-all planning and supervision by federal, state, and private conservation agencies. The narrator urges individuals to join such agencies and to do their part in preserving the land. "Conservation" is shown as the final link in the "chain of life." Committee Appraisal: Unusual photographic techniques, including excellent time-lapse photography, striking color, and a cumulative presentation of certain concepts make this a forceful statement concerning the desperate need for immediate soil conservation measures. The four titles should be used in seriuence because of their structure. Their content should be of interest to all ages from junior high school to adult. The treatment is suitable for both formal and informal grouos. November, 1948 455