106 



KNOWLEDGE • 



[Dec. 



1881. 



QnsJlurro to ConfEfponticntsf. 



•»• Cemmunientiona rAiVA art to rrrficr fitrti/ attnitioH fhould be addrtinfd tv the 

 Klitor nf KICOWI.IDOII, 71 and "6. Oreal Quern.itrefl, London, ll'.C. 



IllNTa TO COBRRJil'OSDKXTH. — I. jVo quettiont aaking /or geirntific ittfortuation 

 can le tintirfred throuffh the pout. 2. Lettcra aent to the Editor /or corre»ponJent» 

 cannot be /oncarded ; nor can the nainet or addreeeee q/* correapondent* be gicen in 

 aH'ieer to private inqitiriea, 3. yo qucriea or repliea aavoitring q/* the nature n/ 

 adcerttaementa can ba inaertcd. 4. Lcttcrt, qucriea, and replica are inaerted, unlraa 

 contrary to Rule 3, /ree o/ ckari/e. 6. Correapondenta ahriuld write on one iiile 

 O'ltit of the paper, and pnt draieinffa on a aeparate lei{f. H. Eaeh letter, qucn/, or 

 replf ahould have a title, and in repli/inei to lettera or qucriea, re/erence akouid be 

 made to the number qf Utter or quert/, t)te page on vhich it appeara^ and ita title, 



Jonn Hautdeit. Lot us take it for (granted that I am the "coward and sneak " 

 you oonsidor mo ; '* my fripnd" the eminent naturalist you name (whom I have 

 never met in my life), "a cheat, a swindler, and a'^huflUn^' cur," and our 

 learned societies "seltlsh, dishonourable, and mischievous conspirators." Ohlige, 

 also, by noting outside vour letters an address to which they can I>e returned.— 

 Kditob of Bbitisii dnsss Magazinb. Manv thanks.—.!. Baxrndell. In 

 saying that the coincidences appear to me to disprove instead of provin(,' your 

 position, I refer to the circumstance that several of them are obviously niore 

 coincidences^ existing as such apart from the pyramid or its measures. They 

 show that coincidences of the most remarkable kind can he found in this case, and 

 presumably, therefore, in other cases, by those who look for them, and yet be, 

 lo all intents and purposes, meaningless, )>ecause accidental. Coincidences, there- 

 fore, do not supply that convincing evidence which the believers in what nmv be 

 called the Great Pyramid religion Hnds in them.— W. Paonvx Nbviks. You are 

 right; the comet is that of 1680. The comet of 1861, referred to at p. 28, was not 

 seen by so many as the comet of ldo8, being conspicuous only for a lew days, and 

 in the early morning, v^■herea8 the comet of 1858 was for months a brilliant 

 object in the skies. But the comet of 1861 was in some respects even more 

 remarkable.— A Fbllow of the Rotal Astbonouical Socibty. You might 

 regard meas "the kettle objecting to the pot its sordid superficies," for, like vou, 

 uiilitaci: ray zc:il is tempered now by the consideration that the world is "cen- 

 sorious, and easily led to misintcr|)ret warmth aa necessarily implying personal 

 feeling. Have we not both found it so ? Moreover, most people are more easily 

 pained than I should have thought possible when I first took part in controversy. -— 

 S. BiDDLB. It would save me a good deal of trouble to exclude thefifth magnitude 

 stars ; but many who use the maps want to have these stars in. It is very easy 

 for those who want them excluded lo take j)en and ink and put them out.— J. 

 T._ Lbightox. Occasional papers on quantitative chemical analysis might be ad- 

 miss-ible, if popular in tone; but at present we cerlainly have not room for a 

 series of papers on the subject.— J. Nobman Lockybb. We regret that you cannot 

 at present spare timo. Prof. Young has promised to write on the subject, and 

 your treatment of it from another point of view would doubtless have been 

 interesting to our readers. Perhaps at some future time you can oblige us. — W. 

 SijioNs. The quotation was sent in a letter from an eminent physician. Did 

 not notice the inaccuracy. The lines run, as you say — 

 fgnoranee is the curse'of God, 

 Knowledge the wing wherewith we fly to Heaven. 

 Thanks for encouraging words in reference to Knowlbdce. — J. W. C, .\verillo. 

 Thanks; corrected in Xumber -1. We began with the idea of a fortnightly 

 limp of the whole heavens, which would have made the pictures too small 

 in scale. In chanjiing our plan the mistake you notice arose, the first, 

 rbird, fifth, &c,, maps being taken with dates and hours, for the second, fourth, 

 and sixth, instead of the true dates and hours.— Mar. S. Ridley. Book 

 received, and forwarded to an enthusiast on the subject, for notice.— G. E. 

