172 



KNOWLEDGE 



[Dec 23, 1881. 



SiniSUjcrsf to Conrsponlirntd. 



'.'All ctmmunUalioff /or «*. Sdilor «»i.irin.« ,arl, all>nlio«,hoM rtacM JA. 

 Om'r on or htTor. Ikr 4W..rJ..y pr>cf.li>g Ihr c«rrr,t i..u, ^ KKOWLr.DOK, th, 

 ,«>rrjii»o<-ir.-«/u/io.io/«-*ioAfoi»t''»"» io ;>> to jirtu tor\<, in (*« «-»f*. 



lllST. lO COEHP..O»D«.1«.-1. .V„ ,,.,.f,o,.. aMn, S.r ,cirnt,Jic ■n/or»,»/..» 

 ra"»rj!,.r.r„/ (»r»,-tf» M, p».f . 2. If"'" .«,( to tU Editor for corrrrpo«d.«,. 

 cannot bt formardr,i ; nor can tic n«mt> or aJJrrt.M qT corrcipoiiJcnIi be gtve« ■» 

 amwtr to ,<r,cale inquiric. 3. Xo qucrif or rcpl,c.,arour„u, qf the nature .J 

 IT^^iLinl.canbX.crlcd t. Letter, qucric. and "f '",'" """''i' "'''"• 

 ^■onlrart to JluU 3, JVf of elkar<ie. 6. Corrttpondenli Mhould <cr,lt on one tut 

 onl, o/ihe paper, and pal draxtngt on a teparatt leaf- 0. La.l, Ulter, query or 

 ,Jl, tioud kat, a mU. and •» repUing to Ullrr.orqaer,,,. refercnct.hoM be 

 made to the number qf letter or qitert/, the page on which it appeari, and >ti lilli. 



A " PislDOI-MoxoBB." Vorj- liki'ly you ore rii!lit ; »illi llio kindest wi.shos an.J 

 Iho bent inlciitioni men malco cnemif«. It will he unfortunate if our evasion ot 

 any particular lubject should be attnbutod to " pri-djudicc ; but wc inKil onut 

 somclhinRs, and amoncst those vour letlor.-S. II. Wbioht ^ousecm to me 

 entirely to mi«under.tand Dr. Wilfon'n first lelter-.t km eiplanatory not .on- 

 trovernial The spider's «eb is not a ereater dilTiculty than the cell-makine 

 instinct in beo3 ; the study of Darwin's reasoning on the latter subject would 

 -how you that there is no real objection iii the arpumcuts you consider vabd 

 li»ain/t the Darwinian hypothesis. If vou remember that of five letters received 

 fSixrmutl be omitted, Vou will see that you have no real rea,son to complain 

 that your former letter was not inserted. It would seem that we are bound 

 to offend fonr-llfths of our correspondents if we keep open a correspondence 

 section at »U.— Rodert Kidd. The point has been corrected already.— Pascal. 

 You are. of course, right ; but is it worth while to reason back so earefully 

 to the Original eqliationP-G. B. Studbs. Thanks. Our Che.,s Editor 

 and " Mephisto" will analyse it.-.T. Jkffabe.s. In his reply to Archimeaean, 

 P. 61. •• Mathemalicus " took it for granted that the former would at onee see 

 what TOU have established, and what H. A. N. says the differential calculus 

 is required to est.iblish. As you say. the substance of the proof w to be found in 

 books; we mutt not find space for it.-F. S. Pilkikgtom. The eipenmen 

 proving that ono part of the retin.i is insensible to visual impressions is well 

 tnown Must reser^■e space for newer matter.--Jis.H. STMiNOTO^f Letters 

 relating to Vivisection will receive due attention, but the matter is hardlv worth 

 discussion; it seems so 'clear that those who hold eitrcme views on either side 

 .ire mistaken. The editor ot the paper you mention is weU known to he an 

 Mtreme opponent of vivisection, one who would not allow a tom-eat to have a 

 hair plucked out if the lives of all his relatives depended on the experiment. On 

 the other hand, there arc some who would let a thousand dogs be tortured to 

 death to estabUsh a physiological law ot no benefit to a hving creature. 

