CHAPTER LVII.
THE MAGIC TOP—THE GYROSCOPE AND SCIENTIFIC GAMES
We will not do our readers the injustice to suppose that they are not familiar with the ordinary top,—the delight of all school-boys and young people,—of which, therefore, we forbear giving any description; but we now desire to give some details of the construction of the wonderful magic top. It is composed of a large disc, with an axis turning on two pivots connected with a circle of iron. When in repose, this plaything exhibits nothing of a remarkable character; it is completely inert, obeying, like all other bodies, the laws of gravity. But when we come to give the disc a movement of rapid rotation, this inert instrument seems to assume a vitality of its own if we attempt to move it; it resists, and seems to thrust back the hand, and executes movements even in a contrary direction. Besides this, it appears to be freed, in a certain measure, from the laws of gravity; if we place it on its pivot, instead of falling, as it would when the disc is motionless, it preserves the upright or inclined position in which we place it, the upper extremity of the axis slowly describing a horizontal circle round the fulcrum of the other extremity.
Few persons are sufficiently familiar with the theory of mechanics to understand these phenomena, and it often happens that such a top purchased to amuse a child becomes an object of wonder and interest to his seniors. We do not pretend here to explain mathematically the reason of the facts before us, but the mechanical principle on which this top is constructed is of such great scientific importance, that we will, in a few words, explain it to our readers. It is sufficient to have a little knowledge of mechanics to be aware that a body in motion, subjected to the action of a force tending to give it a directly contrary motion, will follow a movement in a third direction, which is termed the resultant of the two others; and this resultant approaches nearer to one of the original directions, in proportion as the corresponding movement is more rapid in relation to the other. If, for example, you strike a billiard ball, which is rolling past you, in such a manner that you drive it regularly along in the same direction, it appears only to obey a part of the given impulsion, and continues its course in an oblique direction, the speed with which it commenced rolling combining with the impulsion to produce a resultant movement. If it is rolling very quickly, and you strike it gently, it will scarcely turn out of its course. If, on the contrary, it is moving slowly, and receives a violent shock, it will run off almost exactly in the direction in which it has been struck.
Fig. 871.—The magic top.
Now that which occurs in this example of a body tending to two movements at the same time, is also produced when it is a question of movements of rotation, so that if a force acts upon a body in rotation in such a manner as to give it a movement of the same kind round another axis, a third movement will be originated round a third axis, the direction of which will be nearest to that in which the rotation is most rapid. Let us apply this very simple principle to our top, and we shall see that magic has nothing whatever to do with these movements, which at first glance appears so extraordinary. Having set it in motion, we rest it on its pivot, its axis in a horizontal position; we then find that we have two movements before us; first, that which we gave the top ourselves, and secondly, the movement of rotation which occurs round a second axis equally horizontal passing through the fulcrum and perpendicular line to the first. A movement of rotation therefore originates round a third axis placed between the two first, but whilst the real axis of the top, obeying this resultant movement, takes up its new position, the law of gravity continuing to act, displaces and moves it a little further, so that in endeavouring to reach its centre of gravity, it turns round its fulcrum (fig. 871). From this explanation, it will be easily seen that the more rapid the movement given to the top,—that due to gravity remaining constant,—the nearer will be the axis of the resultant movement to its real axis, and consequently the slower will be the movement of rotation of the whole round the pivot. Thus this apparently incomprehensible phenomenon is easily explained by gravity, vertical force producing a movement of rotation in a horizontal plane. One can also explain by analogous reasoning, and calculation of passive resistance, why the axis of the top gradually inclines in proportion as the speed of the latter diminishes, and the speed of rotation round the fulcrum increases; why it falls immediately if an obstacle is opposed to the latter movement, and finally, why it produces on the hand which holds it, movements which astonish persons so intensely who behold it for the first time.
The principle we have just described is often enunciated, by saying that every body in rapid rotation rests in its plane, and can only be driven out by a considerable force; this, however, is a defective formula. The principle should be stated in the following manner. A body in rapid rotation tends to remain in its plane; that is, its axis rests parallel with itself, and instead of obeying any force tending to divert its direction, it produces in consequence of the combination of two simultaneous movements, a displacement of the axis, generally much feebler and of a different kind from that which this force exercises on the same body in repose. One of the most charming applications of this theory is due to M. Foucault. The Gyroscope, which bears his name, is a heavy disc, the axis of which is supported by a “Cardan” balance, so that, whatever is the position of the contrivance, it is possible to preserve it in a constant direction. Therefore if the disc is, by means of special mechanism, put in rapid rotation, we may give it all kinds of possible displacement without changing the plane in which the gyroscope moves. Supposing then that its connection with the suspension is fixed in a relatively immovable manner, but attracted by a movement towards the ground, the plane of rotation of the disc will not entirely participate in this movement. It is true, it will be carried into the movement of general removal, but it will remain constantly parallel with itself, and only appears displaced in comparison with the surrounding objects, which obey more completely than itself the movement of the globe’s rotation round its poles. Thus can we demonstrate the movement of our planet. In virtue of the same principle, we see every day passing before our eyes a crowd of phenomena with which we are so familiar that they do not excite our attention. Thus it is because the hoop tends to remain in its plane of rotation that it rolls on without falling or deviating, and for the same reason that tops rotate vertically on their points, or when they are running down, describe a series of concentric circles; and for the same reason again, a juggler is able so easily to hold on the point of a stick a plate which he puts in rapid rotation, etc. It is also owing to this property of rotating bodies that we have been enabled to make use of cylindrical or conical projectiles in artillery. The coiled riflings of the cannon causing the projectiles to turn round very rapidly, their axis preserves an invariable direction during their whole course, until they finally strike the object at which they are aimed. Without this rotation they would pirouette in an irregular manner in the air, and besides any precision in firing being impossible, the resistance of the air would diminish their range to an enormous extent.
