Nov. 9, 1883.] 



♦ KNOWLEDGE ♦ 



293 



boundary into Pisces. She will take 72 hours to pass through this 

 great constellation ; in other words, it will be 3 a.m. on the 13th 

 ere she quits it for Aries. She will have traversed Aries by 

 4 o'clock in the afternoon of the I'ith, when she passes into Taurus. 

 Here she remains until midnight on the 16th, when she enters the 

 extreme northern part of Orion. It takes her until 11 a.m. on the 

 l7th to traverse this, and she then emerges into Gemini. Her 

 path over Gemini occupies her until 2 a.m. on the 19th to describe. 

 At this hour she enters Cancer. By 5 o'clock in the afternoon of 

 the 20th she has quitted Cancer for Leo. She descends in Sextans 

 about 3 p.m. on the 21st. At 2 p.m. the next day she re-enters Leo, 

 and it takes her until 4 p.m. on the 23rd to travel over the remain- 

 ing part of this constellation. At the time mentioned she passes 

 into Virgo. We there leave her. 



T 'f ■, , - 





" Let Knowledge grow from more to more." — Alfred Tennyson. 



Only a small proportion of Letters received can posaibly he in- 

 serted. Correspondents must not ie offended, therefore, should their 

 letters not appear. 



All Editorial comTnunications should he addressed to the Editoe of 

 Knowledge; all Business communications to the Publi.shers, at the 

 Office, 74, Qreat Queen-street, W.C. If this is not attended to 



DELAYS AKISE FOR WHICH THE EDITOR IS NOT RESPONSIBLE. 



All Remittances, Cheques, and Post Office Orders should he made 

 payable to Messrs. Wvman & Sons. 



The Editor is not responsible for the opinions of correspondents. 



No COMMUNICATIONS ARE ANSWERED BY POST, EVEN THOUGH STAMPED 

 AND DIRECTED ENVELOPE BE ENCLOSED. 



THE GPtEEN SUN IN INDIA. 



[992] — I last evening received a letter from a gentleman residing 

 at Trichinopoly, dated Oct. 2. It may be interesting, perhaps 

 helpful. 



" There has been a very curious phenomenon seen the last three 

 weeks or so in the rising and setting sun. It presents for a time 

 after rising a light green appearance, and again the same colour a 

 little time before setting. It is very cui'ious to see its colour on 

 the walls of my bed-room of a morning. The natives are in great 

 dread, fearing it portends some great calamity." S. Needham. 



[The length of time named is remarkable. — R. P.] 



A CURIOUS PHENOMENON. 



[993] — I have just seen Mr. Noble's letter in No. 98 of Know- 

 ledge, describing a comet-like appearance in the Eastern horizon 

 Ijefore the rising of the moon. 



A similar cono of light to that represented in his sketch — with 

 the exception that the tail was broader and not so long, and the 

 lines of cloud wore nearer the horizon — was witnessed here by 

 myself and several others one evening in July, about 7.30 p.m. 

 Thinking it might bo the tail of a comet, I went into the house to 

 prepare my telescope, with a view of directing it upon the nucleus 

 directly it arose, but, while thus engaged, the whole faded away. 



It was as nearly as possible E.S.B. over the Karweudel range of 

 mountains, and could not have been caused by light from a town or 

 furnace, there being nothing of the sort for miles and miles. The 

 moon rose about the same spot rather more than an hour after- 

 wards. M. ¥. VV. 



[994] — With reference to the paragraph in Knowledge, num- 

 bered 82C, and headed "A Curious Phenomenon," I have a fow 

 remarks to make. It is generally known that lightning presents 

 itself in various forms, sometimes as sheet liglitning, sometimes as 

 forked liglitning, and sometimes, but more rarely, as earth light- 

 ning. This earth lightning, instead of dropping from the sky, 

 rises from the ground, taking sometimes the form of a fiery globe, 

 and sometimes that of a fiery pillar. 1 have now before me an 

 account of one of these fiery globes which struck a nunnery at 

 Bologna, and which emerged from a large hole into which the street 

 water emptied, finally expending its fury by knocking down a portion 

 of a tower. 



I would suggest that it was a phenouienou of this nature that 



was witnessed by Mr. Noble on the 28th of last month, and re- 

 specting which he solicited exjilanations from the readers of 

 Knowledge. 1 may add that many years ago my wife saw a 

 precisely similar exhibition to the one depicted in Captain Noble's 

 sketch, when walking one evening in the fields in a rural district in 

 the west of France, many miles away from any to^vn or even village. 

