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♦ KNOWLEDGE ♦ 



[Oct. 10, 1884. 



" Let Knowledge grow from more to more." — Alfeed Tennybob. 



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 eerted. Correspondents must not lie offended, therefore, should their 

 letters not appear. 



All Editorial communications should he addressed to the Editor of 

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DELAYS ARISE FOB WHICH THE EDITOR IS NOT RESPONSIBLE. 



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The Editor is not responsible for the opinions of correspondents. 

 No communications are answered by post, even THoroH stamped 



AND directed ENVELOPE BE ENCLOSED. 



SHOOTING STARS AND METEORS. 



[1437] — Permit me to remark, in reply to " Eye Witness," that 

 in the first place, it is certain that all shooting stars, and probably 

 a good many meteors, which are not heated to luminosity approach 

 so near the earth that its attraction must, for the time at least, be 

 much more powerful than that of the sun. This attraction must 

 materially alter their orbits, and, with regard to those which enter 

 our atmosphere, a further alteration is caused by its resistance. 

 In the next place, considering the great velocity of the earth in its 

 orbit and the very considerable depth of its atmosphere (the 

 resistance of which increases the further the shooting star advances 

 in it), the motion of the meteor in rushing through the atmosphere 

 may be so retarded that the solid body of the earth has cleared its 

 track before it reaches the point where a collision would have occurred 

 if the original velocities were unaltered. This, I think, would pro- 

 bably occur if the meteor was vaporised. Vaporisation by itself 

 would have no tendencj- to arrest the motion of the meteor, but the 

 moving vapour would be much more retarded by the resistance of 

 the atmosphere than the moving solid. Thirdly, it is no explana- 

 tion of what becomes of the vaporised meteors to describe them as 

 disintegrated. The question is, what happens afterwards ? We 

 can hardly suppose them to remain in their gaseous condition in the 

 atmosphere, after the great heat which converted them into vapour 

 has passed away. If not, they must again sohdify, and either fall 

 to the earth (probably in fine dust) or else get clear of the atmo- 

 sphere and pursue a course in space, which can hardly coincide 

 with their former orbits. But where did the meteors which formed 

 the great star-showers of 186G and 1872 fall ? And if they did not 

 fall, where are they now ? 



The ring-system of Saturn may have originated in the manner 

 which " Eye-witness " suggests, but whether other planets would 

 be similarly affected is by no means clear. The formation of such 

 a ring would probably depend on several causes — the mass and 

 volume of the planet, the extent and resisting power of its atmo- 

 sphere, its distance from the sun (which by lessening the sun's 

 attraction would render it more easy for the planet to attach the 

 meteor system to itself), the relative velocity of the planet, and 

 the meteors, and the angle at which their orbits intersected ; but, 

 above all, ou the number and mass of the meteors, whose orbits 

 intersected that of the planet. Our greatest star-showers arise 

 from the meteors attached to comparatively insignificant comets. 

 If the orbit of a great comet intersected that of Saturn, under 

 favourable circumstances, a ring might naturally result. Such a 

 ring, however, could hardly be formed within the limits of the 

 atmosphere of any jilanet, owing to the resistance of the latter to 

 its motions. • W. H. S. Monck. 



THE AFTERGLOW AND ITS CAUSE. 



[1438] — 1 differ entirely from " F. G.S." as to the cause of the 

 afterglow. I beg to state that, according to the incontestible 

 assertion of an influential member of the Krakatoa Defence Com. 

 mittee, I kicked up my dust into space far above the limits of the 

 earth's atmosphere ; it consequently remains suspended in space. 

 The earth has again reached that portion of space : hence I, and 

 no one else, am clearly the sole cause of the beautiful phenomenon 

 which delights the eyes of thousands all over the world. 



Krakatoa. 



[What can be more convincing ? — Ed.] 



[1439] — The sunsets and afterglow are now being repeated with 

 an intensity equal to those of last year. The first, more remarkable 

 than usual, was on the 18th of this month succeeded by others on 

 the three following days, that on Saturday, the 20th, being equal 

 to anything seen here last year. TUl last evening, the sky has been 

 overcast at sunset. The afterglow then and this evening lasted 

 till 6.40 and 7 respectively, the colour being red and orange, shading 

 off to pinky purple at the outer edge of the glow. Last evening, 

 the whole eastern horizon was, during the afterglow, spanned by a 

 pink arch, shading off to pinky purple, the glow on the higher 

 mountains being at the same time very remarkable. 



