Mr. Cooper on the Perihelia and Nodes of the Planets. 317 



Fo}- large Planets. 

 Longitude of Perihelion, 1856-0. I Longitude of ascending Nodes. 

 7 from 12° 1' to 168° 19' 7 from 46° 36' to 130° 12' 



1 at 333° 24' I elsewhere 



Middle point of Arc containing greatest number, 

 90° 10' 88° 24' 



■ Mean of these 89° 17' 



Takmg this in round numbers=90°, and dividing the asteroids 

 into three groups in the order of their discovery, we have 



Perihelia. 



0° to 180". 180° 10 360^ 



14 10 4 



14 10 4 



15 9 6 



43 29 14 



Large 8 7 1 



51 36 15 



Ascending Nodes. 

 0° to 180°. 180° to 360°. 

 14 11 3 



14 10 4 



15 7 8 



43 28 15 



/ 



7 



50 35 15 



In the case of the perihelia no other two semicircles give a greater 

 disproportion between the numbers. The semicircle 355° to 175° 

 contains 37 of the nodes, the opposite one 13. 



But in addition to this development of my original plan regardmg 

 the heliocentric longitudes of the perihelia and nodes, Mr. Graham 

 has found a remarkable coincidence between the foregoing numbers 

 and the periods of the discovery of the small planets. It appears 

 that 28 have been detected between the vernal and autumnal equi- 

 noxes, and only 1 3 in the other half-year. 



He states that this circumstance, which at a first glance might 

 seem to throw some light upon the facts, proves, after a moment's 

 consideration, the exact opposite to what might have been expected, 

 at least in its bearing on the periheha, for 



180° to 360°. 0° to 100°. 



Longitudes of Aphelia 29 14 



Longitudes of descending Nodes , . 28 15 



Point of Ecliptic in opposition at 1 ..q , c 



date of discovery j 



"If, then," Mr. Graham adds, "there be any connexion between 

 these results, it is not easy to imagine why discoveries should be more 

 frequent near the desccndimj node ; and it is quite contradictory that 

 there should be a greater facility of finding the planets in the more 

 remote parts of their orl)its," Upon these facts I abstain from 

 making any comment, excepting tbat the present data tend to 

 strengthen the conviction that some physical cause, as yet unap[)lied 

 to these jdienomena, may be in operation, Ajjpendcd to tlie paper 

 are two diagrams, bringing before the eye more clearly than niiinbers, 

 the heliocentric places of the perihelia and nodes which are the sub- 

 jects of this notice. 