The Gyroscope, an instrument now familiar to most scientific persons, is still a problem of which the solution has not yet been found. It may be called the paradox of mechanics, for although it depends on gravitation, it appears to be entirely indifferent to it.
An American scientist has applied electricity to the gyroscope, so as to make its movements as continuous as possible, and to enable us to study it more at leisure and with better results. The gyroscope is mounted on a pedestal which tapers to a point, and supports the instrument. The bar of the gyroscope on which the electro-magnets are fixed rests upon the top of the pedestal. One of the extremities of the bobbin is fixed to the cavity, when the bar and support join, the other extremity communicates with the bar which joins the nuts of the magnets.
An insulator of hardened caoutchouc is so placed that it just touches the axis of the wheel twice in every revolution of that wheel. Its plane of rotation is at right angles to the magnets, and carries an armature of soft iron which turns very close to the magnet without touching it. The armature is put en rapport with the surface of contact of the cylinder, so that when the armature approaches it is attracted; but immediately afterwards, as it reaches the opposite side, the current is interrupted, and the impulse acquired is sufficient to move the wheel to the spot where the armature can again come under the influence of the magnet.
The magnets, the wheel, and all the parts of the instrument together can move around in any direction. When two or four Bunsen cells are put in connection with the gyroscope, the wheel turns with tremendous rapidity, and by permitting the magnets to work (an operation which requires some little dexterity), the wheel not only sustains itself, but also the magnets and the other subjects which are between it and the extremity of the pedestal—in opposition to the laws of gravitation. The wheel, besides turning rapidly around its axis; revolves slowly around the point of the column in the same direction taken by the lower part of the wheel.
When attaching the arms and counter-poise of the machine, so that the wheel and the magnets may balance themselves exactly on the pointed pedestal, the machine remains stationary. But if we give any preponderance to the wheel and magnets the rotation of the apparatus is in a direction opposite to that which would result from turning the upper part of the wheel.
The gyroscope illustrates the persistence with which a body that submits to rotation maintains itself in the plane of its rotation, notwithstanding the force of gravitation. It also shows the result of the combined action of two forces tending to produce rotation around two separate axes, which are, however, situated in the same plane.
The rotation of the wheel round its axis is produced in the present case by the electro-magnet; and the tendency of the wheel to fall, or to turn in a vertical plane parallel to its axis, results in the rotation of the entire instrument upon a new axis, which coincides with the pointed pedestal.
The American Money-Box.
During a recent visit to London, as I was one day walking in the Crystal Palace, my attention was attracted by a curious money-box, surmounted by a pictorial representation of one of the London streets. The carriages, horses, and pedestrians were represented by figures cut out of cardboard, arranged in a groove. A large placard bore this inscription: “Notice to visitors: Throw a penny in the money-box; and the figures will perform.”
I at once responded to this invitation, and immediately beheld the little tableaux become moving and life-like; the cabs rolled along, and the passers-by walked up and down the street. A number of visitors followed my example, and there is no doubt the money-box was full at the end of the day. This ingenious contrivance for obtaining money in so easy a manner, and without having recourse to a “show-man,” appeared to me worthy of investigation and description.
The Scientific American (New York) has recently given an explanation of this curious contrivance, and we will here quote what has been published on the subject.
“Among the inventions intended to obtain contributions of money from the visitors at the Philadelphia Exhibition,” says the American writer, “we will describe the singular money-boxes placed in the salons of the principal hotels and the galleries of the exhibition, etc. These contrivances all consisted of a case or box, with a glass front, through which can be seen a landscape in miniature, with trees, houses, figures, etc., all cut out of cardboard, and painted with great nicety. On the box was a label requesting the visitor to drop a coin into it and await the result of the contribution. When the penny has fallen in it puts in motion some hidden machinery, and then we see the people in the miniature landscape all in motion, riding or walking or hunting, as the case may be.”
Another box is even more successful, for it places in the hands of the contributor a photograph of some celebrated person. But to obtain the photograph we must contribute six pennies. The carte will not come out if we do not put in the proper coins, and the apparatus is perfectly fair and honest.
The illustration, fig. 872, shows the apparatus, which is very simple. On the left the ordinary box is seen, on the right there is a longitudinal section of it.
At the top of the lower portion, where the money is received in, is a hollow support, A, which sustains the box in which the photographs are placed upon an inclined plane, and resting against the glass. The pieces of money, in falling, strike the extremity of a vertical balance, which immediately turns a toothed wheel, C. This wheel has as many teeth as there are pieces of money necessary to purchase the photograph or carte de visite. Upon the escapement wheel is a ratchet arrangement, D, the shaft being moved by a cord rolled around it and attached to a spring, E. A bolt, F, moved by a spring, is kept constantly pressed against the “snail,” D.
Fig. 872.—American money-box.
Thus at each revolution, as the parts of the machinery are animated by the same movement, the bolt is withdrawn sufficiently to permit a carte to fall, and then the card next following will be ready resting upon the bolt. The photographs being placed upon an inclined plane, are pushed forward by a movable frame, G, which has a roller at the base. So as one card falls out another is immediately replaced close to the glass.
