NASA Photo ID: S61-04564          File Name: 10073601.jpg

Film Type: 8x10 b&w               Date Taken: 12/12/61

Title: Astronaut John Glenn tests balance mechanism performance

Description:

Astronaut John H. Glenn Jr.'s balance mechanism (semi-circular-canals) is 
tested by running cool water into his ear and measuring effect on eye
motions  (nystagmus). This view is labeled a modified calonic test.