1881.] ■^'^J [Chase. 



measurements is considered, so slight a difference as tliis is liardly worthy 

 of notice. 



Tlie experiments, which I performed before tlie Society in 1864 and 

 1865,* appear to have furnislied the first direct and positive evidence of the 

 hypothesis that electricity and magnetism consist simply of sethereal vibra- 

 tions, which can be imitated and modified by simple mechanical means. 

 This mechanical modification led, subsequently, to the invention of the 

 telephone and the photophone. 



3. Earth's Orbital Eccentricity and its Correlations. 



The photodynamic importance of the centres of nucleation, condensa- 

 tion and nebulosity (Sun, Earth and Jupiter), in the solar system, and the 

 tendencies to secondary and subordinate synchronisms, are further shown 

 in moduli of rotation and in orbital eccentricities. The modulus velocity 



(^—\ of Jupiter is slightly greater, while that of Earth is slightly less, than 



Sun's wave velocity (v^«7^) 5 the slight differences be'ng due, apparently, 

 to the same causes as Earth's apsidal oscillations and its mean deviation 

 from the centre of the belt of greatest condensation. Jupiter's secular 

 range, from secular perihelion to secular aphelion (.GSSOo^;,), is nearly the 

 same as Earth's orbital radius of spherical gyration (y''. 4 = .63245/53) ; Ju- 

 piter's ratio of minimum eccentricity (.02549) is about three-quarters of 

 Earth's ratio of mean eccentricity (f of .03387 = .02540) ; at Jupiter's secu- 

 lar perihelion, or locus of rupturing oscillation, the projections of Sun's 

 and Jupiter's centres from Sun's surface (.93917 x 5.2028 X 214.55 = 1 -j- 

 1047.37) are inversely proportional to their respective masses. We may, 

 therefore, not unreasonably expect to find similar simple relations between 

 different forms of terrestrial eccentricity and cosmical vis viva. 



If we suppose the air to be condensed to the homogeneous density which 

 is Indicated by the theoretical velocity of sound, we may assign .4 of its 

 velocity of equatorial rotation to the mean vis viva of simple spherical rota- 

 tion, and the remaining .6 to aelhereal or elastic action. The velocity of 

 rotation is 2?! X 3962.8 X 5280 -^ 86164 =: 1525.77 ft.; the theoretical ve- 

 locity of sound, ygh, should, therefore, be .6 X1525. 77 = 915.46, and 

 the height of homogeneous atmosphere 915.46^ -^- (32.088 X 5280j = 4.9466 

 miles. 



This closeness of accordance with the values which have been derived 



from observation, accounts only for the equilibrium between the elastic and 



gravitating actions of daily rotation. The atmospheric particles, in their 



undulatory motion with the velocity of sound, may be regarded as travers- 



h 4 9466 



ing orbits with a mean eccentricity of — r= " =.0012483. This re- 



^ ^ r 3962.8 



suit has been obtained by regarding the atmosphere as homogeneous, in the 



same way as our photodynamic results were obtained by regarding Sun's 



*Ib., ix, 359; x, 151-66. 



