SCIENTIFIC SUMMARY. 
81 
October places tbe cosmical nature of tbe ring beyond all doubt. It proves,, 
in fact, that the meteors are independent of the precession of the equinoxes. 
As this ring crosses our orbit in a certain definite point in space, our 
earth will always traverse it when it occupies the same definite point of 
its orbit with regard to the stars. Our ordinary year, however — the tropical 
year — being affected by the precession of the equinoxes (as it is measured 
from equinox to equinox), we do not measure it by the stars, but by an 
empirical point called the first point of the sign Aries, which is actually at 
the present moment in the constellation Pisces. If we refer the recorded 
star-showers to the sidereal year, we find an almost absolute identity in the 
dates of their appearance. 
The ring is not of uniform density throughout, but in one part of it 
there is a clustering together of the little bodies of which it is com- 
posed — a few stragglers being scattered along the rest of its circuit. Ac- 
cording to Newton, the meteors, which revolve round the sun in a direction 
opposed to the earth’s motion, complete their circuit most probably in 
354*621 days — our own being accomplished in 365*256 days. This is the 
same as saying that the annual motion of the group is 1 + -33V5 revolutions y 
consequently, the densest portion of the ring is brought into contact with the 
earth once in every 133 years, but the earth passes very near this portion 
four times in this interval. 
Now, given our earth in its orbit cutting such a ring as we have described,, 
what must happen ? It will be necessary to enquire into this somewhat 
closely to understand the modification which possibly may result from this 
year’s observations. 
In the first place, the longitude of the spot from which the meteors ap- 
pear to proceed will be 90° behind the sun, as that is the spot towards 
which the earth is progressing in longitude at any moment, supposing the 
orbit circular. Secondly, as the place of a star is subject to variations, owing 
to the motion of the earth in its orbit, and the progressive motion of light, 
so does the latitude of the radiant from which the meteoric bodies appear 
to proceed depend upon their velocity, compared to that of the earth. Thus 
Newton, assuming that the velocity of the meteors was equal to that of 
the earth, but in a contrary direction, argued an inclination of 17° from a 
radiant point, with a latitude of 8° 30'. Professor Adams, we believe,, 
already sees reason to doubt the exactness of the period determined by 
Newton, and the latitude of the radiant this year appears to have been 
somewhat greater than that determined from the prior observations. But, 
as Professor Adams has shown, the fact that the longitude agrees with 
what Mr. Pritchard has aptly termed the apex of the earth's way is beyond 
all question, when we take the elliptic form of our orbit into consideration, 
as the difference between them lies within the errors of observation, and, 
moreover, a correction must also be applied for the position of the observer 
with regard to the position of the earth’s centre and the direction of its 
motion. 
There seems a little doubt as to whether there was not more than one 
radiant point in the last display. The principal one is Leo — the exact 
point in longitude towards which the earth was journeying at the time 
was very marked. 
