Magic with SCEINCE

8/7/2019 Magic with SCEINCE

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by WALTER B. GIBSONIllustrated by RIC ESTRADA

GROSSET & DUNLAPANational General CompanyPublishera- NewYork


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COPYRIGHT 1968 BY WALTER B. GIBSONALL RIGHTS RESERVED

PUBLISHED SIMULTANEOUSLY IN CANADALIBRARY OF CONGRESS CATALOG CARD NUMBER: 68-19198

ISBN: 0-448-11564-6FIRST PAPERBACK EDITION 1973

PRINTED IN THE UNITED STATES OF AMERICA


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Contents

Introduction OPTRIX 32Sources for Materials Tricks and Illusions InvolvingOptical Principles

PHYSITRIX 17 Wine to Water 32Tricks Involving Various The Bending Pencil 33Principles of Physics The Mixed-Up Mirror 33The Mysterious Rod 34Mystic Comeback 17 The Penetrating Rod 34Pillars of Hercules 17 Card Vanishes from Glass 35Strong Paper 18 Making Money Multiply 35Bottle and Straw 19 Triple Your Money 36Comeback Ball 19 Surprise Sausage 37Mystic Rising Card 20 The Floating Ball 37Piercing a Potato 20 Which Is Larger? 37Tearing the Paper 21 X-Ray Tube 38The Restored Match 21 Crisscross Screen 38An Animated Hairpin 22 Restored Paper Napkin 39Grandmother's Necklace 23 Shadow Monster 40Name the Date 23 Candy from Nowhere 41Blocks and Rings 2 4 Through the Glass 4 2The Marked Match 2 5 Magic Lamps 4 2The Perpetual Propeller 26 Rub Away Coin 43The Rising Tube 26 Coin Gone 43Seesaw Sorcery 28 Coin and Glass 44Ups and Downs 28 Coin, Ring, and Card 45Snappy 29 An Appearing Coin 46Brush It Away 29 Metal Through Metal 46The Bouncing Cork 30 Mirror Image 47Cut and Restored String 30 The Roaming Coin 4 7

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6 CONTENTSMAGINERTIA 49 Lifting an Ice Cube 68Tricks Involving Inertia Sink or Swim 6 9Anti-Gravity Handkerchief 70Nine Coins 49 The Spinning Eggshell 71A Remarkable Nutcracker 49 Upright Corks 71Stacked Checkers 50 Strong Thread 72The Spinning Egg 51 Air Versus Water 73The Dropping Eggs 51 The Hydrostatic Glass 74One Quick Stroke 53 Magic Milk 76The Balanced Coin 53 Roller Coaster 76Balanced Bottles 54 Label Inside Bottle 77Flip Itl 54 Spread Away Matches 77Turn It Over 55 Magnetic Matches 78The Mysterious Diver 78

EQUILITRIX 56 ACOUSTRIX 80Feats of Equilibrium and Balance Tricks Involving AcousticsThe Balanced Pencil 56 The Singing Glass 80Another Balanced Pencil 57Amazing Paper Napkin 57 Big Ben 80The Dissolving Coin 81Bewildering Butterfly 57 Clink-Away Coin 82Turnover Match Pack 58Top Side Up 59Egg on End 59 AEROMAGIC 8 4The Balanced Forks 60 Magic InvolVing AerodynamicsThe Knife Stand 6 0Three Baseball Bats 61 Lift the Book 84Lift Five with One 61 Strange Spheres 84The Balanced Potato 62 Chameleon Balloons 85Crazy Cards 86Metal and Paper 86

HYDROMAGIC 63 Blowing Through a Bottle 87Tricks with Water and Liquids A Surprising Lift 89Blow the Book Down 89Amazing Grape Seed 63 An Amazing Dart 90Glass to Glass 63 Funny Funnel 90The Floating Coin 64 An Amazing Pincushion 91Steel That Floats 65 Bring Them Together 92Always North 65Magnetic Plastic 65 ARITHMETRIX 94The Strong Napkin 66 Tricks InvolVing ArithmeticTopsy-Turvy Eggshell 67Pepper and Salt 68 Apple, Egg, and Orange 94


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CONTENTS 7Magic Age Disks 9 5 GEOMETRIX 107The Colors Tell 9 6 Tricks Involving Geometrical PrinciplesThe Mystic Square 9 6Deceptive Dominoes 9 7 Deep in the Heart of Texas 1 0 7The Impossible Loop 1 0 8

The Double Loop 1 0 8ELECTRIX 98 Loop the Loop 1 0 9Tricks with Electricity The Knot That Is Not 1 0 9The Lost Line 1 1 0Salt and Pepper 9 8 It Shall Knot Pass 1 1 1Hypnotized Balloon 9 9 The Vanishing Domino 1 1 1Contrary Balloons 99 The Square That Wasn't There 1 1 2Magic Wallpaper 1 0 0 Push Along Coins 1 1 3Sticky Paper 1 0 1 The Impossible Knot 1 1 4The Magnetic Pen 1 0 1The Balanced Straw 1 0 2Weird Paper Strips 1 0 2 HYPNOTRIX 115The Impossible Match 1 0 3 Feats of Pretended HypnotismThe Magnetic Hand 1 0 3 Hypnotic Breeze 1 1 5Head and Foot 1 1 5

MAGNETRIX 104 Hynotic Fingers 1 1 6Tricks Utilizing Magnets The Hypnotized Knee 1 1 6The Rising Arms 1 1 7Mystic Paper Clip 1 0 4 A Hypnotic Touch 1 1 8Slippery Mucilage 1 0 5 The Brush-Off 1 1 8The Suction Cup 1 0 6 The Heavy Hand 1 1 9


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Introduction

Since the dawn of civilization, science and magic have been closelylinked. Primitive men utilized scientific methods in their daily lives; forthe crude tools of the Stone Age, snares devised to trap wild animals, thefirst implements fashioned from metal, all represented scientific advances.Any discoveries that were easily explained were regarded as natural, butanything of a puzzling nature was assumed to need some special power tocontrol it. That, to a marked degree, represented the dividing line betweenthe scientific and the magicalMagnetism offers a striking example of this. In ancient times, it waslearned that fragments of magnetic ore, called lodestones, would attractiron. A needle stroked with a lodestone would become magnetized and

point north. This led to the invention of the mariner>s compass, a simplescientific device and a boon to navigation. But from the behavior of thecompass needle grew the legend of a magic mountain in the Far North, sopowerfully magnetic that it could draw the iron nails and spikes from ap-proaching ships and leave their wreckage strewn on its shores.When Columbus sailed to the discovery of America in 1492, his crewnoted a variation in the direction of the compass and wanted to turn back,thinking that the needle was bewitched. The real reason was that the com-pass does not point to the true north, but to the magnetic north. Columbuswas enough of a scientist to explain the phenomenon to the satisfaction ofcrew, and thus their superstitions were calmed and the mutiny was quelled.But in 1503, when Columbus and his ships were stranded in Jamaica

during his last voyage, he played the part of a magician to forestall troublewith the natives. Playing upon their superstitions, Columbus promised toinvoke some real black magic upon a specified day; and black it was, forthe natives watched in awe as the sun was blotted out at his command.That kept them subdued until relief ships arrived; for they never realizedthat Columbus had simply predicted an eclipse, which by his calculationswas sure to occur on that date.

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10 INTRODUCTIONIn the year 1609, an obscure Dutch optician, Johannes Lippershey, wasworking on some lenses and happened to hold them to the light, when tohis amazement, the spire of a distant church was brought to a spot just

outside his window. Since Lippershey had a scientific mind, he realized thathe had made a new discovery in optics, and he made it public. Itwas im-proved upon by the Italian astronomer, Galileo, who developed the tele-scope from it.If Lippershey had known less about lenses, he might have mistaken hisdiscovery for something magical and kept the secret to himself. In thatcase, it might have been many more years before the telescope was in-

vented. Ever since Calileo's time, however, lenses and mirrors have beenused in magical illusions which have been presented on the stage, andmany surprising optical tricks can be performed in an impromptu fashion,as will be described in later chapters.Electrical experiments provide a still more remarkable linkage of science

and magic. Until as late as the year 1752, the ancient superstition of awrathful thunder god hurling shafts of lightning from the sky still grippedthe public mind. To give it scientific status, a theory was advanced thatlightning was generated from the sulphurous and bituminous substancescast up by volcanic eruptions. The odor of 'ozone, sometimes noted after alightning stroke, was mistaken for brimstone, furthering the suppositionthat the volcanic stuff was actually hell fire, cast by the hand of Satanhimself.When Benjamin Franklin flew a specially constructed kite in 1752 and

brought electricity down the kite string from the thunder clouds, sciencescored another triumph over superstition. From that success, Franklin in-vented the lightning rod, and within a few years, thousands of Americanhouses were equipped with them. Still there were diehards who clung tothe old notions, one man even claiming that Franklin's lightning rods werecharging the earth with so much electrical substance that severe earth-quakes would surely follow!Along with important advances in science, interest in lesser experimentshad grown steadily, for it was from such trifles that great discoveries weremade. Franklin was intrigued with such gadgets. In his youth, he carried apurse woven with asbestos, a fireproof substance that was just then cominginto vogue. After letting friends try to set fire to it, only to fail, Franklinblandly explained that he carried such a purse so that his money wouldn'tburn a hole in his pocket.With that, Franklin really set the pace for the era of scientific magic thatwas to follow and expand to its modern proportions. A few years before

Franklin flew his famous kite, a French scientist, Jacques Ozanam, pro-duced four volumes which were later translated into English under thethe title, Recreations in Mathematics and Natural Philosophy. The term"Natural Philosophy" at that time meant "science," and some twenty yearslater, another French writer, Guyot, published four volumes of New


