48188
The debate was resolved in 1897 when J. J. Thomson measured the mass of cathode rays , showing they were made of particles , but were around 1800 times lighter than the lightest atom , hydrogen .
 J. J. Thomson
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 J. J. Thomson