September 1, 1886.] 



♦ KNOWLEDGE ♦ 



335 



This may be asserted even of those nebulae with respect to 

 which Sir John Herscbel has remai-ked that the arrange- 

 ment mav be accidental. His own pictures seem to me to 

 prove in the most convincing manner that no such explana- 

 tion can he accepted. The mere aggregation of a large 

 number of stai-s in the ver}' heart of a nebula might be an 

 accident ; the fact, for instance, that the great irregular 

 nebula surrounrling the star Et:i Argus agrees exactly in 

 position with the greatest contlensxtion of the wonderfully 

 rich poi-tion of the ]\Iilky Way on which that surprising 

 variable lies, might be a mere coincidence, though in any 

 case it would be a strange one. But when one examines 



remai'kable nebulous nodules centrally surround two double 

 stars. Admitting the association here to be real, and no 

 other explanation can reasonably be admitted, we are led to 

 interesting conclusions respecting the whole of that nebu- 

 lous region which surrounds the sword of Orion. We 

 become cerfciin that the other nebulae in that region are 

 really associated with the fixed stains there ; that it is not a 

 mere coincidence, for instance, that the middle star in the 

 belt of Orion is involved in nebula, or that the lowest star 

 is similarly circumstanced. It is a legitimate inference from 

 the evidence that all the nebula- in this region belong to one 

 great nebulous group which extends its bi'anches to these 



Fig. 2. — The Nebula extending fbom Mai.\ in the Pleiades. 

 Enlarged from the Pliotograph. 



the structure of this and similar nebulie, and finds that the 

 stai-s are arranged in a manner most obviously related to 

 the arrangement of the nebular condensations — or folds, one 

 may almost say — one cannot doubt that a real and intimate 

 bond of association exists between the stars and the nebulous 

 mas.ses around them. If the extension of the milky light 

 of the great Orion nebula to the star i in the sword, 

 which is centrally involved in strong nebulosity ; to s in the 

 belt which is similarly involved ; and to sevei'al other stars 

 in the constellation, all alike in occupying regions of in- 

 creased nebular condensation — if this be a mere .accidental 

 coincidence, then the laws of probability had better be 

 forgotten as soon as possible, for, as at present understood, 

 they can only serve to lead men astraj'." 



" Amongst other instances," I went on, after referring to 

 illustrations of large nebula?, " may be cited the nebula 

 round the stars c' and c' in Orion. In this object two 



stars. As a mighty hand this nebulous region seems to 

 gather the stars here into close associ.ition, showing us in a 

 way there is no misinterpreting that these stars and the 

 nebnke form one sj'stem." 



I would invite the a.strononiical readers of Kn'OWLEDGE to 

 study the photogiiiph of the Pleiades in the June number, 

 comparing it with Tempel's map of the Pleiades (fig. 1 of 

 the present number), and Woltl's chart (fig. 1 of the June 

 number^, in connection with the above remarks. W^e find 

 in the photograph the evidence of the unbiassed eye of 

 photogi~a])hy to show that the nebulous matter in the 

 Pleiades is really associated with certain of the stai-s in this 

 remarkable star-group. In fig. 2 is shown an enlargement 

 of the nebula, extending from Maia of the Pleiades (see the 

 small chart, fig. 3, in June number, and compare with 

 Tempel's chart, in which Maia appears as Maja). 



If anyone looking at these several drawings, considering 



