Origin of Gravitation and Terrestrial Magnetism. 689 
The Earth having opposite electric charges each of density p, 
their magnetic potential outside the Earth is by (9) 
ead ARTES <) kame ell 
Let p have an average value independent of R, then this is 
Wi 2(6— cw Ol pit? cos. 6/157? 21.24 oie GL) 
The average electric density p may be estimated either for 
the valency charges of the Harth’s atoms or for the electricity 
forming the atoms. We are concerned now with the latter. 
If D is the mean density of matter in the Harth and h is the 
mass of an atom of hydrogen, then the inertia of an electron 
is of the order h/1000, aad ihe number of electrons b per 
unit volume is of the order 500D/h, and so p is 500eD/h. 
For the average magnetic potential V in electromagnetic 
units round a parallel of latitude a/2—@ in 1880 von Bezold 
has given 
BODO ACORN Ge aig gn Rab te ge Mae) 
Hence with V for the velocity of light we have from (11) 
and (12), putting r=R, 
age 330 x JAVA 
10007 R* De 
(13) 
But h/e is a fundamental electric constant having the value 
345 x 10-™ and R=637 x 10° em., (= 27/24 x 60 x 60, 
te Ve x 10. 
These give 
DO 5s vee eo aL) 
and (7) is 
bo oe 
Tt is noteworthy that b+c is of the same order as (b—c)’ 
nearly. As we have 
b= AD < LOR Eb x LO t 
e—= — 4-8) x 10> 16x 10-“ 
we are invited to write with 8 for 2°4 x 10-”? 
b=2 g 
a : (16) 
—2684+6°) 
This makes terrestrial magnetism a first order effect due to 
the small fraction 8, and gravitation a second order effect. 
This simple result invites speculation as to the origin of ~. 
(15) 
