The American Boy's Handy Book/Chapter 39
Who can watch machinery of any kind in motion, without experiencing an indefinable sort of pleasure? No matter how simple the contrivance may be, if it move it immediately interests us. This instinct, if I may so call it, that prompts us Image missingThe Potato Mill. to watch and play with machinery is implanted in the brain of the lower animals as well as of man. I think no one can doubt that a kitten or a dog enjoys chasing a ball, and enters into the sport with as much zest as a college-boy does his game of football. It is this same indefinable desire for observing and experimenting with moving objects that prompts us to throw stones for the purpose of seeing them skip over the surface of the water, and to this instinct must be attributed the pleasure experienced by the school-boy with his
which consists of simply a stick, a potato, a buckeye, or a horse-chestnut, and a string. The stick is whittled into the form shown in the illustration; a string is fastened to the stick about one-half inch below the knob on the top. The buckeye has a large hole bored through the middle, and a small hole bored through one side, to the middle hole; the string from the stick passes through the hole in the side of the buckeye; the end of the stick is sharpened and thrust into a potato.
If the string be wound around the stick, and the buckeye held between the thumb and forefinger, the stick and potato may be made to spin rapidly by alternately pulling the string and allowing it to slacken; the motion imparted by the first pull continues long enough to wind the string in the opposite direction, and thus, for an indefinite time, or until the string wears out by friction, the potato mill may be kept buzzing at a great rate.
Another machine the boys used to be very fond of was called
it was generally made out of the top of a tin blacking-box, with the rim knocked off and the edge cut into notches like a saw. Two strings passing through two holes near the centre gave a revolving motion to the "buzzer" (Fig. 226 shows a saw-mill).
By holding the strings so that the wheel hangs loosely in the middle, and swinging the wheel or "buzzer" around and around until the string becomes tightly twisted, the machine is wound up. As with the potato mill, the revolving motion is imparted by alternately pulling and allowing the string to slacken, only in this case you must hold one end of the string in each hand (Fig. 226). When the boys can make a buzzer actually saw into a piece of board or shingle by allowing the edge of the wheel to strike the wood, the saw-mill is pronounced a success, and its value increased.
Very pretty and amusing toys may be made on the same principle as the saw or potato mills described. One of these little machines, a very fascinating one, is sold upon the streets of New York by the novelty peddlers. As the writer was passing along Broadway the other day, he saw an old acquaintance, known to almost all New Yorkers by the name of "Little Charlie." Little Charlie is not a small man, as his name might imply, but a large, good-natured, red-faced peddler, who stands all day long at the street corners. During the winter he sells small india-rubber dolls, crying out to the passers-by: "Well! well! well! Little Charlie! double him up! double him up!" He doubles the little india-rubber dolls up in a comical manner to attract customers. The torrid summer heat is too much for the india-rubber dolls, and makes them sticky, so that they are laid aside during the hot weather, and Little Charlie, with the perspiration streaming from his face, no longer calls out in his accustomed manner, but stands silently twirling his summer novelty, trusting to the ever-changing colors of the toy to attract purchasers. One was bought that it might be introduced among the other whirligigs in this chapter.
If you have a pair of dividers, make a circle upon a piece of card-board about two inches in diameter; inside this circle make six other circles (Fig. 227). A pair of scissors can be made to do the duty of a pair of dividers by spreading them apart the required distance and thrusting the points through a card to hold them in position (Fig. Image missingFig. 228.A Pair of Dividers. 228). Make a duplicate figure or disk and paint the parts of the inside circles, shaded in the diagram, different colors; for instance, A and D may be made blue, B and E green, C and Fred. The points of the star in the centre made by the intersection of the circumference of the circles should be painted the same color as the parts of the circle adjoining. Upon the second disk paint A and D blue, B and E yellow, C and F red.
Cut a piece of one-quarter inch pine into a square, with sides of about two and one-quarter inches in length; cut off the corners as shown by I, Fig. 229. In a hole in the centre of I fasten tightly the round stick J. Whittle out another piece for a handle K, and bore a hole through the top for the stick J to fit in loosely; Image missingFig. 229.Parts of Rainbow Whirligig. bore another hole through one side for the string to pass through. In the illustration, as in the original from which the drawing was made, there is a large hole bored through two sides; but this is unnecessary, and only put in the diagram to better show the position of the string inside. Upon the wooden plate I, describe a circle about one and three-quarter inches in diameter. In the centre of the two paper disks make holes large enough to fit with shoe-eyelets; then with tacks (L, Fig. 229) fasten the two paper disks on to the wooden plate at the points G and H, in such a manner that the tack passing through the eyelets will allow the disks to revolve freely. Attach a string to the stick J at a point that will come opposite the string-hole in the side of the handle, when the stick J is slid into the hole at the top of the handle K. The wooden disk is made to spin exactly in the same manner that motion is imparted to the potato mill already described. When in motion the colors on the paper disks will blend and produce, with each change of position, a number of beautiful variations. The two paper disks blend together, making a large circle three and one-half inches in diameter, composed of concentric rings of the most lovely hues―red, pink, purple, green, and all the different shades and combinations imaginable are portrayed with ever-changing variety by the spinning rainbow whirligig.