 Fanatics of the first sort consider all who approve of any cipenmcnts whatever 

 on animals to be brutes, while those of the second sort consider all who 

 oppose the wantonest cruelty, to be drivelling idiots. Xo amount of discussion 

 wifi reconcile these, or either sort, with the moderate persons who hold that 

 researches reaUy directed to benefit the human race may be conducted at the 

 expense of pain to animals, provided that every means be adopted to reduce 

 such pain to a minimum. Tour story hardly establishes the intelligence of 

 that particular collie. What did ho gain by taking the chop under the sofa, 

 and returning it uneaten? Are we to assume that he was planning 

 how to get the bone out without injuring the chop? If he had done this it 

 would have shown intelligence ; as it was he only showed the eflect of craving.— 

 R.S. Couch. Tou will find a reply to some of your questions in Found 

 Links," presently to appear in Kvowledge.— H. D. Ocneral information on 

 the subject of your letter will be given in numbers beginning December 30, 

 or January 6, at latest, in a series ot papers by a TeUow of the 

 UoyalAstronomicalSocictv.on work with a 3-inch telescope. Most of the objects 

 he 'will consider will bo perfectly well suited to your telescope, though it is of only 

 3i inch aperture.— F. J. BaODiE. We cannot at present make any arrangement : 

 probably we may follow a plan which we pursued some eight years ago. when 

 editing the natural science department of the Mechanic (not the English Mechanic 

 but the older paper, now merged in Iron).—JoB:i Bbnsett. Thanks. ^ on wiU 

 <ee that the ^' Witch ot Agncsi " has been fully dealt with ; the ceometncal 

 instructions being better suited to these pages than the analytical methods 

 though not so easily phmned. Thedotted curves in your figure, I see, correspond 

 with the cquationw\enj-2 ois writtenfor2o-r.— ACo-vstantRe-ideb ambScd- 

 SCBIBE8. It is not the case that the moon never sets in the polar regions and is 

 never seen inthe crescent form. The moon is only well seen as afull moon in the 

 arctic winter months, and when so seen does not set. The erescent moon can be 

 seen in the day time in the arctic summer months, not at aU in the winter months.— 

 .T A. R. I fancy I have seen your views respecting comets before. ^ as it not 

 in the E'tqlith 'Mechanic? 'They seemed to mo unsound then, and I must 

 .onfess I find no reason now to view them more favourably. They are ineon- 

 sistent with many known facts.-Ron. Oodi-ret. Thanks. Have yon heard the 

 family anec.'.ote ibout R. C.'s eleven reasons for not acknowledging the work?— 

 CooiTO. The triseclion described by Mr. Warren may be extended to any angle 

 liy flrat bisecting, then trisecting the half angle. It is impossible by Euclidian geo- 

 inetry to draw from C a Une CKD suchthat DEshall be equalto OE.— J. Bacox. 

 You are quite right . Sir D. Brewster wrote when the true nature of the spectrum 

 was not understood.- .1. M'Grigob Al.tiAX. Many thanks. Your interesting discus- 

 sion of Sections shall presently appear.— C.T.B. Hardly room for Gems at present. 

