60 H. A. Newton on November Star-Showers. 
(Laplace, Méc. Cél., i, 190) by the formula (- = -}, where @ is 
the semi-major axis. These are, respectively, 10112 and 1:0018, 
the earth’s mean velocity being unity. The rot dea of an 
orbit is obtained by the formula (Méc. Cél., p. 191), 
(2 1 
a(1—e?) =r?sin?e ; ahs 2. 
whee ¢ is the eccentricity, and ¢ is the angle which the earn 
of the meteor makes with a line from it to the sun. Reducin 
we have e? = cos’e+ — sin’. 
The value of ¢ is not well known, but its mean value does not 
probably (12) differ more than two or three degrees from a right 
angle. We may then consider sine as unity. The fraction 
r =“ is 00853. Hence, if we take the base of a triangle equal 
to “00858, and oe Bs eh eta equal to cos¢, the hy oe 
will be equal to mean value of the eccentricity. ing 
is then nearly idieatién! Its inclination 4 is, as before Ae “about 
‘7°; that is, twice the latitude of the ra : 
28. The velocity with which these bodies enter the atmos- 
ere, is easily computed, Allowing for the earth’s attraction, 
rs is about 20°17 English miles per second, or 32°44 kilometers, 
considering the earth’s mean distance 95, 000, 000 miles 
0. The length of the group, as it is ‘at least one-fifteenth of 
the jefigth of the orbit, must be more than 40,000,000 of miles. 
If a shower lasts five hours the thickness of the ring would be 
the distance passed ov r by the earth in that time multiplied by 
aie me of the acdlinintibs of the orbit, or more than 100,000 
21. Since the periodic time is limited to five possible values, 
each capable of an accurate determination, and since therefore 
from the position of the radiant the inclination of the orbit can 
be found, it seems possible to compute the secular motion of the 
node for each periodic time with rth nies accuracy. Since 
now the actual motion of the node is known, we have thus an 
apparently simple method of acaiding which of the five peri 
is the correct one. 
22. It may be well to indicate those parts of the earth in 
which we have most reason to look for unusual numbers of me- 
teors in coming years. The annual period being 365:271 days, 
the “eq over even days is 0-271. This multiplied by 31 gives 
| he excess over eight days corresponds to a 
If, then, a shower occurs in A. D. 1864 (31 
833), ‘it seems m ost reasonable to look for ee arene 
ae, eS a ee ee | 
2 
eS : ; a3 
