430 



KNOWLEDGE ♦ 



[Nov. 21, 1884. 



before the snu rises ; and that the criojsou tint is often apparently 

 upon the ground of the shy itself, and not upon clouds, as in an ordi- 

 nary sunrise. Opifer. 



Nov. 10, 1884. 



[It is, of course, the characteristic of these fore- and after-glows 

 that they appear long before the ordinary dawn and after sunset : 

 showing evidently that the light must be reflected from something 

 at a very great altitude in our atmosphere. The interesting and 

 important question is : What is that something ? The cause, 

 whatever it is, has been in operation for at least a year and ten 

 months. There seems to have been a splendid foreglow visible in 

 Paris during the early morning of Nov. 10. — Ed.] 



THE WEATHEE OF 1665 AND OF 1884. 



[1513] — Have any of your readers noticed the similarity between 

 the weather of the present year and that described to have prevailed 

 during the great plague in London ? We are told that the summer 

 was unusually hot and fine, and the account of the afterglow and 

 the crimson glories of the sky would exactly describe what we have 

 seen during tlie last twelve months. We have had no plague, but 

 there have been the outbreaks of cholera in Egypt, France, and 

 Italy. Can this have been only a coincidence ? On the other hand, 

 the winter before the plague was very severe, and the atmosphere 

 appears to have been more dry and stagnant than it has been this 

 year. K. 



A SPLENDID GROUP OF SUN-SPOTS. 



[1514] — -As we have had of late much to interest us in the 

 activity displayed on the sun's disc — rather against "oflScial" 

 orders — I enclose the drawings of a splendid group that I have 

 done in the interval of three rotations, which is interesting from the 

 fine forms it takes from the straight to the undulating, then to the 

 more detached, still showing a relative affinity. 









;\ 



■tp. 



Sept. 13, 3 p.m. 





<y\" 



, %■ - 



'jti- 



'g^f^^^^'H^: :■■■ . ?St, " 



Oct. 5, 10 a.m. (Definition splendid). 





Oct. 29, 9 a.m. (Screen definition not good ; air unsteady). 



Change in a Group of Sun-spots, in the interval of three Rotations. 

 Drawn at the Screen. Power 120, Wray, 3^ in. 



Geo. L. Bbown. 



LETTERS RECEIVED AND SHORT ANSWERS. 



Dr. Geoth. You invited my candid opinion on yonr theories, ami 

 I gave it. Now you modestly ask me to insert five sheets (!) of 

 your reasons for adhering to your own notions. I cannot possibly 

 afford the space. There is a growing evil to which a peremptory 

 stop must be put. It is this : that every one whose literary work 

 or pseudo-scientific guesses are unfavourably commented upon here 

 seems to have the idea that he is entitled to occupy columns of 

 Knowledge in reiterating his ideas. A little more of this, and no 

 paradoxical or quasi-paradoxical work will ever be noticed again, 

 and the authors of such must seek some other form of advertise- 

 ment. — Some CoRRESPOMiEM of artistic proclivities sends a picture 

 of " K. A. P." coming condignly to grief in — or out of — a flying- 

 machine. By way of emphasis, the liead of the said R. A. P. 

 is coloured green as he moves horizontally, and blue as he is 

 ascending. Like Peter, the policeman, in the " Bab Ballads," 

 the limner " was a meny, genial wag, who loved a mad conceit." — 

 Meteor. Scott's " Meteorology " in the " International Scientific 

 Series " is excellent. So is Buchan's " Handy-book," for practical 

 information. I do not fancy that readers, as a rule, seem to care 

 much for meteorology. The Weather Maps published in our earlier 

 volumes apparently excited but little interest. The solar promi- 

 nences are uprushcs of glowing gas, chiefly hydrogen. See 

 " The Sun," published by Messrs. Longmans & Co. — J. FEEcrsON. 

 The " Comozants," or " St. Elmo's Fire " of sailors, is simply a 



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