ECLIPSES, 



intermediate spaces remain uncovered. This may be very appro- 

 priately illustrated by laying the blade of a circular saw, having 

 finely cut teeth, over a white circle of nearly equal diameter upon 

 a black ground. The white parts between the teeth will appear 

 like a necklace of white pearls. 



Fig. 9. 



Fig. 10. 



Fig. 11. 



Fig. 12. 



27. Immediately after the commencement of the total obscura- 

 tion, red protuberances, resembling flames, appear to issue from 

 the edge of the moon's disc. These appearances, which were 

 first noticed by Yassenius, on the occasion of the total solar 

 eclipse which was visible at Gottenberg on the 3rd of May, 1733, 

 have been re-observed on the occurrence of every total solar 

 eclipse which has taken place since that time, and constitute one 

 of the most curious and interesting effects attending this class of 

 phenomena. 



28. A total eclipse of the sun took place on the 28th of July, 

 170 



