WHEN helium at a pressure of about 25 mm. of mercury is excited in such a way as to produce the line spectrum and the band spectrum in comparable intensity, McCallum and Wills 1 find that the band ...

Mophie yesterday announced the launch of its Juice Pack Helium Spectrum Collection, bringing a host of new color choices including purple, blue, pink, green and red to its line of popular iPhone 5 ...

IN the course of some investigations on the electrical properties of helium at fairly high pressures (about 25 mm. mercury), it was found that, if the gas was excited in such a way as to produce the ...