30355
This became a source of a low-voltage current that could be used to produce more distinct effects , and which was far less limited than the momentary discharge of an electrostatic machine , which with Leyden jars were the only previously known man-made sources of electricity .
 Leyden
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Leyden