 — O. M. The method of trisecting an angle described in Mr. Warren's letter will 

 not do for angles above VHf. simply because when the angle 120° is reached, the 

 point D comes up to the circumference of the semicircle— A. .T. You do not 

 seem aware of '.he fact that the precession of the equinoxes is not explained 

 empirically by the modem theory, but is shovni to be an inevitable conse- 

 nuence. in measure and degree, ot the action ot gravity. It is one of bi-^niost 

 beautiful of the proofs of the Newtonian theory, 'iour theory would be all 

 right it, first, it were certain that there would be no such etfects as the law of 

 -ravity assures ns there must be ; and,seeondlv,if we knew that the sun were circling 

 m a mighty orbit, such as you picture, in •i.i.llOO years or thereabouts. As we are 

 quite certiin the sun is not so moving, and equally certain that the earth being 

 spheroidal must reel preoessionallv precisely as she does, your theory cannot lie 

 -atisfactorilymaintained.— J.T. E. Mr. Foster has yourillusioninhisoollection. It 

 was puWished thirteen years ago in Ihe 7n/e»e.^io( Ol.erier. Mr. Foster complains 

 that the increase of correspondence is destroying all his illusioas.— K. bvMOSS. 

 Mere extravagance. -EnwARD Coi. You arc quiteright ; but proving the earth not 

 fiat is killing the dead. The argument you use ha« been employed olten-by 

 myself am-n- others —but llie Flat men cannot or will not see what to persons of 

 average brain power is so obvious.-TllOMAS novTTKl.i.. You misunderstand Dr. 

 Wilson's reply to "Ign. ramus," whose "frankness," you say, " brought down 

 the wrath of his opponent." There is no trace of warmth.far less of wrath, in 

 Dr. Wilson's letter. The tone of yours is, therefore (you will admit, I think, on 

 .on»ideration).unsuited to the wcasion. Your letter is also not SMlIleiently 

 rondeused. If you had read Dr. Wilson's excellent essays on evolution, you 



iiiper 1 



hit tympanum." wctild h* 

 ride'nee von adduce to " raniih the 

 leni whic^ pujtitles to nuaif ot ut." is 



ist quotes in supjiort of his positioa. 



» Anatomy in the EiLubur|^ 



* "srledge whispered 



would t>« aware that what you desire to 

 werr far from being news to him. The 

 phantom t..ucliing lliose rudimentary mera 

 precisely the evidence which the eioluiioi 

 In any caM. the leitorer on Zoology and Compi 



Me.lieal School, does not nee<l to have su.h . -,' , 



in his ear — T. Smbtiuksi. Wehopc to giie, before hmg. such arli. les vu ,,mr 

 a.youdesire.-CoQ.TO,C.E.,ALOOl, ic. Thant. ; question, alrca-ly answcred.- 

 W:II.Ja,oii. The explanation is simi.lo Your nght eye Wing rerr short- 

 sighted, takes no part ordinarily in the vision of objects beyond it. IffrnBgf. 

 When iou close it you see such objects (vour finger and i lie distant hght, (or 

 instance, in the experiment you de,cribe|j„.t n, you d-d "hen it was opeo. 

 But when you close the left eye U.» right eye is at onee called into action. \oj. 

 see the distant object and your finger willi this eye, though not well defln»l 

 Moreover you see your finger to the left of the light, because the hne from the 

 right eye to the finger muSt obviously fall to the left of the hn- from the sum 

 ej-e t.i the more remote ..bject (this object, the finger and the left eye being in • 

 straight line) .—Titos. IlKBliKS. Thanks. It shall appear early.— W. 0» 



ROLPB 





Thanks 



our article on Seismology to;! .-.-;.- _ ,. 



,._. the subject are already in tyTf-"- Ki'MOSBS, B.Sc. 



liardlv do so without apparently recommending that of whi. U i 

 personal knowledge.-llABBls. toomis's " Treatise on Pnu^t.eal Astr 

 one ot the best.-J. II. G. If there were any recognised connec ion b-twe. n miU 

 Xovembersand the winters following we could a,k -'""■■ n"'»"°". ';'''"',^"'f 

 not -.1 Mitchell. Thanks; but no room. Cho sqiieryalreadv answered. Manrtte. 

