198 H. A. Newtan on Shooting Stars, 
degrees of the horizon than in the whole of the rest of 
The hourly number varies through the night. The value of m 
may be found from observations extending through the night, ot 
from those made near midnight. 
Mr. E. Bouvard, in the year between Oct., 1840, and Oct., 1 
observed at Paris on every clear moonless night. ( Comples 
ndus, xiii, 1029). He always watched between 11 and 
o'clock. During 74 hours and 22 minutes he saw 572 shooting 
stars. Allowing one-fourth of a minute for recording each meteor 
(which is the time estimated by him), and we have an ave 
of 8 meteors per hour. Ri 
By what factor we must multiply the number seen by ono 
to be visible 
ld permit, eq 
1. Number of meteoroids in the space which the earth traverses” 
Suppose many small bodies to be distributed through an inde 
nite space, so that there shall be n bodies in a cubic unit. il 
os fist ese bod fv 
er Spee 
“po beat 
nd as 
d as map 
Bi 
