March 



1885.] 



♦ KNOWLEDGE * 



209 



it. The tree loarfs arc lying loosehj on the gi-onnd, niul, for the 

 most part, are hard and dry. Fi-om their appearance they may 

 have been in this state since their fall from tlie trees la^t autuniu. 



G. W. liur.M.w. 



WEAR OF SILVEK COINS. 



[1651] — I quote the following from an old number of Know- 

 LKOCE (Sept. 12, ISSl) : — "Mr. Miller some years ago miulc a 

 number of precise experiments, from which it was ascertained that 

 moo worth of sovereigns lost ,i'3. 9s. 8'4<1. of tlieir value in a 

 hundred years. Similarly .i'lOi) worth of half-crowns lost 

 £VS. lis. 8Sd., £100 worth of shillings £30. 14s. 3 Id., and £100 

 of sixpences lost £30. ISs. 9Sd. in value, or more than oue-half in 

 the hundred years. It will be noted hero with rogurd to the silver 

 coins that the less the value the greater the amount of wear. Those 

 silver coins are, of course, most used, and so, in the caise of a six- 

 pence, a centnry's wear reduces it to less than half its original 

 value." 



The reason mentioned in the above paragraph is not the com- 

 plete explanation of the difference in wear. The surface rf two 

 sixpences being greater than that of one sKilliiig, the wear of the 

 two six[>ence3 will also be greater than that of a shilling in the 

 same ratio, if they are used only to the same extent. Tak: ng this 

 into account, we can obtain an estimate of the relative amount of 

 use of the above-mentioned silver coins. The surface of any sum 

 <aav, £100) in the three cases when it is used in half-crowns, in 



shillings, and in sixpences will have the ratio 1 to I - I to (5)^, this 



is in the ratio of 1 to 1'3572 to 17 10. 



Hence, if the loss on £100 worth of half-crowns for a given 

 amount of use is £13. lis. 8'8d. that on £100 worth of shillings 

 vronid be about £18. Ss. lOd., and that on £H.O worth of sixpences 

 would be £23. 4s. 8d. Shillings therefore receive raoro use than 

 half-crowns in the ratio of £36. lis. 31d. to £18. 8s. lOtl., approxi- 

 mately twice so much, and sixpences are more used tlian half- 

 crowns in the ratio of £50. 18s. 98d. to £23. 43. 8d., or less than 

 2|, showing that the difference in the amount of use of shillings 

 and of sixpences is by no means so great as indicated in the 

 qaotation. 



It would be interesting to compare these estimates with any 

 others that may have been framed of the relative use of these 

 coins. T. C. Lewis. 



THE NEW TIME. 



systems than to piles of shot, and it is no more possible, from the 

 size of the molecule, to calculate the si/.e of the atoms inside, than 

 it would bo to calculate the size of a [ilanct from the magnitude of 

 its orbit. 



Would it he plausible to hold that the universe is itself an ultra- 

 gas, of which solar systems are moleculca, and plan(>t.s not, indeed, 

 vltimate atoms, but of the same rank as the smallest at(im wo have 

 hitherto discerned ? This teems supjjoited by the " insignilicance " 

 of the attraction of tlio particles in ultra-gas; comparable to that 

 of stars )io( deflecting each other. HAi.LV,viins. 



P.S. — The review goes on: — "His strange to remember that 

 these atoms are themselves inlinitely great as compared with the 

 infinity of smallncss below them. Each may bo a solar system, or 

 even a nebula of fi.xed stars to some immeasurably smaller speck. 

 Great and small, as we call them, are c(iuul in reference to infi- 

 nity." 



Surely this is " cutting it rather too fine." If it is true, how 

 can they be ultimate f And if great and anmll .avo not positivo 

 terms, what basis is therefor matlieniatics ? Moreover, is it not 

 prob'iblo that there is no single orb much bigger than Sirius ? If 

 so, there seems a limit to the size of moleculos on one side ; must 

 there not be one on the other i* Infinite size we cannot deny, 

 though wo cannot conceive it, but infinite xmaXlness seems a con- 

 tradiction in terms — if small, liuw inlinite ? 



[1652] — May I suggest a method by means of which, should 

 the " new time " be adopted, striking clocks would not be any more 

 perplexing than they are now ? viz., by having two bells (a note 

 with its 3rd or 5th, for instance), one to strike tens and the other 

 units. By that means striking twenty-four would only require sii 

 "strokes" — two fens on one bell and four iinifs on the other, and 

 the greatest number of strokes would be ten instead of ficeire, as it 

 is now, viz., one ten and nine units for nineteen. 



Nigel Doisle. 



ULTRA-GAS. 



