A Shilling's Worth Of Science. (From Dickens's Household Words.)
Dr. Paris has already shown, in a charming little book treating scientifically of children's toys, how easy even “philosophy in sport can be made science in earnest.” An earlier genius cut out the whole alphabet into the figures of uncouth animals, and inclosed them in a toy-box representing Noah's Ark, for the purpose of teaching children their letters. Europe, Asia, Africa, and America, have been decimated; “yea, the great globe itself,” has been parceled into little wooden sections, that their readjustment into a continuous map might teach the infant conqueror of the world the relative positions of distant countries. Archimedes might have discovered the principle of the lever and the fundamental principles of gravity upon a rocking-horse. In like manner he might have ascertained the laws of hydrostatics, by observing the impetus of many natural and artificial fountains, which must occasionally have come beneath his eye. So also the principles of acoustics might even now be taught by the aid of a penny whistle, and there is no knowing how much children's nursery games may yet be rendered subservient to the advancement of science. The famous Dr. Cornelius Scriblerus had excellent notions on these subjects. He determined that his son Martinus should be the most learned and universally well-informed man of his age, and had recourse to all sorts of devices in order to inspire him even unthinkingly with knowledge. He determined that every thing should contribute to the improvement of his mind—even his very dress. He therefore, his biographer informs us, invented for him a geographical suit of clothes, which might give him some hints of that science, and also of the commerce of different nations. His son's disposition to mathematics—for he was a remarkable child—was discovered very early by his drawing parallel lines on his bread and butter, and intersecting them at equal angles, so as to form the whole superficies into squares. His father also wisely resolved that he should acquire the learned languages, especially Greek—and remarking, curiously enough, that young Martinus Scriblerus was remarkably fond of gingerbread, the happy idea came into his parental head that his pieces of gingerbread should be stamped with the letters of the Greek alphabet; and such was the child's avidity for knowledge, that the very first day he eat down to iota.
When Sir Isaac Newton changed his residence and went to live in Leicester-place, his next door neighbor was a widow lady, who was much puzzled by the little she observed of the habits of the philosopher. One of the Fellows of the Royal Society called upon her one day, when, among other domestic news, she mentioned that some one had come to reside in the adjoining house, who she felt certain was a poor mad gentleman. “And why so?” asked her friend. “Because,” said she, “he diverts himself in the oddest way imaginable. Every morning when the sun shines so brightly that we are obliged to draw down the window-blinds, he takes his seat on a little stool before a tub of soap-suds, and occupies himself for hours blowing soap-bubbles through a common clay-pipe, which he intently watches floating about until they burst. He is doubtless,” she added, “now at his favorite diversion, for it is a fine day; do come and look at him.” The gentleman smiled; and they went up-stairs, when after looking through the stair-case window into the adjoining court-yard, he turned round and said, “My dear lady, the person whom you suppose to be a poor lunatic, is no other than the great Sir Isaac Newton studying the refraction of light upon thin plates, a phenomenon which is beautifully exhibited upon the surface of a common soap-bubble.”
The principle, illustrated by the examples we have given, has been efficiently followed by the Directors of the Royal Polytechnic Institution in Regent-street, London. Even the simplest models and objects they exhibit in their extensive halls and galleries, expound—like Sir Isaac Newton's soap-bubble—some important principle of Science or Art.
On entering the Hall of Manufactures (as we did the other day) it was impossible not to be impressed with the conviction that we are in an utilitarian age in which the science of Mechanics advances with marvelous rapidity. Here we observed steam-engines, hand-looms, and machines in active operation, surrounding us with that peculiar din which makes the air
“Murmur, as with the sound of summer-flies.”
Passing into the “Gallery in the Great Hall,” we did not fail to derive a momentary amusement, from observing the very different objects which seemed most to excite the attention, and interest of the different sight-seers. Here, stood obviously a country farmer examining the model of a steam-plow; there, a Manchester or Birmingham manufacturer looking into a curious and complicated weaving machine; here, we noticed a group of ladies admiring specimens of [pg 598] elaborate carving in ivory, and personal ornaments esteemed highly fashionable at the antipodes; and there, the smiling faces of youth watching with eager eyes the little boats and steamers paddling along the Water Reservoir in the central counter. But we had scarcely looked around us, when a bell rang to announce a lecture on Voltaic Electricity by Dr. Bachhoffner; and moving with a stream of people up a short stair-case, we soon found ourselves in a very commodious and well-arranged theatre. There are many universities and public institutions that have not better lecture rooms than this theatre in the Royal Polytechnic Institution. The lecture was elementary and exceedingly instructive, pointing out and showing by experiments, the identity between Magnetism and Electricity—light and heat; but notwithstanding the extreme perspicuity of the Professor, it was our fate to sit next two old ladies who seemed to be very incredulous about the whole business.
