A SWARM OF MErEORlTES, A^TD ON THEORIES OF COSMOGONY. 
7 
Suppose that s is “ the radius of the sphere of action” of a meteorite, so that when 
two of them approach so that the distance Ijetween their centres is s there is a 
collision. 
Let L and The the mean free path and mean interval between collisions. Then, 
since the mean velocity is v v/(8/3 tt), we have, according to the kinetic theory of 
gases,* 
L 
(7) 
Then, on substitution from (4), (5), and (6), we have 
oV8' 
id. 
U J \"'0 
a \3 m 
an / M w s" 
T = 
(f \/3 TT 
M,ii, 
L J \“o 
a Y 1 '^0 ™ 
Co/ ^\Mj V w s~ 
( 8 ) 
Now^ let 
and we have 
Un = 
p.MX- 
Tn = 
C|f\/ 8 
ido ’ 
77 
Jdy?6j 
= ^ u 
W = Ur, 
l = L 
U- 
a\i 
M\i 
idj 
L 
T 
= 1. 
= T . 
id. 
o\XP 
m 
Ml w 
1 /ido\* Vo ip m 
/3\iMJ V w j 
(9) 
( 10 ) 
We now proceed to calculate Uq, 1^, Tq, and also using the centiinetre-gramme- 
second system of units. 
The Sun’s mass may be taken as 315,511 times that of the Earth, and the Earth as 
6T4 X 10"^ grammest; hence 
Mq = = 1'9372 X 10^® grammes. 
The attractional constant and the Earth’s mean distance from the Sun are 
_ 648 
^ ~ 10^’ 
(Xq = L-487 X 10’® cm. 
* Meyer, ‘ Kinetiscbe Theoile der Gase.’ 
t Here and elsewFere I generally use Everett’s ‘ Units and Physical Constants. 
