1864. J ^93 [Chase. 



midnight are nearly identical in amount with the variations- of 

 weight produced by solar attraction at the same hours. 



The ratio of the solar to the terrestrial attraction for any particle 

 at the earth's surface, being directly as the mass, and inversely as 

 the square of the distance (M--R==354,936-^ 23,0000, is .00067. 

 The weight of any particle is therefore increased by this proportion- 

 ate amount at midnight, and diminished in the same proportion at 

 noon, making a total half-daily variation of .00134 in the atmospheric 

 weight, and consequently, according to ray theory, in the terrestrial 

 magnetism. 



Theoretical variation, .00134. Observed variation, .00138. 



V. The magnetic variations at intermediate hours, between noon and 

 midnight, indicate the influences of an accelerating force, like that 

 of gravity, modified by fluctuations of temperature and by atmos- 

 pheric or astherial currents. 



Every particle of air may be regarded as a planet revolving about 

 the sun in an orbit that is disturbed by terrestrial attraction and other 

 causes. In consequence of these disturbances, there is an alternate 

 half-daily fall towards the sun, and rise from the sun. By the laws 

 of uniformly accelerated and retarded motions, the mean fall, and the 

 con.sequent mean magnetic disturbances should occur at 12h.-T- 

 v/2=8h. 29' from midnight. 



Theoretical mean, 8h. 29'. Observed mean, 8h. 31'. 



VI. Some of the- magnetic influences appear to be transmitted in- 

 stantaneously, through the rapid pulsations of the kinetic aether, — 

 others gradually, through the comparatively sluggish vibrations of 

 the air. 



VII. The comparative barometric disturbances of the sun and moon 

 exhibit an approximate mean proportionality between their compara- 

 tive difi"erential-tidal and magnetic disturbances. 



Let the solar differential-tidal force be represented by A', and the 

 lunar by A", the respective barometric disturbances by B' and B", 

 and the magnetic disturbances by M' and M". If M' and B" are 

 required, we have 



A'-^A" B' B" M' M" 



Theoretical values, .00012 .00144 



Observed " 2.55 .00057 .00013 .00140 .0000255. 



VIII. The theoretical gravitation-variation of magnetism (Prop. 

 IV) is slightly less, while the theoretical barometric variation (Prop. 