We have remarked that the wheel has six teeth, so that as one piece of money dropped in moves it one-sixth of its revolution, six pieces will be necessary to produce the card. Of course wheels can be made with one or more teeth, and the payment may be varied for valuable objects at the desire of the possessor.
The invention is not only a plaything. It can be made useful in the distribution of pamphlets, or newspapers, which can be introduced into the box folded uniformly. They can also be used in omnibuses or tram-cars, and tickets may be given by the machine on payment of the proper sum of money.
We will close this chapter with an illustration of a spiral bottle, which can be done in the manner now to be described, so that the bottle will actually become a glass spring.
Take a mixture of 180 grammes of lampblack, 60 grammes of gum arabic, 23 grammes of adraganth, and 23 grammes of benzoin. Make these ingredients into a paste by the addition of water, and fashion a pencil of the charcoal thus obtained. This pencil, when heated, will cut the glass wherever it is applied.
The process is commenced by scraping the bottle with a file and following the instrument with the red-hot pencil. Wherever the hot pencil is applied, the glass will be cut as shown in the illustration herewith. It will be necessary to blow upon the heated pencil to maintain the incandescence as long as possible. The bottle as cut and representations of the instruments are given in the cut (fig. 873).
Fig. 873. Spiral bottle.
CHAPTER LVIII.
SCIENTIFIC OBJECTS FOR THE HOUSEHOLD.
Fig. 874.—Reading wheel desk.
At the beginning of the seventeenth century there was at Lyons a very remarkable mansion built by a man named Nicholas Grollier de Servière. This house was filled with all the most remarkable curiosities and inventions of the period. The owner belonged to an ancient family. His great-uncle, Jean Grollier, had amassed a magnificent library, the best in France. His father was also a celebrated adherent of Henry IV., and M. Servière himself had inherited much scientific taste and intelligence from his ancestors. His house was full of curiosities, ingenious machines, and mysterious clocks, concerning some of which things we shall have something to say in this chapter.
M. de Servière’s ingenuity was first apparent in the circular reading desk, or wheel-desk, on which he put all the books he was likely to require within a certain time. He seated himself by this revolving desk, and then was enabled to read any book or paper he desired by merely turning the wheel with his hands and thus bringing it under his vision. In these days it is equally possible to collect useful articles either of an electric nature or otherwise. We have already described the electric pen and the writing machine, with some other things which might be included in our list of domestic appliances, but the Chromograph has not been yet illustrated.
Fig. 875.—The chromograph.
The Chromograph.
When we have written with a certain well-known violet “ink” upon a sheet of paper and applied it to a soft gelatinous surface and rubbed it a few times, we shall obtain an impression of the writing on the gelatine. By pressing blank sheets of paper upon this we may pull off quite a number of copies of our letter or circular. This practice is now so well known that it is scarcely necessary to detail it. The layer of gelatine is made up as follows, and any of the recipes will suffice.
1. Gelatine 100 grammes, water 375 grammes, glycerine 375 grammes, kaolin 50 grammes. (Lebaigueé.)
2. Gelatine 100 grammes, dextrine 100 grammes, glycerine 1000 grammes, sulphate of baryta q.s. (W. Wartha.)
3. Gelatine 100 grammes, glycerine 1,200 grammes, bouillie de sulphate de baryta, strained, 500 cubic centimètres. (W. Wartha.)
4. Gelatine 1 gramme, glycerine à 30° 4 grammes, water 2 grammes. (Kwaysser and Husak.)
Fig. 876.—The chromograph.
The “mixture” is shaken until it cools to the point of thickening, and then poured into a zinc vessel. The kaolin or the sulphate of baryta makes the composition white. It can be treated again with gelatine and molasses employed for printing rollers. When the proofs have been taken from the frame the surface may be rubbed with a damp sponge, and then it will be ready for use again immediately. The introduction of dextrine facilitates the cleansing of the surface plate.
The Campylometer.[42]
This instrument, constructed by Lieutenant Gaumet, is very easily carried in the pocket, and by a very simple process gives (1) the length of any line, straight or curved, traced on a map or plan; (2) the actual length corresponding to a “graphical” length on maps of the scale of 1/80000 or 1/100000, or on maps which are multiples of these numbers.
The instrument consists of a toothed disc, the circumference of which is dentated exactly in five centimètres. The faces of this disc each carry a system of divisions; one is divided into four parts, the other into five. The circumference of the disc (5 centimètres) corresponds to the 4 kilomètres of the scale of 1/80000, and to 5 kilomètres of that of 1/100000. The division 1/40 of the disc in the former scale measures 100 mètres, and is in it the same as 1/50 of the other scale.
Fig. 877.—The campylometer.
The toothed disc moves upon a micro-metric screw, the markings of which are 0·0015 of a mètre, and a small “rule” or “reglet” carries equal graduations, as the screw representing lengths so follow:—
| 1. | 5, 10, 15, 20 | 50 centi. | according to metric scale. |
| 2. | 5, 10, 15, 20 | 50 kil. | scale 1/100000; |
| 3. | 4, 8, 12, 16 | 40 kil. | 1/80000; |
The micro-metric screw is fixed in a frame so made as to form a kind of indicator or guide at one side.
To make use of the campylometer, bring the zero of the disc opposite the zero of the rule (reglet), then place the instrument on the map in a perpendicular position; the point will serve as guide, and move the disc upon the line, whether direct or sinuous, of which you wish to ascertain the length.
When this has been done, note the last graduation of the “reglet” beyond which the disc has stopped, add to the value of this graduation the complementary length shown by the division of the disc which is opposite the “reglet.” To find the length of a material line we must add to the number of centimètres shown by the upper graduation the complement in millimètres furnished by the division to the 1/50th.
