Use linking pronouns--its, your, their, and so on--when referring to other nouns or pronouns. Linking pronouns connect your sentences and help keep your subject in focus.
In 1912, the German chemist von Laue hypothesized that in a crystal x-ray,
scattering patterns are related to atom spacing. A series of experiments
demonstrated the wave nature of x-rays and the periodic arrangement of atoms.
Spots on a photographic plate provided the proof for the hypothesis.
In 1912, the German chemist von Laue hypothesized that in a crystal x-ray,
scattering patterns are related to atom spacing. His series
of experiments demonstrated the wave nature of x-rays and the periodic
arrangement of atoms. Spots on a photographic plate provided the proof for
his hypothesis.