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INTRODUCTION 11Recreations, which included various electrical experiments originated byFranklin.Still later, Dr; William Hooper, a London physician, compiled four vol-umes of Rational Recreations, elucidating the principles of Natural Philos-ophy, by a series of "easy, entertaining, interesting experiments" takenchiefly from Ozanam and Guyot. In a flowery introduction, Dr. Hooperstated, in part:"Should we not endeavor to render useful learning not dull,tedious, and disgustful, not rugged and perplexing, but facile,bland, delightful, alluring, captivating? That Philosophy, with his

sober garb and solemn aspect, when led by the hand of thesportive nymph Imagination, decked in all the glowing, ever-varying colors of the skies, may gain admittance to the partiesof the gay and careless; and while his awful eye restrains theexuberance of her sallies, the beams that dart from her radiantfront may play upon his countenance, and dissipate the cloudthat too frequently hangs over his brow."Today, that can all be put in two words: "Have fun." Some of the ex-

periments described by Dr. Hooper are as intriguing now as they werethen; and during the two centuries since his Rational Recreations werepublished, hundreds of others have been devised and recorded, many in-volving principles unknown in Hooper's time. The best of these have beenchosen for this volume. Substitute the word "science" for "philosophy" and"magic" for "imagination." The result will be Science Magic.Ordinary scientific experiments, while instructive, merely bring results

that everyone expects. In contrast, feats of magic, while surprising, mayrequire skill and practice to perform. By combining science with magic,surprise is gained with ease, so you can embark upon a career of wizardryat the very first try. You may decide beforehand whether you should pres-ent your marvels as scientific experiments or feats of magic-or, for thatmatter, as both. In any case, choice of items is important, for the follow-ing reasons:From your standpoint, as well as that of your audience, all experimentsin Science Magic fall into one of two groups: challenges and mysteries.Their main difference is that a challenge is essentially a puzzle, whichmust finally be explained to people, as otherwise they may think there isno solution and the experiment will be meaningless. In contrast, a mysterydepends upon a trick which enables you to produce a magical effect, with-out revealing the secret. Such tricks can be performed time and again,with the same baffiing results.The best plan is to begin with experiments of the challenge type asthey are often simple and direct. Either you state that you can accomplish

something that is seemingly impossible; or you invite someone to try it.When everyone is sure it can't be done, it is up to you to prove it can be.With feats of balance, demonstrations of inertia, or problems of a geo-


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12 INTRODUCTIONmetrical nature, once you have completed the experiment, the methodis often obvious.Hence you have baffied your friends only temporarily. The upshot isthat they, too, can puzzle people with the same stunts, for which theyshould duly thank you. Very little practice is needed with most of thesechallenges, because if you fail at the first try, you keep on, which makesthe experiment look more difficult and therefore better. Since such stuntswill make you popular, there is no need to worry because you must dis-close the methods in order to prove your point. Often, people forget howthe stunts were done, or want you to do them over for their friends.Finally, so many of these diverting challenges are available that you canalways add a few new ones on the next occasion. In such demonstrations,

there is no need to plan a regular program. Just carry a few needed itemswith you and borrow the others as required. Occasionally you can combineone experiment with another, or use one as a follow-up, as will be sug-gested with the descriptions of certain items. But generally speaking,challenges are individual items in themselves and are most effective whenshown in an off-hand manner, so no set routine is necessary.After puzzling your friends with challenges, you can proceed to baffie

them with experiments of the mystery type. You will still be depending onscientific factors, but in this case, the principle is concealed. Many opticaltricks are of this type, as are those involving static electricity, magnetism,and pretended hypnotism. Since observers do not know the secret of sucha trick, they may credit you with great skill, though actually you are foolingthem scientifically. Inject a few of these mysteries into your usual nm ofchallenges and watch how people go for them!As a rule, you should never divulge the secrets of such tricks as that mayspoil future fun. If you have to admit that someone has guessed right, doit with a smile and go on to something else. Remember that you are ascientist as much as a magician. By making that clear at the start, you maysave yourself some embarrassing moments if a trick fails.Even the Great Houdini occasionally took this way out of a dilemma. Heonce performed with a remarkable "Flying Lamp" that vanished instantlyfrom one table and appeared just as suddenly upon another. Houdinibought the trick from a German magical manufacturer named Conradi,and though it was a marvel of mechanical ingenuity, there were timeswhen it went wrong and reappeared too late, or even worse, too soon. SoHoudini used to say: "This trick was invented by a magician named Con-radi, and I improved it. If it works, you will know it's my trick. If itdoesn't work, it's still Conradi's."You can use a few quips of your own when an experiment fails, such as,

"I forgot to use the magic word for that trick." Or, "The magic word forthat one was 'Abracadabra' but I should have said it backwards. Let's tryagain." Or, "I shouldn't have tried that experiment. I just rememberedthat it only works when the moon is full." All that adds to the fun.


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INTRODUCTION 13Gradually, as you use more and more mysteries as opposed to chal-

lenges, you can stress tricks rather than puzzles and build up a programthat will be almost completely magic. That is when you should make surethat all the required items are available and carry your own, rather thantrust to luck. Often, an article used in one trick will do for the next, sothat you can move smoothly from one experiment to another.Even better, as you build up your act, you will find that you can set the

stage beforehand, with such items as bottles, glasses, candles, rubber bal-loons, and other articles all on display. This will intrigue your audience andenable you to pick each item as needed. After finishing each trick, youcan put its equipment away in a large box or special case that you haveready for that purpose. This will enable you to dispose of certain articlesthat might give away the secret if people had a chance to examine themafter the trick is finished.Rehearsal and routining will help as your experiments veer from the

purely scientific and take on the aspect of a full-fledged magic show. Butno matter how mystifying your performance may become, it is still goodpolicy to inject a few challenges into the act. Letting people worry over apuzzle and then showing them the solution is the best way of addingaudience participation to your performance. Also, by showing them a fewscientific stunts that they can do, you can politely decline to give themexplanations of the more mysterious effects that you prefer to reserve foryour very own.All the experiments that follow have been chosen for definite reasons.

First, all items required are either easy to obtain, or are inexpensive. Next,cumbersome experiments demanding too much preparation have beenavoided. The few that require the lighting of a match or a candle, or theuse of a knife, should be presented with due care and always with anadult present, when performing for children.


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Sources for Materials

Many of the items listed here can be found in most homes. If any are notavailable there, they may be obtained from the following places:DRUGSTORE Adhesive tape Corks Medicine dropper Playingcards' Straws

ART SUPPLY or STATIONERY STORE Ballpoint pen' Celluloidor plastic Cardboard tube Paper clips Rubber bands Ruler Thumb tacks' Acetate, clear, thickness .075

LUMBER or HARDWARE STORE DowelGROCERY Apples Crackers Eggs Matches Orange Potato Walnuts

FIVE-and-DIME or VARIETY STORE Ballpoint pen Balloons Candle Checkers _. Dominoes Drinking cup~ Funnel Glasses Safety matches' Mending tape' Mirrors' Needles' Paper napkins Pins' Playing cards' Rings Rubber bands' Straws' ThimblesHARDWARE Adhesive tape Aluminum Aluminum screening Alu-minum wire Celluloid or plastic Funnel Glass disk Glass rod Magnets Mending tape Plastic Rope String

SPORTS or DEPARTMENT STORE Beads' Blocks" (wooden toyblocks) Cake tins Checkers Dominoes Golf ball Hairpins Mir-rors Ping pong balls Rings Wooden beads Yam Holes may have to be bored into the blocks


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PhysitrixTricks Involving

Various Principles of Physics

Mystic Comeback EFFECT: A large cake tin is set on its sideand rolled along the floor, like a wheel. Soonit stops, then mysteriously reverses itself androlls back the other way . MATERIALS: A cake or cookie tin, 31hinches high and 10 inches in diameter, or ap-proximately those dimensions. A horseshoemagnet, an ounce or more in weight; or anymetal weight and some adhesive tape. WHAT To Do: Attach the magnet to theinner side of the cake tin and put the coveron the tin. The magnet stays of its own ac-cord unless the tin is non-magnetic. In thatcase, any metal weight-such as a bolt ornut-can be fixed in place with adhesivetape. All is then ready for the demonstrationthat followsSet the tin on its side with the weight near

the top and give it just enough of a forwardroll so that it carries past the bottom andalmost to the top again. There, it will stopand roll back the other way. WHAT HAPPENS: If you set the tin withthe weight near the top but slightly towardyou, it will automatically roll in your direc-tion as the center of gravity lowers itself. Byrolling it one way in the manner described,you put the weight in the exact position f.orthe reverse roll. The forward roll loses Itsimpetus and the backward roll takes controlas it normally would have, if this had beenpresented as a scientific experiment at thestart.

Pillars of Hercules EFFECT: To prove that a sheet of paper isquite fragile, it is curved slightly, set onedge, and then crumpled with a lazy down-stroke of the hand. But you can still set suchpieces of paper edgewise and have them sup-port a weight of several pounds. MATERIALS: Four sheets of fairly small pa-per, some mending tape or rubber bands,and several good-sized books. WHAT To Do: Roll each sheet of paper in-

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18 MAGIC WITH SCIENCE

to a tube one inch or more in diameter andeither tape it together or gird it with a rub-ber band. Set these tubes upright as thecorners of an imaginary rectangle. Rest abook flat on these "Pillars of Hercules," asyou can term them, and when it is set inplace, add another book on top, then anotherand perhaps still more. The paper pillars willsupport them all. WHAT HAPPENS: This is a scientific test ofsimple longitudinal stress, where a short pil-lar is compressed by opposite forces appliedat its ends. The paper pillars serve like hol-low metal posts as long as the pressure isstraight downward; in fact, the books mightas well be resting on a stack of paper sheets.But any strain from another angle will resultin compound stress, causing a pillar to col-lapse, as can be tested by adding too manybooks.