For example, suppose we read 20 upon the upper scale, 35 the division to the 1/50 opposite the “reglet”; the length obtained is 20 centimètres plus 35 millimètres, or 0·235 mètres. If we are measuring upon a map on the 1/100000 scale, the upper graduations represent kilomètres, the complementary divisions on the 1/50 scale hundredths of mètres.
For example, suppose again 20 be the superior graduation, 35 the division to the 1/50 of the disc as before; the distance measured is 20 kilomètres plus 3,500 mètres, or 23,500 mètres.
On the map the lower graduation of the “reglet” is used. For instance, if 12 be the upper graduation of the division to 1/40 of the distance opposite to the “reglet,” the distance measured will be 12,700 mètres.
The campylometer has been specially constructed for maps on the 1/80000 and 1/100000 scales, and calculations can be made easily for any maps whose scales are multiples or sub-multiples of these. But the instrument will serve equally well for all maps or plans of which the numerical scale is known. We must multiply the length of the line expressed in millimètres by the denominator of the scale divided by 1,000.
So upon an English map to the 1/63360, a length of 155 millimètres corresponds to a “natural” length of 63,360 multiplied by 155, or 9820·80 mètres.
Thus we perceive that the employment of the campylometer does not necessitate the tracing of a graphic scale, but only the knowledge of the numerical scale. When the former only is known, the campylometer may be used in the following manner:—
Having traced with the disc the line you wish to measure, carry the instrument to the zero of the scale and let it run inversely the length of that scale, until the zero of the disc returns opposite to the zero of the “reglet.” The point at which the disc is stopped on the scale indicates the length of the line measured upon the map. If the scale be smaller than the line measured, repeat the operation as many times as may be necessary.
If it is desirable to ascertain upon a map of a scale of 1/20000 the distance represented by 1,200 mètres, we have only to place the toothed disc so that its position marks four times the required distance—that is, 4,800 mètres on the map of 1/80000 (for 4 times 20 = 80). Then move the disc in the given direction until the zero returns opposite the zero of the “reglet”; this limit will mark the extremity of the length required.
Explanations are not easy upon paper, but the instrument is found very easy in actual use. It is employed by the military staff for calculating distances of any kind, curves or straight lines. On the march, or even on horseback, the campylometer can be employed.
Mysterious Clocks.
The clocks represented in the two following illustrations (figs. 878 and 879), are well worthy of being placed in the house of any amateur of science. They are made of transparent crystal, and though all mechanism is cleverly concealed they keep capital time. The former clock (fig. 878) is the invention of Robert Houdin, and consists of two crystal discs superposed and enclosed in the same frame. One carries the usual numerals, the other moves upon its centre with the minute hand attached, and its rotation induces by the ordinary method the movement of the hour hand. The requisite motion is transmitted to the dial by gear disposed along the circumference and hidden within the metallic frame, and is itself put in motion by clockwork, enclosed in the pedestal of the timepiece.
Fig. 878.—Houdin’s clock.
M. Cadot, in his clock (fig. 879), retains the plates, but adopts the rectangular form, so as to preclude all idea of rotation, and to puzzle those who are acquainted with the working of Houdin’s clock. The minute hand cannot, in this instance, be fixed to the second glass plate, it preserves its independence. This movable plate has only a very slight angular movement around its centre, which oscillation or “play” is permitted in the interior of the rectangular dial. A little spring movement, hidden in the central nut of the “hand,” provides in progressive rotation the oscillation of the transparent plate, which cannot be perceived to move.
To produce this “balance” motion the plate is supported upon a bar in the lower part of the metal frame. After the direct oscillation of which we have spoken, a little spring puts the machinery back. The direct displacement is produced by a vertical piston which raises the end of the bar. This piston rests upon a bent lever communicating with a wheel with thirty triangular teeth. Finally this wheel turns upon its axis once in an hour by a clockwork arrangement in the pedestal of the clock. Each tooth takes two minutes to pass, and the movement is communicated to the minute hand, which thus goes round the dial in the hour. The hour hand is controlled by a delicate arrangement hidden in the base. The illustration and notes will explain the working.
Fig. 879.—M. Cadot’s clock.
M. Henri Robert has also invented a very interesting clock, and one calculated to excite much curiosity (fig. 881).
Fig. 880.—1. Front view. 2. Profile. 3. Detail of movement between the glasses. 4. Detail of movable plate. a. Base of clock. b. Framework. c. Space for movement. d. Wheel support. e. Cogwheel.
We can see nothing but a crystal dial, perfectly transparent, upon the surface of which two “hands” move, as upon an ordinary clock face. There is no machinery visible, and electricity may be credited with the motive power, because the dial is suspended by two wires. But they will soon be perceived not to be connected with the hands, and all search for the mechanism will be fruitless.
The hands, moreover, turn backwards or forwards, and may be moved by a treacherous finger, but will always return as by a balanced motion to their position, not the hour which they were at, but to the time which it actually is. They will take their proper place notwithstanding all efforts to the contrary, and will then, if let alone, indicate the time as steadily as ever.
Fig. 881.—M. Robert’s clock.
The hands of this very mysterious timepiece carry their own motive power, and consist of unequally balanced levers, so to speak, in which the clockwork arrangement is intended to disturb the equilibrium. This property is employed to indicate the hour and the minute, as we will attempt to show.
