THE TOTAL ECLIPSE OF JUNE 8, 1918 535 



phenomenon which gives substantial promise of living to a ripe old 

 age. 



It must not be inferred, however, that the entire earth is visited 

 by eclipses only at such long intervals. Indeed, we have on the 

 average forty-one solar eclipses in a single eighteen-year period, and 

 of those about ten are total. But since the shadow track is not 

 wide — from fifty to one hundred miles, in general — a total solar 

 eclipse at any given locality is a rare sight, occurring on an average 

 about once in three hundred and sixty years. 



Department of Physics and Astronomy, 

 Drake University. 



