A new and rapidly expanding field of research, microwave spectroscopy was practically nonexistent before World War II. Some of the consequences of the research that microwave radar developments made possible are discussed below.
The beta‐ray spectrometer discussed in the following pages has recently been completed at the California Institute of Technology. It is shown in cross section on the cover.
The following article, based on a paper given at the May meeting of the American Physical Society in Washington, describes a recently discovered phenomenon in the behavior of superconducting elements.