The educational screen (c1922-c1956])

May, 1923 Visual Instruction Association of America 221 New York Board of Fire Underwriters, makers and users of film, manufacturers of various sorts of projectors, including the narrow gauge, representatives of various welfare organizations, local fire protection authorities, and finally the National Fire Protective Association, x^s a result a great many conferences were held, and gradually this growing group adopted the practice of large joint conferences for the purpose of threshing out their differences. As a result it finally became possible to line up all these forces behind a program, with slight modifications, first put into form by the National Fire Protective Association, and which corresponded very closely with a project already under contemplation by the producers and distributors of theatrical film. The central feature of this program, is to place the whole burden of regulation upon the dis pensers and users of nitro-cellulose or inflammable film, and to leave the acetate or safety stock absolutely free of all restriction. This is to be accomplished by very rigid licensing regulations governing the handling of the inflammable film, but it is desirable to withhold, the details of these provisions until the entire program has been formulated and promulgated. Suffice it to say that legislation along these lines will be introduced next January in the legislature of every state in the Union and such tremendous forces will be ranged behind these measures, that their ultimate if not their speedy passage is almost a foregone conclusion. Thus the solution of this portable projector problem really seems to be in sight. The Visual Instruction Association of America knowing what that will mean in the extension of film instruction, is gratified" to have been of service in launching this gigantic campaign. The Stereopticon By A. G. Balcom Assistant Superintendent of Schools, Newark, N. J. THERE are a number of factors in connection with visual instruction as applied to the use of slide and film that must be reckoned with in teaching a lesson, where these forms of illustrations are involved. In this article I purpose to consider one factor as applied to the use of the slide, and it is the stereopticon, or the mechanism that makes it possible to flash on the screen an enlarged image of the slide. The stereopticon with the mazda illuminant is so simple of operation that any teacher can Team to operate it in a few minutes and in a few lessons can learn to adjust its several parts to procure the most efficient results. Yet the care of the stereopticon is seriously neglected. It is allowed to stand in the classroom or closet unprotected from the dust and in moving it about the optical system becomes disarranged so that poor results in projection inevitably follow. No matter how good the slides are or how well the teacher has prepared the lesson, if the stereopticon is not working at its maximum efficiency the slide illustrations fail to come across and the lesson becomes only a partial success. Then again it is astonishing how few teachers actually know how to use a stereopticon. I can understand that with the old arc light where the carbon had to be constantly adjusted women teachers especially would hesitate about operating the same, but with the advent of the mazda lamp the operation is so there is no excuse for a teacher not to know how. Within the last year I have met groups of teachers in the Newark schools with a stereopticon at hand and have carefully explained the use of each part, how to put it together and how to make the necessary adjustments for efficient projection. Also the care of stereopticon when not in use and the proper way of handling slides were explained. For this purpose I jotted down the following data and gave it to the teachers in mimeograph form : The Stereopticon in Use The stereopticon with ]Mazda light illuminant is very simple to handle, but in order to get maximum results at all times it should be understood and properly cared for by those handling it. The essential parts of a stereopticon are : (a) Lamp or Mazda bulb (400 to 1000 Watts) with No. 16 wire connections. (b) A spherical mirror which focuses the light it gathers and reflects it through the condenser lens. (c) The condenser lens, which ordinarily consists of two glasses known as plane convex, straight on one side and curved on the other, set with the curved surfaces facing each other. The purpose of the condensing {Concluded on page 240)