Januaky 1, 1897.] 



KNOWLEDGE. 



9 



I now took three instruments similar to Clerk Maxwell's 

 colour-box, and arranged them so as to entirely shut out 

 all the beams but one from either, and made these single 

 beams overlap one another at certain angles on a hori- 

 zontal screen. I succeeded in obtaining the fringed patch 

 of white light. 



I now took the disc painted in the three prismatic 

 colours and placed it in the stead of the screen, allowing 

 each beam to fall on its own separate colour. On applying 

 the multiplying wheel I succeeded in producing white light 

 of very great purity, and such as I had not obtained before. 

 There was no fringe ; the disc revolved in a field of pure 

 white light. 



AN OLD RECORD OF THE CORONA. 



By E. Walter Maunder, F.R.A.S. 



TWO features of a total solar eclipse never fail to 

 impress modern spectators : one, the effect of the 

 growth of the weird darkness — "awful" in the 

 legitimate and not the slang meaning of the word 

 — the other, the appearance of that strange halo 

 which encircles the dark disc of the moon when the total 

 phase is attained, and which we have learned to call the 

 " corona." 



It is not possible to watch such an eclipse, even with all 

 the knowledge and preparation which science has given us, 

 without feeling some answer of solemnity, and it requires 

 no great effort of imagination to conceive of the terror and 

 distress such an event must have caused to the ancients, 

 or to savage tribes, who did not understand the meaning 

 of the darkness, who were unprepared for its coming, who 

 knew not how long it would last, or, indeed, if it would 

 ever pass away. The " horror of great darkness " must, 

 indeed, have fallen upon such people, and it need cause us 

 no surprise that eclipses figure somewhat largely in ancient 

 records. 



Nor that the only circumstance reported is the dark- 

 ness, or some circumstance connected with it. Terror at 

 an event so strange, so threatening, so unforeseen, must 

 have, in general, paralyzed the power of observation, and 

 the statement that " the sun had been turned into darkness " 

 would seem to tell the tale completely. That amazing 

 portent was so much in itself that there was no need or 

 room for the addition of trivial detaO. 



But some amongst the ancients had a very con- 

 siderable knowledge of astronomy, and there can be little 

 doubt that the Chaldeans — to whom the invention of the 

 Saros, or eighteen years eclipse cycle, is supposed to be 

 due — had a fairly clear idea as to the cause of solar 

 eclipses. And, therefore, as they were able, to a certain 

 extent, also to predict their occurrence, the great over- 

 whelming terror which the ignorant felt cannot have been 



Fio. 1. — Miss Kate Wolcott's Drawing of the Corona. 



shared by them to the same extent. Their minds will 

 have been free to receive the impressions which the details 

 of the eclipse would create. 



f..And what would those impressions have been? We 

 must remember that they worshipped the sun, moon, and 



planets. We are not to suppose that in so doing the more 

 thoughtful conceived that the actual material sun, which 

 they beheld, was itself the intrinsic Deity. The untaught 

 and thoughtless may indeed have done so, but to the 

 cultured there can be little doubt that the sun was 

 regarded partly as a symbol, partly as a manifestation 

 of the unseen, unapproachable Divinity. Its light and 

 heat, its power of calling into active exercise the mysterious 

 forces of germination and ripening, the universality of its 

 influence, all seemed the fit expressions of the yet greater 

 powers which belonged to the Invisible. 



What happened in a total solar ecHpse '? For a short 

 time that which seemed so perfect a divine symbol was 

 completely hidden. The light and heat, the two great 

 forms of solar energy, were withdrawn, but something took 



Fig. 2 — M. E. L. TrouTelot'a Drawing of the Corona. 



their place. A mysterious light of mysterious form, unlike 

 any other light, unlike any other single form, was seen in 

 its place. Could they fail to see in this a closer, a more 

 intimate revelation, a more exalted symbolism of the 

 Divine Nature and Presence ? Just as in the various 

 Greek " mysteries " the student was gradually advanced 

 from one set of symbols to another even more abtruse and 

 esoteric, so here, on the broad face of heaven itself, 

 vouchsafed for a brief space of time and at long intervals 

 apart, the Deity revealed Himself to the initiated by a 

 higher and more difficult symbol than ordinarily. 



The symbol would vary in shape. We may take it for 

 granted that the old Chaldeans, as modern astronomers 

 to-day, had at one time ur another presented to them 

 every type of coronal structure. But there would, no doubt, 



Fig. 3. — Assyrian "King with Wings.' 



be a difficulty in grasping or remembering the irregular 

 details of the corona as seen in most eclipses. It occa- 

 sionally happens, however, that the corona shows itself 

 under a form of grand and striking simplicity. It is now 

 widely recognized that the typical corona of the minimum 

 of the sunspot cycle consists chiefly of two great equatorial 

 streamers, streamers of such length that Professor New- 

 comb was able, in July, 1878, to trace them some eleven 

 millions of miles from the centre of the sun. 



The great eclipse of July, 1878, was most admirably 

 observed throughout the United States, and a superb 

 volume of the observations made of it was published by 