 Bo.vNFY. Many thanks. The bookseller who thought the public likely lo be 

 interested in Kno\vi.edge would be less than we expected has certainly not 

 thus far been confirmed Ijy the event. The sale we hoped to attain in perhaps 

 half-a-year or a year has already been exceeded twofold. Booksellers have 

 a theory that nine-tenths of the" journals started from time to time perish 

 at the critical sixth number; possibly when we have reached the seventh your 

 tiookseller may have faith in our existence thereafter. We shall see.-J. B., 

 .Vorxich Adcertiaer. Thanks.— F. C. Armstrong. Your query is uot suited to 

 our columns, though le^al matters may tie regarded as included in knowledge 

 taken in its wider aspect.- P. A. Fotheroii-i., F.R.A.S. Thanks— Eiclid. 

 We have inserted your queiT; but though you maybe readily shown how to 

 tnseet an angle by aid of a hyperbola, or" the cycloidal curve called the 

 'naectrix, you may depend no one will ever show you how to trisect an 

 angle by use only of the straight line and cirele,'as in Euclid.— A Studext. 

 We are not free to comment on instruments advertised in our columns. 

 )nit in this case the names of the advertisers stand very high indeed. We feel 

 satisfied that you could rely entirely on any statement their house might make as 

 lo Ihe quahtics of theirinBtruments.-J. ir. HoDD. Manv thanks. Mr. Foster has 

 some kindred illusions ah-eady in hand, and finds the explanation in a peculiarity 

 of Fig. 4 in No. 1. Your illusory picture shall be added lo his collection, drawn 



"■■ suggest.- H. Griffith. Thanks for encouraging letter.— Hbnby Nobtox. 



make out your letter. Possibly y 



You 



der that readable writing and ordinary spelling would have been thrown away 

 on persons so " hinevolint " as to cater for " circle squairers, petty school- 

 iiianters, and enquiring schoolboys." Your letter is absolutely alone thus far, and 

 alone among so m.any, that we venture to conclude you are aa exceptional in your 

 views about KNOwtKiioK as in your system of orthography.— Ja8. O. Jacksox. 

 On consideration, does il not appear to you that vour request is a little unfair? 

 To oblige many readers, we printed the map on a' separate leaf. It is thus better 

 printed, onr numlier is enlarged by a full page of matter, and the map is 

 made more convenient for study. As a reward tor thus considering our 

 readers' wants, you ask us to go lo the expense of having each map separately 

 pasted in Apart from the consideration that most of our readers prefer to have 

 1 he map loose, do you not think that your Society could pin or paste the map in ? 

 We pnnted »),000 copies of each of t1ie last two numbers, and these 20,iXX1 extra 

 h'aves added considerably to the cost of those numbers ; to have had Ihem piistert 

 in or an extra fold made for each would have involved additional expense, and 

 have been unsatisfactory to many of our readers.- O. W N'lVBK. Your long 

 article on "Clairvoyance" (seventeen very large and eloeely-writteu pages of 

 M.S.) would occupy much more space than we can afford even for objects other- 

 wise perfectly suitable for our pages ; vour subject can scarcely be so described.— 

 t. Cl. We shall be d.-lighted u. receive your paper on '• The Place of Dreams in 

 the Growth of Primitive Beliefs. "-Akurbw Aitkeh. Thanks for the construe- 

 tione of parabola, which shall appear if v\e can make space. First and fourth arc 

 scarcely suitable for " Oeomclricus," being so obviously deducilile, one from the 

 definition of a parabola, the other from the fundamental relation between the 

 ordinate and the abscissa, that he could not have failed to recognise them, lie 

 wants on easier construction. The two others arc in reality one, depending on 



Ihe proposition that a series of equidistant concentric circles cut a iwries of equi- 

 distant parallels io a series of parabolas, having the centre of the circle* aa 

 focus, and a line through that point perpendicular to the parallels aa axis. Therr 

 is a simiUr property for the ellipse, and the hyperl»ola, equidistant concentric 

 circles replacing the parnlleln. Diagrams illustraling these relations have already 

 been drawn for KxowLl-lir.E, in accordance with promise made at foot of " Geo- 

 melricus's " letter. There are simpler and belter methods tlian these, however. 

 — M. E. Prxobfu. Yourlirsl letter does not appeared, bec-auseunsuitalile. If you 

 areso fearful of science you had better leave it alone. We cannot ..trengthen your 

 faith; we can only wonder why vou are troubled.— Joiix Steele. Many thanks 

 for nroflered M.S. (16 pp. clo"'-ely written foohtcap) in favour of ihe sun's tieine 

 rigidly cold, and showing that we are chiefly indebted to water for both light and 

 heat." Rut- please don't,- Hbxbt GRiusnAW. Your illusions next week, if 

 possible. We know nothing ourselves aliout Ihe Extract referred to ; the adver- 

 tising and edilin;; are distinct departments.— A Loveb of Kxowlbdgb. 

 Declining and inclining are different matters. The lines of the addreoa, which 

 arc really horizontal, appear to decline— that is to be lower down — on the left. 

