92 



• KNOWLEDGE • 



[Feb. 9, 1883. 



(Pur ^anraliov Cornrr. 



TlIK SOLAR SYSTEM ALL KQUALLY ILLUMINATED 

 BY THE SUN. 

 [The Otfurd Chronicle and Beika and Buclts flazrltc liaa dis- 

 oovorud that wo are possessed by a very angry feeliiiR towards Mr. 

 Collyns Simon, tlic discoverer of the theory indicated by the above 

 title. This is manifest to our clear-sighted contemporary, and 

 must liave been observed by oiu- readers; for in December, 1S81, 

 not more than fourteen months ago, wo animadverted in terms of 

 bitterest animosity upon the tlieory — oven going so far in our 

 mah'gnity as to express the opinion that it is "quite untenable." 

 Thi.s was in answer to a letter which came from the neighbourhood 

 for which our contemporary provides instruction ; and though the 

 writer in the Oxford Chronicle expresses his belief that we wrote 

 that letter ourselves to ourselves, we believe he has reason to know 

 considerably better. To show further our intense au.xiety to demolish 

 Mr. Simon's theory, we have even gone to the terrible length— re- 

 ceiving, as it chanced, no more questions about it — of saying nothing 

 more on the subject for fourteen months ! But the Oxford Chron icte 

 and JJerku and Bucks Gazette has had our evil courses in view, and 

 has only been waiting till time was ripe to crush ns utterly. We 

 are " full of astronomical parodoxes," we treat everything as a 

 paradox which is contrary to our own notions, and worst of all, we 

 have " attacked, in turn, every scientific man in the land." Now, 

 since Messrs. Herbert Spencer, Tyndall, Huxley, Darwin, Huggins, 

 Owen, and a host of others of like or scai-ce inferior eminence have 

 never been attacked here, this last can only mean that there are no 

 scientific men in the land but Hampden, Parallax, Newton Cros- 

 land, and Collyns Simon. For though we have shown reasons for 

 dissenting from views held by Dr. Siemens (on a subject outside his 

 own field), by Sir W. Thomson (on a purely speculative subject), 

 by Prof. Tait, and om- friend, Mr. \V. M. Williams, these belong to 

 the same class as Messrs. Huggins, Huxley, and the rest, and can- 

 not, therefore, be included among scientific men by the Oxfurd 

 Chronicle and Berks and Bucks Gazette. — The Editok.] 



" When we drew attention to this new and remarkable fact in 

 cor issue for Nov. 12, 1881, we were able to say that no scientific 

 writer nor (sic) journal had attomjited to dispute its truth. But this 

 is now no longer the case. We cannot say this now. One writer has 

 presented himself, endeavouring to make this great fact appear 

 improbable ; and we now again revert to the subject in order to 

 show how this writer, instead of throwing any doubt on the fact, 

 as he, with a good deal of a)iimii.s, labours to do, helps very con- 

 siderably, but most unconsciously, to make it clear to unscientific 

 people, as it has long been to the scientific, that there is no room 

 whatever for doubt respecting it. 



" The discovery in question is that, outside the atmosphere of the 

 planets, the sun's light falls equally upon each point of space 

 exposed to it, and that consequently it falls with equal intensity 

 upon the atmosphere of each planet. Wo now repeat here the two 

 very obvious principles, as stated in our former notice, which 

 render this proposition easily intelligible : — • 



" 1. Outside the atmospheres of the planets the sun's light passes 

 through no medium which could diminish this light to any per- 

 ceptible extent whatever. Upon this point all writers have been 

 long agreed. 



"2. The medium thus existing outside the atmosphere of the 

 planets being nil in its effects, each point of space, remote as well 

 as near, which is exposed to the disc of the sun receives upon it a 

 line of light (of luminous waves, if that expression is jireferred) 

 from each point of the disc; whereby a cone of light is formed, 

 with its base upon the disc and its apex upon the illuminated 

 l)oint._ Thus the highest degree of light which the source naturally 

 gives is concentrated upon each of the points exposed to the source, 

 just, as if there were but that one point exposed to it in the whole 

 unn-erae, and this cone is formed at every distance from the source, 

 and lu all directions. The converging linos wliich constitute it arc 

 not rendered fewer upon any point by the mere circumstance of 

 there bemg two or more points instead of one, nor are these lines of 

 light icwer upon the more distant point than upon the point that 

 IS nearer to the source. 



" These arc the two simple principles from which the fact results 

 but simple and obvious as these principles are, they have found an 

 energetic opponent in a writer who scorns to think that it is the 

 apparent expanse not the real cxjianso of the disc that gives out 

 the light, and that therefore, the greater the apparent diminution 

 IS, the less light is there to give out. 



