non-simple cases the coefficients of all soecies must also be input a i d if needed the pH at which the titration will be performed. The temperature is assumed to be 25% A program listing and sample output are availablefrom the author. This project was partially supported by NSF grant no. SED76-02130.
Easy Stereoscopic Transparencies for Lecture Demonstration Harold R. Hunt, Jr. and J. Aaron Bertrand Georgia Institute of Technology Atlanta, Georgia 30332 We wish to describe a simple and inexpensive procedure for preparing colored transparent overlays and 2 X 2-in slides for stereoscopic projection. The technique is similar to that of Crozat and Watkins (J. CHEM. EDUC., 50,374 (1973)),hut differs in that red and green images on a dark background are projected, rather than red and blue images on a light background. These changes allow the transparencies to be intermixed with the stereo slides hy Brady ("Stereo Slides for General Chemistrv." John Wilev & Sons. New York.. 1975). ~, and viewed using the same colored filters; Either original stereographic line drawings made using a computer program, or Xerox copies of such drawings from the scientific literature may be used to make the stereo transparencies. Best results are obtained using distinct drawings having a minimum of fine detail. The drawings should he
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smaller than the mounted transparency, or ahout 6 X 6 in. if allowance is made for a 1-in. margin. Red and meen Gestetner thermaltrans~arenciesare used to make coibred projection copies of the irawings prepared for the left-eye and the right-eye view, respectively. Each transparency makes both a pmitive and a negative projection film, but onlv the latter is used for stereosco~ic~roiection. The red negative transparency prepared for i h e left-eye view is taped to a trans~arencvmount. and then the green negative transparency prepared for the right-eye vGw is overlaid on the red trans~arencvand taped in dace. The transparencies should be iliRnedsothat the titles-are superimposed or the centers of the models are coincident. Theresuiting red-green stereo pair is projected using an ordinary overhead projector, and viewed through colored filters (green for the left eye, red for the right eye) such as those provided by Brady. We have also constructed viewers using medium green (Edmund No. 82041) and medium red (Edmund No. 82015) plastic filter sheets. Stereo slides mav be made from the redmeen transnarencv double overlay usihg a 35 mm camera and-~igh~ p e ~hk t a chrome film. We have obtained good results by backlighting the transparency using a lighted copy table equipped with a GE F8T5 fluorescent tube, with a daylight fluorescent filter on the camera. A trial exposure is made by taking a meter reading from the lighted c o ~ vtable with the transDarencv removed, and then giving 5 id 8 times the exposure time indicated.
Presented at the American Chemical Society Southeast Regional Meeting, Gatlinhurg, Tennessee, October, 1916.
Volume 55, Number 4, April 1978 / 247
