297 



ft between 45 and 135 = 



135 and 225 = 11 

 225 and 315 

 315 and 45 



But, be it remembered, that in 1853 of the then known planets 

 the greatest number of L. P.'s were found to be situated in the 

 heliocentric semicircles to 180 or 10 to 190. At present we 

 shall find the perihelia of thirty out of the forty-one planets in either 

 of these semicircles. The greatest number of nodes were then (1853) 

 between 35 and 3 15= 29 ; and 45 and 225= 28. At present, of 

 forty planets there are thirty nodes in either of these heliocentric 

 semicircles. These facts are at least very singular. I may tabulate 

 them 



o o 



Of forty- one planets, L. P.'s between and 180=30 



10 and 190=30 



Of forty planets ft between 35 and 2 1 5 = 30 



45 and 225 = 30 

 and between 354 to 355 and 174 to 175 = 31 



We here perceive that there are thirty L, P.'s situated in the helio- 

 centric semicircle between to 10 and 180 to 190. It is also 

 the fact, that there are thirty ascending nodes between 357 to 7 

 and 177 to 187, which may be called the same semicircle as that 

 in which the thirty L. P.'s are found. 



The quadrant containing the greatest number of L. P.'s of the 

 forty-one planets, is that between 10 and 100=20. 



Those containing the greatest number of ascending nodes, are 



between 36 to 43 and 126 to 133 = 20 

 and between 62 to 66 and 152 to 156 = 20. 



Surely there must be an undiscovered cause determining the 

 orbits in this way. Having laid these facts before my first assistant 

 Mr. Graham, he computed the degree of probability of such a law, 

 arguing thus: "Were the nodes and perihelia indifferent to all 

 heliocentric longitudes, it would of course be an equal chance in 

 the case of a planet whose orbit had not been determined, in which 

 semicircle either would be found ; and the a priori probability that, 



