July 6, 1883.] 



♦ KNOWLEDGE ♦ 



13 



THE FACE OF THE SKY. 



From July to July 20. 

 By F.R.A.S. 



THE snn Tpill bo -watclied, as usual, for groups of spots and 

 faculae, which have recently become both more numerous and 

 interesting. The face of the night sky will be found depicted on 

 Map VII. of " The Stars in their Seasons," but there is no real 

 night in the United Kingdom until July 22. The heavens continue 

 to offer a practical blank to the observer, as far as the apparition 

 (if any of the planets is concerned. The moon is 1'9 day old at 

 noon to-day (July 6), and quite obviously 15'9 days old at the same 

 hour on the 20th ; hence she is favourably placed for the 

 observer dmring the greater part of the period of which we 

 are treating. Her south declination, however, becomes con- 

 siderable during the latter half of it. Two occultations of stars 

 occur during the next fourteen days. The first is that of the sixth 

 magnitude star 28 Libra;, which will disap])ear at the moon's dark 

 limb at 11 h. 11 m. p.m. on Jnly 14, at an angle of 119° from her 

 vertex ; but she will have set ere it reappears. The second occul- 

 tation occurs on July 17, and is of B. A. C. G,081 (also a star 

 of the sixth magnitude). This will disappear at the dark 

 limb of the moon at 11 h. 31 m. p.m., at an angle of 133° 

 from her vertex ; and reappear at her bright limb at 12 h. 41 m. 

 p.m. at a vertical angle of 277°. During the next twenty-four 

 hours the moon travels from Cancer into Leo. There she remains 

 on the 7th, passing into Sextans during the early morning of the 

 8th. She leaves Sextans and travels into Leo again about 3 a.m. on 

 the 9th. She remains in Leo until about 6 a.m. on the 10th, when 

 she moves into Virgo. She does not leave this constellation until 

 about four o'clock in the afternoon of the 13th, when she crosses 

 into Libra. There she continues until about 6 p.m. on the 15th. 

 In the course of the next ten hours she travels across the northern 

 part of Scorpio into the southern portion of Ophiuohus, where she 

 continues until six o'clock in the evening of the 17th, when she 

 enters Sagittarius. She remains in Sagittarius until 8 a.m. on the 

 19th, and by noon on the 20th has travelled into Aquarius, where 

 we leave her. 



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



Only a sviall proportion of Letters received can possibly he in' 

 verted, Correspondeiits must not he offended, therefore, should their 

 letters not appear. 



All Editorial coinmunications should he addressed to the Editor op 

 Knowledge ; all Business communications to the Publishers, at the 

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



DELAYS arise FOR WHICH THE EDITOR IS NOT RESPON.SIBLE. 



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

 payahle to Messrs. Wyman & 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. 



RATIONAL DRESS. 

 [864] — The female members of my family complain that 

 " Pedestricnne " fails to describe the only part of her dress which 

 they want to know how to make, viz., the " divided skirt." They 

 would like to try the costume recommended, but ask for a detailed 

 descrijition of what " I'edcstriennc " means by a " divided skirt." 



Cyclist. 



GENEALOGICAL PUZZLE. 

 [865] — The following may amuse some of your younger readers : — 

 A and B are two persons in no way related — of no consanguinity. 

 They meet, and one asks the other : — " How is our brother Tom f " 

 [Tom being brother to both of them.] Show how this may bo. 

 "j.M. 



LETTERS RECEIVED AND SHORT ANSWERS. 

 J. R. (Malta). — As to " Stars in their Seasons," note advcrti.iie- 

 ments. — Moke Light. Yes ; if your facts are " firmley established," 

 you can — as you say — "afford calmley to wait." (You seem, in- 



deed, to take your e's pretty freely.) I really cannot say who is 

 " the best living authority on the subject ; " not being quite clear 

 what subject you mean ; you only mention your " facts of the 

 weather," which you apprehend I " may think ronsencical " (here 

 you are clearly " half c'a over "), " and therefore worthless" (which, 

 if nonsensical, they probably would be) ; but I don't know what 

 they are. However, on nearly all subjects there is variety of 

 opinion as to who is the greatest authority. As you say, " some 

 old one man and some another." — G. Mackixl.w. Thanks. Both 

 statements relate to cannon balls flying athwart the range of vision, 

 though this is not expressly stated. In mid-flight, which was what I re- 

 ferred to, a cannon ball has not a greater rate than 500 yards per 

 second, even when its initial velocity has been as great as 900 yards 

 per second. I have myself frequently seen cannon balls in mid-flight 

 from behind the gun. — A. Parnell. Many thanks; an occasional 

 article might find insertion ; but, as you may have noticed, space 

 is crowded. The subject is full of interest.— A Learner. Six 

 inches square = 3 in. by 1 ft.; that is what was meant. — W. B. 

