412 



KNOWLEDGE 



[Mabcu 10, 1882. 



cTcn in iiiiicli liitpr tiinoH tliaii tlidHi- ynu mptition, no tlie poliir 

 coniitcllutioii, oxoi'i't liy llio I*li(piiii-iiiiiH, wli<> tCHik tlio Hiiiallcr 

 circling of tlio Cyiiomiro for tlipir {piiilo. Thr> mution of 

 tho npHiiics in no wrv nffi'cis tlio ]iri'ccB8ionnl period. — T. Vf. 

 Hope one dny to ffivo such an ftrtido. — W. St. C. Hok- 

 CAWKN. A pnppr on Clinldpnn Fcstivnia only delayed. "Omit- 

 tanro i» no (piittance." — SrFri-i.vM. \Vc cnn, however, live in nir 

 mrofled onou);l> to support coniliiistion so ill that a bnd lire 

 would go out in it.— C. T. II. Nay, they do not neutralise onrh 

 other; the parts illuminated on tho slant look less hrif^ht, eniis.^inn 

 diniiuifiliinf; as cosino of onglu with normnl to surface. Taking 

 shot for mcdieine must, wo agree with you, bo a dangerous practice, 

 though not nccpssorily rery dangerous. Luckily, tho ra-rntti does 

 not get all it might get, or scnrccly a child would grow^ tu maturity. 

 •^Unsatis'FIKD. The pres.sure upwards is ecpiivftlent to weight of a 

 column of air as largo as mouth of glass, and 100 miles or so high 

 (reaching, in fact, to tho limits, if such there be, of tho ntrao- 

 sphere) ; tho downward prossure is that of the wine-glass fnll 

 of water. A column of water about UD feet high can bo sup- 

 ported in this way, a column of mercury about 29 inches 

 high : 8o that yon might fill your wineglass with mercury, if suitable 

 snbstanco were placed over it. — Ji'mbo. Tho fancy is a queer one. 

 I can SCO that it might prove very useful in keeping account of 

 nmnbers. Like you, 1 have the numbers in sets from 1 to 12, then 

 to 20, then tu 30, then to 50, but after that I do not go straight to 

 100 but stop at 80. They do not, however, go in a bent line, as 

 with yon, but in a set of verticals. — W. A. F. Have never heard 

 that tlio Jordan was for a time stopped up by masses of rock falling 

 down, but as half Niagara was once for a wliile stopped (so they 

 say), it seems conceivable that the same might happen to another 

 river. Hojio your question is not meant to infringe our rule about 

 science and religion. — F. IlErBOCRX. You conld only now obtain 

 Button's " Recreations" at a secondhand bookshop (unless, perhaps, 

 our exchange or si-tpcnny sale column might help you. — Excelsior. 

 Oouff ! here comes a long one ! First, you are quite right. The 

 objection was first advanced by Tycho Brahe : the answer is that 

 the orbit of the earth is so utterly insignificant compared with the 

 distance of tho fixed stars, that no such effect can be recognised, 

 except in the case of the very nearest stars, and then only with tho 

 most powerful and closely-measuring telescopes. Thus, Alpha 

 Centauri, being only at the trifling distance of 20,000,000,000,000 

 miles, describes an ellipse having a major axis nearly 2 seconds of 

 arc in length, one-93(3th of the moon's apparent diameter. 2. 

 Twinkling of fixed stars duo to moisture in our air. 3. Do not 

 know why expeditions are not made now to South Pole; conditions 

 there probably not similar to those at North Pole ■ — more ice, 

 Maury says more land. It is also a longer journey, except 

 from places in southern hemisphere. Uranus is now very 

 favourably situated for observation, and visible to naked 

 eye. 4. The satellites of Mars arc utterly beyond the range 

 of a 3-inch achromatic. 5. Spots oftener seen than not, except 

 at the time of minimum, when sometimes for months together 

 none are seen. 6. Cannot show planet's paths now the whole sky 

 shown in a single map. For reasons we are obliged to keep the 

 block free from anything not belonging to the stellar heavens. The 

 zodiacal map does better in every way. To see Uranus or Nepttme 

 to tho least advantage, a good telescope is wanted, and if a map is 

 trusted to show where tho planet is, it must be on a much larger 

 scale than our star map. This applies also to tlie nebulse, except 

 those visible to the naked eye. Am glad to hear you have been so 

 thoroughly well pleased with tho telescope yon obtained from Mr. 

