Electrons can never be found between the electrbits orbits, they can only jump betweens-called quantized.
Lyman Series: Ultraviolet
Balmer: Visible light
Bohr Modem: It looks like a ladder, but its different looking in between. It jumps between the rungs. Going up the rungs, that means the electron gains photons. If it loses it, it goes back down. He saw that it was a very simple way of explaining the atoms and predicting where it was.