 She says the sketch given in Knowledge represents what she 

 saw on the above occasion as perfectly as it she had drawn it 

 herself. I myself, about fifteen years ago, whilst driving one 

 evening in a country district a few miles north of Bolton, in 

 Lancashire, saw three pillars of fire rise out of the earth within a 

 few yards from my phaeton. The first pillar rose on my left-hand 

 side ; then, after I had proceeded about a quarter of a mile, a 

 second pillar rose on the right-hand side ; and the third one 

 appeared at the junction of two roads a few hundred yards further 

 on. These fiery pillars seemed to be, as far I can recollect, about 

 twelve feet high, and in circumference about the same as the 

 funnel of a large steamer. My groom, who sat beside me, saw 

 these appearances as distinctly as I did myself, and the same may 

 be asserted with respect to my horse, which was so terribly 

 frightened that it required all the restraints possible of reins, and 

 soothing persuasion of voice, to keep him from bolting off in a 

 frantic gallop. G. M. 



[Arago cites many cases of globe-lightning ; but " G. M." 

 scarcely makes out the connection between the phenomena de- 

 scribed by Captain Noble and what he witnessed himself. We 

 have no evidence, by the way, that forked lightning drops from the 

 sky.— R.P.] 



BRILLIANT RAINBOW. 



[995] — The most briliant rainbow I remember having ever 

 noticed was visible from here (Peckliam) on Oct. 21, at about 

 4 p.m. Both the primary and secondary bows were bright and, as 

 far as the houses allowed them to be seen, complete. Inside the 

 primary, and seeming to touch it, was a third bow, colours reversed, 

 and very faint. This sight made me look into the theory, and I 

 'find that this faint bow is the sixth. The fifth, which should be 

 between the first and second, was invisible, a circumstance of which 

 an explanation would be welcome. V. Cotter. 



NEW MOON ON SATURDAY— DAY OF WEEK. 



[996]— That the writer of the " Companion to the Almanac " 

 and the corrector of all paradoxes should himself make a slip when 

 trying to excuse one of his protcjes, shows only that he was human. 

 The occurrence of new moon on Saturday, March 24, 1859, brought 

 to light defenders of the old sayings about bad weather connected 

 with Satui-day's new moon and Sunday's full. To expose the want 

 of evidence for these proverbs was not ditScuIt for Professor de 

 Morgan, but, in further speculating on the subject, he based an 

 argument on the likelihood that the completion of the lunar cycle 

 would bring back the Saturday's moon (see pp. 195 and 196, 

 "Budget of Paradoxes"). Nineteen years later, found a new 

 moon on the same date, but, alas ! it was Tuesday, March 24, ISGS, 

 instead of Satiu'day. 



To calculate mentally the day of the week for any given date is 

 a species of number-conjuring more practically useful than some 

 recently contributed to your pages. 



The given date is analysed into four parts — (1) hundreds, (2) 

 years (%vithout the hundreds), (3) month, (4) day of month. Each 

 one of these four parts contributes a week-day equation as fol- 

 lows :— Say for Sept. 13, 1883. 



I. Hdndreds. — Divide by 4, and subtract twice the remainder 

 from 6.* 18-J-4 leaves 2 ; twice 2 from 6 leaves 2.) 



II. Year.— Divide by 4; and from twice the quotient subtract 

 the remainder, and subtract what then remains from the nearest 

 multiple of 7 (83-i-4 = 20-H3; twice 20-3 = 37 ; 37 from 42 leaves 5. 



III. Month. — The equations for the successive months are: — 

 1, 4, 4 ; 0, 2, 5 ; 0, 3, G ; 1, 4, C. They can be committed to 

 memory more easily by threes, calling them 12 squared, 5 squared, 

 G squared, and 12 squared plus 2. (September = 6.) If date is in 

 January or February leap-year, subtract 1. 



IV. 'i'lio day of the month is its own equation (13). 



These four" eipuitions of tho day of week (2, 5, 6, and 13) 

 are added together (26), divide by 7, and the remainder (5) is the 

 day of week (Thursday). If remains, it is Saturday. A rapid 

 calculator can give the answer almost instantly. 



J. Gbeeves Fisher. 



* This is the rule for New Style, which began ^on Thursday, 

 Sept. 14, 1752. Old Stylo ended on Wednesday, Sept. 2, 1752. For 

 Old Style dates add 3 to the hundreds, and subtract total from. 

 a multiple of 7. 