[1653] — I desire to ask a little elucidation of the following from 

 the Sa'tirday Vinvxevi on P. Mnir's " Chemistry " : — 



" In the solid the molecular motion is limited, and is not attended 

 with permanent change of position. In the liquid, motion is more 

 free ; the molecules change their respective positions, but do not 

 escape from the range of each other's attraction. In the gas, and 

 still more in that ultra-gaseous condition revealed to us by the 

 splendid researches of Mr. Crookes, the motion of the molecules is 

 so great that their mutual attractive force becomes insignificant." 



Does this contradict, or not, the law of universal attraction as 

 laid down by Newton ? Or, is it to be understood, as a matter of 

 coarse, that that law operates only within certain limits? As a 

 matter of fact, has the sun any pull whatever on the nearest star, 

 and vice rernd, ? "Insignificant" is an ambiguous word. Has 

 Crookes shown that in ultra-gas there is no attraction demonstrable? 



" Thronghont these changes of state the substance retains its 

 identity, becatise the molecules which determine its nature remain 

 unaltered. But the molecules are themselves composed of still 

 smaller, and, as far as we know, ultimate particles called atoms." 



(He had previously called the molecules "ultimate particles." 

 How can they be so if they have still lesser bodies within them ?) 

 " The molecules are, in a sense, clusters of atoms, but atoms in 

 motion, and not at rest. They are more fairly compared to solar 



LETTERS RECEIVED AND SHORT ANSWERS. 



NioEL DoELE. I am much obliged for your quotatiou from Bell, 

 but it refers to the Newts, and not to tho Land Salamander at all, 

 to which Mr. Gansby's iuipury liad reference. — J. Gavev (Cardiff). 

 Will yon be good enough to read the italicised paragraph which 

 appears (among other places) on p. 473 of tho last volume of 

 Knowledge ? — E. W. P. I have no map of England on a large 

 scale. In a table appended to an Atlas now before me, tho longi- 

 tula of Ellesmcro is given as 2" 51' (i.e. 11m. 3Gs.) west of Green- 

 wic'i. — Pro Bono Publico. Tho (so-called) "religions" journal 

 from which you forward mo a cutting is much too insignificant to 

 do any hurt; and tho 'mere calling attention to such terribly mis- 

 chievous qu.ackery can only do more harm than good. Equally 

 circumstantial details of alleged "cures" at Ilanley were given, 

 and you saw what they came to. I must decline to insult the writer 

 of the article on " Eaith-llealings" by forwarding such rubbish to 

 him ; but, of course, you can yourself do so if you please. His 

 address is Wm. Dunnett Spanton, Esq., F.R.C.S., Hanley. — 

 F. W. H. The discussion on Mind and Matter is now closed.^ 

 H. O. C. Before attempting to instruct any one upou a given 

 subject, it is just as well to take care that you possess some rudi- 

 mentary knowledge of it yourself. "Science" does not "teach 

 that there existed in pre-Adamite ages a race of animals with man- 

 like skeleton," who were not " men in tho sense," &c. What 

 Science really does teach is that tool making man lived in society 

 contemporaneously with tho mammoth, tho reindeer, tho Hon, the 

 cave bear, .and the hippopotamus ; nay, that ho was even pre- 

 glacial. Suppose that prior to dogmatising, you were to read Joly's 

 " Man before Metals," Lyell's " Antiquity of Man," Sir John 

 Lubbock's " Pre-historic Times," 4c. j whence you would learn 

 that your "race of animals" possessed tho artistic faculty to an 

 extent which enabled them to depict, from life, tho reiudeer upou 

 his own horn and the mammoth upon one of his own tusks ! 

 Man, quite probably the equal of tho existing Fuegian, 

 lived where I am writing, when as yet the English Channel 

 was not, and Norfolk and Germany wore oonteruiinoua. — 

 De. Lewins. I must adhere to my decision. Your reply to " Hall- 

 yards " is marked for insertion, though. Do not imagine that I 

 am opposed to " the utmost latitude in speculation " because I do 

 not print all you send me. I exclude it because, if I am to admit 

 a contention in favour of atheism pure and simple, I cannot, in 

 common fairness, exclude dogmatic theology, which our rules 

 expressly exclude. Moreover, the pressure on our space, of matter 

 of much wider and more popular interest, is enormous. I am at 

 least as much alive to the evil wrought by superstition as you can 

 possibly be. Your letter was unfortunately destroyed, with a 

 fcore of others, when I decided on its rejection. — Ciukles 

 Few. Having uttered your protest, and delivered your con- 

 science, I trust that you fee! that you have now douo your 

 duty. — J. H. Beowne. My education as a shipbuilder and rigger 

 having been neelected, I cannot define all your technical (and 

 some even obsolete) terms. Tho " spritsail yard," though, is 

 a yard carrying tho square spritsail beneath the bowsprit, and 

 tho "run of a ship" is tho number of "knots" (115 mile) 

 she makes in a day. "Manroo Doctrine" is (I fancy, but am not 