Strong Paper EFFECT: A single sheet of paper is laidacross two drinking glasses with a wide spacebetween. A third glass is set on the openstretch, and the paper naturally caves down-ward. But in repeating the experiment, witha certain modification, the paper is shownto be strong enough to support the weightof the glass. MATERIALS: A sheet of paper and threeglasses. WHAT To Do: First, lay the paper acrosstwo glasses and show that it can't supporta third. Then pleat the paper lengthwise,folding one edge %-inch forward, thendoubling it lh-inch back, then forward, back-ward, and so on, until the entire sheet has

been pleated. Place it across the two glassesand you can safely set the third on the spacebetween. WHAT HAPPENS: In pleating, the papersheet is formed into a series of upright seg-ments, which, when compressed together,become a solid support. In spreading into azigzag formation, they still retain sufficientstrength to withstand a simple downwardstress, provided there are enough pleats tokeep the formation from becoming too wide.


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This is why corrugated metal can standgreater stress or strain than a Hat sheet ofmetal. The experiment simply applies theprinciple to paper.

Bottle and Straw EFFECT: A drinking straw is inserted in anempty soda water bottle and immediatelythe bottle is lifted by the straw. MATERIALS: A few straws and an emptybottle. WHAT To Do: Bend the straw a few inchesfrom one end and insert this end well downin the bottle. Lift the upper end slowly andthe bent straw will bring the bottle with it.

WHAT HAPPENS: The bent portion of thestraw wedges at a cross-angle, thus servingas a brace. The curvature of the longer por-tion brings the center of gravity directly un-der the point of suspension, thus completingthe requirements for the experiment. Testswith several straws may be necessary to in-sure success.

PHYSITRIX 19Comeback Ball

EFFECT: A small ball is rolled along a tablefrom hand to hand. Finally, it is given a shortroll in which it stops halfway and thenwhizzes backward entirely of its own accord. MATERIALS: Almost any small ball rangingin weight from a ping-pong ball to a golf ball. WHAT To Do: Roll the ball easily a few

--~~jtimes, from the right hand to the left. Thenhold it in the right hand, thumb above, sec-ond finger below, with the knuckle of thefinger close to the table. Give the hand aslight jerk toward the left, and at the sametime, snap the thumb and fingers in oppositedirections. The ball will travel along the ta-ble toward the left, stop and scoot back tothe right in a most surprising fashion. WHAT HAPPENS: The jerk sends the ballforward along the table although the snapof the fingers spins it backward, or towardthe right. The ball appears to roll forward-or to the left-but it really slides. Oncethat motion is counteracted by the spin, theball rolls the other way. REMARKS: Different techniques are neededwith balls of different weight, and sidewiseor angled spins are also possible. A good for-ward slide and back spin give the effect ofan automobile wheel coming out of a skidand starting off as its tire tread takes hold.


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20 MAGIC WITH SCIENCEMystic Rising Card

EFFECT: A playing card is chosen from apack and pushed down into a drinking glass,which is then covered by the pack, imprison-ing the chosen card. The pack is then liftedand given a sharp snap. At that command,the chosen card rises of its own accord, eventoppling from the glass. MATERIALS: A fairly tall glass, slightlywider than a playing card, at the top, butconsiderably narrower at the bottom. A packof fairly new playing cards with a glossy orplastic finish, so the edges are quite smooth.A small piece of dry soap. WHAT To Do: Rub the inner walls of theglass with soap, which can then be spreadwith the fingertips so that it becomes a thinfilm which is no longer discernible. Havethis glass ready with the pack.

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WHAT HAPPENS: When a card is chosenand pushed down into the glass, its lower

end, being pliable, tends to spread with themechanical action of a spring. This wouldforce the card upward, except for the slightfriction from the gradually widening sidesof the glass, but that, in turn, is counteractedby the application of the soap, which actsas a lubricant. The weight of the pack pre-vents the card from rising too soon, butonce it is removed, the experiment goes intoautomatic action. The quick snap given tothe pack is simply byplay to make the risingof the card seem more magical. REMARKS: Many types of drinking glassesare suitable for this experiment, so severalvarieties should be tested to find the best. Aduplicate glass should be kept handy, so thatthe soaped glass can be laid aside after thetrick and the duplicate used in a later experi-ment. Anyone trying to make a card rise fromthe untreated glass will be disappointed.

Piercing a Potato EFFECT: An ordinary drinking straw is heldin one hand and a potato in the other. Witha forward thrust, the straw is driven straightthrough the potato, piercing it completely.Yet, when the straw is withdrawn, it can bebent and folded to prove that it is quiteordinary. MATERIALS: A raw potato of average sizeand a common drinking straw. WHAT To Do: Both the potato and thestraw can be given for examination before-hand, but when the straw is returned, it istaken at the far end between the right thumband fingers. The potato is then poised in theleft hand, while the right thumb secretlybends the end of the straw inward and flat-tens it against the fingers, keeping it firmlypressed there. All that remains is to give thestraw a straight, direct thrust against the


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side of the potato, and it will continue onthrough. In withdrawing the straw, the rightthumb straightens the end, so that it appearsordinary; but it is a good plan to give thestraw a few folds later on, so that no one willsuspect anything . WHAT HAPPENS: By sealing the far end ofthe straw, no air can escape when the nearend is driven squarely into the potato. Theair, being compressed by the thrust, acts asinterior rod or pillar, strengthening the strawsufficiently to insure the penetration.

Tearing the Paper EFFECt: A piece of newspaper is torn partway through in two places, forming a rowof three strips. Anyone is invited to take the

PHYSITRIX 21end strips and tear them in opposite direc-tions at the same time, so that the centerstrip will fall entirely clear. Strangely, who-ever tries it is sure to fail. MATERIALS: Several fair-sized pieces ofnewspaper. WHAT To Do: Make two preliminary tearsas described, leaving about two inches stillto be torn in each case. In tearing, a personwill find that one tear invariably gives way,leaving the other intact. Always, one endpiece will come free; never both.

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WHAT HAPPENS: There is sure to be dif-ference in the original tears, such as theirlength, their direction, or the weakness ofthe paper fibers at a particular point. As aresult, one always gives way before the other,and you prove conclusively that this simplestof experiments is so difficult it can't be done.

The Restored Match EFFECT: A large match is wrapped in thecenter of a handkerchief. Through the cloth,the match is deliberately broken into threeparts. Yet when the handkerchief is un-


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22 MAGIC WITH SCIENCEfolded, the match drops on the table, com-pletely restored. MATERIALS: A match and a plain handker-chief. WHAT To Do: Fold the match in the centerof the handkerchief, show its shape throughthe cloth, and actually break it with yourthumbs and forefingers, about one-third ofthe way from one end. Then move along andrepeat the breaking process near the otherend. Now, gather the center folds moretightly and as you do, carefully straightenthe broken portions of the match throughthe cloth. Take the handkerchief by one cor-

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ner, shake it slightly and the match willdrop on the table, appare~tly restored.

WHAT HAPPENS: Here, the pliability ofwood fibers plays the vital part. When thematch is broken with a sharp snap, its sec-tions bend inward, with the innermost fibersremaining intact and acting like a hinge. Bypressing' the segments outward, the hingedportion will guide them back into place sothat the broken fibers will mesh. Thus thematch is straightened and shown apparentlyrestored. REMARKS: This can be tested without usinga handkerchief, in order to note the scientificprinciple upon which the experiment de-pends. To break a match fully, it must besnapped one way, then the other. A singlesnap is not sufficient, but that fact is con-cealed by breaking the match inside thehandkerchief.

An Animated Hairpin EFFECT: A hairpin is set astride a rulerwhich is held so that the ends of the hairpintouch the table. At command, the hairpinwalks along the ruler, forward and back-ward, in a manner which is not only lifelike,but uncanny. MATERIALS: A large hairpin and a ruler,preferably of the 12-inch type.


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WHAT To Do: Set the hairpin on the rulerand hold the near end of the ruler level, butjust clear of the table, gripping it in yourfist. When you lower the ends of the hairpinto the table, you will find that the hairpin, ifleaning slightly forward, will automaticallywalk away from you. By raising the ruler,then lowering it so the hairpin leans back-ward, the hairpin will walk toward you of itsown accord. Just the slightest of tilts willspeed up the pace. WHAT HAPPENS: The muscular vibration ofyour hand supplies the motive power forthe animated hairpin. Since your hand is notresting on the table, it is impossible to keepit absolutely steady. Imperceptible thoughyour muscular reaction may be, it makes thehairpin walk forward and backward, accord-ing to its tilt.

Grandmother's Necklace EFFECT: Three wooden beads are strung ona pair of strings. The strings are crossed andone pair is given to a person on the left; theother pair is given to someone on the right.The beads are covered with a handkerchiefand beneath the cloth, they are mysteriouslyremoved from the strings, which are drawntight by the surprised spectators. MATERIALS: Three wooden beads withholes drilled through their centers. Small

PHYSITRIX 23wooden blocks can be used instead. Twopieces of soft white string, exactly alike andabout two feet long. A bit of white thread. WHAT To Do: Tie the thread about thecenter of the strings, which are laid togetherevenly. This enables you to bend back theends of the strings, so they become twoloops, joined at the center by the thread. Runthem through the beads, so that the loopedcenter is concealed within the middle bead.Exhibited thus, the two strings appear to

run straight through the beads in normalfashion. But when each person is given twoopposite ends and the strings are pulled, thethread breaks, the beads drop off and thehandkerchief is removed to show the stringsas good as ever. WHAT HAPPENS: The beads naturally dropbecause only the thread sustains them. Butthe switch of the ends actually gives eachperson an end of each string, so they finishwith the strings exactly as they were ori-ginally supposed to be. REMARKS: This is one of the oldest experi-ments in scientific magic, dating back to thejugglery of the Middle Ages, and from ithave derived more intricate tricks that arestill popular today.

