OBSERVATIONS Or - LUMINOUS METEOKS. 165 



same original importance, and were to be comprised in tlic same Table with 

 his own independently observed determinations. A separate table (p. 1G8) of 

 eleven such comparisons is annexed; and from the care bestowed upon its re- 

 duction and verification, a very important one is besides included in the previous 

 table, presenting a very close analogy with the orbit of Donati's comet, near 

 tho date of the earth's nodal conjunction with it on September 8th. It is 

 scarcely possible to say exactly what importance may really be attached to 

 such apparent accordances of meteor-showers with comets, whose recorded 

 paths are in general very far from even nearly intersecting the earth's orbit 

 where they pass nearest to it ; but many such cases of exact accordance in 

 time and position of the radiant-points of some meteor-showers with those 

 of comets whose orbits are far removed from proximity to the earth's orbit 

 have now been detected. One of the most memorable and at the same time 

 extreme instances of such defective correspondences is afforded by the coin- 

 cidence first noticed by Schiaparelli (and here reproduced in the second 

 list of Mr. Denning's accordances), where the perfect parallelism of the 

 ' Coronids ' (of about April 11th) with the distant orbit of the great comet of 

 1847 must, in spite of the excellent agreement between them, be ascribed to 

 accident, unless very bold hypotheses of the mode of derivation of meteor- 

 streams from comets may be adopted to explain it ; for the nucleus of the 

 comet in its node and perihelion almost grazed the body of the sun, and only 

 the lengthy tail which it swept or wheeled round with it can be supposed to 

 have reached and even to have extended far beyond the orbit of the earth ! 

 What quantity of matter, visible and invisible, may be thrown off from comets 

 by the cloud-jets which appear to be projected from them on all sides during 

 their circumsolar passages, and what forms and varieties of meteor-streams 

 this matter and that projected in the tail may possibly produce, associated 

 with large comets, remains a reasonable subject for conjecture ; and no im- 

 possibility exists that feeble streams, allied in their radiant-points to such 

 large comets as Donati's and the first comet of 1847, and perhaps to all tho 

 ancient comets and to those recent ones which have been more or less plainly 

 visible to the naked eye, may be occasionally detected by observers. It is in 

 fact remarkable that among the plentiful instances of good agreement which 

 might now be enumerated, at least one half (as will be seen by consulting 

 the above two lists) are partial or defective by the remoteness of the comet's 

 orbit, and not nearly so many can be ranked and regarded as unexceptional 

 by the closeness of the conjunction or by the practically direct intersection 

 of the comet's orbit with the orbit of the earth. The new-found accordances, 

 and those which aro now established much more closely than before by Mr. 

 Denning's recent observations and reductions, are marked with an asterisk (*) 

 in the lists ; and fifteen out of seventy good resemblances (which the total 

 number of approximate cometary coincidences has now reached) have either 

 been brought to light or are raised to a position of considerable certainty, for 

 such determinations, by the close watch and well-directed labour of a few 

 months of meteor-mapping with which Mr. Denning has (prompted by no other 



shooting stars made in Austria, under his directions, during the years 1867-70 and 1871- 

 74 ; tho first, of these volumes contains 319G and the second 3039 observations, in which 

 are included some lists and accounts at the Bielan shower of November 1872, and 'many 

 observations at Herr von Konkoly's observatory at Ogyalla, in Hungary, to whom the 

 Committee is also indebted for a list of meteor-tracks recorded there during the years 

 1872-73. Besides these lists, Mr. Denning examined and projected the unreduced meteor- 

 tracks contained in Captain Tupman's Catalogue, and the long lists recorded at the Ead- 

 cliffe Observatory, Oxford, and, during the year 1869, by Padre Denza, at the Observatory 

 of Moncalieri, near Turin. 



