Thus we see that the effect of limiting the magnitude to 3.5 is that the hydrogen stars are now practically all within the sphere SP, and it is only the helium stars, whose absolute luminosity is still greater, that are more widely distributed.
The striking discovery was, in 1903, made by the same investigators that the spontaneous luminosity of radium gives a spectrum of a kind never before obtained without the aid of powerful excitation, electrical or thermal.
It was soon found, however, that compounds possess their own characteristic spectra, and that an element may give under special conditions of luminosity several different spectra.
For The Simpler Gases, Which Are Highly Diathermanous And Radiate Badly Even At High Temperature, The Energy Of Vibration Is Probably Very Small, Except Under The Special Conditions Which Produce Luminosity In Flames And Electric Discharges.
This organism is quite distinct from that causing the luminosity of marine fish.