Narne the Date EFFECT: Several pennies, all alike exceptfor their dates, are lying on a plate. Whilethe performer's back is turned, a person istold to take one of the coins and dump therest into a hat. The chosen coin is then passedto all persons present, so that each can notethe date and remember it. That done, it is


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24 MAGIC WITH SCIENCEtossed into the hat and shaken up with therest of the coins. Yet the performer, reach-ing into the hat and bringing coins out oneby one, stops when he comes to the rightcoin, looks at it, and names the date, whicheveryone confirms. MATERIALS: Several pennies with differentdates. A cold plate. A harrowed hat.

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WHAT To Do: Have the coins spread onthe plate so everyone can see how similarthey are. Turn your back and tell someone totake a coin and immediately pour the restinto the hat, directly from the plate. Addthat you want everyone to note the date onthe chosen coin, as the more persons think-ing of it, the better your chance of namingit. After the chosen coin is dropped into thehat, pick out the coins one by one. You willnote that all feel cold, except one. The warmone will be the chosen coin. WHAT HAPPENS: Metal normallv becomes.

cold, particularly when kept in contact withanything like a cold plate. But when a coinis handled, it absorbs heat from the humanhands. By insisting that everyone look atthe date, the coin is passed around suffi-ciently for you to distinguish its warmththe moment you touch it.

Blocks and Rings EFFECT: Three wooden blocks are shownon two strings which run through holes inthe centers of the blocks. The ends of thestrings are crossed and a pair of finger ringsare strung on each pair of ends. People holdthe ends of the strings, and the blocks andrings are covered with a handkerchief. Whenthe ends are pulled, the blocks fall from thestrings, but the rings mysteriously remain inplace. MATERIALS: Three blocks with holes drilledthrough their centers. Two finger rings whichmay be borrowed. Two pieces of identicalstring, a short thread, and a handkerchief. WHAT To Do: Prepare the strings as with"Grandmother's Necklace," (see page 23 )bending back the ends and running themthrough the holes in the blocks so that thedoubled center is hidden within the middleblock. Cross the strings, but before givingthem to anyone, slide a ring over each pairof ends. Let people hold the ends and pullas soon as the handkerchief covers the blocksand rings. The thread breaks, releasing theblocks, but the rings remain on the strings. WHAT HAPPENS: The blocks fall from thebroken center, but the rings stay becausethey were not put on the strings until after


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the ends were crossed. That made them twostraight strings-exactly what people tookthem to be-so far as the rings were con-cerned. REMARKS: If either "Grandmother's Neck-lace" or the "Blocks and Rings" are set upbeforehand, the strings can simply bedoubled and inserted in the middle bead orblock, without using a thread as a link. Butwith the thread, it is possible to conceal thecenter between the thumb and fingers of onehand, while openly threading the strings withthe other hand.

PHYSITRIX 25

The Marked Match EFFECT: Several large wooden matches areexamined and found to be absolutely iden-tical. One match is then marked with fourshort pencil lines along each side, so lightlythat it would be impossible to feel the marks.The performer then places his hands beneaththe table, where he is given the matches, one

by one. He passes each one back until he re-ceives the marked match. Though he has ab-solutely no chance to see it, he announcesthat it is the marked match-and he is right! MATERIALS: A dozen wooden matches. A


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26 MAGIC WITH SCIENCEpencil. Two pairs of steel pliers. Some bitsof paper. WHATTo Do: Prepare one match by wrap-ping bits of paper around its ends; then gripthe ends with the pliers. With one hand,twist an end of the match slightly forward,with the other hand twist the opposite endslightly backward. Continue this action withthe pliers until the match will yield whentested with the thumbs and fingers alone.Have the flexible match with the otherswhen you present the experiment. Mark itwith the pencil and let people examine themarked match with the rest. Whatever elsethey do, they will never think of twistingthe ends in opposite directions, rotary fash-ion. But you think of it, when the matchesare handed to you beneath the table. Theone that gives when you apply the right twistwill be the marked match, every time. WHATHAPPENS:From the scientific stand-point, this is one of the most ingenious ofmagical experiments. Here, you take advan-tage of the fact that wood fibers weakenunder continued strain. You are dealing withtorsion instead of just pliability, for if youbend the matches slightly, as though to breakthem, you will find no perceptible differencebetween the marked match and the others.All this is important scientifically, for itexplains why unexpected accidents may hap-pen, even though supposedly thorough pre-cautions have been taken. Metals, too, canweaken as the result of fatigue, as in the caseof airplane wings or the cahles of suspensionbridges.

The Perpetual Propeller EFFECT:A two-bladed propeller cut fromcardboard is tacked to the end of a notched

stick. When the stick is rubbed rapidly, thepropeller starts to whirl and keeps on goingas if impelled by some perpetual force . MATERIALS:A cardboard propeller, a tack,and a piece of dowel or a similar stick, witha series of notches cut at regular intervals. WHATTo Do: Hold the end of the stickwith your left thumb and fingers. Doubleyour right fingers and run your extended rightthumb along the notches. A quick, repeatedaction will start the propeller spinning andit will continue as long as the same motionis applied. WHATHAPPENS:Due to the notches, themotion of the right thumb and fingers veersfrom a straight line and causes the stick torotate very slightly. The rotation is trans-mitted to the improvised propeller which re-volves accordingly. By reversing the rubbingprocess, the propeller can be spun in theopposite direction. When whirling at fullspeed, the effect is highly baffling.

The Rising Tube EFFECT:A long cardboard tube is shownthreaded on a still longer string. One endof the string is held upward, and the tubeis allowed to slide downward to the otherhand. There is nothing phenomenal yet, but


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wait! At the word "Rise!" the tube mys-teriously ascends the string almost to thetop. It repeats this, falling and rising, asoften as desired. MATERIALS: A cardboard mailing tube, 18inches long, 11Minches in diameter. A string,36 inches in length. Another string, 22 inchesin length. (All dimensions approximate.) Asmall curtain ring of less diameter than thetube. A thumbtack. WHAT To Do: Tie the ring to one end ofthe short string and drop it down throughthe tube, so it just barely emerges at thelower end. Lay the tube flat and push thethumbtack just inside the lower rim of thetube, so that the tack points outward. Tieone end of the long string around the headof the thumbtack. Push the other end of the

22,".S n. . +

IIIII1 3 , r t . IT lA b e - :

IIIIII

PHYSITRIX 27long string as far through the ring as it willgo.Now, take the end of the short string atthe top of the tube and draw it upward untilthe ring is hidden inside the lower end ofthe tube. Hold the end of the short stringwith your right hand and take the free endof the long string with your left hand. Drawthe ends of the strings taut, then lift the tubeupright, your right hand above, your lefthand below.You will find that the tube hangs steadily

near the top of what appears to be a singlestring more than twice the length of thetube. This is the way you show the tube andstring to start, so it is a good plan to gripthe top of the tube by bending one or twofingers inward and pressing the rim of thetube against the right palm, as if you wereholding the tube in place.Relax the left hand's hold on the lower end

of the supposedly single string and the tubewill slide down nearly to the bottom as itpresumably should. Then pull the endsstrongly and the tube will rise to the top, ap-parently o f its own afcord. It can be madeto fall and rise las often as you want; and itcan be stopped halfway by simply keepingthe strings taut instead of pulling them orrelaxing the lower end. WHAT HAPPENS: It is a simple illustrationof the pulley principle, with the long stringhoisting the tube, just as pulling the end of adoubled rope raises a weight on the otherend. If done openly, there would be no mys-tery, but the tube conceals the block-and-tackle arrangement which is responsible forthe lift. Here, science is strongly applied tocreate a baffling illusion. REMARKS: The supposedly single string be-comes shorter each time the tube is raised,and it lengthens whenever the tube is low-ered. This, however, is not noticed, due tothe length of the tube itself. A shorter tubecan be used, with the strings proportionately


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28 MAGIC WITH SCIENCEshorter, but the extent of the rise necessarilywill be reduced and the experiment will beless effective.

Seesaw Sorcery EFFECT: A ruler is laid across a pencil, andtwo paper cups partly filled with water arebalanced on opposite sides, like a seesaw.Without touching either of the cups or theruler-or even the pencil-you make thethe cups seesaw up and down. MATERIALS: Two paper cups, some water, apencil, and a ruler. WHAT To Do: Pour water into each cup,until each is more than two-thirds full andboth balance nicely. Dip your right forefingerin one cup and that side will go downward.

Dip your left forefinger in the other cupand lift your right finger; down goes the leftside. By alternating your fingers in this fash-ion, you can keep the seesaw going back andforth, without ever touching cups or ruler. WHAT HAPPENS: Dipping an object into a

cup of water increases the weight accordingto the amount of water displaced. An an-cient Greek named Archimedes discoveredthis while taking a bath and you can prove ittoday by simply demonstrating the seesawcups.

