Lesson xiv.] ECLIPSES. 63 



happen ; because it is only then that the Earth is 

 between the Sun and Moon : neither do they hap- 

 pen every full Moon (as they would do if the 

 orbits of the Earth and Moon were coincident) 

 because of the obliquity of the Moon's path with 

 respect to the Earth's ; but only in such full Moons 

 as happen at the intersections of those two paths, 

 called the Moon's nodes; or at least on those full 

 Moons which happen but a little distance from 

 the nodes. 



The chief circumstances in lunar eclipses, as 

 they are given by Dr. Hutlon in his Mathemati- 

 cal and Philosophical Dictionary, are as follow: 

 1. All lunar eclipses are universal, or visible in 

 all parts of the earth which have the Moon above 

 the horizon ; and are every where of the same 

 magnitude, with the Fame beginning and end. 

 2. In all lunar eclipses, the eastern side is what 

 first immerges and emerges again; i.e. the left 

 side of the Moon as we look toward her from the 

 north ; for the proper motion of the Moon being 

 swifter than that of the Earth's shadow, the Moon 

 approaches it from the west, overtakes it and 

 passes through it with the Moon's east side fore- 

 most, leaving the shadow behind, or to the west- 

 ward. 3, Total eclipses, and those of i he-longest 

 duration, happen in the very nodes of the eclip- 

 tic ; because the section of the Earth's shadow^ 

 then falling on the Moon, is considerably larger 

 than her disc. There may, however, be total 

 eclipses within a small distance of the nodes ; but 

 their duration is the less as they are farther 



from 



