44 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 
the pole, drive a stake. Connect these stakes by a stout string 
314 feet above the ground, and from each stake, at that height, 
stretch a string to the top of the pole. . 
In Fig. 4, A is the station, Aa the pole. At distances and 
heights stated, the stakes Bb and Ce are connected by string 
be; and strings stretch from a to b and from a to e. 
An observer, full length on the ground, his head at A and 
feet toward the stakes, scanning at his ease that part of the sky 
which appears within the triangle of strings, abe, will see just 
one-eighth of all the clear sky above the hazy zone around the 
horizon 30 degrees high. Eight observers so placed about A, 
each watching only the part of the sky marked off by his: tri- 
angle of strings, would see all the shooting stars that appear 
in the clear sky while they watch. 
On a fair evening it is found that each such observer sees a 
shooting star about every four minutes, or an average of 16 
per hour. Eight observers see 128 shooting stars per hour. 
Thus through the upper air surface—all of it that is above the 
30 degree belt around the horizon—there must enter daily 24 
times 128 shooting stars, or 3072 per day. 
Fig. 5 will serve to show the full significance of this result— 
