66492
Meanwhile , the discovery of hydrogen led Joseph Black to propose its use as a lifting gas in about 1780 , though practical demonstration awaited a gastight balloon material .
 person: Joseph Black
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: Joseph Black 
Answer:
 person: Joseph Black