“If heat and light are the same thing,” asked one, “why don't a flame come out at the spout of a boiling tea-kettle?”
“The steam,” answered the other, “may account for that.”
“Hush!” cried somebody behind them; and the ladies were silent: but it was plain they thought Voltaic Electricity had something to do with conjuring, and that the lecturer might be a professor of Magic. The lecture over, we returned to the Gallery, where we found the Diving Bell just about to be put in operation. It is made of cast iron, and weighs three tons; the interior being provided with seats, and lighted by openings in the crown, upon which a plate of thick glass is secured. The weighty instrument suspended by a massive chain to a large swing crane, was soon in motion, when we observed our skeptical lady-friends join a party and enter, in order, we presume, to make themselves more sure of the truth of the diving-bell than they could do of the identity between light and heat. The bell was soon swung round and lowered into a tank, which holds nearly ten thousand gallons of water; but we confess our fears for the safety of its inmates were greatly appeased, when we learned that the whole of this reservoir of water could be emptied in less than one minute. Slowly and steadily was the bell drawn up again, and we had the satisfaction of seeing the enterprising ladies and their companions alight on terra firma, nothing injured excepting that they were greatly flushed in the face. A man, clad in a water-tight dress and surmounted with a diving-helmet, next performed a variety of sub-aqueous feats, much to the amusement and astonishment of the younger part of the audience, one of whom shouted as he came up above the surface of the water, “Oh! ma'a! Don't he look like an Ogre!” and certainly the shining brass helmet and staring large plate-glass eyes fairly warranted such a suggestion. The principles of the diving-bell and of the diving-helmet are too well known to require explanation: but the practical utility of these machines is daily proved. Even while we now write, it has been ascertained that the foundations of Blackfriars Bridge are giving way. The bed of the river, owing to the constant ebb and flow of its waters, has sunk some six or seven feet below its level since the bridge was built, thus undermining its foundation; and this effect, it is presumed, has been greatly augmented by the removal of the old London Bridge, the works surrounding which operated as a dam in checking the force of the current. These machines, also, are constantly used in repairing the bottom of docks, landing-piers, and in the construction of breakwater works, such as those which are at present being raised at Dover Harbor.
Among other remarkable objects in the museum of natural history we recognized, swimming upon his shingly bed under a glass case, our old friend the Gymnotus Electricus, or Electrical Eel. Truly, he is a marvelous fish. The power which animals of every description possess in adapting themselves to external and adventitious circumstances, is here marvelously illustrated, for, notwithstanding this creature is surrounded by the greatest possible amount of artificial circumstances, inasmuch as instead of sporting in his own pellucid and sparkling waters of the river Amazon, he is here confined in a glass prison, in water artificially heated; instead of his natural food, he is here supplied with fish not indigenous to his native country, and denied access to fresh air, with sunlight sparkling upon the surface of the waves—he is here surrounded by an impure and obscure atmosphere, with crowds of people constantly moving to and fro and gazing upon him; yet, notwithstanding all these disadvantageous circumstances, he has continued to thrive; nay, since we saw him ten years ago, he has increased in size and is apparently very healthy, notwithstanding that he is obviously quite blind.
This specimen of the Gymnotus Electricus was caught in the river Amazon, and was brought over to this country by Mr. Potter, where it arrived on the 12th of August, 1838, when he displayed it to the proprietors of the Adelaide Gallery. In the first instance, there was some difficulty in keeping him alive, for, whether from sickness, or sulkiness, he refused food of every description, and is said to have eaten nothing from the day he was taken, in March, 1838, to the 19th of the following October. He was confided upon his arrival to the care of Mr. Bradley, who placed him in an apartment the temperature of which could be maintained at about seventy-five degrees Fahrenheit, and acting upon the suggestions of Baron Humboldt, he endeavored to feed him with bits of boiled meat, worms, frogs, fish, and bread, which were all tried in succession. But the animal would not touch these. The plan adopted by the London fishmongers for fattening the common eel was then had recourse to; a quantity of bullock's blood was put into the [pg 599] water, care being taken that it should be changed daily, and this was attended with some beneficial effects, as the animal gradually improved in health. In the month of October it occurred to Mr. Bradley to tempt him with some small fish, and the first gudgeon thrown into the water he darted at and swallowed with avidity. From that period the same diet has been continued, and he is now fed three times a day, and upon each occasion is given two or three carp, or perch, or gudgeon, each weighing from two to three ounces. In watching his movements we observed, that in swimming about he seems to delight in rubbing himself against the gravel which forms the bed above which he floats, and the water immediately becomes clouded with the mucus from which he thus relieves the surface of his body.
