428 COSMOS. 



have, therefore, to arrange the planets according to their 

 absolute (actual) magnitudes, proceeding from the larger to 

 the smaller : 



The small planets with involved orbits, of which the 

 largest appears to be Pallas and Vesta : 

 Mercury, Neptune, 



Mars, Uranus, 



Venus, Saturn, 



Earth, Jupiter. 



The apparent equatorial diameter of Jupiter, at a mean 

 distance from the earth, is 38*-4, while that of Venus, which 

 is nearly equal in magnitude to the Earth, is only 16*-9 ; 

 that of Mars 5"' 8. But the apparent diameter of the disc of 

 Venus increases in the inferior conjunction to 62", while that of 

 Jupiter attains only an increase to 46". It is necessary to 

 call to mind in this place that the point of the orbit of Venus 

 at which it appears to us with the brightest light, falls 

 between the inferior conjunction and her greatest digression 

 from the sun, because in that position the small luminous 

 crescent gives the most intense light, on account of its greatest 

 proximity to the Earth. Upon the average, Venus appears 

 the most beautifully luminous, even casting shadows in the 

 absence of the sun, when at a distance of 40 east or west 

 from the sun; the apparent diameter then amounts to only 40", 

 and the greatest w r idth of the illuminated phase is scarcely 10*. 



Apparent Diameter of Seven Planets. 



Mercury at a mean distance 6"- 7 (oscillates from 4" '4 to 12") 

 Venus 16"-9 ( 9"-5 to 62") 



Mars 5"-8 ( 3"-3 to 23") 



Jupiter 38"-4 ( 30" to 46") 



Saturn 17"- 1 ( 15" to 20") 



Uranus ,. 3"'9 



Neptune 2*-7 



