-
Antoine Lavoisier
Proposed the Law of Conservation of Mass, which states that even if matter changes its shape or form its mass stays the same. -
Atomic Structure
Scientist began probing what stuff was made of using Discharge Tubes, basically gas filled tubes with electrodes at each end, which admits light when an electrical current passes through them. -
German Physics
Found that the tube also admitted light from the positive electrodes, basically a ray heading in the opposite direction which meant there must also be a positive charge in matter. -
Joseph John Thompson
He measure how much heat the cathode ray generated, how much they could be bent by magnets and other things. He was able to estimate the mass of the rays and the mass was about a thousand times lighter than Hydrogen. He concluded that the cathode rays weren't rays or waves at all.