the school. The booklet was typed and bound in triplicate. One copy became the property of the boy. A second copy was given to the school and placed on the reference shelves of the school library for the benefit of any one who might wish to repeat the work another year. The third copy went to the instructor who, I can assure you, was delighted to have this memento of the project in his personal files. The idea of substituting this type of project and report for the usual obnoxiousto both student and instructor-semester paper was a very happy outgrowth of this piece of work. I have now completely discarded the old type of semester paper drudgery in favor of this new, live-interest method of getting a student to go somewhat beyond the textbook and regular course of study in the field of chemistry. It does all and more than was ever accomplished by the semester paper by bringing real interest and enthusiasiasm into the work. The drudgery of reading the usual uninteresting, technical material, the painful note-taking, and the distressing composition of dead material is all supplanted by intriguing work leading to a goal desired by the pupil, and followed by living composition of actual interest material gathered at first hand by the student.
Movie Actors Skate on Hypo "Ice." Ice-skating in the movie-dramas isn't done on ice a t all. The Hollywood climate is too balmy. Chemists have came t o the rescue, and photographer's "hypo" has been substituted for the ice. For example, the motion-picture director is desirous of staging a supposed Canadian championship skating tournament. Following the suggestion of Prof. Arthur R. Maas, industrial chemist of the University of Southern California, he now buys a ton or two of hypo. The chemical is spread about the premises, groomed with a hot iron, cooled, and is ready far the skaters. All of the fancy stunts done on ice seem equally well performed an hypo, and the movie patron doesn't know the difference. Hypo is known t o chemists as a compound of sodium thiosdfate with a considerable quantity of water. At normal temperatures it is a dry, glassy, hut somewhat soft solid of much the same texture as ice. Unlike ice, however, it melts a t 118 degrees instead of 32. At the elevated temperature i t dissolves in its own water of crystallization. and is easilv . armlied .. t o the surface which is to represent a frozen lake. Under the pressure of the running skate hypo is scored much as ice. Semi-transparent flakes and grains fly into the air during the course of the movie-drama. Under the eye of the camera the delusion is almost perfect. At .the end of the day, a gentle sprinkling, followed by a hot iron, restores the fake ice to its pristine luster. The use of the mstalline thiosulfate has been proposed for amusement rinks, but would likely have too stiff a competition from artificial ice as now employed. On the vaudeville staae, .. as well as in the movies, it has been successful. It is possible that some new and cheaper material of moderately high melting point may he brought forth to displace ice, thus eliminating the high cost of refrigeration.-Science Service
