Astronomers Henry Russell & Ejnar Hertzsprung devised a diagram displaying the luminosity of these
Hertzsprung Russell Diagram - Teach Astronomy  Hertzsprung-Russell diagram showing color and size of stars. ... that exist, their first step was to devise a sensible way to arrange and study the data to find ... astronomer Ejnar Hertzsprung and the American astronomer Henry Norris Russell ... The Sun is near the middle of the diagram (one solar luminosity, spectral type G).
safety lamp | coal mining | Britannica.com  In 1815 Sir Humphry Davy invented the lamp that bears his name. ... Consequently, a flame safety lamp must be kept burning within easy view of the workers, or frequent inspections must be made, using ... Learn More in these related articles:.