148 Meteoric Astronomy. (April, 
meteors, in the circumstance that great displays of these 
shooting-stars occur at mean intervals of about 334 years, and 
assigning a period amounted to assigning the velocity with 
which the meteors cross the earth’s track; and secondly, 
the comet which agrees in its motions with the November 
meteors was dealt with separately, and the agreement only 
recognised after both orbits had been independently worked 
out. But the choice of 33+ years as the period of the 
November meteors was still an assumption ; and there were 
many eminent astronomers who regarded 34-33rds, or 
32-33rds of a year as the more probable period. In any 
case, assuming a period, the task of determining the orbit 
from the observed position of the radiant was mere mathe- 
matical child’s-play. But Professor Adams achieved a 
much nobler work. For he proved from the observed dis- 
placement of the node of the November meteors,—that is, 
of the point where the meteors cross the earth’s track,— 
that the period must be 334 years or thereabouts. This was 
a task which none but a mathematician of the highest order 
could possibly have accomplished: and even to such a 
mathematician the task was a most laborious one. Ido not 
say that Schiaparelli’s case was not made out without 
Adams’s assistance. The chances against the observed 
agreement as a result of accident were as great in the case 
of the November meteors as in the case of the August 
meteors, and the chances against both coincidences being 
accidental were therefore overwhelming. But Adams un- 
doubtedly removed whatever element of doubt still remained ; 
and, furthermore, if Schiaparelli’s theory had never been 
started, Adams’s work would of itself have sufficed to esta- 
blish the true figure of the orbit on which the November 
meteors travel. It has seemed fitting to say thus much in 
recognition of the remarkable labours of our great English 
mathematician ; but it need hardly be said that the value of 
Schiaparelli’s ingenious researches and theories is in no 
way affected by the matter here referred to. The great 
importance of Schiaparelli’s work consists in the light which 
it throws on cosmical problems of extreme interest and 
difficulty. 
The fact, then, is demonstrated that two of the meteor 
systems encountered by the earth are so far associated with 
two comets as to travel on the same orbits. We may not 
unsafely infer that all the meteor systems encountered by 
the earth are in like manner associated with other comets. 
Nor is it very rash to assume that all comets are in like 
manner associated with meteor systems. ‘Two cases may 
