[BMCDA]

This site should answer your question ;)

http://physics.njit.edu/~dgary/321/Lecture4.html

[PatrickHenry]

Thanks. Good site:

Looking at the meaning of this equation, it says that electrons are allowed only orbits of certain (quantized) radii, where n = 1, 2, 3...

This confirms the impression I got from Cramer's article. (I must admit, I skimmed over the equation.)

[jennyp]

Pretty, pretty pictures, indeed. But for all your pretty computer simulated drawings, it's still only the "electron cloud theory". Until you can show me (in a laboratory) a nested sphere turning into a group of toruses, you better not be teaching our children that it's a fact!