is a very ingenious toy, consisting of a circle of white card-board, upon the surface of which any number of black rings are painted, one within the other, until it resembles an archery butt or target.
The disk is tacked or glued securely to a stick or handle (Fig. 230) so that it is impossible for it to really revolve, yet if you grasp the toy by the handle and give your arm a motion similar to that of the shaft of an engine, the disk upon the stick will appear to revolve like a wheel, and so closely does the optical delusion resemble actual motion that it will deceive almost any one who is not familiar with the experiment.
A picture of a wagon, with wheels made like the disks of the paradoxical whirligig, may be made, and the wheels will have all the appearance of revolving when a wabbling motion is imparted to the picture. There are many curious experiments that can be tried in this line―spirals may be made to twist around; pictured machinery may be given the appearance of actual moving wheels, etc. The philosophy of all this is best explained in the description of the next whirligig.
The phantasmoscope, or magic wheel, is comparatively simple, consisting, as may be seen by the accompanying illustration, of a disk of any diameter revolving upon a pin in the centre. Figures in different poses of arrested action are painted or pasted upon the one side; under each figure is an oblong opening or slot. Much amusement can be derived from this old and simple toy. We herewith give one with the correct positions of a horse trotting a 2:40 gait, drawn in silhouette upon the outer margin of the wheel.
Make a careful tracing of the illustration (Fig. 231) with a lead-pencil upon tracing-paper; reverse the tracing-paper upon a piece of card-board so that the side with the pencil-markings on it will be next to the card-board; after which fasten both card-board and paper to a drawing-board or table-top with tacks, so that neither tracing nor card-board can slip. With the point of a hard pencil, a slate-pencil or any similar instrument, go carefully over each line of the tracing as seen through the tracing-paper; be careful not to omit a single mark; it is very provoking to discover, after removing the tracing-paper, that part of the drawing is wanting; but if you have been careful, when the tacks are removed you will find the picture neatly transferred on the card-board. Go carefully over each line on the card-board with a pen and black ink, and fill in the outlines of each picture with ink, making a silhouette of the figures.
Cut the phantasmoscope, or magic disk, out, following the outer circle with the scissors, and under each figure, where the oblong places are drawn, cut a corresponding opening through the pasteboard. Fasten the wheel to a stick or handle by means of a pin at its centre, on which it can freely turn.
If a larger machine be wanted, the illustration here given may be enlarged by the process described on page 250. To use the magic wheel, stand in front of a mirror, as shown in the small illustration; hold the disk before the eyes; look through the slots under the figures, and turn the wheel rapidly. Image missingMaking the Horses Trot. The horses' legs will commence to move as in life, and as each successive position drawn upon the phantasmoscope is the exact one taken by a trotting horse, the horses in the mirror will all appear to be in actual motion, on a fast trot. If the eye is directed over the margin of the paste-board disk, an indistinct blur is all that is seen. The principle is generally well known and easily explained. It pertains to the phenomenon known as the persistence of vision. When the eye is directed through the slot, the figure of a horse is seen for an instant as the opening passes the eye, and the impression is retained after the object is shut off by the intervening portion of the board between the slots until another horse appears through the succeeding opening, when an additional impression is made, the same as the preceding impression, except a slight change in the position of the legs. These impressions follow each other so rapidly that they produce upon the retina of the eye the effect of a continuous image of the horses, in which the limbs, replaced by a succession of positions, present the appearance of a file of horses in actual motion.
The instantaneous photographs taken nowadays of people, horses, and other animals in motion, opens a new field for investigation, and one which, with the aid of the simple toy described, will be found very entertaining as well as instructive.
Mr. Muybridge's celebrated photographs of animals in motion can all be adapted by smart boys to home-made phantasmoscopes, and it will probably not be long before the wonderful photographs of birds and bats on the wing, taken by E. J. Marcy with his revolving photographic gun, will be within reach of the public. Then with the magic disk the reader can make birds fly, horses trot, men ride bicycles, and reproduce every movement as correct as in nature.
For young scientists these beautiful experiments will be found very entertaining.