Eclipses. 27 



every other necessary particular may be easily 

 found for any given instant of time. Dr. Halley 

 has also given a catalogue of all the eclipses that 

 took place from the year 1701 to 1718, which 

 the author of " L'Art de verifier les Dates," 

 and others, have continued up to the year 1800 ; 

 and other computers again to the end of the 19th 

 century. 



In De Lalande's History of Astronomy for the 

 Year 1800, it is asserted that M. Goudin has, 

 by his analysis, fully determined the eclipse of 

 1847, the most considerable of the new century. 

 That M. Duvancel, who has delineated eclipses 

 for thirty years past, has likewise delineated this 

 for every country on the globe. By his diagram 

 it appears that it will be annular in England, 

 France, Turkey, and even in Cochin-China. The 

 solar eclipse of September 7, 1820, will be large, 

 and in some parts of the continent beautifully 

 annular. 



With regard to the number of eclipses in cer- 

 tain given periods, it may be remarked, that in 

 tjie space or cycle of 18 years and 10 days, there 

 are usually about 70 eclipses ; that is to say, 29 

 of the moon, and 41 of the sun. These numbers 

 are nearly in the proportion of 7 to 10. 



The greatest number of eclipses that can hap- 

 pen in a year is seven , and the least number is 

 two. If there be seven, five must be of the sun, 

 and two of the moon. If there be only two, they 



c 2 



