478 



• KNOWLEDGE • 



[Maiicu 31, 1882. 



IcttcrEf to tftc Cbitor. 



{Th« Editor tloff not XnU himself rftporiMibUJor tMf opinioni of Mis eorre^findenti. 

 St cannot undtrttike to rrturn maniiBcrtytt or to corretDond u-UM tMrir itrttert. Alt 

 eommmnieatio»» thoutJ bf ii» thort oj potnblt^ eonsisttntlj/ icitk full and cleur ftutf- 

 mmt$ ofths vrttrr't mfttninp.'] 



Atl Sdiioruit communiraiionM «Aoh/J bf addrested to tht Editor qf KNOWI.sno»; 

 all Bugine»> cMmmunietition* to tk« Publishfrt, at tJt* OJice, 74, Great Queen- 

 ttrtft. W.C. 



AH Semittanrea, Chtquf$, and Po$t-Offlc9 Ordert $kould bt madt pajfabU to 

 iie$*r$. Wymnn 4r Sont. 



*^* AH UtttT* to tht EJUor teilt be Xumbgred. For convenience of reference, 

 corregpondenft, when refrrring to any letter, trill oblige by mentioning its number 

 and the page "»» »rAi>4 it uppearf. 



AH Lrtfere or Querie$ tu the Editor vMrh require attention in the current is»ue of 

 Kito\vi.VTtom,»houtd reach the Publishing OJice not later than the Saturday preceding 

 the J<jy (ff publication. ^.^—^ 



(l.) T.«tlpni to have nc)iiinc<« of appoarinff muit be concise; they most be drawn 

 op in tho fom» adoptpti fur li'ttors here, bo tliat tboy may go untouched to the 

 printers: privnto roinmtinicalionR. therefore, aa well aa queriea, or replies to 

 querie<( (Intendrd tonpprnr n» Kuch) whouUIbe written on separate leaves. 



(II.) Queries and replioH fthotild be oven more concise than letters ; and drawn 

 npiii tho form in «Inili Ihoy are hero prescHfcd, with brncketH for number in caao 

 of qiieriefl. andih^ proj.or qunrvnumber (bracketed) incase of replies. 



(III.) Letter*', qireri'-s. imd renlien which (either because toolonff, or unfruitoble, 

 or doalinff with mntier- which others have discussed, or for ony other rea.son) can- 

 not llnd place here, will either be briefly referred to in answers to correspondents, or 

 acknowledged in a column reserved for the purpose. 



"In knowledce, that man only id to bo contemned and de^pt^ed who is not in a 



state of transition Nor is there anything more adverse to accuracy 



than fixity of opinion." — Faraday. 



*' There is no hcrm in miikinc a mistake, but preat harm in making none. Show 

 xne a man who makes no mistakcii, and I will show you a man who has done 

 Dothin^." — Li*hia. 



" God's Orthodoxy is Truth."~CAar/« Kingsley. 



d^ur CoiTf^poninue CoIiimuEf. 



SCREW-DRIVEK. 



[359] — I am almost ashamed to make my first commnnication to 

 Knowledge on snch a humble subject as a screw-driver. But 

 thouf^h a humble serv-ant, it is one that we are never likely to be 

 able to do without ; and 1 should think there are few of its era- 

 ployors who have not been inclined sometimes to use strong 

 language at its |>erver8ity in slipping out of the nick, and in refusing 

 to enter it. I wonder that it never occurred to me until the other 

 day, when I saw a man continually meeting with this trouble, that 

 it may easily be prevented by tho simple contrivance of putting on 

 a tube to embrace the screw-head. 



There are, however, a few details to be attended to. Screw- 

 heads, for which the same driver is suitable, are not all of the same 

 size. Moreover, the jioint of the screw-driver of the now u.sual 

 round shape (which is the nicest to handle) is widened out, so that 

 a tube which will go over it will be loose on the shank above. The 

 ■way to meet both those difficulties is to put a piece of leather round 

 tho shank while you slip the tube on, of such thickness that it will 

 hold moderately tight. Tlio consequence of that also will be that 

 as the screw-head goes down into the wood, the tube will bo sponta- 

 neously pushed up. For larger screws than tho driver is generally 

 used for, yon only want a larger tube and thicker leather. 



I never believe in anything that involves motion till I have tried 

 it. I have tried this with a tube made only of strong tin, like an old- 

 fasliionod slate-pencil ease, and it answers perfectly. You need not 

 even look at your screw. Just put tho sockettcd driver on and 

 tnm ; it straightway walks into tho nick, and stays there until the 

 screw-head is imtieddcd in tho w^ood, or metal, as the case may be. 



I also abhor patents, and I thercforo neither patent this, nor tell 

 it to a to<)l-nuikor. The last time I suggested a practical improve- 

 ment (not to a tool-maker, certainly) the man straightway went 

 and patented it. Luckily, however, it turned out not to be new, and 

 so the oilier makers lauglie 1 at him. Epm Beckett. 



COLOUU OF PALAEOLITHIC MAX: CIUUSTMAS EOSE.S. 



