226 Intelligence and Miscellaneous Articles. 



CONFIRMATION OF THE NEBULAR HYPOTHESIS. 

 BY PLINY EARLE CHASE, LL.D. 

 Herschel's " subsidence " hypothesis is corroborated by the fol- 

 lowing extensions of Laplace's satellite-harmonics, from Jupiter to 

 Earth :— 



1. Earth's accelerated rotation : the acceleration by condensation 

 to a centre of linear oscillation : : Jupiter's radius of accelerated 

 rotation : Callisto's (Sat. IV) radius of accelerated rotation. 



36Q'2o65 : 9 : : 4332-5848* : 16-6891* 



Searle gives 16*689 for Callisto's period ; Newcomb and Holden 

 give 16-7535524. 



2. Jupiter's mean perihelion distance from Earth (4-978245 — 1, 

 according to Stockwell) : Callisto's mean distance from Jupiter : : 

 Jupiter's mass : Earth's mass. 



3 - 978245: -° 12585:! T0^879 <SriW 



If we take # = 32-088 feet, Earth's isochronous radius (satellite- 

 period = 1 year) is 



/3 1558149 secAl 3962 . 8== 1340291-5 miles. 

 V 5073-6 sec. ) 



The equation, m? x isochronous radius =p, gives 



331245* X 1340291-5 miles =92736000 miles. 



The reason for these harmonics is to be found in the fact that 

 Earth is the centre of the belt of greatest condensation, while Jupi- 

 ter's mean aphelion is central between Neptune and Uranus at 

 their opposition. 



Haverford College, Feb. 8, 1881. 



ON THE CHOICE OF THE UNIT OF FORCE IN ABSOLUTE ELECTRIC 

 MEASUREMENTS. BY M. LIPPMANN. 



It is known that the electric measurements called absolute rest 

 upon the choice of the three units employed to measure the times, 

 lengths, and forces ; and it will be remembered that in 1863 a 

 Committee of the British Association proposed to take for the unit 

 of force the dyne — that is to say, the force capable of impressing on 

 the mass of 1 gram, at the end of 1 second, a velocity of 1 centim. 

 per second. Is the dyne in every respect the most advantageous 

 that could have been chosen ? Without wishing to discuss here 

 that complex question completely, I may at least facilitate its solu- 

 tion by the following remarks, which have not, perhaps, been made 

 in a sufficiently explicit and general manner by authors : — 



1. The absolute electromagnetic units of electrical resistance and 

 capacity are independent of the choice of the unit of force*. jN'ow 



* In fact, let L, T, F be the length, time, and force, measured w T ith any 

 units. The quantity of magnetism ft is given by an equation of the form 



