Vor. 7, No. 3
THE CHRMISTRY STUDENT
659
as a binder, and molded into cylindrical rods resembling the "grains" of smokeless powder used in big guns. Additional dummy specimens are readily made from pieces of broomstick, etc. In general, the length of a grain is about twice its diameter. Demonstration No. 1 G A good imitation of T. N. T. is made from land plaster (calcium sulfate) tinted a light yellow by adding powdered sulfur. This mixture is practically inert and may be used to fill a large bottle. A smaller container holding a few grams of the potassium chlorate-sulfur mixture--may be buried in the mass. CAUTION! Powder the sulfur and the potassium chlorate separately and mix by folding gently together on a paper. Do not attempt to mix by grinding, and make up only a few grams a t a time. Throw any unused portion in the sink after the lecture and flush down with water. Demonstration No. ll-The special stick of fake dynamite used in this trick is made from a large stick of candy wrapped in many folds of tissue paper and finally inclosed in the usual oiled cartridge paper used for real dynamite. It should have the word "DANGER" printed in large red letters on the outside. Other very convincing dummies are made from sections of wooden curtain pole wrapped in oiled paper and marked "DANGER." Fake fulminate caps are made by rolling up tubes of thin copper foil and soldering lightly down one edge. They should be of the diameter of a 22-cal. rifle cartridgewhich serves as an excellent base for the cap. The waterproof fuse is obtainable a t hardware stores: it burns a t the rate of about 2 seconds to the inch. It should be split or cut on a slant, and is best dipped in some "match h e a d mixture to insure quick ignition. Demonstration No. 12-Wax "vesta" matches are rarely on sale nowadays. Get some of the wax tapers used in barber shops and cut into lengths. The heads of ordinary Swedish safety matches may be grafted into these wax stems with the help of a few turns of white thread. A wax match so made, having the same length as the ordinary safety match, will burn for a full minute if held upright. To get the maximum effect of suspense, Prof. V. should not even glance a t the match while telling his story, and should not give the slightest evidence of being hurried. This requires careful timing. First World Rayon Exhibition. From information received from the Dechema (Dcutsche Gesellschaft fiir chemisches Apparatewesen E. V. Seelze, near Hanover), we learn that the first world rayon exhibition will take place on the occasion of the Sixth Achema, to be held a t Frankfurt-am-Main between June 10 and 22, 1930. There is to be a special exhibition section for machines and appliances for the manufacture of rayon, which will show the latest technical development in the production of rayon, and will be under the direction and co6peration of the leading experts in the trade.-Chemistry and Industry