The minute hand is the balance, and it is very exactly poised. In the round box fitted to the end of this hand a plate of platinum is displaced by clockwork. The centre of gravity being displaced every instant by the revolution of the weight which goes round once in an hour, the minute hand is forced to follow, and carries the hour hand with it. By the hidden arrangements the hands are dependent one upon the other, but remain independent in movement. If they be moved backwards or forwards they will return automatically to their respective places, and if turned quickly round the minute hand will return to the proper minute, and the hour hand to the hour.
The mechanism is simple and ingenious; the principle, however, is not absolutely novel, and before M. Robert applied it many attempts had been made to move indicators by the machinery they themselves contained. But M. Robert has succeeded in adapting the idea beneficially and usefully, giving it a practical as well as an elegant shape.
A New Calculating Dial.
Fig. 882.—A new calculating dial.
Fig. 883.—Reverse view.
The small instrument herewith illustrated (figs. 882 and 883) is very serviceable for calculators, and its size adapts it for the waistcoat pocket. It can be used to calculate by addition, subtraction, multiplication, and division. Logarithms can be found, and the powers and roots of numbers—even trigonometrical calculations may be made by its aid. We need not go into any details regarding the principle of the little “circle.” Such explanations are only wearying and unsatisfactory at best. The principle is, simply stated, the theorem that the logarithm of the product of two numbers is equal to the sum of their logs. The size of the dial will of course regulate the length of the calculation. The instrument depicted permits of calculation to three figures with exactitude. M. Boucher, the inventor, hopes to succeed in perfecting an instrument of small size which will combine all desiderata, and calculate to high powers.
The Pedometer.
We all know how useful it is to be able to calculate distances approximately when upon an excursion or walking tour, and much trouble is taken by many tourists to ascertain the number of miles they may have walked in a certain time. The rapid success which the Pedometer has gained is a testimony to the need it has adapted itself to fill.
The pedometer is much like an ordinary watch in appearance and size. We perceive a dial with figures and spaces to show the number of paces walked. The cut represents the mechanism, which is exceedingly simple.
Fig. 884.—Pedometer.
In the fig. 884, B is a counter-poise at the extremity of a lever, which oscillates around an axis, A. A screw, V, serves to limit the extent of these oscillations, and a spring which acts upon the counter-poise holds the latter to the upper end. The apparatus is completed by a movement which counts the number of oscillations of the lever.
So much being understood, it will be presumed that if we give to the instrument an “up-and-down” movement, the spring which holds the counter-poise, B, being too weak to compensate the force of inertion of the latter, it gives way and presses against the screw, V. When the opposite movement takes place the counter-poise is at the end of its course, and so on. Thus during a walk each step produces an oscillation which the counter registers.
In the hands of a careful observer, such a pedometer is capable of registering exact results, and the number of paces being counted, a very good idea of the number of yards and miles passed over can be arrived at.
CHAPTER LIX.
SCIENCE AND DOMESTIC ECONOMY.
All branches of applied science are capable of giving us important hints and rendering us great service in all the conditions of our daily life, and as we have at various times throughout this volume mentioned useful domestic inventions applicable for use by means of water, air, etc., we may describe some more particularly relating to the inside of the house, and the science of domestic economy.
Fig. 885.—Double window.
Sometimes during the winter we may feel it very difficult, if not impossible, to keep the room warm. This we can do, however, by means of double windows.
Why is it that the double window as used in Russia keeps out the cold so well? Is it because the room is defended against frost by two windows instead of there being only one to resist it?—Not entirely. Such an explanation is not sufficient. If one be protected against the exterior cold, it is, thanks to the mass of air which is imprisoned, between the two windows. Extraordinary as it may appear, the air is a very bad conductor of heat, and forms the best insulator that one can find. The heat of the apartment is then perfectly retained by means of the air between the double windows.
In the same way the double window is not less useful during the summer, for it prevents the entrance of the heated air into the house. The double window may therefore be compared to the bournous of the Arab and the cloak of the Spaniard, which preserves from heat as well as guards against cold.
The double windows also perform another service. The glasses form a hot-house. The sun heats the air which is enclosed, and thus between the panes ferns and even vines will flourish. The windows are very easy to make, and in the event of any reader desiring to construct one or more, we give the dimensions. (See fig. 885.)
T T, is the exterior frame of the window. The two panes are mounted on a frame of wood, and are represented by A A´ and B B´ The sashes are represented apart, P and P´ are the shutters of sheet iron, which, if the walls be not so thick as represented, can be replaced by a spring-blind, which descends between the windows.
Sewing Machine worked by a Dog.
Fig. 886.—Sewing machine worked by a dog.
Animals have been employed for all time to draw carriages and the plough, etc. But these animal “motors” are usually employed under defective conditions, and therefore without full profit. The inert mass of the animals remains quite unutilized, his force only is employed, and there are many objections on the score of humanity, as well as from a mechanical standpoint, and great muscular tension with suffering may be inflicted upon an animal which is continually mounting a wheel or such contrivance for raising water. There was in the Paris Exhibition a threshing machine put in motion by a horse walking upon a pair of rollers which constituted an “endless” way, and we will now briefly describe a machine which utilizes animal force and weight. It is the invention of M. Richard of Paris, who has made many mechanical apparatus for industrial purposes.
The principle of the invention (fig. 886) consists in the animal utilizing all the force resulting from his dead-weight. A small box contains the dog very easily. In the illustration we see the dog at rest, and in that case he maintains his centre of gravity and exercises no force upon the wheel. But when the box is inclined, the mere weight of the animal is sufficient merely to turn the wheel in the direction of the arrows. The dog, finding himself sliding away, naturally endeavours to move forward, and the rotation of the wheel is continued; the best results are obtained when the body is placed entirely upon the descending line, and this result is owing only to the weight of the animal.
