342 



NATURE 



[Fed. 13, 1S79 



coinpletely known aside from our knowledge of that of 

 the comet. Every August, about the tenth day, we have 

 an unusual number of meteors — a star-sprinkle, as it has 

 been called. A comet whose period is about 125 years 

 moves in the plane, and probably in a like orbit with these 

 meteoroids. 



So near the first of December we have had several 

 star-showers — notably one in 1872 — and these meteoroids 

 are travelling nearly in the orbit of Biela's comet In 

 April, too, some showers have occurred which are thought 

 to have had something to do with a known comet. 



Thus much as to the meteors of the star-showers. The 

 sporadic meteors are with good reason presumed to be 

 (and observed facts prove some of them to be) the out- 

 liers of a large number of meteoroid streams, and the 

 leading problem of meteor-science to-day is to find these 

 streams so faintly shown, and, if possible, the comets 

 they belong to. 



Come back with me to the November stream and its 

 comet. The several bodies move along a common path 

 not at all by reason of a present physical connection. 

 They are too far apart, in general a thousand times too 

 far apart, to act on each other so much that we can 

 measure the effect. No; their connection has been in 

 the past. They must have had some common history. 



Looking now at the comets, we see that they have been 

 apparently growing smaller at successive returns. Hal- 

 ley's comet was much brighter in its earlier than in its 

 later approaches to the sun. Biela's comet has divided 

 into two, if not more than two, principal parts, and seems 

 to have entirely gone to pieces. It could not be found in 

 1872, when and where it ought to have been visible. 

 Several comets have had double or multiple nuclei. In 

 the year 1366, in the week after the star-shower, a comet 

 crossed the sky exactly in the track of the meteors. A 

 second comet followed in the same path the week after. 

 Both belonged no doubt to the November stream, and 

 one of them may perhaps hare been the comet of 1866. 



This stream of meteoroids is a long thin one. In 

 miniature it would be perhaps a mile long to an inch in 

 thickness. We have crossed the stream at many places 

 along a length of a thousand millions of miles, sometimes 

 in advance of, and sometimes behind, the comet, and all 

 along this length have found fragments, sometimes few, 

 sometimes many. This form of the stream suggests 

 continuous action producing it. A brief violent action 

 might give this form, but_ a slowly acting cause seems 

 more natural. 



Again, in the history of Biela's comet we have distinct 

 evidence of continued action. The comet divided into 

 two parts not long before 1845, ^iid yet in 1798 fragments 

 of it were met with so far from the comet, that they must 

 have left the comet long before, probably many centuries 

 ago. 



Thus are we led to say, first, that the periodic meteors 

 of November, of August, of April, &c., are caused by 

 solid fragments of certain known or unknown comets 

 coming into our air ; secondly, that the sporadic meteors 

 such as we can see any clear night are the like fragments 

 of other comets ; thirdly, that the large fireballs are only 

 larger fragments of the same kind ; 2in6. finally, that this 

 stone, which was broken off from one of those large 

 fragments in coming through the air, must once have been 

 a part of a comet. 



Here I should naturally close, yet I am sure that you 

 will ask, How came the comet to break up ? Perhaps 

 the prior question would be. How came the comet to- 

 gether ? In its history there is much that we cannot yet 

 explain, much about which we can only speculate. Thus, 

 how came this stone to have its curious interior struc- 

 ture ? As a mineral it resembles more the deepest fire- 

 rocks than it does the outer crust of our earth. It seems 

 to have been formed in some large mass, possibly in one 

 larger than any of our existing comets. Some facts show 



that the comets have almost surely come to us from the '> 

 stellar spaces. Out somewhere in the cold of space a 

 condensing mass furnished heat for the making of this 

 stone. The surrounding atmosphere was unlike ours, 

 since some of these minerals could hardly have been made 

 in the presence of the oxygen of our air. Either in cooling, 

 or by some catastrophe, the rocky mass may have broken 

 to pieces, so as to enter the solar system, having little or no 

 cohesion, like a mass of pebbles ; or, it may have come 

 and probably did come, a single sohd stone. In either 

 case, as it got near to the sun, new and strong forces 

 acted on it. The same heat and repulsion that develops 

 and drives off from a comet in one direction a tail, some- 

 times a hundred millions of miles long, may have cracked 

 off and scattered in another direction solid fragments. 

 One of these contained in it this stone, and it wandered in 

 its own orbit about the sun, itself an infinitesimal comet, 

 how many thousands or millions of years we know not, 

 until three years ago it came crashing through the air to 

 the earth in Iowa. Thence this fragment came here to 

 serve as a text to my discourse. 



METEOROLOGICAL STATION ON BEN NEVIS 



WE are glad to learn that the Scotch Meteorological 

 Society's scheme of a station on Ben Nevis is 

 evoking cordial support from those who hare the adminis- 

 tration of Government funds available for such objects. 

 The London Meteorological Council, of which Prof. 

 Henry Smith is chairman, has unanimously agreed to 

 offer to the Scotch Society 100/. yearly towards the sup- 

 port of the station, provided a copy of the observations is 

 sent regularly to London. This is at once testimony by » 

 the most competent judges to the importance of the ■ 

 scheme, and a proper encouragement to the Scotch " 

 Society to proceed in its spirited enterprise. We under- 

 stand that to uphold the station and induce two com- 

 petent observers to take it by turns to live on the top of 

 the mountain with an assistant will cost about 300/. 

 yearly. It is estimated that to purchase a full stock of 

 instruments and erect a building for them and the ob- 

 servers a capital sum of 800/. will be required. The 

 Scotch Society has applied for a grant of 400/. towards 

 this expenditure from the Committee appointed by Go- 

 vernment to distribute 4,000/. annually to encourage 

 scientific research. We believe the Committee has not 

 yet met to consider the various claims which are, no 

 doubt, as usual made on the funds. 



RESEARCH UNDER DIFFICULTIES 



THE following short preface to a very valuable account 

 of the stages of development from the fg^ of one of 

 the centipedes (Geophilus), no member of which group 

 had been studied previously to this account, gives so con- 

 vincing a picture of the enthusiasm for investigation 

 which may animate the modern naturalist, that it is 

 worthy of a place in NATURE for the encouragement of 

 the " craft." Elias Metschnikoff has during the past 

 fifteen years worked more assiduously with the micro- 

 scope at the observation of the minute details of embryo- 

 logy than any other student. To him we are indebted 

 for our first accurate knowledge of this subject in the 

 case of many important animal forms, e.g,, sponges^ 

 various jelly-fishes, marine worms, the scorpion, and the 

 book-scorpions, various insects, crustaceans, starfishes, 

 and ascidians. One result has been the injury of his eye- 

 sight. In reading to-day his memoir on Geophilus, pub- 

 lished in 1875 {Zeitschr. fiir wiss. Zoologie), it occurred 

 to me that the following passage has more than technical 

 interest : — 



" After having for many years sought in vain for mate- 

 rial suited for the investigation of the embryology of the 

 centipedes, I chanced to obtain a quantity of the eggs sfc 