Ups and Downs EFFECT: Two empty paper cups teeter onthe ends of a ruler whenever you dip a fingerinto one; yet you never touch the cups. MATERIALS: Two paper cups, a ruler, anda pencil. WHAT To Do: Balance the ruler across the

the pencil, with the cups on opposite sides.As you dip a finger into a cup, lean in that


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direction and blow downward into the cup.Do the same with the other cup and you cankeep them going up and down as long as youwant. WHAT HAPPENS: The cups are so light thata mere breath can disturb their equilibrium.Being open, they catch a puff of wind likelittle sails. Hence it is easy to blow so gentlythat the action will not be detected.

Snappy EFFECT: A rubber band is put around acalling card or any piece of thin cardboard ofsuitable size. The card is cut in half with apair of scissors, squarely across the rubberband. Yet the rubber band is uninjured andcan be snapped back and forth to prove it. MATERIALS: A fairly thin rubber band anda thin card just wide enough for the rubberband to be girded about it and kept taut. Apair of old scissors, which must be large andloose. WHAT To Do: Put the rubber band aroundthe card and cut straight through the card,directly across the rubber band. A long, care-

PHYSITRIX 29ful cut will sever the card, leaving the rub-ber band intact. If you have trouble finishingthe cut, start from one edge and go as faras the rubber band. Then turn the cardaround and cut from the other edge so thatthe cuts meet soon after the scissor bladespass the rubber band. People will still bepuzzled by the survival of the rubber band. WHAT HAPPENS: The card, being stiff, iseasily cut, while the rubber band, being pli-able, is squeezed down between the looseblades of the scissors. Thus two simple scien-tific principles of cutting are at work, eachproducing an opposite result. This should betested beforehand, to make sure the scissorsare neither too sharp nor too dull; too tightnor too loose.

Brush it Away EFFECT: A penny is laid in the palm ofyour hand and you give someone a hairbrush,


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30 MAGIC WITH SCIENCEtelling him to sweep away the coin. To hissurprise, he is unable to do so. MATERIALS: A coin and a brush. WHAT To Do: Lay the coin in your handas described, but tell the person that he musttry to brush it away in long, straight sweeps.He can't succeed because the brush willride over the coin without contacting it. WHAT HAPPENS: The coin rests in the hol-low of your palm, which is much deeper thanmost persons realize. The brush is too wideto dip down into the hollow, hence it missesthe coin entirely.

The Bouncing Cork EFFECT: A person is given an ordinary corkand asked to drop it on the table so it standson end. Always, the cork bounces when it

hits and lands on its side; that is, until youtry it. Then it stands on end. MATERIALS: A cork, with a table handy. WHAT To Do: Drop the cork so it hits onits side. Itwill bounce, of course, but with alittle practice you can gauge the drop so itfinishes standing upright. WHAT HAPPENS: Due to its lightness andresiliency, the cork will bounce no matterhow it is dropped. Landing on its side, it willoften bounce on end; and the bounce beingmuch less forceful than the drop, the corkcan stay balanced on end. Test this before-hand to specify the distance of the drop,which in turn governs the force of thebounce.

Cut and Restored String EFFECT: A length of string is cut in halfwith a pair of scissors, and both sections areshown separately. The ends of the string arebrought together and it is allowed to dropfrom one end. The string promptly danglesin a single length, restored to its originalform. MATERIALS: A piece of yarn, 12 inches ormore in length. A pair of scissors or a knife. WHAT To Do: Show the yarn, but call it"a piece of string." Cut it near the center,show the two pieces and bring the cut endstogether between the thumb and fingers ofyour left hand. Gather the two dangling endswith your right thumb and fingers, so thatthe ends overlap an inch or so.As you bring those lower ends upward, roll

them together, at the same time raising yourleft hand and remarking, "Here we have thetwo cut ends, so I'll put the other ends with


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them, making four ends in all." Bring thehands together, move them up and down,then hold one cut end and let the other fall.The string will dangle freely, apparently re-stored to a single piece. WHAT HAPPENS: Since the supposed stringis actually yam, its fibers are fluffy and ad-here closely when the ends are rolled to-

PHYSITRIX 31gether. Be sure to use yam with a loose twistand test it beforehand. Keep the dangling"string" slightly in motion and no one willnotice the slight thickness near its center.At the finish, you can gather it together andput it in your pocket without any chance ofits coming apart.


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OptrixTricks and Illusions

Involving Optical Principles

Wine to Water EFFECT: A small glass is shown filled withdark, purplish wine. It is covered with ahandkerchief and changes to a light red wine.Covered again, it becomes water, which any-one may drink. MATERIALS: A small glass, preferably thetype with a stem. Two thin but stiff pieces ofcelluloid or plastic, one red, the other blue orgreen. These are cut to fit the glass exactly;this can be done neatly by using a piece ofstiff paper for a pattern. Some water, a hand-kerchief and an object to serve for a stand,such as a book or a box. WHAT To Do: Beforehand fill the glass andinsert the plastic cut-outs together, so thatwhen they are viewed broadside, the waterwill appear to be dark wine. Set the glass on

a box and cover it with the handkerchiefuntil you are ready to perform the experi-ment.Then lift the handkerchief and state thatyou have a glass filled with dark wine, aseveryone can see. Cover it momentarily andin lifting the handkerchief, insert your thumband forefinger behind the hem and bringaway one cut-out, leaving only the red. Dropthe cut-out behind your improvised stand.Now you have what appears to be a lightred wine. Cover the glass completely withthe handkerchief and this time lift the red

cut-out through the cloth itself. Drop thehandkerchief, pick up the glass and showthat it is water, nothing elsel WHAT HAPPENS: Without the water, thecut-outs would look like what they really are.But once the water has been poured into theglass, the colors are diffused due to the re-fraction, and they create the illusion thatthe liquid itself is colored.Red, combined with either green or blue,creates a color resembling dark wine; thered alone, appears as wine of a reddish hue.Simply be careful never to show the glass

with cut-outs edgewise toward the onlookers,or the illusion will be dispelled. REMARKS: This is an excellent stunt to in-clude in an exhibition of "Chemical Magic"as the spectators, after witnessing actualchemical changes, will be really puzzled bythis one.


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The Bending Pencil EFFECT: A pencil is held horizontally byone end, gripped between the thumb andfingers of the right hand. The hand beginsan up-and-down motion and the pencil be-gins to wiggle, as though made of rubber.Yet it proves to be an ordinary woodenpencil. MATERIALS: A fairly long pencil. WHAT To Do: Hold the tip of the pencilbetween thumb and forefinger; keep it leveland make short, quick, up-and-down mo-tions. Watch the pencil and when it seemsto wiggle, you will know that you are doingit right. WHAT HAPPENS: When you move an objectrapidly up and down, it produces a blurredeffect. With a wheel and other moving ob-jects, this follows a normal pattern, eventhough it is an optical illusion. But in the

case of the "bending pencil," the far end iscovering a much greater distance than thenear end, with its short, jerky action. The re-sult is a double illusion of a slight bend anda greater one, so the pencil itself looks pliable. REMARKS: Some novelty dealers sell imita-tion pencils made of rubber that really willbend when people try to write with them.With such a pencil, you can do the "wiggletrick" and then show everyone that it workedbecause the pencil was made of rubber.Then, repeat it with a wooden pencil andthey will be all the more surprised.

OPTRIX 33The Mixed-up Mirror

EFFECT: Two words are printed on a cardand held in front of a mirror. Everyoneknows that the letters should be reflected inreverse, but in this case, it doesn't hold true.One word remains exactly as it was, thoughletters in the other are turned about.

MATERIALS: A card, a pencil, and a mirror. WHAT To Do: Print the words CHOICEQUALITY on the card and tum it upsidedown as you hold it before the mirror. Thefirst word will still read CHOICE, butQUALITY will have most of its letters topsy-turvy and two of them (Q and L) reversed. WHAT HAPPENS: The optical law of re-versed mirror writing works as usual, but acareful study will show that the letters H,0, and I are the same backward, forward orupside down; while C and E, when inverted,assume their regular appearance in a mirror.If people fail to notice that the card is turnedupside down in front of the mirror, they willbe doubly mystified.


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34 MAGIC WITH SCIENCEThe Mysterious Rod

EFFECT: Two words are printed on a cardand viewed through a glass or plastic rod.One stays the same; the other turns upsidedown and backward. M A TE RIA LS : A card, a pencil, and a glassor plastic rod. WHAT To Do: Use the CHOICE QUAL-ITY card and the result will be the same aswith a mirror. CHOICE stays as it is, whileQUALITY takes on a mixed appearance.

WHAT HApPENS: Due to refraction, thecurved surface of the transparent rod invertswhatever is viewed through it. ThusCHOICE apparently remains the same, whileQUALITY is inverted and some of its lettersare backward.

The Penetrating Rod EFFECT: A short, rounded wooden rod isimpaled on the loose bar of a large blanketpin, which is then closed. The rod is thenbrought around until it is blocked by thesolid bar of the pin. With a stroke of the fin-ger, the rod is apparently knocked right

through the solid bar. This amazing feat isrepeated time after time with the samebaffling result. MATERIALS: A large blanket pin; a small-size dowel from 3 to 4 inches in length, witha small hole bored crosswise through thecenter. WHAT To Do: Impale the dowel on thefree rod of the pin, and close it. Hold the pinhorizontally with the left thumb and fore-finger at either end, but with the solid baron the near side. With the right forefingerpush the far end of the rod around until itcomes up beneath the solid pin.Now comes the amazing part. Bring the

right forefinger up beneath that same end ofthe rod, giving it a hard, upward Hip. You,yourself, will be nonplussed to see thewooden rod come right up through the solidbar. Swing it around and snap it up throughagain. If you do it right, you just won't be-lieve it happened, it is that good. But it doeshappen, though differently than most ob-servers suppose. WHAT HApPENS: The hard upward snapcauses the rod to bounce back in the oppo-


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site direction, so that instead of coming upthrough the steel bar-which is utterly im-possible-it Hies around the other way andcomes downward and frontward so rapidlythat it actually seems to come up through.The result is a most remarkable illusion ofthe rare type where quickness actually de--ceives the eye. REMARKS: Repetition makes this all themore wonderful, once the knack of snappingthe rod is acquired. Even a false Hip will notinjure the illusion, but will simply pass as atime the "penetration" did not occur. But thebetter the knack, the stronger the effect.To test this penetration," take a largekitchen match, break off the head, and im-pale the matchstick on the loose end of alarge safety pin. It may take a few trials tofind a matchstick that will work effectively,but when it does, the result is quite as good.So the matchstick version makes an excellentmodel for the larger device.

