ASTRONOMICAL PHENOMENA AND PROGRESS. 



67 



Mr. Lockyor's observation, that tho 



i, must, inteiis,- \\ h"n til-.- planet's atmos- 



froo iViini clouds, is quoted in support 



of tiii" vieu ; aii'l so aiv tho photometric ob- 



f Scidel :ml Xollnor. 

 opposition of Mars 011 January 10, 1867, 

 place while tin- planet was not very far 

 from a'>lnTion. Tho earth also being very near 

 p.'rilii-lioii. was as far away from Mars' orbit as 

 that cans,' permitted her to In.'. Mars was 

 . at liis greatest distance from tho planet 

 of tin.- ecliptic; and thus his distance from tho 

 was niii.'h greater than at tho opposi- 

 tions of 1S60, 1862, ami 1864. In fact, tho ab- 

 solute distance of Mars was not less than 



."no miles. 



The Or hits of Comets and Meteors. In com- 

 putirir tiio orbits of the meteoric showers of 1866, 

 ,1 astronomers appear to have been struck 

 with tho identity of the orbits of the meteors 

 and thos... of certain comets. Signor Schia- 

 paivlli, of Naples, was tho first to make public 

 these points of resemblance. According to his 

 calculations, the elements of the orbit of the 

 August (1866) meteors agree very closely with 

 those of the orbit of comet IL, 1862, as the fol- 

 lowing table shows: 



The period of the comet has been calculated 

 by Dr. Oppolzer to be about 142 years, and tho 

 orbit extends into space far beyond that of 

 Neptune. 



Professor Adams, of England, has compared 

 the elements of the orbit of the November me- 

 teors (1866) with those of the orbit of comet I., 

 1866, with the following result : 



This approximation would be still more re- 



markablo should we assume, as we are free to 



do, that tho period of tho meteoric shower is 



\ ears, instead of 83.25, which is confess- 



a rough approximation. 



I>r. Kdmund Weise, of Vienna, has pointed 



out the coincidence of other observed meteor 



tracks with cometic orbits. lie conceives the 



whole orbit of a comet to be strewn with me- 



hodies, not following each other in one 



path, but dispersed many thousands, perhaps 



millions, of miles on every eide of the central 



If we consider, lie says, the circum- 



M under which a comet approaches the 



sun, we shall see that individual particles must 



be repelled to a distance, where "collecting 



under the original laws of aggregation, around 

 now centres of gravity, they will r.-volve ubnut 

 the sun in orbits closely resembling those of 

 the parent comet. In the case of period i-.-d 

 comets, these dispersed aggregations will grad- 

 ually collect along tho whole orbit, and if the 

 comet's orbit intersect, or approach very near 

 to the earth's orbit, the phenomenon of peri- 

 odic showers will be produced at the annual 

 passage of tho earth through the point of in- 

 tersection." 



Professor d'Arrest, of Copenhagen, concludes 

 an interesting paper on the subject as follows: 

 " Finally, it may be asked whether the intense 

 northern lights, frequently observed coinci- 

 dently with meteoric showers, may not have been 

 the united glimmer of more distant portions of 

 particles dispersed through the orbit of a comet ? 

 That some connection exists between meteoric 

 showers and northern lights has been incontes- 

 tably proved by Quetelet many years ago. If 

 showers of shooting stars and rings of meteors 

 really have any connection with cometary 

 phenomena, the hope is afforded that some ex- 

 planation may be arrived at concerning the 

 nature of the aurora borealis and also concern- 

 ing magnetic storms." 



Mr. Faye has presented to the Paris Academy 

 of Sciences an hypothesis which connects the 

 shooting stars, the zodiacal light, the rays of 

 the corona, seen in a solar eclipse, and the re- 

 sisting medium, which is believed to shorten 

 the time of Encke's comet, with the matter 

 which is seen to flow from the nuclei of .comets 

 forming their comas and tails. 



A writer in t\\Q American Journal of Science 

 (II. xxxviii., 57) is entitled to credit for an 

 early and valuable suggestion, upon the subject 

 of tho orbit of the November meteors (1866), 

 which was tho basis of the discoveries of M. 

 Schiaparelli, Mr. Adams, and others. In that 

 article it was shown that the periodic time of 

 those meteors must be one of five accurately 

 determined periods, as follows: 180.0 days, 

 185.4 days, 354.6 days, 376.6 days and 33.25 

 years. The longitude of the node was also 

 shown to increase, with respect to the ecliptic, 

 1'.711 in a year, which is equivalent to a pre- 

 cession with respect to the fixed stars of 29' in 

 a cycle of 33.25 years. It was also suggested 

 that by computing the theoretical secular mo- 

 tion of the node for each one of the five pos- 

 sible orbits, and by comparing it with the ob- 

 served motion, we should have an apparently 

 simple means of deciding which of the five or- 

 bits is the true one. The last period, as has 

 already been shown, was the one determined 

 by the investigation of Professor Adams : a re- 

 markable instance of accordance between tho 

 results of theory and observation. (See METE- 

 ORS.) 



Jupiter without his Satellites. This was one 

 of the most remarkable astronomical phenome- 

 na of tho year, and the subject of an interesting 

 paper by Richard N". Proctor, in the Popular 

 Science Review, No. 24. On August 21st the 



