99 



Chase.] ^^ [April 16, 



aad of barometric pressure," showing a numerical equivalence between 

 tidal attractions and magnetic disturbances. In 1873, in liis "Electricity 

 and Magnetism" (vol. ii, p. 127), Maxwell suggested the tidal hypothesis, 

 apparently without knowing that I had already adopted it and adduced 

 evidence to sustain it. 



In 1875, I showed that analogues of Ohm's law are operative in General 

 Physics, Electricity, Chemistr}^ and Cosmogony, and that Maxwell's de- 

 ductions, when combined with my theoretical assumptions, led to the 

 ratio : Earth's mass : Sun's mass : : 1 : 327710.* 



Prof. Robert B. Warder has lately called my attention to the fiict that 

 the co-efficients of elasticity seem to lend some confirmation to Mendele- 

 jefF's and Meyer's hypotheses of periodical chemical functions, and thus I 

 have been induced to look for further chemical illustrations of the univer- 

 sal influence of luminous undulations. 



In the general equation of absolute measure, u = F {I, m, t), 



u, I, m and t represent, respectively, units of velocity, length, mass and 

 time. 



In Mechanical measure, the dimensions of the unit of force (k), which, 

 in unit of time, communicates unit of velocity to unit mass, are I m t-^. 



In Electrostatic measure, the unit of quantity (^s), whicii repels an 

 equal quantity at unit distance with unit forcj, is 1} m^ t-'^. 



In Magnetic measure, the unit of quantity (^ij.\ or strength of unit pole, 

 is also, Z| m^ t-'^. 



Kohlrausch's equation, u=^lt~'^ ^^ Vy, has been subsequently investi- 

 gated by Weber, Thomson, Maxwell, and Perry and Ayrton, each succes- 

 sive examination increasing the probability that the electric dimensional 

 value of I t-'^ is precisely equivalent to the velocity of light. 



If we adopt for our mechanical unit,,tlie maximum energy of gravita- 

 tion in the solar system, we get the following equation : 



g = Imt-^ = mu t-^ A 



The units of Electrostatic and Magnetic measure, both give the equation : 



3 i _1 1 i. 



I- m'^ t r= mu. w 2 ^2 _ _ J3 



From these dimensional equations the value of the unit of absolute mo- 

 mentum (m'(), is readily deduced. If we multiply (A) by the identical 



.1 -J 

 equation t=t, and (B) by the equation of orbital velocity (« = m'^ I -f ), 



we get gt^=mu^^mv. 



£'0 = mu = mv U 



p_v = mu = niD. E 



Under the guidance of foregoing investigations I find the following in- 

 terpretation for this equivalence. 

 The centre of gravity of the solar system has a locus of secular range 



*Ib. xiv, 607—9. 



t SabsLituting r for /, the equations (/ =^ -^ and v =r h^m-, S^^^ ''^ =^ m'^ T 



