Canal Rays and Protons

Tiny oil droplets fall through the hole and settle slowly through the air. 

X-rays cause air molecules to give up electrons to the oil droplets, which become negatively charged. 

Investigator observes droplet and adjusts electric charges of plates until the droplet is motionless. 

Different elements give positive ions with different elm ratios. The regularity of the elm values for different ions led to the idea that there is a subatomic particle with one unit of positive charge, called the proton.The proton is a fundamental particle with a charge equal in magnitude but opposite in sign to the charge on the electron. Its mass is almost 1836 times that of the electron. 

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Canal Rays and Protons 5-12 Atomic Spectra and the Bohr... 

Canal rays and their positive nature (proton)... 

The study of the so-called canal rays by the German physicist Eugen Goldstein, observed in a special cathode-ray tube with a perforated cathode, let to the recognition in 1902 that these rays were positively charged particles (protons). Finally, years later in 1932 the British physicist James Chadwick discovered another particle in the nucleus that had no charge, and for this reason was named neutron. 

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