A TEST-TUBE CONTAINER for PHOTOCHEMICAL EXPERIMENTS SAUL S. HAUBEN Bmoklyn Technical High School, Brooklp, New York
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XPERIMENTS or demonstrations in photography and blueprinting, to be carried out properly, require some means of preventing light from affecting sensitive compounds or mixtures. For photography, laboratory manuals direct that a portion of freshly precipitated silver bromide or chloride be kept in the dark for a few minutes, while another portion of the same material is exposed to sunlight or artificial light. A similar procedure is necessary in the study of the blueprinting process. Manuals recommend the use of a dark place or wrapping of black paper around the test tube. Instead of these incompletely satisfactory means of keeping the lightsensitive materials in darkness, the writer makes use of the simple metal test-tube container shown in the diagram. The container was constructed in the metal-working shops of this school by one of the instructors. All of the seams are soldered. The container stands upright. The interior surface is darkened with black ~ a i n t . The test tube fits into the container snugly. Solutions to be used are poured into the test tube in the container and tube is then stoppered. This renders the interior of the test tube completely dark Mixing of the solutions is done in darkness. One is thus assured that the results obtained will be those desired. 188