 R. Lenormant, and Wilkinson quite out of date, liunsen nearly •»• } »" q'^*;" 

 about first infant, and how it fed, reads like a Joke.-^ BOA. Question 65 now 

 sulHcienlly answcred.-EscELSloa. \Ve were referring to another. Have DO 

 knowledge of the instrument you mention. Why not wnteto makers,asking what 

 cuaraiitees they can give as to performance, ie.->\ . C. Bltthb Thanks ; your 

 rnleresfng letter slialT appear. I'bof. Lvm.e. Thanks.-CHAs Moclto». ioo, 



•■- submitted to publislers , t-"! i' '•'^'^ <>?'y '°"'»'^=" ''',° P^ff" '' '° P"i 

 ' ,gh the paper for thcmselves.-p. K.\ourjdea thai the snn-spota 



ndS'hemer 



the stitch througn tne paijcr lor iuciu»e..i-^.--y. «• * — • ■— 

 maybe intra-mcrcurial phinets was the hrst which Gahleo, Fat: 



entertained (and disposed of) when the spots were di.scovered 271 .. 



F. W. DiLLOX. The cat who put her paw on your knee when you were eatmg, 

 so that she might receive a share of your attention and of > »" '"Plf ■•. ;;^°-"» 

 intelligence im doubt ; but the case is not so unusual aa you seem to thinkj- 

 Ervest C a A:to:». Thanks.-TuoJiAS Xbwbitt. Thants. Query now suffl. 

 cent" aniwered.-T. R. Regret that we have no space at pr«ent for your 

 sound discussion ot the moon's rotalion.-CcPIDLS SclEXTIJi. Puzzle marked 

 ^""insertion early-A. J. Mabiin. The eyepiece of a telescope is a microscope, 

 by which the i^ge formed at the focus of the object.gla.H9 is ^?"'«f;J- 

 Testativi. We cannot admit the ordinary stones of sp.ntualism but anything 

 tested by due experiments, properly conducted and ;°"'^>>'^. '';;"^.^°"'''' °| 

 course be in our line. — Mbmb. Soc. Bibl. Abch. Many thanks for your 

 interesting letter Wc slightly alter one or two passages, lest they 

 IhouTdTe^ad to rejoinders ol an ""desirable kind - Cesa. The leU™ 

 S P R were used on Roman banners, *c. They stood for SenatOB 

 Populusque Romsnus (the .«enate and People of R™")-"^ "•,h\°'T£; 

 Your 8uS"e3tion is a good one. but at present something more than tae 

 name sfeS wanted - A. A. YorXG. '^Questions sulHciently ««wer,d. 

 T>'AnT*rvAX " EncTaver " wants more special instructions.— J. A. K. i^uer on 

 r«ib"wpr:sentl,^Xan make space, bu.?benroof belongsto '"^';;=«1= matter- 

 J. F. SiVpsox. Many thanks. Corresponcfenee occupies so much t™^ •n* 

 space that other matters, which I regarcf as more important, stand a chance of 

 b'eii^g neglected, unless a very strict hand is kept ™, °"/?,""/™deno,t eol>^- 

 -AiPHA Certainly, " would " and " could." tor " vnll 'and can, are si^- 

 gestae of Mr? Brown.-H. E, Pareeb. Chemical question answered si£- 

 cienly-E F. B. Habsto>. It is easier lo eiphiin than to name 

 suitable book. You only get the t''"^o.,^'^'^""\^J''"^^i £. 

 body outside the circle. So long as it ">.»"' ..■° ,'.''' .^■L^'tlJi' 

 forci always act at right angles to t£e direction m which the '^''.y move., 

 and therefore neither hastens nor retard, it.-A HAyiLA>-T.^ W '" .'ffi,^^?°'„'^i 

 -C. J. Shaw. Thanks. Q'><-ries already answ_ered.-b.o«A. The iUusiotd^^ 

 striking in the picture, which would cost a good df"' '» ^"S"".:^"^'^'^ 

 The advertisement may or may not involve a reference to KsowLgpoE. At any 

 rate wrclim no ri"alVy in one of the subjects named . The last thing we shouhi 

 "ink of wTldb? to assert any claim i to the other. \\ e must let readers 

 aec"de-OEio" We cannot see that there is any difficuty, even now; later 

 fhe numbers will bo widely different. Enough has ^"I'Ys^i'ln^'jfntdl^W 

 question we cannot but think.-SoxXET. Our heart is hardening rapidly.-«. 