 Bateman for the small price of £5. 15s., "being and doing all 

 that is stated of it in the advertisement, and more too." — Anxious 

 OxE. If there is the danger you fear, it is far too serious a matter 

 to bo trifled with. Wo should bo wronging you if wo inserted 

 your letter for casual reply, and we have no right to ask 

 medical men, especially mind doctors, to discuss the matter. 

 Indeed, we know they would not do so (because they know they 

 could not properly do so) without careful study of the case. Pray 

 believe that if wo could do anj-thing, rightly, by which your anxiety 

 might be relieved, we would most willingly do so. One thing we 

 can say — the symptom you describe should either lead you to seek 

 medical advice, or you ought not to allow it to worry you at all. A 

 doctor would probably tell you how much you should notice it, and 

 with what object. But merely noticing it, ami being worried by it, 

 can do nothing but harm. — J. 0. Lindsay. Thanks for extract. 

 The publishers will probably issue covers for binding. A yearly 

 volume would be too thick. Taking twenty-two pages per number, 

 without advertisements, there would be l,ll-4 pages ; far too many 

 forasingle volume. — James Ukkinsox. Thanks forthe microcrosm ; 

 but the article on Sound is written by one who understands not. — 

 J. V. M. Yon seem to misunderstand my remark, that one of 

 OUT contributors was "not writing for" a correspondent (who 

 objected te his reasoning). No sneer as to that correspondent's 



capacity was intended. 1 trust I am incapable of such rudoncaa. 

 I meant aimply what I said, that Ur. Wilson'R rcaitoning waa not 

 direct<-d to miet the particular objection urged by that objector. 

 You think scientific men lieland each other too much. Is nut that 

 better than belittling each other? Would yon havo them likn^tho 

 I'rofcHsor of Greek, who wished an opponent " 'confounded '(for 

 his theory of the irregular verba"? I cannot admit that Dr. 

 Draper did not orguo honestly. Ho woa a hard hitter, but honirty 

 itself. Tho cago you cite i» not very «eriou«. Draper aaya I'lli'- 

 was not answered, and Ilacon said I'ilato would not stay for mi 

 answer ; do you know which opinion was right ? You go on to 

 object to stories about animals. You say. What would acientific m. n 

 say to evidences of religion consisting of stories of f>ious men. * 'ur 

 stories of animals are not meant as evidences of science. Then y.ii 

 think ourarticles too short, iiut others want variety. Your litter 

 does seem rather wandering, but doubtless " the gaps arc causal ny 

 suppression before birth of much that you wished to say." — 

 K. W. P. Both papers received. Thanks. Great pressure ' f 

 matter only has prevented our using them yet. — U. W. J. .Staf- 

 mcnt about tides in Chrislian Ol«be utterly wrong. .Scientilio 

 authorities differ as to details, of course ; but none sujiport tho 

 ridiculous statement you quote about "geological time approaching 

 tho limits," &c. — M. H. JinoK. Sorry ; but letter reached us only 

 when No. 18 was already in type. — SiBlfs. Statement in Times 

 ])robably near the truth. From best estimates, Sirius gives out 

 about 300 times as much light as sun (at samo distance), which 

 would give surface 300 times as great (if of same intrinsic lustre) ; 

 diameter about fourteen times as great. Of course, this is but 

 an estimate. — F. Matin. Thanks. — A. A. Feegcsox. Smoke and 

 fog best seen where light was, in cases cited ; not attracted by 

 light. The theory impossible. — C. A. C. Theory not reconcilable 

 with evidence of former existence both of water and air on moon. — 

 CoxsTAX.s. In such a subject. Dr. Ball was obliged to assume either 

 that readers were acquainted with those laws, or would take them 

 for granted. Your questions chiefly relate to the more doubtful and 

 perplexing matters. You may see from my article in Contemporary 

 Review, and hereafter more fully in Gentleman's ilayazine, that there 

 is room for considerable variety of opinions as to details. — G. S. 

