KNOWLEDGE ♦ 



[Aug. 14, 1885. 



the less tint could get through to the moon, and Herschel 

 distinctly speaks of the tint as transmitted. When 

 recently the twilight glows were particularly ruddy 

 the sun himself looked greenish. 



It should not be necessarj-, I need hardly say, for me 

 to defend Sir John Herschel's explanation against Mr. 

 M. Williams's interpretation, which in reality reduces it 

 to something scarcely distinguishable from absurdity. 

 Wliat Herschel really says, is, — that our atmosphere, 

 ^\ liich through its normal absorptive power makes the 

 sun look red when setting, must make him — that is, his 

 distorted image — look doubly red as (supposed to be) 

 seen from the moon ; fur while we see the setting sun 

 through a certain range of our atmosphere, the imagined 

 lunarian would see the sun (much reduced in ajjparent 

 size and strangely distorted in shape) thi-oitgh double that 



Mr. Willid 



21,1, 



ust really nut ask any one ■« ho undt r- 

 1 1(1 iKiiionstrable interpretation of 

 I 1 rmit the existence (as a li\ i> 

 \\ hich he first set up as '• the 

 , . I . MrJolmUer.sehel" andth.n 



'.,U.lu,\UmshUv in the U.nthman-^ 



Tlii 



,.11 I , 



;plam f, r . 

 stood clejrh ' i 

 the same ti 



and physic- ■ I 



the consider.Umu^ ;u tu illy ii 

 3eIf-glo-i\ ing tufaceou' 



. Mr. Wil 



.n,.), and t 



IklK 



s for s 



ippo 



maybe left to itself. 



is tufaceous, but manj- for sujiposing otherwise; I can 

 see no reason fur sapposing that " a tufaceuus lunar sur- 

 face if it existed would become self-luminous under solar 

 radiation,'' but on the contrary I find evidence, in the 

 thermometric observ,iti'in«; liii tlw li-. t^til lunar ecliji.'-e 

 visible in England, a Pi '1-1 ■ m ■ ^ the reverse. 

 But I do not think tl 



As for Mr. William. - , \.n .,_ s ,y that all 



experiments yet made in the ^va^- oi measiiring the 

 moon's radiation of beat are entirely inconsistent with 

 them. So much the wor.se, he may think, for the 

 experiments. I take a diffurout view. 



I ul.j^.rt to Mr. Williams's st::,t.,-mrut that I and others 



L'r, 



observational—on which I based them, in lecture's 

 delivered before the Royal Institution at M;iJiehester (the 

 syllabus of each lecttire is preserved in the records of that 

 institution), several months before the '-Fuol of the 

 Sun" was ptiblished. It was in that ^^<n■k that Jlr. 

 Williams published his views. How lun- he had enter- 

 tained them, or perhaps talked about them, befm-e, 1 d.. 

 not know. But I know that I had never heard of his 

 holding them, till long aft«r I had publicly discussed 



I do not say this as caring two straws about priority 

 in the matter. I have always pointed out that Buffon 

 e.T.me long before any of us in the idea that Jupiter 

 and Saturn are fiery-hot planets. And very likely others 

 preceded him. Sir Isaac Newton certainly showed long 

 before Buffon that larger masses are longer than smaller 

 ones in cooling. But while only children and simpletons 

 are concerned about priority in such matters, 1 emphati- 

 cally object to being described as accepting Mr. Williams's 

 views, in presence of the fact that I have never referred 

 to him as having in the slightest way or degree suggested 



the views I hold. If I had borrowed from him, my whole 

 conduct in the matter would have been excessively mean, 

 and therefore exceedingly foolish. I object to being 

 presented as either one or the other. 



Let me remark, in conclusion, that !Mr. Williams twists 

 a remark of mine quite out of it.s real nieaning when he 

 represents me as saying that " 1 9-20ths cif his ' Ftiel of the 

 Sun ' is out of the pale of science." Every one would 

 understand that to mean that I considered nearly the 

 whole of his book as unscientific, as inconsistent with 

 known scientific facts. My actual words were very 

 different, and cottld not be understood in that sense, — I 

 said '-I doubt even if 19-20ths of my friend's 'Fuel of 

 the Sttn ' must nut be res'arded as otitside the fairly- 

 ddinid limit, . f til. tiil.l.f Un..\Nlul-u.- I am satisfied 



that nu .in. iiii.l i~l 1 un t.. mt .11 lu.nu than that some 



such [.It] 11 . f .\1 W ilh.ms. ,1,,, 11, s must be regarded 

 as n.,t 1. 1 , - oi.i^ I I . uj. iiuth- Ills hypotheses are 

 fui til I ,1 I , I, but thi.s i.s not saying that 



tin \ ' 1 1 still less is it saying that 



-Ml \. Mired that if one-twentietb 



uf tin 11. \\ I 1 -hall come to be regarded as 



et.talili-li. It I ', is well worth the praise 



whith h. , , . -.. I ,. iks Lyellgave to it. Con- 

 .suUiinn tluii maii^ ill t\tn Xewton's ideasabout physical 

 matters have not only nut been established or confirmed, 

 but have been definitely disproved, Mr. Williams could 

 hardly hope tu be rii,'lit all throtigh or even in the greater 

 part uf his w. ik , -nil 1. — t.udd he exj.Lct his hypotheses 

 to li.' i/Z,,.. ., I, iKb.l a- . >t,il,lished truths,— that is, 

 within th. f.nh.l. I.in 1 In. Ills, f the known. 



:^lr. Willi ,m-" niijit ln.\i added that "the idea pro- 

 phetically sugge.sted by Sir Isaac Newton " was widely 

 known at th"e time when it was started, and (unlike 

 Newton's theory of gravitation) was somewhat profusely 



TEICYCLES IN 1885. 



By John Browxino. 



(Chairman of the London Tricycle Clul.) 

 rXSAFE TYRES. 



SOME yrai's ao-n a distinp^uished man of Science com- 

 mittu.l suicide. Nu light could be thrown on the 

 cau.sc fur lii.s doing su. Speaking to a well-known 

 physician on the subject he said the suicide was caused 

 by suppression, " the man had never given vent to his 

 feelings." Now as I do not wish to die of suppression, 

 I pr. ijiose tu uxprtss my feelings freely on the subject of 



Hublit r tyi.j- .iu-lit clearly to be made to stick firmly 

 on to uur wliuels, liut they are now generally made to 

 come easily C'ff. Considering that a tjTC is most likely 

 to come off when the machine is running down a steep 

 rough hill, it is wonderful to me that we have not had 

 more accidents from this source than have happened. 



Riding one day "along the Brighton road, I saw a strange 

 object coming towards me, which looked like a small cart 

 with the wheels uppermost. On coming closer I found 

 that it wn= n -j-i-antic labourer holding a tricycle, with 

 oOiii. ■■ : ' .nns'-length above his head, and in 



this 111 • . - it along the middle of the road. 



" That s a 11 ;. h. said I, as he was passing by. " Not 

 for me, ' sanl the gi.int, grinning from ear to ear; "it 

 will get me and my kids a dinner to-morrow." " Wiere's 

 the rider ? " said I. " They've put him in the train at 



