Feb. 17, 1882.] 



KNOWLEDGE 



341 



us, for instance, I made in 1868 of the epochs of the 

 lic'jjinnings and endings of the transits of Venus in 1S7 t 

 and 18Sl' for different parts of the eartli's surface. As a 

 matter of fact, the prediction is not mine, but Herr ilartli's 

 (quoted, and, as a qnotation, given in .smaller type than 

 the rest) ; it is not advanced definitely, but in tlie fol- 

 lowing terms : — " I should not be at all surprised," says 

 Herr Marth, " if it should turn out that this comet of ISSO 

 is the same as the comet of 1843 and that of 1668, and 

 that its revolution has been so much affected that possibly 

 it may return in, say, seventeen years." (This was M-ritten 

 in 1880.) 



I go on to show that if this is so, the comet must befon^ 

 long be absorbed by the sun^— still not naming 1897 or anv 

 other year, but .speaking with due scientific caution — 

 "after only a few cii'cuit.': — possibly one or two."' 



had gone the wron 



I then note the only way in which the absorption of r- 

 comet might do harm — that is, not as Newton thought, h} 

 adding fuel to the solar tires, l>ut by the conversion of th' 

 momentum of the meteoric masses forming or followin;: 

 the head, into heat I mention, in passing, my own belief 

 that the sudden incre^ise of splendour observed in the sta' 

 T Coronw (not r, as has been mistakenly asserted) was 

 due to the fall of a large comet, followed by a train o' 

 closely-aggregated meteors upon that distant sun. This 1 

 fully believe to be the most probable, if not the onl_< 

 available interpretation of that and similar phenomena 

 "Without saying," I proceed, and this seems to me tin 

 only passage in my essay which could have suggested am 

 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 184;i shall be 

 absorbed by him (a result which will, in my opinion, 

 most certainly take place), I will go so far as to e.xprcs.s 

 my belief that if ever the day is to come when ' tie 

 heavens shall dissolve with fervent heat,' the cause of the 

 catastrophe will be the downfall of some great comet on the 

 sun." ^\ hat I here consider as certain may, perhaps, have 

 been misunderstood as the coming of such a cat^xstrophir 

 end; but it should be manifest tliat I only regard thr 

 absorption of the comet of 184.3 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 cf 

 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 in my " Pleasant Ways in 

 Science," in which essay I refer back to the other in " Myths 

 and Marvels," wthout in either case indicating any rhange 



J^iL. a. — A cornel wluih nnglit injure a solar sysium, tliuu;,'li 

 uot ours. 



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 Mat/atine for December last, there is a paper, 

 bearing my initials, on " Dangers from Comets," in which 

 it is sho\\ni — as sundry newspaper articles have l}een 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 

 18+3, 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 proliability 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 re- 

 garded as thp most sensational, it is its extremely cautious 

 wording. I may go so far as to poke a little fun at myself 



