PROF. L. VEGARD'S recent note 1 on the atomic lines in the auroral spectrum calls for some comments. While it is true that the presence of the Vegard-Kaplan bands in auroral spectra was first observed ...

I THINK Lecoq de Boisbaudran was the first who called attention to the fact that the line spectra of the elements are by no means so irregular as they seem to be at first sight. He discovered the ...

Astronomers have now observed the radio emission from the neutral hydrogen gas (HI) in a nearby galaxy. Hydrogen gas emits radio emission in a spectral line at a very specific frequency of 1420 MHz.