Card Vanishes from Glass EFFECT: Several playing cards are placedbeneath a handkerchief, and one card isdrawn away through the cloth. Still covered,the card is pushed down into a tall drinking

OPTRIX 35glass. The handkerchief is whipped away andthe card has vanished from the glass. MATERIALS: A few playing cards; a piece ofthin transparent plastic or celluloid cut to thesize of a playing card. A thick handkerchief,and a tall, wide glass. WHAT To Do: Beforehand, place the plas-tic card beneath the group of playing cards .Spread the cards to show that there areseveral in the group, then throw the hand-kerchief over them. Push the plastic card intothe center of the cloth and ask someone todraw the card away in the handkerchief.Someone does, thinking that it is an actualplaying card.Lay the rest of the cards aside, take theplastic card through the cloth and push itdown into the glass, or let someone else do

so. Hold the glass high beneath the hand-kerchief, which you then pull away and showthe glass apparently empty. WHAT HAPPENS: Due to the curved sides ofthe glass, the edges of the transparent cardare totally obscured when people look di-rectly through the glass and card. Actually,the supposed playing card has become in-visible, even though it has not really van-ished. The glass can even be turned about,provided it is kept in motion until the broadside is again toward the viewers. REMARKS: The glass can be laid aside andthe transparent card can be reclaimed later.Or the rest of the cards can be pushed intothe glass to show there is no trick about it.In drawing them out again, the plastic cardis brought with them.

Making Money Multiply EFFECT: A dime is dropped into a clear,straight-walled drinking glass which is partlyfilled with water. A plate is set over the top


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36 MAGIC WITH SCIENCEof the glass so that nothing can leave or enterit. Glass and plate are then turned over to-gether, with a most amazing result. The coin,falling to the plate, becomes a quarter, butthe dime also remains within the glass, forit can be seen actually Boating in the water,just above the larger coin. MATERIALS: A dime, a glass containingwater, and a plate.., WHAT To Do: Drop the dime in the glassof water. Put the plate on top, take the glassin your right palm and press the plate down-ward with your left hand. A quick, bold turn-over and the plate will be resting on yourleft palm, with the coin lying beneath theglass and the water still in the glass, but nowcontacting the plate. Let people look throughthe side of the glass at a downward angle andthey will think they see a quarter on theplate and a dime above it.

WHAT HAPPENS: By viewing the surface ofthe water at just the right slant, you gain aview of the coin through the glass and di-rectly into the water, producing a magnifiedimage of the coin, like objects at the bottomof a goldfish bowl. But you also view thecoin through the air within the glass anddown through the surface of the water, whichrefracts the light rays and produces an imageof a normal-sized coin near the surface, asin An Appearing Coin," (p. 46.)

Triple Your Money EFFECT: Two nickels are shown on thepalm of the outstretched left hand, one be-ing in the open, the other covered by aninverted drinking glass. The glass is liftedand the coins are shaken in the fist, thendropped on the table. Instead of being worthonly ten cents, their value has jumped tothirty cents, for the coins are now a nickeland a quarter.

MATERIALS: A nickel, a quarter and a glasswith a slightly curved bottom, as is commonwith most drinking glasses. WHAT To Do: Lay the coins side by side,but invert the glass and cover the quarter,before showing the coins in the palm of yourhand. Viewed downward through the bottomof the glass, the quarter will appear to bethe same size as the nickel, making a totalof ten cents. By simply laying the glass asideand shaking the coins, you can triple" yourmoney by showing that you hold a nickeland a quarter. WHAT HAPPErj'S: The bottom of the glassacts as a reducing lens, which is just theopposite of a magnifying glass. Being side


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by side, the coins are easily compared andwith a proper type of glass, the quarter willappear as a nickel. REMARKS: With some glasses, the reductionis better when the glass is set right side up,with the quarter just beneath the bottom.By testing various glasses, you can find thebest type to use, whether inverted or keptwith bottom down.

Surprise Sausage EFFECT: The tips of the forefingers areheld together directly in front of the eyes anda tiny sausage appears between them. MATERIALS: No special materials required. WHAT To Do: Hold the tips of the fore-fingers together at a little less than arln'slength and stare beyond them. Move thehands closer, if need be, until the sausage ap-pears clearly. WHAT HAPPENS: Obstructing the distantview with the close-up of the fingers, causesthe tips to fonn separate images, which blendinto the optical illusion of a sausage.

OPTRIX 37The Floating Ball

EFFECT: A thimble is placed on each fore-finger and when they are pointed together, atiny metal ball floats between them. MATERIALS: Two metal thimbles. WHAT To Do: Hold the fingers as with the"Surprise Sausage," then draw them slowlyapart, until the image of a metal ball appearsin the space between them, as you stare be-yond. WHAT HAPPENS: The overlapping images

of the fingertips are confined to the thimblesas the fingers are separated. By adjusting thespace and moving the hands closer or fartheraway, the thimbles produce the optical illu-sion of a suspended or magnetized ball.

Which Is Larger? EFFECT: Two curved pieces of cardboard,one red, the other blue, are placed upon thetable. Someone is asked which is larger andhe replies, "The blue," which happens to bebelow the red. But when the curved cardsare transposed, with the blue above the red,everyone will be amazed to see that the redhas become larger than the blue. MATERIALS: Two cardboard cut-outs, one


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red, the other blue, which may be made tothe exact size shown here . WHAT To Do: Set the red cut-out abovethe blue, as shown in the first illustration. Theblue will look larger than the red. Transposethem, as shown in the second illustration, andthe red will appear larger than the blue . WHAT HAPPENS: Due to the curve of thecut-outs, they produce an optical illusionwhen one is placed above the other. Always,the lower cut-out will look larger. So byswitching their positions, first the blue, thenthe red, will be classed as larger.

X-Ray Tube EFFECT: A person holds his left hand along-side a paper tube and looks through the tube

with his right eye. A hole appears in thepalm of his hand and he sees straight throughit. MATERIALS: A sheet of paper about 11inches long. WHAT To Do: Roll the paper into a tubeone inch in diameter. Hold the tube to yourright eye and place the side of your left handagainst the middle of the tube, with yourleft palm directly toward your left eye. Keepboth eyes open as you look through the tubeand you will "see through" your left hand. WHAT HAPPENS: Since one eye is lookingthrough the tube and other is looking at thehand, the two views blend to form an opticalillusion of a hole in the center of the leftpalm. A slight shifting of the tube may im-prove the illusion.

Crisscross Screen EFFECT: Within a square frame of lightcardboard is a thin paper screen crisscrossedwith horizontal, vertical, and diagonal lines.When the screen is placed upon a printedpage, nothing can be read through it. Yetwith a few "magic" words and a little actionproperly applied, the screen becomes trans-parent and the printing is revealed and read . MATERIALS: A_sheet of tracing paper, meas-


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uring 5 x 5 inches. A strip of cardboard, oneinch wide, which can be cut into lengths andpasted around the edges as a frame, reducingthe center to 3 x 3 inches. The center is fur-ther prepared by drawing lines on it with

pencil and ruler, forming horizontal, vertical,and two diagonal rows, the lines being aboutan eighth of an inch apart, though this maybe varied. WHAT To Do: Set the crisscrossed screenover some printing or place it upon a spe-cially lettered statement, as:YOU CAN READTHESE WORDSQUITE EASILYBY ROTATINGTHIS SCREENWITH STEADY

EASY ACTIONThe lines on the tracing paper will renderthe words illegible. But by simply rotatingthe screen, running it over the letters in acircular fashion, the printing will spring tolife and show right through the movingscreen. WHAT HAPPENS: The constant motion al-

OPTRIX 39lows a continuous view through the screen,like looking through the pickets of a fence orthe uprights of a bridge railing, while ridingpast in a car. The cross-lines create a hazyeffect, but they no longer completely obscureany part of the printed words as they didwhen the screen was motionless. This is atype of optical illusion that was used inearly efforts to create motion pictures.