 As to the other point, we hibour under great difllcullies with regard to corre- 

 spondence. We should require twice the space we have, to find room for all. 

 We will do our beat to make room early for all that needs early pubhcation, and 

 in the long run for all that is worth preserving.— loxoRiui'S. "'Vou misinterpret 

 my remark in " Ualf-hours with the Telescope." I do not say Mars shows a 

 larger disc or more striking features, but the reverse. \\'hat I say is, that we see 

 him on a larger scale ; as, of course we do, seeing that he is much nearer the 

 earth. No doubt you were looking at Mars. He is a disappointing object in 

 the telescope. — B. H. Tuwaitb. Your letter is too long for what, after all, is 

 an exposition of a very unsound doctrine. Take such a sentence as this ;— " May 

 not tne rings of the planet Saturn be produced owing to that planet having 

 two atmospheres capable of absorbing lipht from the solar rays?" Without 

 wishing to discourage your efforts at original theorising, or to quote authorities 

 against you, we must yet point out that a study of the facts known about 

 Saturn's rings will enable you at once to decide that your explanation "may 

 not " be accepted. — Again we find a great pressure on our correspondence 

 columns. Our own letter, promised in Number 4, was the first sacrificed. 



SvNciiRoxizi.NG Electric Clocks. — At the first ordinary meeting 

 of tlie Society of Tele<,'raiih Engineers and of Electricians for the 

 autumnal session, Professor G. C. Foster, president, in the chair, a 

 paper was read by Jlr. John A. I.und, on " The System of 

 Synchroiiizing Clocks adopted in London and elsewhere." Mr. 

 Lund said his paper was an attempt to demonstrate the re- 

 sults to he obtained by even a limited acquaintance with the 

 science of electricity when patiently and perseveringly brought 

 to bear upon some of the practical demands of daily life. The 

 attention of electricians in the early dajs of their science 

 was, he stated, as much devoted to synchronizing clocks as to 

 message telegi'aphy, but the repeated failures in the former 

 field, as contrasted with the triumphant successes of the latter, 

 caused the application of electricity to tclegi-aphy to become the 

 favourite path of the electrician. Electric clocks were capable 

 of being divided into six kinds. None of the old forms of electric 

 clocks obtained a general public acceptance, the most successfnl, 

 the Wlieatstone, having only worked some five or six clocks from 

 one motor. Their failure was due to the desire to make the clock 

 subservient to the system, inste.ad of vice versa. The criteria of a 

 successful system of synchronizing, to obtain the approbation of the 

 public while receiving the sanction of science, were that each citx'k 

 should have a vitality distinctly independent of the time signal, and 

 not stop through a failure of the regulating electric current to reach 

 it ; universal application to all kinds of existing clocks ; lastly, 

 due provision for the correction of errors. The system exhibited 

 satisfied these conditions. Mr. Lund proceeded to say that, how- 

 ever perfect the mode of synchronising might be, it could not be 

 successful without a complete " system." The system consisted of 

 a coiTcct standard clock, which, assisted by a well-erected and well- 

 maintained system of telegraph wires, should send out the needed 

 signals to the synchronisers. Two " standards " were osed (one to 

 fall in automatically should the other fail) for transmitting the 

 currents of electricity, and those [standards received their motion 

 from a standard clock. The applicability of time current wires for 

 telephone purposes was instanced by telephones being placed 

 at each end of a circuit between the lecture-room (Institution of 

 Civil Engineers) and Messrs. Barraud i Lund's establishment, Pall 

 Mall, upon which wire there were also twelve electric clock 

 .synclironiscrs, through which conversation was carried on. 



CotUetUs of Knowledge No. 4. 



The Origin of Buttercups 65 



Solids, Liquids, and Gases.— Part II. 



By W. Mattieu WiUiams 

 Ger'msof Disea.se and Death. By Dr. 



Andrew Wilson, F.R.S.E 



The Ijiwsof Probability 68 I Qi 



Intelligence in Animals— (///utfrafrrf) 69 Kepli 



FACE 

 Map of Eastern Skies— Celestial 

 Objects — Are Women Inferior to 

 Men? (J6»<rMcO -Speed of Ame- 

 rican Ice- Yachts— Are Men's Heads 

 Smaller than of Yore? ic 73 



lllu 



trated) . 



By Thomaa Foster— (i««, 



itoQu 



70 



-Authors and Publishers 72 

 COBRESPONDKSCK;— ToOur Readers, 

 *c.— The Missing Link The Sun's 

 Ueat-The Sun's Heat (.\bitract) 

 —Star Names :— Comets' Tails- 

 Practical Work with the Telescope : 



Anniversary Meeting of the Bir- 

 mingham* and Midland Institute 

 I'liiou of Teachers aud Students. 



Bv W. Mattieu WilUams 81 



Our' Malhcnuitical Column 81 



Our Chess Column 82 



Our Whist Column 83 



Answers to Correspondenta 81 



