devoted to qualitative analysis and that the work should not partake too much of applied chemistry; that a full second year should be devoted to organic and physiological chemistry with more attention paid to the application of these subjects to the special interests of the household economics students. No other generalizations can safely be made.
Globe Trotting Radio Waves Latest Trouble. Radio engineers now have t o find a way t o prevent their transmitted waves from going around the earth, thus illustrating the great advances that have been made in radio in recent years. Not so long ago, their problem was to get the signals across a gap of a few thousand miles. NOWthey have a problem because the signals sometimes not only go the shortest way between the transmitting and the receiving stations, but also go around the long way, causing an echo. They may keep on going and travel around again and again, causing a series of echoes. This effect has been noticed in a series of experiments carried out a t Geltow, near Berlin, by E. Quaeck. Records were made of signals received from Rio de Janeiro, It was found that the signals were always accompanied by this echo, and sometimes by several of them. The significant thing was that when there was a series they were a multiple of a seventh of a second after the direct signal. As radio waves, which travel with the speed of light. take just a seventh of a second to encircle the globe, it seems to indicate conclusively that the series of echoes is caused by the waves going on around and around the earth many times. As for the echo caused by the wave traveling the wrong way, it is rather strange, because the Brazilian transmitter is of the beam type which is only supposed to radiate in one direction.-Science Service Cathode Rays Make Nitrogen Ice Glow Green. "Ice" of frozen nitrogen gas, which becomes solid at a temperature of 166 degrees below zero, Fahrenheit, glows with a brilliant greenish light under the influence of cathode rays. This is one of the results obtained by Prof. J. C. McCleanan, of the University of Toronto, in experiments made with the cathode ray developed recently by Dr. W. D. Coolidge, of the General Electric Co. Prof. McClennan and his associates ~reviouslvmade experiments with solidified nitrogen in a vacuum tube, in an effort to determine what caused a strange green light in the aurora borealis. When the auroral light is passed through the prisms of a spectroswpe, a green line appears. For a long time, the origin of this line was uncertain, but a few years ago a French scientist, Prof. Vegard, claimed that it resulted from solid nitrogen when bombarded with cathode rays from the sun. Prof. hIcClcunan. however. announced at thr Toronto meeting of the British Association for the Advancement of Science in 1924, that he had found the luminescence of solid nitrogen of a different color from that of the green aurora line. I n the new experiments made with the Coolidge cathode ray tube, the experimenters find that there is not only the green luminescene while the solid nitrogen is bombarded by cathode rays, but that following the turning off of the tube, there is a greenish red phosphor&cence that wntinues for a time. This, they believe, is due to the solid nitrogen changing from one molecular form to another, the second form being the one that continues to glow. The red glow, however, is not of the same wave-length as one that Prof. Vegard claimed to have discovered.-Science Senice