Restored Paper Napkin EFFECT: A paper napkin is tom in pieceswhich are rolled together and placed in adrinking glass. From a bottle, the demonstra-tor pours "invisible glue" into the glass. Thetom napkin is brought from the glass andfound to be completely restored. MATERIALS:Two identical paper napkins. Aglass with ribbed or ornamental sides, butotherwise transparent. A piece of cardboardcut to fit vertically in the center of the glass.A small sheet of aluminum, polished on bothsides, which can be cut to the exact shape ofthe cardboard. An empty bottle. WHAT To Do: Cut the aluminum to fit theglass and place it crosswise, separating theglass into two sections, front and back. Whenviewed directly from the front, the aluminum"fake"-as it is styJed-acts as a mirror, sothat the glass appears to be empty. Roll onenapkin into a loose ball and thrust it downin back of the mirror, where it remains per-fectly concealed. Set the glass on the table.All this is done beforehand.In your presentation, start by showing apaper napkin and openly tearing it into sev-


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40 MAGIC WITH SCIENCEeral pieces. Roll those into a ball and pick upthe empty bottle, stating that it contains amagical "invisible glue." Rather than spill anyof the priceless elixir, you decide to put thetorn papers in a glass. So you lay aside thebottle and take the "mirror glass," showing itas though it were quite ordinary and empty.Push the torn papers down in front of themirror, then tum to the table and as you do,give the glass a half tum so that the rearsection is toward the audience. Set the glasson the table, pretend to pour liquid into theglass from the bottle, lay the bottle aside anddraw the good napkin from the glass. Openthe napkin and show it "restored." WHAT HAPPENS: By reHecting the front halfof the glass, the mirror makes it look com-pletely circular and therefore apparently a

simple, empty glass; but the direct reflectionalso makes the mirror noticeable, particularlyif it catches the light. That is where theribbed glass plays a vital part. It diffuses thelight rays so the reflection is somewhat in-direct, yet still gives the glass a normal, cir-cular effect.Once the paper is in the glass, it hides the

mirror sufficiently so that the glass can beturned around. The paper in the rear sectionlooks like part of the original napkin thatwas inserted in front. The motion of the glassprevents the edge of the mirror being noticedduring the tum.The reflective quality of the aluminumdoes not need to be very high. Testing inthe light will enable you to compare the ap-pearance of the glass with and without themirror in place, so you can see just how itshould be held to appear empty. All in all,it makes a most interesting experiment inoptics, even though the onlookers do notrealize it.

Shadow Monster EFFECT: When a person approaches thecomer of a lighted room, the shadow of hishead and shoulders naturally looms up aheadof him, completely black. But in this case,your shadow becomes very real, leering atyou with bulging eyes and grinning mouth.It's enough to scare people, including your-self, if you didn't know the secret. MATERIALS: A fair-sized wall mirror. Asheet of paper about the size of the mirror.Some adhesive tape. An electric light. WHAT To Do: Place the mirror on the sidewall near the comer, so that the light, shin-ing from a greater distance away, is reflected


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by the mirror, forming a lighted block on theend wall. Cut holes in the paper to representeyes, nose and mouth; tape this to the mirror.Move your head and shoulders close to theend wall so your shadow appears there andit will take on the weird features of themirror monster . WHAT HAPPENS: Once the paper is inplace, it eliminates all the reflection exceptthe cut-out features of the monster mask.Those still show in luminous form againstthe end wall. By bringing your head andshoulders still closer to the end wall, the re-flected cut-outs show against your ownshadow, since the reflection comes in at anangle from the more distant light.

OPTRIX 41 REMARKS: Proper placement of mirror andlight are essential to this illusion. Whetherto use a ceiling light or a floor lamp will de-pend upon the arrangement of the room.After experimenting beforehand, take yourposition, then have someone turn on thelight, and the sudden appearance of the"shadow monster" will be startling and effec-tive.

Candy from Nowhere EFFECT: A drinking glass is shown emptyand is covered with a handkerchief. Whenthe handkerchief is whisked away, the glassis filled with little candies, materialized fromnowhere I MATERIALS: A glass, a shiny aluminum di-vider, some small hard candies, and a hand-kerchief. WHAT To Do: Put the aluminum "fake" ordivider in the glass, so it forms a "mirrorglass" (as described with the "Restored PaperNapkin" on page 39.) Fill the rear space


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42 MAGIC WITH SCIENCEwith the candy which remains hidden behindthe fake.In performing, show the glass apparentlyempty by keeping the mirror toward the on-lookers. Cover the glass with the handker-chief and grip the fake through the cloth.Whisk the handkerchief away and pocket it,fake and all. The candy remains in the glassand can be poured on a plate, so the glassitself is quite ordinary at the finish. WHAT HApPENS: The shiny aluminum fakegives the glass the appearance of being en-tirely empty. Only one side needs to bepolished as the "mirror" effect is needed onlyin front, due to the removal of the divider.Small peanuts, or flaky cereal can be usedinstead of candy.

Through the Glass EFFECT: Two candlesticks with candlesare set on opposite sides of a sheet of glass.When one candle is lighted, the other auto-matically appears to become lighted too. MATERIALS: Two candlesticks, two can-dles, a small sheet of window glass, twolarge books to prop the glass, and somematches. WHAT To Do: Set the glass upright be-tween the books. Place each candlestickwith its candle an equal distance from theglass. Have people look straight at the can-dle on the near side, so they can see throughthe glass and observe the candle on the farside. Light the candle on the near side andthey will see the flame ignite the far candle,with both flames continuing to burn. WHAT HAPPENS: When the lighted matchis applied to the near candle, it throws itslight against the glass, causing the flame to

be reflected as in a mirror. The far candlecan still be seen through the glass, due totransparency, but its wick will appear to belighted, due to the reflection producing animaginary flame the same distance from theglass. REMARKS: Tests should be made before-hand to make sure the candles are placed atexact distances. A special frame can be madeto support the glass if so desired. Also checkthe lighting of the room to make sure it iswell suited for the illusion.

Magic Lamps EFFECT: A sheet of glass is set upright be-tween two table lamps. When one lamp isturned on, the other becomes illuminated ofits own accord. MATERIALS: Two identical table lamps, asheet of glass, and two books or a frame toserve as a prop. WHAT To Do: Set the glass exactly be-tween the two lamps. Let people look fromone side, so they see through to the other


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lamp. Turn on the lamp on their side andboth will light up. WHAT HAPPENS: This is simply a moderni-zation of the two-candle experiment known

as "Through the Glass." People see the re-flected light from the near lamp and it givesthe impression that the far lamp is also il -luminated. However, since the electric lightis much stronger than the candle flame, theentire lamp can be reflected, hence it mustbe perfectly placed to blend with the farlamp. REMARKS: If the light in the room is verysubdued to start, the far lamp will be scarcelyvisible when the near lamp is turned on. Inthat case, the reflection of the near lamp willbe accepted in its entirety as representingthe far lamp. Still, the images should be syn-chronized as well as possible, otherwise thefar lamp will produce a "ghost" effect of thetype sometimes encountered during a tele-vision show.

Rub A w a y Coin EFFECT: Three large coins are held withthumbs and fingers at each side. The coins

OPTRIX 43are rubbed back and forth, but when theaction ceases, one coin has been rubbedaway, leaving only two. MATERIALS: Two coins the size of a quar-ter, or larger. WHAT To Do: Hold the two coins so theyoverlap and keep thrusting them back andforth with thumbs above and fingers below.Tell people to "Watch the three coins" andthen add, "Now one has been rubbed away."Drop the two coins on the table and theywill be quite amazed, for until then, theywill be sure they saw three coins. WHAT HAPPENS: In rubbing the coins asdescribed, the lower coin appears elongatedas it emerges in front and back of the uppercoin. This creates an optical illusion of threecoins instead of only two. A steady, rhyth-mic motion is more effective than too muchspeed.

Coin Gone EFFECT: A coin is placed on the palm ofthe left hand and a glass of water is set onthe coin. Looking down through the water,observers see the coin. Then, suddenly, youmake it vanish.


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MATERIALS: A glass almost filled with wa-ter. A coin. WHAT To Do: Set the coin and glass onyour left hand and let everyone view thecoin as described. Press your right palmsquarely on top of the glass.When they lookfor the coin itwill be gone. WHAT HAPPENS: Your right hand cuts offa direct look down through the water. Peo-ple must now look through the side of theglass, from an angle beginning beneath thesurface of the water. Due to the refractionof the light rays, they can't quite see to thebottom of the glass, so the coin is renderedinvisible.

Coin and Glass EFFECT: A transparent drinking glass isstanding upside down on a dinner table with

a coin lying beside it. A paper napkin iswrapped around the glass, which is thenplaced over the coin. When the napkin isremoved, the coin has vanished. Everyonecan look down through the glass and seethat the coin is not there. But when the glassis again covered by the napkin and liftedaway, the coin returns. MATERIALS: A table with a white or plain-colored cloth. A drinking glass. A paper diskof the same diameter as the mouth of theglass and the same color as the tablecloth.Apaper napkin. WHAT To Do: Beforehand, paste the paperdisk to the mouth of the glass, making sureit fits exactly, even if the edges must be


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slightly trimmed. Invert the glass on the ta-ble, lay the coin beside it and you are readyto perform.Wrap the paper napkin around the glass,

making sure that it is completely covered,so that the paper disk will not be seen whenyou lift the glass. As soon as you place theglass over the coin, it is safe to remove thenapkin, as the paper disk looks like part ofthe tablecloth. The coin, being beneath thepaper, has vanished. To bring it back, yousimply reverse the process. WHAT HAPPENS: Actually, this is an opticalillusion in which the paper is mistaken forthe tablecloth, both being the same in color.The curve of the glass helps the illusion andthe rimhides the edge of the paper disk, sothat the disappearance and return of thecoin is automatic.

