288 ' 
EASTMAN. 
“ The elements of the mean of the orbits of the different 
groups composing the partial ring are: 
Semi-major axis = 0.98049, 
Inclination = 17°, 
and the ring is nearly circular. 
“ The velocity with which these bodies enter the earth’s 
atmosphere is about 20.17 English miles per second.” 
The most elaborate American paper on meteors up to the 
date of its publication was prepared in 1865 by Prof. II. A. 
Newton ,* who discussed the subject under the following divi¬ 
sions, the conclusions being briefly stated in each case : 
“ 1st. The average altitude of the middle points of the 
luminous portions of the meteor paths is found to be 59.4 
English miles. 
■“ 2d. The relative frequency of meteors when the heavens 
were divided into eight equal parts was about equal in all— 
perhaps a slight preponderance in the southeast—and the 
relative frequency in different parts of the visible heavens 
may be considered a function of the zenith distance only. 
“ 3d. Not quite one in fifty of all the meteors seen at any 
one place should have the middle points of their apparent 
paths within 10° of the zenith. 
“ 4th. The number of visible meteors that come into the 
atmosphere every day would be 10,460 times the number 
visible at one station ; or the average number that traverse 
the atmosphere daily, that are large enough to be seen with 
the naked eye, if the sun, moon, and clouds would permit, 
would be 30 x 24 x 10,460 = 7,531,000. 
“ 5th. The number of meteoroids in the space which the 
earth traverses is discussed at length and formulae are de¬ 
rived for computing the whole number when the average 
number is known for a given unit of time. 
“ 6th. The average length of the apparent paths derived 
from 213 European and 803 American observations is 12°.6. 
“ 7th. Adopting the theory that for every meteor visible to 
1 Mem. Nat. Acad. Sciences I, 291. 
