Proceedings of the British Association, 99 



through vast regions of space in a vaporous or cloud-like state, under- 

 going, or awaiting the slow process of aggregation into masses by the 

 power of gravitation, was originally suggested to the late Sir W. 

 Herschel in his reviews of the nebulae, by those extraordinary objects 

 which his researches disclosed, which exhibit no regularity of out- 

 line, no systematic gradation of brightness, but of which the wisps 

 and curls of a cirrhus cloud afford a not inapt description. The 

 wildest imagination can conceive nothing more capricious than their 

 forms, which in many instances seem totally devoid of plan as much 

 so as real clouds, — in others offer traces of a regularity hardly 

 less uncouth and characteristic, and which in some cases seems to 

 indicate a cellular, in others, a sheeted structure, complicated in folds 

 as if agitated by internal winds. 



Should the powers of an instrument such as Lord Rosse's succeed 

 in resolving these also into stars, and, moreover, in demonstrating the 

 starry nature of the regular elliptic nebulae, which have hitherto 

 resisted such decomposition, the idea of a nebulous matter, in 

 the nature of shining fluid, or condensible gas, must, of course, 

 cease to rest on any support derived from actual observation in 

 the sidereal heavens, whatever countenance it may still receive in the 

 minds of cosmogonists from the tails and atmospheres of comets, 

 and the zodiacal light in our own system. But though all idea of its 

 being ever given to mortal eye, to view aught that can be regarded 

 as an outstanding portion of primaeval chaos, be dissipated, it will 

 by no means have been even then demonstrated that among those 

 stars, so confusedly scattered, no aggregating powers are in action, 

 tending to draw them into groups and insulate them from neighbour- 

 ing groups ; and, speaking from my own impressions, I should say 

 that, in the structure of the Magellanic Clouds, it is really difficult 

 not to believe we see distinct evidences of the exercise of such a power. 

 This part of my father's general views of the construction of the 

 heavens, therefore, being entirely distinct from what has of late been 

 called "the nebulous hypothesis," will still subsist as a matter of 

 rational and philosophical speculation, — and perhaps all the better for 

 being separated from the other. 



Much has been said of late of the nebulous hypothesis, as a mode 

 of representing the origin of our own planetary system. An idea of 



