We see, indeed, that other suns have suffered in this way, assuming cometic downfall to be the true cause of stellar outbursts. There are so many millions of suns, however, in the region of space to which telescopic survey extends that the occurrence of ten or twelve such outbursts in the course of four or five centuries need not be regarded as implying any serious danger. Moreover, all the suns which have thus suffered lie within a particular region of the heavens,--viz., in the Milky Way, and in that half of the Milky Way which is most irregular, one may almost say _ragged_, in structure. (With one exception--the star in the Northern Crown, which, nevertheless, lies on a faint outlying streamer of the Milky Way not discernible to ordinary vision.) If then our sun belongs to this region of space, the danger for him and for us is somewhat greater than my previous argument would indicate. For, in that case, we must compare the number of outbursts, not with the total number of stars within telescopic range, but with the number of those stars which lie within this particular region of space. On the other hand, if our sun does not lie within that region of space, the danger for him and for us is very much less; for instead of a certain small number of accidents among his fellow suns, there have been no such accidents, only accidents affecting other suns which must be differently classed. The case may be compared to the estimation of the dangers, let us say, of travelling by ocean steamships on a particular route. If we take the total number of accidents, for instance, to steamships travelling between England and the United States, we should estimate the risk of the journey as very small, the number of passengers who have lost their lives being very small compared with the number who have made the journey. But even this small risk is diminished if we estimate the danger for a passenger by Cunard steamships, simply because no passenger has yet lost his life through accident to one of these Cunard vessels. So in the case of our sun, the danger of an outburst such as has affected the stars in the Northern Crown and Cygnus is small enough when we estimate it by comparing the number of such accidents with the total number of stars, but vanishes almost into nothingness when we note that no insulated star like our sun seems hitherto to have undergone one of these tremendous catastrophes.