Smithsonian Report, 1951.— W. O. Roberts 



PLATE 2 



Typical behavior of a single chromospheric spicule. The total lifetime is shown in pictures 

 1 through 9. The average spicule passes through all these stages in but 4 or 5 minutes. 

 A spicule usually is brightest in its early development, at about frame 4. The spicule 

 shown here is larger and longer-lived than average. The actual elapsed times of the 

 successive frames shown are, in minutes, 0, 2, 3, 5, 7, 9, 11, 13, 17, 



