PLATE I. 



Passage of Comet Brooks through Jupiter's Satellite system. The 

 plane of the drawing passes through the center of Jupiter and is 

 parallel to the ecliptic. The orbits of the Satellites are inclined ap- 

 proximately 2° to this plane : the orbit of the comet is inclined 6i° 

 to this plane and intersects the plane of reference in the line i2 y. 

 See pp. 277-280. 



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