CLAYTON, — THE ECLIPSE CYCLONE, 



311 



in different portions of the eclipse area. The eclipse shadow travelled 

 with a velocity somewhat greater than two thousand miles an hour. By- 

 placing the stations at their proper distances from the path of the umbra 

 and plotting the successive fifteen minute observations at intervals of about 

 five hundred miles, a synoptic chart is obtained showing the conditions 

 observed at any given station or group of stations when they were in dif- 

 ferent portions of the eclipse area. In this way Figure 4 was constructed. 

 In this diagram the direction and width of the path of the umbra is 



Figure 4. 



shown by parallel lines forming a long arrow. The central shaded area 

 shows the umbra, and the outer unbroken circle shows the outer limit of 

 the penumbra. The data north of the path of the umbra are derived from 

 the mean of the observations at Ithaca, Toronto, and Blue Ilill ; the data 

 along the path are derived from the mean of observations at Washington, 

 Ga., and Wadcsboro. N. C. ; the dita south of the path are from Havana, 



