METEORS AND METEOR SYSTEMS. 
15 
his theory of identity in cometic and meteoric orbits. He was 
led to this remarkable discovery by investigations of the August 
meteors in 1866 ; and it at once raised this branch of astronomy 
to a much higher position than it had formerly occupied, for it 
gave the phenomena of shooting-stars a significance far beyond 
what had been accorded to them. They were shown to he purely 
astronomical in nature and origin, revolving in elliptical orbits 
about the Sun, and existing in infinite numbers in interstellar 
space. The constituent atoms of a shower became visible when 
upon the intersection of the Earth and meteor orbit they en- 
tered the atmosphere with such velocity as to produce instan- 
taneous ignition and combustion, resulting in the immediate 
disruption and collapse of each particle so entering into collision. 
Only in rare cases and in the instance of the more massive 
fragments would one he found of sufficient solidity to penetrate 
completely through the atmosphere and fall upon the Earth. 
By far the greater number of such bodies being of miniature 
size were consumed in the upper rarefied limits of the atmosphere, 
and obviously that would be an exceptional incident in which 
a meteor overcame the resistance of the dense air strata lying 
closely over the surface of the Earth. 
The intimate relation of comets and meteors being clearly 
demonstrated by their accordant orbits and by the occurrence 
of star- showers at the very times when the Earth passed through 
cometary tracks, it was sought to establish the theory on the 
basis of a large number of such agreements. But apart from 
the meteoric displays of April 20, August 10, November 13 and 
27, there are no instances, which can be safely and certainly 
accepted, of exact coincidence in the calculated orbits of meteors 
and comets ; and this is a little surprising when we admit into 
the comparison the large number of results which have accu- 
mulated. In many cases the positions of the radiant points 
agree closely, but the shower of meteors appears to be diffused 
over a long period, with no evidence of condensation on the 
sjDecial night when the Earth approaches the node. Take the case 
of Comet I. 1850 13, radiant point at 313°*5 + 60°’5 on June 
23 + . Now there has never been observed a well-defined 
outburst of meteors on or about that date, though from the point 
mentioned a lingering shower (or series of showers) is sustained 
during the long interval from April to November with an 
average radiant at 315°*5 + 60 o, 0, derived from twenty-three 
independent observations. Another instance of like nature is 
afforded by Comet II. 1850 13, radiant at 2° + 54° Oct. 19 + , 
which falls very near a series of showers near a Ccissiopeice at 
7°*2 + 52°T July — Nov. (twenty-two observations). Now the 
inference of physical connexion between these pairs of radiant 
points is rendered untenable by the remarkable persistency of the 
