splendour observed in the star T Corona (not т, as has been mistakenly asserted) was due to the fall of a large comet, followed by a train of closely-aggregated meteors upon that distant sun. This I fully believe to be the most probable, if not the only available, interpretation of that and similar phenomena. "Without saying,"-I proceed, and this seems to me the only passage in my essay which could have suggested any anxiety about the earth's future,"without saying that I consider there is absolute danger of a similar outburst in the case of our own sun, when the comet of 1843 shall be absorbed by him (a result which will, in my opinion, most certainly take place), I will go so far as to express my belief that, if ever the day is to come when the heavens shall dissolve with fervent heat,' the cause of the catastrophe will be the downfall of some great comet on the sun. What I here consider as certain may, perhaps, have been misunderstood as the coming of such a catastrophic end; but it should be manifest that I only regard the absorption of the comet of 1843 as most certain-regarding the time as quite uncertain, and the effects as extremely problematical. I have, indeed, shown elsewhere (see "Suns in Flames," in my "Myths and Marvels of Astronomy") that there is every reason for believing that all comets of the destructive sort have long since been eliminated from the solar system. So that, as in the essay referred to by the Spectator, I refer back to an essay "Pleasant Ways in Science," in which essay I

in my

refer back to the other in "Myths and Marvels," without in either case indicating any change of view, I might fairly claim to have very definite views as to the perfect safety of the solar system, even if I had not recently pointed out, with special reference to the comet of 1843, our probable complete immunity from danger. In the Cornhill Magazine for December, 1881, there is a paper, bearing my initials, on "Dangers from Comets," in which it is shown-as sundry newspaper articles have been good enough to explain in turn to myself—that if there were any real danger, save for the comet itself, we should have known it by great increase in the solar emission of heat in 1843, when the comet was checked so importantly in its career, and again in 1880, when it was subjected to another equally severe interruption of its onward

course.

The article finally points out the kind of danger which in all probability would ensue if a comet of the larger sort fell into the sun. If there is anything remarkable in this part of my essay, which seems to have been regarded as the most sensational, it is its extremely cautious wording. I may go so far as to poke a little fun at myself by saying that it is almost absurdly cautious. I point out, that if there are planets circling around the sun which blazed out in Corona in May, 1866, to eight hundred times its former lustre, and if there were living creatures on them at all resembling ourselves, those creatures must most certainly have been destroyed. It takes no wizard to know this. I

с

then go on to say that "if at any time a great comet falling directly upon the sun" (which the comet of 1843 and 1880 most certainly will never do) "should, by the swift rush of its meteoric components, excite the frame of the sun to a lustre far exceeding that with which he at present shines, the sudden access of lustre and of heat would prove destructive to every living creature, or, at any rate, to all the higherforms of life, upon this earth." And, though I knew when I wrote this that I was making no rash prediction, I protest I never noticed, until the rash predictions assigned to me by the Spectator and the Bishop of Manchester set me reading over my own essay, that this amounted only to an announcement of the following highly-impressive nature:-If such a comet as we have no reason to suppose actually existent (nay, every reason to consider certainly nonexistent in the sun's case) should produce a degree of solar heat (which such a comet may, or may not, be capable of producing), exceeding hundreds of times the sun's present heat, and if that heat lasted but a few days, the earth's inhabitants must all perish. This very cautious announcement does not mean, I venture to point out, that fifteen years hence the comet of 1843 falling into the sun will so raise his heat that all of us will be destroyed.

I

may remark that the newspaper announcement has elicited various expressions of opinion, showing the great ignorance which prevails even in these days of cheap scientific literature respecting scientific

matters.

Thus it has been carefully explained by some that comets are entirely vaporous, evidently in ignorance of what has been learned respecting the meteoric nature of comets; by other writers, that Lexell's comet was absorbed by Jupiter or by his

not ours.

satellites (which Leverrier entirely disproved); while another writer (in the Christian World, and followed by the Globe) propounds the amazing statement that the sun's heat does not travel so quickly as his light,

so that, even though we saw a great outburst, due to the destruction of a comet, some ninety or a hundred years would have to pass before the earth would receive the heat then generated! It would be interesting to ascertain whence this singular idea was obtained-by what strange misapprehensions of some statement in a scientific work. Of course, there is not the slightest foundation for it. The sun's heat comes to us with his light, not only travelling at the same rate, but being a part of the very same undulatory disturbance, and a considerable portion being derived from the very same waves. Some of the waves, indeed, which affect us as light affect us very little as heat, and some of the waves which affect us as heat produce no effect which the eye can appreciate as light. But the orange and red light waves are very active as heat-waves too, and there is not the slightest reason for supposing that the so-called dark heat-waves, which, with these, make up the total supply of solar heat, would lag many seconds behind. them on the journey earthwards.

However, there is not the slightest reason to fear that the comet of 1843 and 1880 (assuming they are the same) will do any harm to the solar system when finally absorbed. It would be quite otherwise, I believe, if such a comet as that of the year 1811, Fig. 3, were to fall directly upon the sun. This, the most remarkable (in reality, though not in appearance) of all known comets, was fortunately some 100 million miles from the sun at the time of its nearest