When this species of fish was first discovered, marvelous accounts respecting them were transmitted to the Royal Society: it was even said that in the river Surinam, in the western province of Guiana, some existed twenty feet long. The present specimen is forty inches in length; and measures eighteen inches round the body; and his physiognomy justifies the description given by one of the early narrators, who remarked, that the Gymnotus “resembles one of our common eels, except that its head is flat, and its mouth wide, like that of a cat-fish, without teeth.” It is certainly ugly enough. On its first arrival in England, the proprietors offered Professor Faraday (to whom this country may possibly discover, within the next five hundred years, that it owes something) the privilege of experimenting upon him for scientific purposes, and the result of a great number of experiments, ingeniously devised, and executed with great nicety, clearly proved the identity between the electricity of the fish and the common electricity. The shock, the circuit, the spark, were distinctly obtained: the galvanometer was sensibly affected; chemical decompositions were obtained; an annealed steel needle became magnetic, and the direction of its polarity indicated a current from the anterior to the posterior parts of the fish, through the conductors used. The force with which the electric discharge is made is also very considerable, for this philosopher tells us we may conclude that a single medium discharge of the fish is at least equal to the electricity of a Leyden Battery of fifteen jars, containing three thousand five hundred square inches of glass, coated upon both sides, charged to its highest degree. But great as is the force of a single discharge, the Gymnotus will sometimes give a double, and even a triple shock, with scarcely any interval. Nor is this all. The instinctive action it has recourse to in order to augment the force of the shock, is very remarkable.
The professor one day dropped a live fish, five inches long, into the tub; upon which the Gymnotus turned round in such a manner as to form a coil inclosing the fish, the latter representing a diameter across it, and the fish was struck motionless, as if lightning had passed through the water. The Gymnotus then made a turn to look for his prey, which having found, he bolted it, and then went about seeking for more. A second smaller fish was then given him, which being hurt, showed little signs of life; and this he swallowed apparently without “shocking it.” We are informed by Dr. Williamson, in a paper he communicated some years ago to the Royal Society, that a fish already struck motionless gave signs of returning animation, which the Gymnotus observing, he instantly discharged another shock, which killed it. Another curious circumstance was observed by Professor Faraday—the Gymnotus appeared conscious of the difference of giving a shock to an animate and an inanimate body, and would not be provoked to discharge its powers upon the latter. When tormented by a glass rod, the creature in the first instance threw out a shock, but as if he perceived his mistake, he could not be stimulated afterward to repeat it, although the moment the professor touched him with his hands, he discharged shock after shock. He refused, in like manner, to gratify the curiosity of the philosophers, when they touched him with metallic conductors, which he permitted them to do with indifference. It is worthy of observation, that this is the only specimen of the Gymnotus Electricus ever brought over alive into this country. The great secret of preserving his life would appear to consist in keeping the water at an even temperature—summer and winter—of seventy-five degrees of Fahrenheit. After having been subjected to a great variety of experiments, the creature is now permitted to enjoy the remainder of its days in honorable peace, and the only occasion upon which he is now disturbed, is when it is found necessary to take him out of his shallow reservoir to have it cleaned, when he discharges angrily enough shock after shock, which the attendants describe to be very smart, even though he be held in several thick and well wetted cloths, for they do not at all relish the job.
The Gymnotus Electricus is not the only animal endowed with this very singular power; there are other fish, especially the Torpedo and Silurus, which are equally remarkable, and equally well known. The peculiar structure which enters into the formation of their electrical organs, was first examined by the eminent anatomist John Hunter, in the Torpedo; and, very recently, Rudolphi has described their structure with great exactness in the Gymnotus Electricus.
Without entering into minute details, the peculiarity of the organic apparatus of the Electrical Eel seems to consist in this, that it is composed of numerous laminæ or thin tendinous partitions, between which exists an infinite number of small cells filled with a thickish gelatinous fluid. These strata and cells are supplied with nerves of unusual size, and the intensity of the electrical power is presumed to [pg 600] depend on the amount of nervous energy accumulated in these cells, whence it can be voluntarily discharged, just as a muscle may be voluntarily contracted. Furthermore, there are, it would appear, good reasons to believe that nervous power (in whatever it may consist) and electricity are identical. The progress of science has already shown the identity between heat, electricity, and magnetism; that heat may be concentrated into electricity, and this electricity reconverted into heat; that electric force may be converted into magnetic force, and Professor Faraday himself discovered how, by reacting back again, the magnetic force can be reconverted into the electric force, and vice versâ; and should the identity between electricity and nervous power be as clearly established, one of the most important and interesting problems in physiology will be solved.
Every new discovery in science, and all improvements in industrial art, the principles of which are capable of being rendered in the least degree interesting, are in this Exhibition forthwith popularized, and become, as it were, public property. Every individual of the great public can at the very small cost of one shilling, claim his or her share in the property thus attractively collected, and a small amount of previous knowledge or natural intelligence will put the visitor in actual possession of treasures which previously “he wot not of,” in so amusing a manner that they will be beguiled rather than bored into his mind.