120 CLASSICS OF MODERN SCIENCE 

 in much darkness, may now be explained with some degree of sat- 

 isfaction, since the uniform and very considerable brightness of their 

 apparent disc accords remarkably well with a much condensed, lu- 

 minous fluid ; whereas, to suppose them to consist of clustering stars, 

 will not so completely account for the milkiness or soft tint of their 

 light, to produce which it would be required that the condensation 

 of the stars should be carried to an almost inconceivable degree of 

 accumulation. The surmise of the regeneration of stars, by means 

 of planetary nebulae, expressed in a former paper, will become more 

 probable, as all the luminous matter contained in one of them, when 

 gathered together into a body of the size of a star, would have nearly 

 such a quantity of light as we find the planetary nebulae to give. To 

 prove this experimentally, we may view them with a telescope that 

 does not magnify sufficiently to show their extent, by which means 

 we shall gather all their light together into a point, when they will 

 be found to assume the appearance of small stars ; that is, of stars at 

 the distance of those which we call of the 8th, 9th, or loth magnitude. 

 Indeed this idea is greatly supported by the discovery of a well- 

 defined, lucid point, resembling a star, in the centre of one of them ; 

 for the argument which has been used, in the case of nebulous stars, 

 to show the probability of the existence of luminous matter, which 

 rested on the disparity between a bright point and its surrounding 

 shining fluid, may here be alleged with equal justice. If the point 

 be a generating star, the further accumulation of the already much 

 condensed, luminous matter may complete it in time. 



How far the light that is perpetually emitted from millions of suns 

 may be concerned in this shining fluid, it might be presumptuous to 

 attempt to determine; but, notwithstanding the inconceivable subtilty 

 of the particles of light, when the number of the emitting bodies is 

 almost infinitely great, and the time of the continual emission indefi- 

 nitely long, the quantity of emitted particles may well become adequate 

 to the constitution of a shining fluid, or luminous matter, provided a 

 cause can be found that may retain them from flying off, or reunite 

 them. But such a cause cannot be difficult to guess at, when we 

 know that light is so easily reflected, refracted, inflected and de- 

 flected; and that, in the immense range of its course, it must pass 

 through innumerable systems, where it cannot but frequently meet 

 with many obstacles to its rectilinear progression not to mention 



