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H, A. Newton on Shooting Stars. 201 
and the ratio of those actually seen through one telescope to 
those which are bright enowgh to be visible in it is 58 x 12°-6: 
860 x 60 x 180+ 7, or, 1:1858. I have selected the larger 
diameter of the telescope that the ratio may not be too large. 
For the same reason I prefer to reject in the divisor that part of 
the surface of the heavens within 15° of the horizon. This 
makes the ratio 1 + 1371. 
e have seen that according to Bouvard’s observations one 
_ person should see an average of eight shooting stars per hour. 
| ence if ,®, is taken as the ratio of the number seen in acomet 
seeker to those seen by one person with the naked eye, there 
4 1 F 
should be in each hour pPeasise = Shi or 1582 shooting stars 
hourly that might be visible through a comet seeker if the whole 
eavens could be watched. The ratio between those visible at 
one place and those visible somewhere over the whole earth is 
1+10,460 for common meteors. If the same ratio applies to 
i¢ data in our possession are inadequate to furnish the mean 
distance .of the meteor-paths from an observer, yet limits to this 
Po tee rea} 
msible are always the most distant ones; __ an 
Sg that the paths which become invisible are distributed 
ine the oblique line in proportion to the numbers along the 
‘ine, 
It is evident that the first supposition affords a mean distance 
Tess than the truth, and that the second affords one that is too 
_. Breat. These two limits are found to be about 282 and 140 kilo- 
4 "8. It must, however, be admitted that in this computation 
. the unavoidable errors arising from using finite summation for 
_ ‘Mlegration, and from other sources, are considerable. 
taste ean Joreshortening of the meteor-paths by perspective.—To 
Sttermine the effect of perspective in shortening the apparent 
#08 We have need to use the following geometrical proposition: 
__ Hf asphere whose radius is a be supposed to have an indefinite 
: ®umber of diameters, and the extremities of these diameters are 
