November 2, 1899] 



NA TURE 



little way in this direction by means of some figures 

 which I have noted. The point is to see whether there 

 is any difference in the distribution of those nebula', 

 which are undoubtedly masses of gas, and give us the 

 so-called nebulous spectrum, and those other nebulae 

 about which at present we know very little, but give 

 us so-called continuous spectra. It is clear that on 

 this point, undoubtedly at some future time, even if 

 we cannot do it now, a great deal will be learned. 

 The table I give brings the results up to the year 

 1894. If we take the region near the Milky Way, 

 the region bounded by lo" galactic latitude north and 

 south, and consider the planetary nebul.e distinguished 

 by bright-line spectra, we find that there are forty- 

 two ; but if we deal with those which are further than 

 10° from the Milky Way, that number drops to five. 

 If we take other nebulae, not neces- 

 sarily planetary, but gaseous like 

 planetary nebuke, inasmuch as they 

 give us a spectrum of bright lines, 

 we find that there are twenty-two in 

 or near the Milky Way, and only six 

 outside. If we take the so-called 

 nebuke known to have continuous 

 spectra, which need not be nebuke at 

 all — we only imagine them to be 

 nebuke because they are so far away 

 that we cannot get a really true ac- 

 count of them — we find that the 

 conditions are absolutely reversed. 

 There are only fourteen of them in 

 the plane of the Milky Way, but 

 there are forty-three lying outside 

 it ; so that the percentage within 

 10' of the Milky Way comes out 

 to be eighty-four in the case of the 

 planetary and the other nebulae 

 which give us bright lines, and in 

 nebulae with continuous spectra only 

 25. Therefore we get an absolute 

 identity of result with regard to the 

 bright-line stars and the other objects 

 which give us bright-line spectra. 



There is another class of bodies 

 of e.xtreme interest. In fact, to some 

 they are more interesting than all 

 the other stars in the heavens put 

 together (because they are "new 

 stars") ; each new star being sup- 

 posed to be a new creation, so 

 that for this reason everybody is 

 very much agog to find out what 

 they are like. When we come to 

 examine these so-called new stars 

 we find that they also are almost 

 absolutely limited to the Milky Way, 

 as shown in the table which gives 

 the number of new stars, so-called, 

 which have been observed in historic 

 times. It begins at 134 years before Christ, and it 

 ends last year. The number of stars thus reported 

 as new stars is thirty-one, and of these only three 

 have been seen outside the Milky Way. The glass 

 globe will show in a convenient way what the facts 

 are with regard to the new stars. The bright line 

 stars being distinguished by dark wafers, the new stars 

 are shown by white wafers. We notice that where we 

 get practically the greatest number of dark wafers we 

 get a considerable number of white ones. That means 

 that these new stars take their origin in the same part 

 of space as that occupied by the bright-line stars, and 

 it is also interesting to point out that the void which I 

 mdicated where the Milky Way is single, where there 

 were no bright-line stars, is equally true for the 



NO. 1566, VOL. 61] 



new stars ; only one new star has been recorded in 

 this region. 



.As I have said, a great deal of interest has been 

 attached by many people to the question of the new 

 stars, for the reason that whenever a new star appeared 

 in a part of the heavens where no star was seen before, it 

 was imagined that sometjiing miraculous and wonderful 

 had happened. That was justifiable while we were 

 ignorant, but recent work has shown, I think almost to a 

 certainty, that the real genesis of a new star is simply 

 this. We have near the Milky W^ay a great number of 

 nebulie, planetary or otherwise ; we have more planetary 

 nebuke near the Milky Way than in any other part of 

 the heavens ; the nebulous patches also observed in it 

 may include streams of meteorites rushing about under 

 the influence of gravity ; the origin of a new star is due 



• 4- — The Milky W.»y, where double in relation to the Equator and Gould's belt of stars, 

 sho vine th.it the bright-line stars (dark wafers)' and new stars (white wafers) are limited 

 to the Milky V* ay. 



to the circumstance that one of these unchronicIecJ 

 nebuke suddenly finds itself invaded by one of these 

 streams of meteorites. There is a clash. These meteor*- 

 ites we know enter our own atmosphere at the rate of 

 thirty-three miles a second, and we may therefore be 

 justified in assuming that any metcoritic stream in space^ 

 even in the Milky Way, would not be going very much 

 more slowly. If we get this rapidly-moving streanr 

 passing through a nebula, which is supposed to be a 

 mass of meteorites more or less at rest, of course we 

 must get collisions ; of course, also, we shall get heat^ 

 and therefore light. When the stream has passed 

 through the nebula the luminosity will dim and ulti- 

 mately, attention having been called by this cataclysm to 

 that particular part of space, we shall find that there is a 



