420 



NATURE 



[Marc/i 4, 1886 



between. It will in general rise in the east and set in the 

 west, like the sun or a star, keeping always its fixed place 

 among the stars. 



Need I tell you how much we would like to have some 

 of these bits from the meteoroid streams to handle, to 

 try with the blowpipe and under the microscope, perhaps 

 thus to learn something of their history ? We do have 

 something like this. At times large meteor masses come 

 crashing into the air. They burn with a light bright 

 enough to be seen over several States. Coming down 

 usually a little lower than the shooting-stars, most 

 frequently to a height of 25 or 30 miles, they break up 

 with a noise like the firing of heavy artillery, to be heard 

 over several counties. Fragments scattered in e\ ery 

 direction fall to the ground over a region 10 or 20 miles 

 in extent. I can show you .several such fragments. There 

 are over a hundred of them in our College Cabinet, one of 

 which weighs nearly a ton. 



Between these stone-producing meteors and the faintest 

 shooting-star I cannot find any clear line of division. We 

 have meteors that break with a loud detonation, but no 

 fragments are seen to fall. One such was seen in 1S60 

 from Pittsburgh to New Orleans, and from Charleston to 

 St. Louis. It exploded over the boundary line of Tennessee 

 and Kentucky. We have others which are only seen to 

 break into pieces, no noise being heard. Then we have 

 those which quietly burn out. Like the larger ones, these 

 may leave smoky trains that last for minutes. One such 

 1 have seen for 45 minutes as it slowly floated away in 

 the currents of the upper air. 



Thus through the whole range, from the meteors that 

 give us these stones and irons for our museums, down to 

 the faintest shooting-star hardly seen by a person watch- 

 ing for it, we pass by the smallest differences. They 

 differ in size, in colour of flame, in direction, in train, in 

 velocity. But in astronomical character all seem to be 

 alike. They move in long orbits like comets, and like 

 comets at all angles to the earth's orbit. In fact, a 

 meteoroid is a small comet, not having, however, the 

 comet's tail. 



Let us turn from this long digression again to the story 

 of Biela, and tell you what we saw of it in November 

 1872. We of course looked for a few fragments from the 

 comet the last week in November, but not quite as early 

 as the 24th. But on that evening they came, in small 

 numbers it is true. Before midnight wc saw in New 

 Haven about 250 shooting-itars, three-fourths of them 

 from Biela. Very few of them were to be seen the ne\t 

 morning and evening. Then for a day or two it was 

 cloudy. But in the early part of the evening of the 27tli 

 they came upon us in crowds. Over 1000 were counted 

 in an hour. By 9 o'clock the display was over. But we 

 saw only the last few drops of a heavy shower. Before 

 the sun had set with us the shooting-stars were seen 

 throughout all Europe, coming too fast to be counted. .At 

 least 50,000, perhaps 100,000, could have been seen then 

 by a single party of observers. 



Notice what was really seen. Here is a chart of the 

 paths of the shooting-stars as actually seen on thatevening, 

 and drawn with care at the time upon maps of the stars 

 (Fig. 13). You see a few stray flights cutting wildly across 

 the others. These are strangers to the system. 



You see also that the paths do not, as we had reason to 

 expect, all meet in one point. This is not due to errors 

 of observing, for we see it in every star-shower. It is 

 probably because the small bodies glance as they strike 

 the air, just as a stone skips on the water. In fact, we 

 often see the meteors glance in the air— the paths being 

 crooked. 



The meteors came from the northern sky. A German 

 astronomer. Prof Klinkerfues, at once thought that if this 

 was the main body of the comet it ought to be visible as 

 it went oft" from us. For this, however, we must see the 

 southern sky. He telegraphed to Mr. Pogson at Madras 



m India : " Biela touched earth Nov. 27. Search near 

 Theta Centauri." Mr. Pogson looked for the comet and 

 found it. On two mornings he saw a round comet with 

 decided nucleus, and having on the second morning a 

 tail 8' long. But clouds and rain returned the next day. 

 This IS the last that has been seen of Biela's comet. 



Was this Pogson comet one of the tu-o parts of Biela 

 seen in 1845 and 1S52 ? This is yet an open question 

 among astronomers. It may have been, but I think it 

 was not. The Biela comets should have been nearly 

 200,000,000 miles away. Their orbits had been computed 

 with care. The comets, as single or double, had been 

 observed for 80 years, that is 12 revolutions, and we knew 

 well their orbits. All known disturbing forces had been 

 allowed for. It could hardly be that they should have 

 gone so large a distance out of the way. It is much more 

 probable that this was a third large fragment, thrown off 

 centuries ago. The two observations made by Mr. Pogson 

 were not enough to compute an orbit from, but they do 



show that his comet was very near us, and were such as 

 one travelling in the Biela stream might give. But they 

 also show that the earth did not pass through the Pogson 

 comet centrally. 



Orbit of tlic Biela Meteors. — In 1798, when the earth 

 was at N, and Brandes saw the fragments from Biela, the 

 comet was at C (Fig. 14). In 1838 Mr. Herrick and others 

 saw such fragments of the comet at N, 300,000,000 miles 

 ahead of the main body at h, and in 1S72 we met like 

 fragments at n, 200,000,000 miles behind the main body, 

 which should have been at I!. Thus the fragments are 

 strewn along the comet's orbit, probably in clusters, for at 

 least 500,000,000 miles. 



My story of Biela's comet and of its fragments has 

 covered 100 years. Do we get any glimpses of its earlier 

 life, and can we guess how it grew into its present shape ? 

 Yes, we may make our hypothesis. But we must not for- 

 get that to tell others how God must have made the world 

 is bewitching to many minds, and that of the thousands 

 of trials at world-building almost all have been grievous 

 failures. With this caution let me give you a plausible 

 form of this early story of Biela. 