"Mr. Kichard A. Proctor, lecturer and journalist, a writer full 

 of astronomical paradoxes himself, but regarding everything as a 

 paradox which is contrary to his own notions, and wlio has, in his 



journal called Knowledcjk, attacked in turn every scientific man in 

 the land, falls foul, in the number for Dec. 16, 1881, page 144, of 

 the great fact that the wholo system is equally illumimited by the 

 Bun — mainly, it would appear, because this great fact was not dis- 

 covered by himself — the questioner there and the answerer being 

 evidently the same jierson. 



" After seeking to throw a little confusion over the wholo subject 

 by affecting to think that the degrees of light seen on the disc 

 itself— seen, moreover, through our dense medium — is the degree of 

 it here spoken of as surrounding the atmospheres of the planets 

 after seeking to make this confession (sic), he proceeds to argue 

 that when the source is apparently diminished — when, without being 

 really diminished it is made to appear so to the eye (as, for instance, 

 by perspective) — then the real and undiminished source of light 

 itself really gives out, in all probability, less light to those spots of 

 space than it does to others where this apparent diminution does 

 not present itself; that, in short, an unreal (merely apparent) 

 difference in the size of the source most probably makes a real 

 difference in the light it gives. Upon what grounds he advances 

 this strange probability he declines to tell us, beyond saying that it 

 is in every case the diminished disc, and not the original un- 

 diminished disc, which must be regarded as emitting the light thai 

 falls upon the atmosphere of each planet, the feebler light pro- 

 ceeding in each case from the smaller disc, and that for this reason 

 the sun's light outside Neptune's atmosphere is truly said to bo 90O 

 times a feebler light than ours. ' If we receded from the sun,' says 

 Mr. Proctor, ' till our distance were twice as great as it is, his disc 

 would look only one-fourth as large as it does. The correct infer- 

 ence is that we should get but one-fourth of the light we actually 

 receive. Bat, somehow, Mr. Simon makes out that we should get 

 quite as much as we do at present.' 



"The fallacy of this reasoning (which is fully discussed in Dr. 

 Collyns Simon's work upon the subject) will become quite clear, 

 even to Mr. Proctor, if he will only look at the sun with his 

 telescope reversed. He will find the disc can be diminished u<l 

 infijiitum to the eye without its making the least difference in the 

 degree of light around us. He will find that, not.vithstanding all 

 apparent variations in the size of the sun, there is no real variation 

 whatever in the light he gives, and that even when the perspective 

 disc is as small as when seen from Neptune, there will, nevertheless, 

 proceed light from each point of the original un|ierspective disc t<> 

 each point of interplanetary space exposed to it, precisely as if ^ 

 there were no perspective disc, and precisely as if there were but . 

 that single point to be lighted in the Universe. 



" Now the proposition in question is (we repeat), that when there 

 is no medium to obstruct the sun's light it all goes from every part 

 of the original disc to each spot of space exposed to it indepen- 

 dently of our eyes and of all laws of perspective ; aud when a 

 writer can find no other argument against this fact than the bald 

 assertion that perhaps it is not so, and that perhaps the original 

 and real disc gives less and less light to the solar system in propor- 

 tion as it can be made to appear diminished by perspective or other- 

 wise, it is evident that such a writer must be hard set to find any 

 argument whatever for his purpose ; and this is the lii'st inference 

 we draw from Mr. Proctor's remarks. The rottenness of the argu- 

 ment he brings forward shows how utterly he is without any solid 

 objection to the discovery. 



"But again, when a fact, acknowledged to be of great import- 

 ance, has had public discussion (a prize of fifty guineas having 

 been offered for the detection of any error connected with it), and 

 has been, moreover, laid before all the leading scientific men of 

 Europe for three or four years, if, in such a case, no one comes 

 forward with a dissentient voice but Mr. Proctor, this circumstance 

 also will be apt to strike most people as very strong evidence that 

 Mr. Proctor's .irgument is not a solid one, even before they become 

 acquainted with what this strange argument is, in which he con- 

 fuses in so grotesque a manner the physical fact with the physio- 

 logical ; a blunder, however, quite in keeping with his assertion on 

 the following page of his journal (query 90) that the pressure of 

 bodies on each other is something different from the attraction of 

 the earth ! — and this is the second inference which we draw from 

 Mr. Eichard A. Proctor's attack upon this great discovery. His 

 being the only opponent of it is, even for those unacquainted witli 

 the subject, pretty clear proof that the discovery is established 

 beyond all dispute." 



[And what a discovery it is ! A globe 1,000 miles in diameter, 

 can entirely hide from any point on the sun a globe 10,000 miles in 

 diameter, ten times as far away — receiving on its surface all the 

 light which otherwise would have fallen on a surface 100 times as 

 large. Yet the same amount of light will illuminate the larger 

 surface as brightly as the smaller ! Then, again, how fooliish 

 people are to draw near a light when they want to see better. It 

 gives quite as much light farther off ! — R. A. P.] 