[3G0] — There is no evidence that Paltcolithic man was black ; it 

 is a sheer stretch of imagination on tho jiart of the present writer. 

 But when wo consider that black is tho common colour of the skin 

 in all tho anthropoids, that all the existing lowest human races are 



black, and that tlio oarly PaUcolithic skulls of tho so-rallod Canitadt 

 type cloftely reseniblo those of tho mfjilorn .\uHtrulianR, I think wo 

 arc fairly justified in assuming that the <lrift-Dion at least woro 

 black and woolly-haired. Whiteness is, after all, a mere acr|airod 

 tniit fif tho very highest races, and it may well bu doubtc<l whether 

 aiiyliody was white till a \cTy recent period, a mere trilli' of forty 

 Ihiiusund years or so ago. Prof. Boyd Dawkinn, indeed, believe* 

 that the cave-men or later Paliroliths rcncmliled the Eskimo; bnt 

 if ho means us therefore to conclude they were as light-skinned u 

 those modern people, I think the harden of proof certainly lies 

 with him. 



The little cup-like organs in tho Christmas rose arc really de- 

 graded petals ; the white (ictal-liko outer leaves are really sepals. 

 Tlie petals secrete honey, and therefore were describod by Linnoms 

 aH nectaries. It is a common habit of tho buttercup family (to 

 which the Christmas rose belongs) todevolope coloured sepals for the 

 attraction of insects, and then cither lose the petals altogether, or 

 dwarf them into small honey-secreting organs. Green hellebore 

 and bears-foot, two closely allied plants, grow wild sparingly in 

 England, and have the same arrangement of parts as the Christmas 

 rose. Tho beo alights on the centre of the flower, visits the eight 

 Or ten tubular petals one after another, and du.>its himself in doing 

 so with pollen from the stamens, which he then cirries to a neighbour- 

 ing blossom. Tho pistils of each flower mature before the stamens, 

 and so, even if the bee drops some of the pollen on the same flower, 

 it does not interfero with cross-fertilization, because the pistil will 

 in all likelihood have been alre.idy impregnated. But when ho 

 passes from an old blossom, in which the stamens are shedding their 

 pollen, to a young one, in which the pistils are mature while the 

 stamens are yet unripe, ho at once fertilises the ovary, and thos 

 ensures a plentiful crop of healthy seed. Geant Allen. 



HIGH NUMBERS. 



[361] — A parenthetical remark of yours in an early number of 

 Knowledge prompts mo to ask you if you will be kind enough to 

 say what you consider to be the scientific method of notation in 

 respect to very large numbers. That is to say, since a million is a 

 thousand thousands, should we call a thousand millions a billion, 

 and a thousand billions a trilUon, and so on ; or should we reckon a 

 billion as a million millions, a trillion as a million billions, and so 

 on, multiplying by a million for each one ? Or, peradventure, is 

 neither of these methods right ? Wixter. 



[It has always seemed to mo the English system of calling a 

 million million — that is, a million to the second power — a billion, a 

 million to tho(7u'ri7 power, a trillion, and so on, is sounder than the 

 American system of calling a thousand millions a billion, a million 

 millions a trillion, and so on. Xo meaning can be given to the 

 his, tris, &c., in the compound word on the American plan, whereas 

 there is a verv obvious and natural meaning on the English plan. — 

 Ed.] " 



JDPITEK IN CASSIOPEIA. 



[362] — I presume that the Eev. H. H. Higgins, who sets down 

 the statement that " Wallenstein saw Jupiter in Cassio]>eia," as an 

 absurd mistake, {vide" Answers to Correspondents," p. 392), refers 

 to a passage in Schiller's " Wallenstein" s Tod," where the famous 

 warrior is made to say (Act V. sc. 3) : — 



" Kein Stembild ist zu sehn ! Der matte Schcin dort, 



Der einzelne ist ans der Kassiopeia, 



Und dahin steht der Jupiter." 

 If such be tho case, I hope you will allow me to state that the 

 error is not Schiller's but must be laid to the chai-go of his com- 

 mentators and translators, who have construed the word dahin 

 as if it meant " therein," whilst it is employed in the sense of 

 " yonder ; " for the speaker points with this expression to another 

 direction than that where he had seen Cassiopeia. I may add that 

 I have interjireted the above passage in the same sense in my com- 

 mentary to Schiller's " Wallenstein." 



C. A. BicnnEiM, Ph.S. 

 [Does Dr. Buchheim mean that tho interpretation he puts upon 

 Schiller's words is the one which would naturally be put upon them 

 by German readers ? — Ed.] 



SPACE PAIUDOX. 

 [363] — I fancy the following problem might interest your readers. 

 — Two bodies, A and B, have been travelling in tho same path 

 through space from eternity. B goes a mile an hotu- faster than A. 

 Since they have been travelling for an infinite number of horns, 

 there is an infinite number of miles, or any other unit of length 

 between them. Honco a line drawn from A to B will be infinite, 

 although bounded at each end by A and B. 



