THE COMING TOTAL ECLIPSE OF THE SUN. 



13 



tails of the corona itself; they burn out very near the disk by 

 over-exposure while the faint outer extensions are being taken. 

 Wet plates having the requisite quickness are harder to prepare, 



Chart VI. — Tracks of the Eight Total Eclipses of the Sun seen on the North 

 American Continent during the Nineteenth Century. 



but are smoother and hold the coronal rays better from the base 

 to the outer edge, and there is always plenty of time to give the 

 necessary exposure. The No. 26 Seed plate requires from 0.5 to 