There is a resting-place, just above and outside the “endless” way traversed by the dog. A basin with water is also provided for the animal.
Fig. 887.—A clock-lamp.
M. Robert was let to this discovery in the following way:—He employs a large number of sewing-machine hands, and finding that the working of the machines had an injurious effect upon the health of the workers, he determined to substitute, in part, other labour for that of female hands. He then thought out his “quadrupedal motors,” which are worked by intelligent dogs. There is very little trouble or expense connected with the working, so a great saving is effected, as the dogs cost little, and are cheaply fed. The result is that M. Robert has four heavy machines occasionally at work, which are kept in motion by dogs at a very small expense.
A Clock-Lamp.
The illustration (fig. 887) represents an ingenious arrangement, which, by means of combustion of oil in a lamp, indicates the hour of the night. The design explains itself. Two vertical tubes are fixed above the reservoir of oil. The left tube contains oil, and is marked with the hours; the right tube burns the oil as a lamp.
The apparatus is so constructed by the inventor, M. H. Behn, that a certain quantity of oil is consumed exactly in one hour between two graduations of the hour-tube. A reflector placed beside the lamp enables one to see the time by night very plainly.
An “Alarum” Lamp.
Fig. 888.—An “alarum” lamp.
The apparatus represented below (fig. 888) is an ordinary “alarum” lamp. It is surmounted by a petroleum lamp, which carries a burner that remains lighted all night, and which serves as a night-light. The “alarum” carries an index, represented by the dotted lines in the illustration, and the hands are fixed (with the index) to the hour you wish to rise in the morning. The index is fitted with an arrangement which lets loose a vertical bar represented on the right of the figure. This bar is held by a spring, and carries a toothed rack which acts upon and raises the wick. At the proper time the bar is loosed, and the lamp-wick is raised, diffusing a strong and sudden light through the apartment. This illumination, in concert with an alarum-bell, generally succeeds in awaking the heaviest sleeper.
A Good Petroleum Lamp.
This lamp (fig. 889) burns gazoline without the least odour or danger of explosion. It will serve equally well for petroleum or naphtha. The gazoline used ought to be 660 grammes weight to the litre.
Fig. 889.—A good petroleum lamp.
The central portion of the lamp under consideration has an orifice, A B, which extends through the upper part, and by which the air is admitted to the centre of the flame. Two vertical plates divide the air-current into four portions. The chimney-rest, or gallery, forms with the glass three concentric envelopes, so arranged in stages that the air, when it reaches the plates, may be more and more carried under the flame. The orifices, a b, carefully regulated, give access to the exterior air. Including the central one, there are four currents of air, of which three strike against the flame. These are very excellent conditions for obtaining perfect combustion, and, consequently, there is an entire absence of smell and smoke, while the light is very powerful.
We may add that any glass will be found suitable to this lamp, and that, in consequence of the separation of the hot air by the currents mentioned, all danger of the glasses breaking from over-heating is avoided. In provincial districts, where lamp-glasses are not plentiful, this characteristic will be appreciated. The lamp can only be filled when it is extinguished, and thus the chances of explosion are practically obviated. A burner of twelve lines will give double the light of a moderator of the same capacity, and cost only a penny or less per hour. The light is perfectly still and clear.
A New Tap.
This new tap is the invention of M. Guyonnet, a Frenchman. The illustration (fig. 890) gives a very good idea of its construction, and it permits the gradual release of the liquid without any of the sudden rush which ordinary taps, or “bungs,” are apt to do. The plug is covered with indiarubber, and follows a double curve, which reduces the force of the liquid, and the indiarubber removes any incrustation from the bung hole into which it may be fitted, and closes the aperture effectively without force.
Fig. 890.—A new tap.
In order to guard against a contingency, which, however, is an unlikely one, the “envelope” (casing) has been made in two pieces, one of which can never be displaced; the head only can be moved, and it is easily detached. The plug adapts itself to the aperture as a button to the buttonhole, and only costs about three halfpence (15 centimes). Ice has no effect upon the aperture of the barrel, thanks to the indiarubber covering of the plug. So, altogether, such a tap will be found useful and very cheap.
The Trapeze and Swing.
We may here notice the simple trapeze and swing for children, which can be easily fitted up in any house between two rooms. The advantages of gymnastics for the young are incontestable, but practically there are difficulties in the way, particularly for those living in towns, but a skilful American has solved the problem in an ingenious way. He has found means to suspend the trapeze and a swing between the doorposts of a room without nails or any unsightly wood supports. The trapeze is simply suspended as represented in the accompanying illustrations.
Fig. 891.—The house swing.
Fig. 892.—The house trapeze.
The bar, B (see fig. 892), is of wood, terminating in screws enclosed in the grooves of the wood, at the extremity of which indiarubber discs are fixed (C and C´). When the bar is placed between the side posts of the open door and with the indiarubber in contact with the sides, the bar, B, is vigorously screwed in the direction of the arrow, and this motion is transmitted to the indiarubber discs which press against the door, and the apparatus remains fixed. The trapeze cords, or the swing ropes, can be fastened to the bar with hooks, as shown in the illustration, and the solidity and safety of the bar may be tested by putting heavy weights upon the ropes before venturing upon the swing, or trapeze. Even violent exercises may be indulged in without any fear of falling if the bar be firmly screwed against the sides of the door.
