: 
1884.] 609 [Chase. 
466. Neptune's Dependence on Luminous Undulation. 
The varied harmonies which have been pointed out between the Nep- 
tune-Uranus belt and the dense belt, may naturally lead us to seek for 
some additional evidence of luminous influence at the outer limit of the 
solar system. Such evidence is furnished by the proportion : 
Pa * Pp : * Py py 
In this proportion p, = Neptune’s secular aphelion -+- Harth’s mean 
aphelion ; pg = Neptune’s secular aphelion; p, = centre of belt of 
greatest condensation. Substituting Stockwell’s apsidal elements and the 
harmonic value of p,, the proportion gives ¥, = 185492 miles. The ex- 
treme range of discrepancy in the three estimates (Notes 464-6) is less 
than +4; of one per cent, or less than ten miles per second. 
46%, Harmonic Estimate of the Constant of Aberration. 
Earth’s mean orbital velocity is 12960007 ~- 31558149 = 0.041067 ; 0, 
== 185497.2 miles, if we take the mean of the three foregoing estimates, 
To find the constant of aberration we have the proportion : 
185497.2 : 92542800 : : 1 sec, : 498.89 sec, 
0/4.041067 X 498.89 = 20//.488. 
The close accordance of this value with Nyrén’s estimate (Note 449), 
furnishes satisfactory confirmation both of the accuracy of Stockwell’s cal- 
culations and of the precision of the harmonic estimate. 
AOS oes 
The foregoing results abundantly show that the principle of harmonic 
motion is of ‘‘immense use not only in ordinary kinetics, but in the 
theories of sound, light, heat, etc.” * Analogy, the law of parsimony, 
the theories of kinetic correlation, and the various principles enumerated 
in Note 461, all point to the value of »,, which is given in the foregoing 
note, as equivalent to the ratio ‘“V’’ between the electrostatic and electro- 
magnetic units of electricity, electric current, magnetic potential, electric 
displacement, surface density, magnetic force, and strength of current at 
a point. The corresponding resistance in the field of rotation is 29.853 
Ohm’s. This agrees very closely with Foucault's estimate, 29.836 Ohm’s. 
Weber’s estimate} was 81.074; Thomson’s{ 28.2 ; Maxwell’s { 28.8 ; 
Michelson’s§ 29.982. The modulus of light which is represented by the 
harmonic constant of aberration may be found as follows: 7 = p, -- 
214.4518 == 481582.8 miles ; gy == 27 12 + Mg My = -16878 miles ; x7 + 
%, == 7.3085 sec. ; 7.80859, = 1.283 miles = 0 of solar rotation ; V go 1%) = 
269.82 miles ; 269.82 -- 1.283 = 218,833 ; (218.8337)?79 = 47268879 = modu- 
* Thomson and Tait, Vat, Phil,, i, Sec. 52. 
1 Pogg. Ann,, Aug, 10, 1856, 
{ Rept. Brit, Assoc,, 1869, pp. 434, 436. 
2Am. J. Sci, NOV., 1879. 