The halo or haze round the sun has been more conspicuous this 

 month, and of a deeper copper hue. On the evenings of the 1st, 

 2nd, and 3rd, the moon had a similar halo. I may add that I have 

 never once this year seen the sky of the intense bine us»al here, 

 and that I have been unable — on some days apparently clear — to 

 detect Sirins and other stars at transit, usually distinctly visible by 

 day in my instrument. On these days the solar haze seemed to be 

 of a deeper copper. 



Notes of last year's snnsets and afterglows observed by myself 

 and others were sent by me privately to another scientific jonmal. 

 but having been made the subject of insulting editorial comment— 

 the editor's apparent wish being to prove Krakatoa responsible for 

 the afterglow — I prefer on this occasion to send them to Knowledge. 

 in the hope that they may be acceptable as helps towards a solution 

 of the afterglow difficulty. M. F. Ward. 



PS. — I omitted in my letter yesterday to state that whether seen 

 from the plain or from a height of 2,000 ft. or 3,000 ft. above it, the 

 colouring of the afterglow is the same, the evening haze or mist 

 which exists in the plane not affecting it in the least. 



Partenkirchen, Bavaria, Sept. 27, 1884. 



[I have received another letter from Captain Noble on the same 

 subject, which is too long for insertion here. In it he quotes from 

 a second communication recently received by him from jlr. Neison. 

 the Government Astronomer at Natal, in which that eminent man of 

 science reiterates the expression of his great surprise that any of his 

 confreres in Europe should attribute to the Krakatoa dust a pheno- 

 menon occurring repeatedly under circumstances which rendered it 

 impossible that the Javan Volcano could have had anything to do 

 with it; in point of fact, long before the eruption ever took place 

 at all.— Ed.] 



VISUAL PHENOMENA. 



[1440]— Referring to letter 1,296, by Mr. P. J. Beveridge, on 

 " Squinting," I should like to make a few remarks which may not 

 be altogether irrelevant. 



As regards the eye becoming tinted with the complementary of 

 the colour at which it looks fixedly, I have observed that this effect 

 becomes so marked if the stare be continued, that if a person gaze 

 steadily at anything, keeping his eyes fixed on one point all the 

 while, he will soon see nothing. This remark would seem to 

 answer the question put in the second paragraph of above-men- 

 tioned article, and I think that the fact of our becoming deaf to a 

 continued sound, and blind to a continued scene, may be all referred 

 to the principle, that we can only be cognisant of any fact, idea, or 

 impression by its difference from that which preceded it (we only 

 judge by comparison). Thus, we see that monotony causes oblivion 

 of ideas, as seen in the case of persons who have been lost in some 

 mammoth cave, being foimd in a temporary state of insanity, 

 attributable to the oppressive silence reigning in these places. 



Respecting the ([uestion asked by Mr. Beveridge, whether any 

 one had effected a super-imposition by divergence of the eyes to a 

 more distant point, I may mention that this is my regular practice 

 with stereoscopic views, and could, therefore, not understand the 

 object of the wicked destruction recommended, until reading the 

 last paragraph. I think any one could succeed in doing this with a 

 little practice. All 



LIFE AFTER DEATH. 



[1441] — "Eye-Witness" represents soul as an entity, distincr 

 and independent of the body. Now, may I ask where is or was this 

 immortal entity before the body came into existence ? what did it 

 do? where are all the souls "yet to come into bodies " not yet 

 born? Or can "an immortal" thing be born? The idea of im- 

 mortality appears to me to be born of the wish for it. 



Again, I see with my eyes, smell with my nose, hear with my ears. 

 feel with my nerves, think with my brain. What can the soul do 

 without the body and the senses ? All these organs are, as science 

 teaches us, entirely destroyed in death, and used up — every atom of 

 them — to build up other and similar lives and living bodies. The 

 .soul, therefore, having no senses, again I ask what can it do ? It 

 can't see, bear, smell, feel, or think. What does it do ? How does 

 it occupy its existence ? 



