53 



SCIENCE. 



ON THE FIRST COMET OF 1861 AND THE 

 METEORS OF APRIL 20. 



By Professor Daniel Kirkwood. 



M. Arago was the first to call attention to the frequent 

 appearance of shooting stars in unusual numbers about 

 the 20th of April, and to suggest the theory 1 that they 

 are derived from a ring which intersects the earth's 

 orbit. We are indebted, however, to the late Edward C. 

 Herrick, of New Haven, for the collection of the princi- 

 pal facts by which the suggestion of Arago was fully 

 sustained. 



I. 



THE GREAT METEORIC SHOWER OF APRIL 20, 1803. 



More than thirty-six years after the event the old 

 newspaper accounts of this wonderful display were 

 sought out by Mr. Herrick and rescued from oblivion. 5 

 The following description of the phenomena as seen at 

 Richmond, Va., is taken from the Virginia Gazette, of 

 April 23, 1803. 



" Shooting Stars. — This electrical phenomenon was ob- 

 served on Wednesday morning last, at Richmond and 

 its vicinity, in a manner that alarmed many, and aston- 

 ished every person that beheld it. From one until three 

 in the morning, those starry meteors seemed to fall from 

 every point in the heavens, in such numbers as to re- 

 semble a shower of sky rockets. ' The inhabitants hap- 

 pened at the same hour to be called from their houses by 

 the fire-bell, which was rung on account of a fire that 

 broke out in one of the rooms of the Armory, but which 

 was speedily extinguished. Every one, therefore, had 

 an opportunity of witnessing a scene of nature, which 

 never before was displayed in this part of the globe, and 

 which probably will never appear again. Several of these 

 shooting meteors were accompanied with a train of fire, 

 that illuminated the sky for a considerable distance. 

 One, in particular, appeared to fall from the zenith, of 

 the apparent size of a ball of eighteen inches diameter, 

 that lighted for several seconds the whole hemisphere. 

 During the continuance of this remarkable phenomenon, 

 a hissing noise in the air was plainly heard, and several 

 reports, resembling the discharge of a pistol. Had not 

 the city bell been ringing, these reports would prob- 

 ably have seemed louder. The sky was remarkably clear 

 and serene, and the visible fixed stars numerous the 

 whole night. We are anxious to know at what distance 

 from Richmond this phenomenon has extended. It is 

 hoped that persons who have remarked it in other places 

 will not neglect to inform the public of the particulars ; 

 as such information may add in a great degree to the 

 knowledge of meteorology. 



Since writing the above, we have been informed that 

 several of the largest of these shooting meteors were ob- 

 served to descend almost to the ground before they ex- 

 ploded. Indeed, many of these which we saw, appeared 

 to approach within a few yards of the house tops, and 

 then suddenly to vanish. Some persons, we are told, 

 were so alarmed that they imagined the fire in the 

 Armory was occasioned by one of these meteors, and in 

 place of repairing to extinguish the earthly flames, they 

 busied themselves in contriving to protect the roofs of 

 their houses from the fire of heaven." 



The display was also witnessed at Raleigh, N. C. ; 

 Wilmington, Del. ; Schoharie County, N. Y. ; Ports- 

 mouth, N. H. ; and at several points in Massachusetts. 

 The descriptions of the shower as seen at these respec- 

 tive localities declare that, " the heavens seemed to be all 

 on fire from the abundance of lucid meteors ; " that they 

 were " too numerous to be coun.'ed ; " and that " part of 

 the time the light was so great that a pin might be pick- 

 ed up on the ground." The shower, in short, would seem 



> In 1836. 



* See Herrick 's article in the Am. Journ. of Sci. fcr July, 1839, p. 358. 



to have been one of the most extensive and brilliant on 

 record, and hence to have been derived from a meteoric 

 cluster of extraordinary density. 



According to the catalogues of Biot and Quetelet 3 a 

 great meteoric shower was seen in China on the 1 6th of 

 March, B. C. 687. This date corresponds with the 20th 

 of April in the nineteenth century. The display was 

 therefore a shower of Lyraids. The interval between 

 this extraordinary apparition and that of 1803 was 2490 

 years which may be regarded as a multiple of the true 

 period. 



The year 558 of our era, 4 midway between those brill- 

 iant displays, was the date of another great meteoric 

 shower. The month and day are not given, but we may 

 assume with reasonable probability that it was the great 

 April display. Mr. Herrick found several other showers 

 derived from the same stream. They seem, however, to 

 have been of inferior brilliancy. They will be consider- 

 ed hereafter. 



II. 



THE FIRST COMET OF l86l. 



The first comet of 1861 was discovered by Mr. 

 Thatcher on the 4th of April. It was visible to the naked 

 eye, and had a tail three degrees long. Its elements, cal- 

 culated by Dr. Oppolzer, of Vienna, are as follows : 



ELEMENTS OF THE FIRST COMET OF l86l. 



Perihelion Passage 1861, June 3. 



Longitude of Perihelion 243 22'. 



Longitude of Ascending Node 29 55'. 



Inclination 79° 45'. 



Eccentricity 0.98345 . 



Semi-axis Major 55 67 



Period 4 T 5-4 years. 



Perihelion Distance 0.9207. 



Aphelion Distance 110.425. 



Motion Direct. 



Professor George Forbes has shown 6 that the comets of 

 1444, 1032 and 616 were former apparitions of this 

 comet ; the mean of the three periods being 415 years. 

 The dates of ancient perihelion passages would 

 therefore have been about A. D. 201, B. C. 214, and 

 B. C. 629. In 1867, soon after the discovery, by 

 Schiaparelli and others, of the connection between the 

 comets of 1862 and 1866 with the August and No- 

 vember meteors, the probability of a similar relation 

 between the first comet of 1 861 and the meteors of 

 April 20th was pointed out by Drs. Weiss and Galle. 6 

 The orbit of the comet nearly intersects that of the earth 

 in longitude 210°, the point passed by the earth at the 

 epoch of the April meteoric shower. An approximate 

 equality of the periods of the comet and the meteoric 

 stream was thus rendered highly probable. 



The facts here collated constitute several very strik- 

 ing coincidences. 



1. Dr. Oppolzer 's period of the comet, derived solely 

 from observations, is 415 years. 



2. The mean period from 616 to 1S61 was 415 years. 



3. The interval between the gieat meteoric showers of 

 B. C. 687 and A. D. 1803 is equal to 6 periods of 415 

 years. 



4. The shower of A. D. 558 was midway between B. C. 

 687 and A. D. 1803. 



5. The comet and the meteoric swarm seem to have 

 equal periods. 



It is by no means surprising that all returns of the 

 meteoric group have not been recorded. The observa- 

 tions were restricted to the eastern continent ; or, as 



3 Quctelet's Physique du Globe, p. ago. 

 * Quetelet's Catalogue. 



'In a paper read before the Royal Society of Edinburgh, Feb. 16, 1880. 

 "Astr. Nach., Nos. 1632, 1635, and 1710. 



