Uliase.l boo INov. 4, 



126. Relation of Magnetic Disturbances to Thermal Currents. 



The secondary character of the solar disturbances of vertical force at St. 

 Helena is further indicated by a comparison of culminating times. The 

 coincidence of the daily minimum of vertical force with the various maxi- 

 ma of gravitating pressures (Note 130) is only approximate ; but the rela- 

 tion both of maximum and of minimum to the culmination of ascending 

 and descending currents is very close. The mean time of maximum tem- 

 perature is 1 h 39.5 m ; of minimum temperature, 17 h 41.6 m ; of greatest 

 vertical force, 4h 4.4m ; of least vertical force, 19 h 55.8 m. Therefore, 

 the vertical force continues to increase for 3 h 24. 9 m after the time of 

 greatest daily heat, and to diminish for 2 h 14.2 m after the time of greatest 

 daily cold. 



137. Relation of Barometric to Gravitating Disturdances. 



During the forced vibrations of half-daily terrestrial rotation towards 



and from the Sun, terrestrial gravity acts on all the heated and otherwise 



disturbed particles of the atmosphere. The sum of the cyclical acceler- 



16.05 X 430832 

 ations, at St. Helena, is f^oGQ = 5643000 miles =^ a. The sum 



of the synchronous "forced oscillations" of rotation towards or from the 

 Sun is cos. 15° 56' 41" X - X 3963.8 = 11970.7 miles = /?. The mean 

 sum of the barometric pressures of the atmospheric particles is 28.378 in- 

 ches = V. The sum of the mean half-daily disturbances of pressure is ^ 

 (38.315 — 38.248 + 38.303 — 38.252) = .0585 inch = (5. The ratio of a to /3 



P o 



is nearly the same as that of v to ^ ; i^ = .002133 ; — = .003069 ; the 



a r 



deviation from exact accordance being about 3.56 per cent. 



138. Succession of Forced Oscillations. 



The "nascent" velocity of the Sun, or the limiting velocity between 



complete dissociation and incipient aggregation, is, as we have seen, —^ 



= velocity of light. On the principle of forced oscillations, theluminifer- 

 ous sethereal undulations force the sun into rotary oscillations synchron- 

 ous with the cycles of superficial gravitating activity which would com- 

 municate the velocity of light. 



The ratio of the mass aggregation at the principal centre of nucleation 

 (Sun), to the mass aggregation at primitive nebular centre (Jupiter), is, 

 as we have seen, the same as the ratio of the rupturing radius-vector of 

 Jupiter to the rupturing radius-vector of Sun. The rupturing energy of 

 the sethereal oscillations is thus traceable to the primitive condition of 

 statical equilibrium, when the two products of mass by rupturing radius 

 were equal. 



These two principal masses of the solar system tend to produce a system 