Coin, Ring, and Card EFFECT: A thick ring, two inches or morein diameter, is resting on a sheet of brightlycolored paper, with a square of plain card-board beside it. A penny is set on the paperand the ring is placed around it with thecardboard on top. When the card is lifted,the coin has vanished, only to return in thesame mysterious manner. MATERIALS: A large key ring, curtain ring,or any ring of a similar type. A paper disk,the same diameter as the ring, and matchingthe color of the paper sheet, which shouldbe at least 6 or 8 inches square. A cardboardsquare slightly larger than the ring. Apenny. WHAT To Do: Paste the paper disk to thebottom of the ring. When the ring is laid onthe sheet of paper, people think they see

OPTRIX 4 5

clear through the ring, since the diskmatchesthe sheet. Lay the coinbeside the ring, coverthe ring with the card, and place both overthe coin..Lift the card and the coin has ap-parently vanished from within the ring. Areversal of the action will bring it back.But that is only part. By way of variation,

you can drop the coin into the ring as it lieson the table; then cover the ring with thecard. Ring and card are lifted together andlaid aside. The coin has apparently vanished,having been carried away by the paper disk.Put the ring back where it was, with thecard still on top. Lift the card and the coinwill reappear within the ring. WHAT HAPPENS: This works on the sameprinciple as the "Coin and Glass," the paperdisk matching the sheet and thereby hidingthe coin. The disk is also unsuspected whenused to take away the coin. A brightly col-ored paper, or a sheet with a mottled designwill make the optical illusion more effective.


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An Appearing Coin EFFECT: A large coin is placed in the verycenter of a a fair-sized bowl, which is seton a table some distance from an observer,who is seated in a chair. Because of theangle, the person cannot quite see the coin.Yet without touching or moving either thecoin or the bowl, the coin is made to appearbefore the observer's fixed gaze. MATERIALS: A coin, a bowl, a pitcher ofwater. A table and a chair . WHAT To Do: Seat the person so that the

coin is just below his angle of vision. Whilehe watches, pour water from the pitcher in-to the bowl, carefully and slowly, so as notto disturb the coin. By the time you havenearly filled the bowl, the coin will have ap-peared for the observer. WHAT HAPPENS: Due to the refraction ofthe water, the light rays are bent at an angle,bringing more of the bottom of the bowl intoview. During the pouring of the water, thebottom of the bowl will actually seem to rise,but so imperceptibly that the observer willnot know it until the coin comes into his bentline of vision; and even then, he may notknow why.

Metal Through Metal EFFECT: Two large safety pins are linkedtogether and then clamped. A quick, simplepull, and the pins come apart, yet remainas solidly clamped as before. MATERIALS: Two large safety pins. WHAT To Do: Close one pin, "A," with itsloose bar to the left and its head extendingoutward as you hold the small end betweenyour left thumb and forefinger. With theright hand, hold the second pin, "B," by thesmall end, between thumb and forefingerwith the loose bar to the left and the headpointing outward.The larger the pins, the better, as they al-low a firmer grip at the lower end. If youfind that the pins tend to slip, use a largersize.Slide the head of pin "B" downward be-tween the bars of pin "A," so the head goesunder the loose bar of "A." The loose bar of"B" goes over or above the loose bar of "A."Pin "B" is then clamped shut and the handsresume their holds on the small ends of theirrespective pins. "A" being held by the lefthand; "B" by the right.All is then ready for the vital action. Drawthe pins apart by bringing them head tohead, tilting both heads inward and giving


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a quick, smooth pull. A neat, sliding motionwill separate them without unlocking them. WHAT HAPPENS: Actually, the solid bar ofthe right hand pin, "B," does unlock the loosebar of the left-hand pin, "A." But with thebars almost parallel, the opening is so slightthat pin "B" comes free before the loose barof pin rcA" is fully undamped. As a result,pin "A" relocks itself, as it is designed to. do,whenever its loose bar engages the speciallyconstructed head. That is what makes asafety pin safe and it also makes this experi-ment a good one.

Mirror Image EFFECT: Some long words and a long rowof figures are written on a pad, which is thenheld in front of a mirror. A person is askedto read off the words and the numbers, whichhe does slowly and with difficulty becausethe letters and figures are reversed in themirrored image. Yet yo u can look into themirror and read them off without the slight-est pause! MATERIALS: Two mirrors, preferably a wallmirror and a hand mirror. A pad and pencil. WHAT To Do: Print some words like IN-COMPREHENSIBLE or ANTEDILUVIANon the pad, along with a row of figures, as3515429076384. Have someone hold the writ-ing toward the hand mirror and try to readit in reverse. Let someone else do the samewith the wall mirror. When your tum comes,hold the writing toward the wall mirror withyour left hand, then tum away and pick upthe hand mirror with your right hand. Holdthe hand mirror so you can look back overyour left shoulder and see the reflection ofthe pad in the wall mirror. Reading the

OPTRIX 47

words and the numbers then becomes sim-plicity itself. WHAT HAPPENS: By using both mirrors asdescribed, the writing reversed in one isagain reversed in the other, which brings itback to normal, so it can be read off rapidly.It is a case of doubling up a scientific prin-ciple to neutralize the effect. REMARKS: Let anyone write words andnumbers for you to read in a mirror, butspecify that the letters and figures be printedlarge. Another mode of operation is to holdthe writing and the hand mirror both towardthe wall mirror, but tum the pad 45 to theright and the hand mirror 45 to the left.Then look toward the right and read themessage in the hand mirror.

The Roaming Coin EFFECT: A coin is dropped within a largering, which is covered with a card and


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4 8 MAGIC WITH SCIENCEmoved away, leaving the coin in full view.The coin is covered with another ring andcard. Both cards are lifted and the coinamazingly has roamed from one ring to theother. MATERIALS: Identical with those used inthe "Coin, Ring, and Card," but in this case,a second ring is used. It is prepared with apaper disk exactly like the first ring, and alsohas a square card to go with it. A duplicatecoin is also required. WHAT To Do: Have the two rings lyingon the sheet of matching paper. Have theduplicate coin under Ring "A," at the left.Both rings are uncovered, but appear empty.Lay the coin within "A," cover the ring withits card and lift both together, placing thembeyond Ring "B," which is near the center.People see the duplicate coin at the spot

where you picked up "A" and suppose it to

be the original coin, which normally wouldhave stayed there. Now, cover "B" with itscard and place it over the visible coin at theleft. Lift the cards from both rings. The coinwill be gone from Ring "B" at the left andwill be seen reposing in Ring "A" at the right,which is baffiing indeed. WHAT HAPPENS: The two principles usedin "Coin, Ring, and Card" are simply workedin combination. The first coin is taken awayby the disk pasted to Ring "A"; the diskpasted to Ring "B" covers the duplicate coinand conceals it. You can repeat the experi-ment by taking the coin from within the ringat the right and dropping it in the ring atthe left, then going through original routine.At the finish, cover each ring with its cardand drop them in your pockets, with the ex-tra coin.


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MaginertiaTricks Involving Inertia

Nine Coins EFFECT: Nine coins are placed in a rowin groups of threes, with a space of an inchormorebetween each group. All in one quickaction, a coin is moved from the group atthe right to the center group, while anothercoin ismoved fromthe center to the left. Yetthis is done without touching either of themoved coins in any way whatever, whilenone of the other coins are moved more thana trifling fraction of an inch.

A

MATERIALS: Ten coins, all of the same size;as ten pennies, ten nickels, or even ten quar-ters. A smooth surface, like a polishedwooden table top. WHAT To Do: Line up nine coins in groupsof three, with spaces between. All must bein an exact row, the spaces to be determinedby experiment. After stating your purpose, as

already described, bring out the tenth coinand lay it a few inches to the right of thebroken row. With your finger, give it a hardslide against the first coin in the group onthe right. A coin will slide from that groupand join the center group. That coin, in tum,will send the far coin of the center group tothe group on the left. WHAT HAPPENS: Inertia causes the inter-vening coins to remain practically unmoved,but the force of the arriving coin is trans-ferred to the free coin at the other end ofthe group. That coin is sent to the centergroup, where the same thing happens again,sending another free coin on its way, butwith diminished effect, so that the group atthe left remains undisturbed as it receivesthe coin.

A Remarkable Nutcracker EFFECT: A table knife is suspended by athread from the top of a doorway. Awalnutis placed directly below the knife and thethread is clipped with scissors. The knifedrops down and cracks the walnut. MATERIALS: A nail or push-pin, a thread,a knife, some adhesive tape, a walnut, anda glass of water. Scissors. WHAT To Do: Fix the nail in the top ofthe doorway and tie one end of the threadaround it. Tape the other end of the threadnear the tip of the knife blade, so the handlepoints straight downward, five or six feet

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50 MAGIC WITH SCIENCEabove the floor. Lay the walnut on the floorbeneath the knife. All is then ready for thetest.Bring the glass of water straight up to-

ward the knife sothat the handle of the knifeis partly immersed, but the knife still hangsfree. Lower the glass, put it aside and watchthe drop of water that falls from the knifehandle. Move the walnut to the spot wherethe drop strikes and watch succeeding dropsuntil they actually land squarely on the wal-nut.The experiment is then in order. Cut the

thread with a quick snip. The knife will

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drive straight down and the handle will hitthe walnut full force, cracking it wide open. WHAT HAPPENS: The law of gravity causesall obects to fall directly toward the centerof the earth. Each drop of water thereforemarks the path that the knife will follow,provided it is hung straight downward. Theheavy handle gives the knife a low center ofgravity, which also contributes to its exactfall. REMARKS: This experiment requires con-siderable preparation, but it is worth it, andtherefore should be given due care. Makesure the knife is heavy enough and that it isproperly suspended, either by taping thethread straight down the blade or tying itaround the blade. Keep the knife steady andimmerse the handle repeatedly if furtherstudy of the water drops proves necessary.

Stacked Checkers EFFECT: Six checkers are stacked, allblacks, except for a red checker next to thebottom black. Another red checker is set onits edge and snapped along the table. It hitsthe stack and knocks out the lone redchecker, leaving the blacks intact. MATERIALS: Two red checkers and fiveblack checkers. A flat

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