Simple Toys.
The accompanying illustration shows us a circlet of paper, very thin, fastened upon a frame, with paper wings fixed to the radii. This “screw” fashioned wings and the circlet can be kept up in the air by means of a hand screen. The effect will be observable in the rapid revolution of the little paper wheel, which must be very light and thin. (See fig. 893.)
Fig. 893.—The paper wheel.
There are many toys which can be controlled by the use of indiarubber springs. The bicyclist in the cut (fig. 894) is an instance in point. He turns around a pivot, and the tension of the spring keeps the machine in its place.
Fig. 894.—The bicycle toy.
The swimming-fish (fig. 895) is moved by an indiarubber spring, much as the drawing-room kite is elevated in the air. The spring of indiarubber is twisted to make the fish swim, and the caoutchouc is adapted to a toothed wheel which has a clock-work motion that gives the tail a motion sideways and round, acting like a propeller, and thus the fish swims.
Fig. 895.—The fish.
It is perhaps as well to say how these fish are managed, because then children will not break them, when they have been purchased, to see what is inside. Very young students are very fond of analyses of this nature, but synthesis, or putting together, is a far superior occupation in these circumstances to analysis, and to put together more lawful than to pull asunder.
Tree-felling by Steam.
The machine constructed a few years ago by Messrs. Ransome, and which was tried at Roupell Park, near London, seems to combine all the desiderata in the matter of mechanical tree-felling. Many experiments have been previously made by people to cut down trees by means of steam machinery, but none of them included all the conditions necessary for success. The Ransome Machine cut down four large trees in forty minutes.
Fig. 896.—Ransome’s tree-felling machine.
The apparatus, as shown in the illustration, is not unlike, in appearance, the perforating machines employed in boring rocks, in which the drill is replaced by a saw. The cylinder is small, and works at high pressure; a piston moves the saw in a guide-frame. The machine is firmly fixed against the tree, and the support is fastened by a chain.
A rack arrangement provides for the turning of the machine as the saw continues to cut its way through the trunk of the tree.
The weight is not excessive, and the necessary steam is supplied by a portable furnace and boiler, which communicates with the saw-motion by a flexible tube. The saw can cut through a horizontal as well as through a perpendicular trunk—thus timber can be rapidly cut up.
Another ingenious sawing machine is that invented by Mr. W. W. Giles, of Chicago, United States, America. This apparatus is about eight feet long, and one extremity is fixed to the trunk of the tree to be operated on.
Fig. 897.—Sawing machine.
The operator sits upon a ledge or saddle at the opposite end, and putting his feet upon the treadles, pushes them and the saw forward; this movement is assisted by the weight of the hands on the lever. The saw, under these circumstances, cuts into the wood with great force, and when the operator pushes the lever forward he brings the force of his legs to bear at the same time, and carries the saw back again. So feet, hands, dead weight with the saw itself, combine at once upon the tree, and the blade quickly does its work. The saw is three feet long and is very easily manipulated.
A Way of Preserving Grapes.
Remarkable progress has been made of late years in the conservation of various articles of food, and we may here speak of the preservation of the grape.
We will first mention M. R. Charmoux’s method, which is called the “Fresh Grape” system. The portion of the building used for the business is on the first floor, as nearly as possible in the centre of the building, so as to be guarded from damp. Two windows are sufficient for all purposes, one to the north, and one to the south. They may be merely kept shut on ordinary occasions, but when frost comes they must be draped and “packed” with nets filled with moss or dried seaweed. The principal one of the windows is to admit of the cleansing of the room and for the admission of air in the summer time, when there are not many grapes left.
Fig. 898.—Grape preserving.
In winter the apartment may be warmed by hot air, and if this cannot be managed the ordinary means must be resorted to to keep up the temperature. The upper clusters of grapes should first be picked, for shade conduces to longevity of the fruit, and the 20th October is about the time to commence. A fine day should be chosen; a cloudy day will suit provided there is no dew or dampness in the air.
The finest bunches are cut first, and care must be taken to separate them at the end of the stalk, having three “eyes” under the grape and two above it. The leaves should be at once cut off, and the grapes put with great caution into boxes or baskets to be taken to the preserving house, where each stalk is plunged into a phial holding about 125 grammes of water, into which, two or three days previously, a teaspoonful of wood charcoal has been put.
Fig. 899.—Hanging the grapes.
The phials are suspended as shown in the accompanying illustration (fig. 899), and then certain precautions must be observed: they must not be disturbed, nor must any draught be admitted, as the temperature must not descend below 1° to 2° cent. There is no necessity to change the water in the bottles; very little will evaporate between November and May, when the process ought to be finished, but the phials must neither be corked nor concealed.
Fig. 900.—Drying process
In the dry process the same house can be used, and stagings are employed. These frames are furnished with grooved boxes inclined towards each other, and lined with very dry fern-leaves or straw (fig. 900). Some days after the phials have been filled cut the grapes successively at the first time, which generally begins about the 6th to the 12th of November. The grapes are then put in baskets and carefully carried to the preserving room, where they are ranged in the boxes so as not to touch. Each box contains about six kilogrammes of grapes.
All the time of the conservation process care must be taken to eradicate all grapes which change colour or alter in any way. If dampness be feared have a lighted stove in the room for a time. Grapes are also preserved en espalier, but not so well. Sometimes a mouldy smell will be perceived in the room; to prevent this ventilators should be placed in the ceiling, which must, however, never be opened until the mouldy smell renders such a proceeding absolutely necessary.
