A section of a Liberty Loan War Relic Train. Canvas covers can be thrown over the framework to protect the exhibit from the rain. This framework also provides a support for arc lights, so that the exhibit can be displayed at night.] EXHIBITS Having selected the subject matter, you have a choice of presenting it through exhibits, demonstrations, talks, or all three. For still exhibits the use of models, objects, cartoons, posters, transparencies for the windows, and brief slogans or statements on placards have been found most suitable. As is brought out in a later section under methods of display, the dimensions of a car place severe limitations on the forms that may be used to advantage, and the same principle applies to the selection of these as to the content of a train exhibit. Just as there should be few ideas so there should not be too many sizes, shapes, and forms of exhibits which confuse the eye in the way that variety of topics confuses the mind. Because of the necessity of moving people through the cars rapidly enough to make way for others to follow, it is essential that whatever is displayed may be quickly seen and understood. This limitation rules out many forms that might be shown satisfactorily in halls. Anything that is expressed chiefly by words may better be left to speakers and printed matter for distribution as there is not time to read words and figures and, indeed, visitors have little inclination to do so. Diagrams, particularly those presenting detailed facts, also call for close examination and delay the progress of visitors. One train exhibitor of experience says: “One of the greatest dangers to be avoided is an excess of charts and small type. The exhibit should be such that the crowds can be kept moving through the car and, nevertheless, be able to seize the principal points intended to be taught.” A description of a part of a single health car in one report includes “75 wall charts illustrating the cost in human lives of tuberculosis, typhoid fever, and diarrhea. Each series of charts has grouped about it from two to twelve models. Several hundred photographs show occupational conditions favorable to tuberculosis.” Such a collection as this is suited only to intensive study and not at all to a popular traveling exhibit. Methods used to attract attention to one thing should not distract attention from other things. For example, in a certain health car a bell struck every three minutes tolling the one hundred and seventy-five thousand deaths annually from tuberculosis. This is a striking and effective way of making people heed a startling fact, but unfortunately every time the bell rang in so small a space as the car it interfered with the study of other features being presented.