552 



♦ KNOWLEDGE * 



[JasE 26, 1885. 



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THE RECENT LARGE SUX-SPOT. 



[1778] — The splendid spot on the sun's disc last month has been 

 succeeded by two other fine ones. I enclose drawings o£ the 

 most important, to show the rapid change that occurred in the 

 short interval of two days. This spot appeared on the E. limb on 

 the 6th of this month. 



years. I believe the flaming sword of Eden to be a mythic tradi- 

 tion of an actual occurrence ; and that would go even further 

 back. The Arcadian assertion was hardly a " myth," in our sense, 

 though no doubt a ^nythos. 



The High Rocks at Tunbridge Wells, at any rate, do not dis- 

 credit it ; for they must have been abraded in almost historic times ; 

 and not by tides so much as by storms : their face is peppered by 

 spray-drops as by small-shot. (One would say, indeed, that the 

 stone must have been soft, or the spray corrosive, to make such 

 marks.) Besides, the sun raises tides also. 



The moon's diameter is one-half that of liars, two-thii'ds that of 

 Mercury. Xo one, therefore, could see any incongruity in her 

 journeying alone, as we do see in the case of the asteroids. In a 

 word, she is the only attendant orb that is not a mere speck com- 

 p.ired with its " big brother." Mr. Proctor has called her a 

 " companion planet," to emphasize this peculiar proportion. She 

 is big enough to bear a drama like our own history ; none of the 

 other satellites are,* or the asteroids. 



I am at a disadvantage in having no books to refer to as to Mr. 

 Mackie's figures re aqueous vapour. He may be right in saying 

 that all the water we see through in the air, would, if condensed, 

 be much less than a foot in thickness ; but I guess that condensa- 

 tion is not essential to its blueness becoming visible. We look 

 through many miles of closely-packed spherules (or bubbles) of 

 distilled water ; and this may very likely show the colour. A 

 Scotch or Irish mountain looks very much bluer than a French one : 

 I should say because of the greater humidity. Nevertheless, since 

 water is itself nine-tenths osygen, this may well be bine, as Mr. 

 Mackie thiuks. 



What I meant about oxygen, re Mars, was that bis air may be aJl 

 osygen, or thereabouts ; in which case he would be far more life- 

 sustaining than we ever were. 









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8th June, O.iu p.m. (Power 00— Direct). Uth, 7 p.m. (Power VlQ — Direct). loth, CIO p.m. (Power 120 — Direct). 



Showing the change in the interval of two days. Apeiture, 3i in. Wray. 



On the 9th, the definition being good, the fine runs (?) of faculai 

 through the penumbra were very distinct ; at 9 a.m. there was a 

 bright and sharply-defined tongue, stretching well towards the 

 central mass of f acute ; at 1 a.m. only the faintest trace of it could 

 be seen. On the 10th, at 6.40, on the squared disc of the screen, 

 in eitreme length it appeared fully 1' 30". To-day, the 12th, it 

 is divided into two fine spots ; the largest is 1' in length. 



From April tc present date, the fine groups and spots we have 

 had are, I think, for size, variety, and general interest, fully 

 equal to those of last summer. G. L. Brown. 



Stirling, June 12. 



LUNE.S. 



[1779] — In reply to Mr. Mackie (1713) I certainly do not 

 helieve the Arcadian's tradition of their pre-lnnar origin ; I wrote 

 *' this of course is an extravagant paradox." But a man may 

 believe it, it he likes ; there is nothing impossible in it. It is not 

 an origin " within the traditional memory of man," if by that is 

 meant the ascertained length of tradition; this, however, does not 

 bar the possibility of a fact being so handed down, say, ten thousand 



There is no " argument " in my may-bes. My anjument was that 

 aqueous vapour proves heat enough for life. 



Mr. Proctor has described the earth as being "greenish-blue" 

 when viewed from the moon. 



Does Mr. Mackie mean to say that oxygen and hydrogen cannot 

 be frozen ? We have barely got oxygen to the fluid state, and 

 suspect we have solidified hydrogen when alloyed with palladium ; 

 but surely all matter can be either soUd, liquid, or gaseous. The 

 cold of space, I fancy, would solidify oxygen ; or anvthing else. 



I cannot conceive any reason why the Pyramids "should not last 

 as long as the earth itself. The pyramid is the solid of greatest 

 stability ; they are therefore more durable than any hill. In an 

 airless, waterless world, like the moon, what could destroy our 

 great human works ? Nothing, but the alternate roasting and 

 freezing of day and night. Would that alter general outlines, such 

 as ramparts, river-beds, &c. ? 



* Jupiter's Satellites vary in diameter from 2,200 miles (the 

 Ilnd) to 3,700 miles (the Illrd). This latter is really not so very 

 much smaller than Mars, while Saturn's Satellite, Titan, is notably 

 larger than Mercury. — Ed. 