CHAPTER LX.
SOME CURIOUS MODES OF TRANSIT.
We have already noticed some novel means of locomotion in the water and in the air, and now a few of the means whereby locomotion is attained as a recreation or as an exhibition may be mentioned.
Fig. 901.—New car.
For instance, here is a very curious vehicle, and the explanation of it we give in the words of the anonymous inventor:—
“My vehicle will carry four people without counting the driver. It is strong, easy to draw, and can turn in a horse’s length. The driver completely controls the animal, and no dust is thrown up to inconvenience the sitters, for by the time it rises the car is well in advance of it. It is cheap; the harness is simple and safe. The horse is sheltered from heat and rain and flies. If he should fall, there is no more than ordinary danger to life and limb than if he fell in a carriage; and, last of all, no very showy animal is needed, so long as his wind is sound, and his legs and tail respectable. Travellers in this “trap” can sit in any position, back to back, or face to face, two and two. The weight is all near the collar, and the animal is under control most perfectly.
Fig. 902.—Side view of vehicle.
“The estimated cost is £40; the horse about £40, or less; harness (say), £7, which contrasts favourably with the expenses of an ordinary one horse vehicle.”
Endless Rails.
These adjuncts to locomotion can be adapted to any kind of vehicle, and are in pieces about two feet long, articulated, and resting upon a base to give the necessary stability. The endless rail entirely envelopes the wheels all along the train, and the right and left rails are quite independent of each other, and as the vehicles advance the rails are put down and raised again when the carriages have passed. In front there are two distributing wheels governed by the tractive power, so that as the engine, or the animal drawing the train turns aside, the rails are still laid down parallel as before, but the hind wheels will not permit of very sharp curves.
There are wheels also at the rear of the train, and as on curves one wheel will pass over more rail than another, and in the hinder wheels a differential arrangement is used, and when one goes back the other advances as much, and so the relative distance is kept up, for the rail does not alter in length at all. The wheels have double flanges to retain them on the line.
Fig. 903.—Endless rails.
The system, considered from a mechanical point of view, gives striking results, and very little effort is required to put the train in motion. The resistance is very small, and much greater weights can, of course, be transported upon the endless rail than upon the ordinary road.
The experiment has been tried in the Tuilleries Gardens in Paris. Three carriages filled with children are drawn by two goats without any fatigue, and in the ordinary goat carriages at least twelve of the animals would be necessary—that is, four to each carriage. The economy of this mode of transport is therefore incontestable. The usual rate is about three-and-a-half to four miles an hour, so it is not adapted for travellers, but for merchandise.
The system might be applied to numerous vehicles on all kinds of roads for horses and oxen, in mines and factories, and in colonial plantations. M. Ader, the inventor, intended the system to be applied in the Landes, where the rails would lie close upon the sandy soil, and the expense of “metalling” roads would be entirely done away with. The adoption of the endless rail method of conveyance would prove a fortune to the Landes, where pine forests abound, and the wood and resin which is lost for want of transport could be removed and sold to advantage.
The endless rail may also be used upon the ordinary road in places where the highways are out of repair.
Fig. 904.—The Nina.
The Smallest Steamboat in the World.
The picture (fig. 904) shows us the Nina, the tiniest steamer afloat. The keel is somewhat over twelve feet in length, and about three feet wide, the depth of water ten inches. A speed of about five-and-a-half miles an hour can be obtained with a pressure of one hundred pounds. It is a twin-screw “ship” with propellers of three blades. The Nina was built on the lines of the Nautilus, of cedar and oak, and coppered. It is stated to be a marvel of solidity and lightness. The chimney is movable, and can be lowered at pleasure if a bridge be too low. There is ample room for provisions for the occupant in a frame which can be attached to the sides or fixed astern. The boat is easily carried in sections, and can be transported easily from place to place.
The weights of the various portions are as follows:—The hull 90 lb., boiler 80 lb., engine 25 lb., machinery 20 lb.; total, 215 lb. Forty pounds of good charcoal can be packed into the sides of the boat in racks. The rudder can be so connected by wires that the feet will perform the function of steering, thus leaving the hands free to attend to the engine, so the occupant is perfectly at liberty to go where and how he pleases.
Fig. 905.—An old chaise.
For river navigation or calm sea-steaming the Nina is admirably adapted, and any one who can be stoker, steersman, and engineer, as well as passenger and crew, will enjoy a trip in such a boat. Such a steamer costs about £250, but it might be less. It may be added that the Nina has uniformly behaved well, and was built by Fordham of New York.
A Mechanical Carriage.
A distinguished savant of the seventeenth century, Ozanam by name, a member of the Academy of Science, gave in 1693 a curious description of a mechanical carriage, which may perhaps be regarded as the parent of the velocipede and the bicycle. We here reproduce the engravings from Ozanam’s work and his words.
“Some years ago,” wrote the philosopher in 1693, “there may have been seen in Paris a chaise,” as in the picture, “and which a servant, by pressing alternately upon treadles” (as in the detail), “caused to progress by turning two small wheels hidden in a frame between the hinder pair of wheels of the chaise. The description I give as I received it from M. Richard, the doctor of Rochelle.
“A A is a roller attached to the box behind the vehicle, B is a pulley, over which the cord that works with the treadles passes; C and D are the treadles, with pedals, F F. The wheels, H H, being thus put in motion, the large wheels are moved, and when the hind wheels move forward, the foremost ones must advance also, and the sitter has only to guide the machine by the reins he holds attached to the guiding axle.”
Fig. 906.—The movement.