 Thanks ; but answer about lightning too vague. — W. Ceisp does not 

 consider tho evidence of Mallicolese skull so decisive against 

 phrenology as Miss Buckland suggests (in passing) that it is ; con- 

 volutions not stunted in growth, but forced in other directions. He 

 notes that capacity of Neanderthal skull cannot be estimated, as it 

 is a mere skull cap. — J. F. Lawrence. Should advise you not to use 

 copper bowl for lemon-squeezer until thoroughly retinned. — F. NoiB, 

 Hope you will occasionally send translated extracts from Al Muktataf. 

 Of course, I understand Arabic perfectly, but " faitcs commo si je ne 

 le savois pas," as M. Jourdain says. — An Engineer writes plea- 

 santly-worded note explaining that "F.K.A.S.'s" remarks about 

 ice had seemed to him insufficiently clear. — A. R. Senxett. Do not 

 know ; cannot answer correspondents per letter. — Tabanaki. Wo 

 may hereafter publish some southern star-maps, but at present our 

 hands are full. You see we italicise words in question, at your 

 suggestion, and may hereafter adopt the system, if printers do not 

 object. — F. F. PoERELL. Red Sea was once thought to bo higher 

 than Mediterranean ; disproved first by measurement, then em- 

 phaticallyi by canal. — H. L. MAcquARP. Nos. 2 and 3 quite out of 

 print ; Nos. 1, 1, 5, 6, 7, 8, and 9 not very far from it, or might 

 reprint 2 and 3 ; as it is, it would be useless. — F. C. S. Will 

 try soon to find room for " Wood Gas," but " Beet " is waiting. 

 In fact, wo are choked with matter at present. — Alei. F. 

 If you read Sir J. Herschel's essay on "Light" ("Familiar 

 Science Essays)," you will see what a very diflScult question yours 

 is. — A. W. Buckland gives for benefit of " Experto Crcde " address 

 Professor Rudler, Jennyn-street Museum, for information about 

 mineralogical objects. — A. J. D. saw cat on sill of fanlight over 

 door, who presently lowered his hind legs, and, lifting knocker, let 

 it fall, walking in when door was opened. — Daleth, T. A. Prestok, 

 R. MAcriiEEsoN, and others. Thanks, but query already answered 

 when yonr reply came. — W. Middleton Butters says in " Pig and 

 Whistio"apig == a cup or bowl, and whistle = wassail ;" Bear and 

 Ragged Stump," crest of Warwick, the King-maker; in "Magpie 

 and Stump," mag = large coin, guinea ; pie = pay; and stump -■ 

 be off.- — J. T. B. Ere long electrical matter will be dealt with aa 

 fully as possible. — Leo. U. Walker. Afraid to publish your sug- 

 gestion, lost some mother should be tempted to squeeze "baby's" 

 brain to make a chief of him ; what a terrible thing if a father 

 should find mamma or "nurse" >vith copy of Knowledge before 

 her carefully trying to squeeze baby's head into semblance 

 of young Mallicolese chieftain ! — Asiatech Botaxist. Questions 

 about preparing colours for magic -lantern slides and plant 

 collection require articles to themselves. — Miss J. Yorjio. 

 Thanks, but we havo a surplus of original stories. — ARTnCB E. 

 Paluek. Thanks. I ought to have added that when I am pressed. 



