what did goldstein discover

Eugen Goldstein discovered canal rays (also known as anode rays or positive rays) in 1886. These rays are streams of positively charged ions that travel in the opposite direction to cathode rays in a cathode ray tube with a perforated cathode. Goldstein observed that these rays passed through the holes in the cathode and struck the glass tube near the cathode, leading to the conclusion that they comprised positively charged particles. This discovery was significant as it was the first observation of positively charged subatomic particles, later identified as protons. Goldstein's work laid essential groundwork for the modern understanding of atomic structure and positively charged ions in gases.