 No ; the question whether a wager is won or not is quite out of om- 

 line. Of the wager in question, one can only say that it was vulgar 

 to offer it, unwise to accept it. Science has nothing to do with 

 wagering, except to say that all forms of gambling are essentiallj- 

 immoral. — T. J. Dewar. Your manner is so rough (not to say 

 rude) that though your matter has been in part useful, it is scarcely 

 worth getting at through such breakers. Hereafter, I fear your 

 handwriting (or signature, if handwriting not recognised) will cause 

 our trusty sub-editor to "basket" yourcommunications rather sum- 

 marily. If a passer-by flings a stone through my drawing-room 

 window, he would probably be removed by A 21 before I had learned 

 from him that he only wanted to give me his opinion about the kitchen 

 chimneys. I trust I make myself understood. Yon fling "awful 

 rubbish" at my head or that of a valued contributor — 'tis the 

 same thing : do you suppose I go beyond that to read your de- 

 tailed criticisms ? — E. A. Hoeson. Many thanks; the Indian obser- 

 vatory most interesting. There is a description of it in one of the 

 earlier volumes of the Penny Ma,jazine.—1^E. (1) The position of 

 the earth's axis varies sensibly (to instrumental tests) from summer 

 to winter, through the effects of precession and nutation. (2) 

 Try " York's List of Astronomical Diagrams." (3) See ad- 

 vertised list of lectures. (4) Algebra certainly essential. — H. 

 Malim. Calculation given this week. — A Worthy Correspon- 

 dent. Many thanks.— Tim J. W. Cannot answer by post. — 

 G. Duncan." Thanks; your communication submitted to the 

 proper persons to decide about such matters. — G. Jordan. The 

 movements of the moon, as seen from all latitudes, north and 

 south, have been in precise accordance with accepted theories. 

 Why should the moon not be seen every month in the Arctic 

 regions, seeing that every month the moon is half the time north 

 of the celestial equator r — J. M. Thanks. Puzzle not very 

 difiBcult. In my own family "our brother" appears in another 

 way. Thus, if widower having a child marries a widow who also 

 has a child, a son by this marriage is for his child and hers " onr 

 brother," though they are in no way related by blood. — Zoologist. 

 Have no idea. — Mary, Housem.aid. Not bad, my dear sir, not bad ; 

 nay, " the stars and their seasonings" very good— rather too good 

 for " Mary, Housemaid." The " combination " [of J accidents 

 impossible". N.B, Anyone who would spell "minute" with two 

 " n's," would spell it with two " i's," not " minnute." Both mw 

 " i's" open so that I C through U with E's.— S. Truro. See solu- 

 tion this week. — G. W. Really we do not know what you ought 

 to do under the dismal circumstances you mention. When " you 

 start a meal you scarcely know when to finish ;" no wonder tliat 

 at night you " feel weary, and also your eyes are heavy too." 

 The best advice we can give you about over-eating is " Don't." 

 But we are not medical. — W. Fitzroy. We do not know how your 

 namesake acted ; and the question is not one we should like to 

 ventilate here. — Equites. Reallj', some readers ask curious ques- 

 tions. You say that when riding, the sides of your knees get sore, 

 and you ask how to avoid that trouble. Keep on and it will go off. 

 Besides, its the best way to keep on. If this fails, try riding with 

 the other sides of your "knees towards the horse ; you have no idea 

 how effective that will be (and also look). But why do you ask 

 7116 this particular question H Now, if you were to try the editor 

 of Nature, who compares the motion of the earth to the motion of 

 a galloping horee on a smooth plain, of which motion the rider re- 

 mains — he says — unconscious, you might learn how to save your 

 knees. I have never reached this stage in riding, but still remain 

 emphatically conscious of motion during a gallop, even over the 

 smoothest fields. 



Sub-Editorial. 



K. L. W., Perple.\ed, J. Hawkins, M. E. W., H. N. Medlicott, 

 K. R. and N. M., Langu.\ge, Halloween, and others. Unsuitable 

 — T. J. Dewar (later communication). See editorial remarks. 



