STAR CHARTING. 215 



in a plane common to all ; and, as it is also evidently the case with 

 spiral nebula?, the matter is arranged in a plane, of which the 

 diameter is enormously greater than the thickness, so I think we 

 may safely assume that the Nubecula major is a great spiral struc- 

 ture, of which we see the greatest diameter, and that its thickness, 

 measured through in the line of vision, is comparatively small. Now, 

 in addition to the main central spiral, there are two nebula?, and at 

 least three clusters of stars arranged as spirals, having the same 

 characters as the main one, that is nearly circular, and these are all 

 arranged in space so that they appear to us in the same or parallel 

 planes and near together ; and it may, I think, be safely assumed that 

 all are parts of the grandest spiral structure that we know, and all in 

 one plane, because if they are not in the same plane, then, being 

 optically close together and in parallel planes, they must be arranged 

 one after the other in a long vista which happens to be in our line of 

 sight, that is, a series of great spirals one behind the other at 

 different distances towards infinity, and all revolving as if on a 

 common or parallel axis, a conclusion which is highly improbable, 

 and impossible to receive when the simple and more rational alter- 

 native of their being all in the same plane is available. Now, 

 accepting the condition of their all being in the same plane, imagine 

 what we should see if transported to some star near the centre. All 

 round us would be an infinity of stars, which, on closer inspection, 

 would seem more crowded together in a great plane, and in the same 

 plane we should see two nebula; like straight lines, because looking at 

 them from the plane in which they revolved, in some directions the 

 stars would be relatively thinner than in others, because in those the 

 extensions of them are not so great, and there would also be apparent 

 rifts owing to the dark spaces in the great spiral, where we would 

 seem to see into the infinity beyond to other systems, with their 

 nebula? and star clusters at all angles. If you look at the photograph, 

 and assume, as I have done above, that the whole universe of stars is 

 spread out in the plane of the photograph, you will see that there 

 would be no difficulty in finding positions from which the observer 

 would see through some of the comparatively dark places, as well as 

 in other directions in which countless multitudes of stars of all magni- 

 tudes would meet the gaze. In fact, his vision would be much the 

 same as ours — in one plane, that of the whole universe. There would 

 be an inconceivable wealth of stars, with here and there dark spaces, 

 coal sacks, due to the dark rifts above referred to ; and looking out of 

 that plane the number of stars would decrease, although they would 

 still be abundant. Now, although amongst the infinitude of heaven 

 we cannot find two star clusters or two nebula? alike, we can still find 

 classes of different kinds which have many points in common, and I 

 think we have here reasonable ground for supposing that Ave have 

 presented to us in the Nubecula Major a universe similar to that in 

 which we are, and that instead of seeing it from within, where it is 

 impossible to make out its form, we are here, with the aid of teles- 

 copes and the still more powerful star camera, able to see just such a 

 universe, to trace out a rational explanation of the many puzzling 

 features of the stars and milky way around us, and to see how such a 

 universe may be arranged. In reference to another well-known 



