Chase.] ^40 [May 2 and 16, 



Sun, Mercury, Venus, Mars, Jupiter, Saturn ; we have, therefore, the 

 means of approximating to the velocity of primary undulation (v. 2 ) with 

 which each of those orbs is accordant, and perhaps, of lending indirect 

 confirmation to the estimates of v and v t . The values in the following 

 table are given in miles per hour ; the computed values are marked C, 

 the observed, O ; the column of equivalents gives the velocities which 

 are expressed numerically in the preceding column (v 2 O). 



Velocity of Undulations Accordant with Rotation. 



The most satisfactory of the accordances is undoubtedly the one iden- 

 tifying the velocity, of the primary undulation which is in simultaneous 

 accordance both with the planetary velocities and with the velocity of 

 solar rotation, with the velocity of light. This furnishes, as it seems to 

 me, a crucial test of Newton's hypothesis that gravitating action is trans- 

 mitted through the medium of the same aether to which Huyghens 

 attributed the undulations of light. Challis's Hydrodynamic Re- 

 searches (P. Mag., 1862, sqq.), and Norton's Investigations in Molecular 

 Physics, (Am. Jour, of Sci., 1864, sqq,) have shown that the phenomena, 

 both of attraction and of repulsion, can be produced by elastic undula- 

 tion, and if the undulating velocity is the same in the two great sources 

 of cosmical and molecular phenomena, solar radiation and attraction, 

 what more can we ask for their complete identification, as opposite 

 phases of a single primordial activity '? 



There is, however, still a discrepancy of about one per cent, between 

 the computed and observed values of our supposed equivalents. This 

 difference is exceedingly slight, it is true, and it could be readily over- 

 come by adopting values, for the period of solar rotation and the solar 

 radius, which are quite as probable as those I have employed. But such 

 a forced agreement would render the result less, rather than more satis- 

 factory. It is well known that there is a degree of uncertainty in each of 

 the elements of the equation, greater than the one indicated by the result. 

 This uncertainty must therefore remain, until it is reduced by more ac- 

 curate observations, more careful study of modifying influences, and 

 more complete comparison of such investigations, in various fields of 

 research, as may help to illustrate the nature and degree of sethereal 

 elasticity and the laws of its action. 



In the case of the Moon, we have a virtual particle resting on the sur- 