 ABTHrB How many have other knowledge than from books on tlie subject 

 named? and if Ihose^ho have are inarticukte what 8°°^ «ou M they do our 

 readers.-.A^s OLt. BoT. We qmte agree with you ; (:assell s £«, . .^ewt- 



?XT-sh"wM;„w^^. ^gfe-lf l'3.Tmatt ^ZJ^-^'c^LJ^.. 

 K a. angle s equal to fhe half of threi- right angles or to three half right 

 anirles this can hardly be regarded as the solution ot the general problem, 

 " hfch is vJhatTs w2nt<^l. The%ther angle trisected '-yrjrZtoiT^^t 

 nient ot 221 degrees, <" ^'i degrees, tRe third of "';■'''» °";-'°"'";r»X 

 nnele Ksowledge should reach Liverpool earher than 1.30 p.m. on Saturday. 

 - \ A McmI^ster You are certainly nght. The length of tlie rope niakes no 

 differenclu the action on the weight i. afong ">' '»r.,.e*J,7»1u Tn etw^s 

 the axletrees would make a difference, because part of '*',%'!;»■" "","•?? ''^t^J 

 parallel totheaxle, and, of course wasted.-F J. D. Selbst ^J'" ^."PJ.'JJ 

 remarks about water spheroids tor t"rtl>",^»n''d""''''"'--,fj' J^,^' ,>'„; '^v, 

 find room for your question about worms. It seems clear V"^' "f^^^'^4"S^j 

 W. A. U. Should have put in note, but hoped to publislj "< "^ '^"•-^- ''• ■*; 

 Thanks. Would insert\your answer to f beta's paradox had "<• n»«- ^ 

 paradox is usually regafded as opposed to what is orthodox^ - M J H. 

 Wnossible to answer your query without breaking through rules— W . A. L. 

 S^e'Tei'iy above to J. H^^SymiV'ton-H. A, Bvllev Will repeat ^." on yon 

 lunar iiews.-W. G. Rolfb. Alas 1 no room '"^f.P'.'-; I'. » "„" ," 1"1!'"'y;„ 

 "may" and " might," but of " """s^""' »"* ™>no'- -P«"»'f.^^^^° 

 shallkeep your "knowledge in a box," we keepmg our flv^e shilling with no 

 further tA.uble." Seriously, that is not the way »'. ™'^■ "J'-Tf^*"-^^;, "g^ 

 not know CvTles' book. We might reply to all queries if we kj'«"J.°''- B"! 

 knowledge is very wide.-FBKsBllas. The reverend doctor of medicme said 



Kiiowieui.o IB r . „_-...rt A man who would say that 'not a little of 



much more than he could prove. A man wnowouiu ~...i , p ^ Von 



idence could be found for evolution," would say anvthmg.-J. r. t. lo" 

 misunderstand the way in which according to the '^~ry of "»'»" 

 - 'opards have become spotted. The case more nearly resembles 



rath 



selectit'i.. ....( - V""\.- 



modem breeding than the Jacobii 



1 svste 



rrfer to. 



Pojto'b Bctbict is a certain cure tor Rheumatism and Gout. 

 Pond's Extract is a certain cure tor Hoemorrhoids ( I lies) . 

 - - - • , certain cure for Neuralgic pains. 



Pond's Extract 

 Pond's Extract 



rill heal Bum 



..d Wo 



^ and Bruises. 



ill Chemists. Oct the genuine. 



riort. 



