Chapter 3

But both these weights, the one going upon the short journey, and the other upon the long, will start down exactly the same inclination or declivity. The reader will see that this must be the case if he will draw two circles on paper round a common centre, the one at the distance of one inch, and the other at the distance of nine inches. Having done this, let him cut a notch out of the paper, extending through both the circles to the centre, and including a twelfth part, or thirty degrees, of each between its converging sides. He will then observe, that the two arcs cut out by the notch are everywhere concentric with each other; therefore, their beginnings and endings are concentric or inclined in exactly the same degree to a perpendicular crossing their centres. These concentric beginnings and endings represent correctly the concentric directions in which the swinging weights commence their downward movements.

Now, since it has been shewn that bodies begin to run down equal descents with equal velocities, it follows that the weight on the short string and that on the long string must commence to move down the concentric curves of their respective arcs at an equal rate. But it has been also shewn that the one of these weights has a nine times longer journey to perform than the other; it is clear, therefore, that both cannot accomplish their respective distances in the same time. The weight on the shortest string in reality makes three vibrations, and the weight on the string that is next to this in length makes two vibrations, while the weight on the longest string is occupied about one; and the differences would be as 9, 4, and 1, instead of as 3, 2, 1, but that the weights moving in the longer arcs benefit most from acceleration of velocity. Although all the vibrating bodies begin to move at equal rates, they pass the central positions directly beneath their points of suspension at unequal ones. Those that have been the longest in getting down to these positions, have of necessity increased their paces the most while upon their route.

Suspended weights, then, only vibrate in equal times when hung upon equal strings; but they continue to make vibrations in equal times notwithstanding the diminution of the arcs in which they swing. This was the fact that caught the attention of Galileo; he observed that the vibrations of the lamp slowly died away as the effect of the disturbing force was destroyed bit by bit, but that, nevertheless, the last faint vibration that caught his eye, took the same apparent time for its performance as the fullest and longest one in the series.

The instrument that has been designated by the learned name of pendulum, is simply a weight of this description placed on the end of a metallic or wooden rod, and hung up in such a way that free sideways motion is permitted. This freedom of motion is generally attained by fixing the top of the rod to a piece of thin, highly elastic steel. A pendulum fitted up after this fashion, will continue in motion, if once started, for many hours. It only stops at last, because the air opposes a slight resistance to its passage, and because the suspending spring is imperfectly elastic. The effects of these two causes combined arrest the vibration at last, but not until they have long accumulated. The weight does not stand still at once, but its arc of vibration grows imperceptibly less and less, until at last there comes a time when the eye cannot tell whether the body is still moving or in absolute repose.

Now, suppose that a careful and patient observer, aware of the exact length of the suspending-rod of a vibrating pendulum, were to set himself down to count how many beats it would make in a given period, he would thenceforward be able to assign a fixed value to each beat, and would consequently have acquired an invariable standard whereby he might estimate short intervals. If he found that his instrument had made exactly 86,400 beats at the end of a mean solar day, and knew that the length of its rod was a trifle more than 39 inches, he would be aware that each beat of such a pendulum might always be taken as the measure of a second. The length of the rod of a pendulum which beats exact seconds in London is 39.13 inches.

But there are few persons who would be willing to go through the tedious operation of counting 86,400 successive vibrations. The invention of a mechanical contrivance that was able to break the monotony of such a task, would be hailed by any one who had to perform it as an invaluable boon. Even a piece of brass with sixty notches upon it, which he might slip through his fingers while noting the swinging body, would enable him to keep his reckoning by sixties instead of units, and so far would afford him considerable relief. But if the notched brass could be turned into a ring, and the pendulum be made to count the notches off for itself, round and round again continuously, registering each revolution as it was completed for future reference, the observer would attain the same result without expending any personal trouble about it. It is this magical conversion of brass and iron into almost intelligent counters of the pendulum's vibrations, that the clock-maker effects by his beautiful mechanism.

In the pendulum clock, the top of the swinging-rod is connected with a curved piece of steel, which dips its teeth-like ends on either hand into notches deeply cut in the edges of a brass wheel. The notched wheel is connected with a train of wheel-work kept moving by the descent of a heavy weight; but it can only move onwards in its revolution under the influence of the weight, as the two ends of the piece of steel are alternately lifted out of the notches by the swaying of the pendulum. The other wheels and pinions of the movement are so arranged that they indicate the number of turns the wheel at the top of the pendulum completes, by means of hands traversing round a dial-plate inscribed with figures and dots.

It is found convenient in practice to make the direct descent of a weight the moving power of the wheel-work, instead of the swinging of the pendulum, for the simple reason, that the excess of its power beyond what is required to overcome the friction of the wheel-work, is then employed in giving a slight push to the pendulum; this push just neutralises the retarding effects before named as inseparable from the presence of air and imperfect means of suspension. The train of wheel-work in a clock, therefore, serves two purposes--it records the number of beats which the pendulum makes, and it keeps that body moving when once started. As far as the activity of the pendulum is concerned, the wheel-work is a recording power, and a preserving power, but _not_ an originating power. If there were no air, and no friction in the apparatus of suspension, the pendulum would continue to go as well without the wheel-work as with it. With the wheel-work it beats as permanently and steadily upon material supports and plunged in a dense atmosphere, as it would if it were hung upon nothing, and were swinging in nothing; and also performs its backward and forward business in solitude and darkness, to the same practical purpose that it would if the eyes of watchful and observant guardians were turned incessantly towards it.

Galileo published his discovery of the isochronous property of the pendulum in 1639. Richard Harris of London took the hint, and connected the pendulum with clock-work movement in 1641. Huyghens subsequently improved the connection, and succeeded in constructing very trustworthy time-keepers, certainly before 1658.

But notwithstanding all that the knowledge and skill of Huyghens could do, his most perfect instruments were still at the mercy of atmospheric changes. It has been said, that the time of a pendulum's vibration depends upon the length of its suspending-rod. This length is measured, not down to the bottom of the weight, but to the centre of its mass. For the weight itself is necessarily a body of considerable dimensions, and in this body some particles must be nearer to, and others further from the point of suspension. Those which are nearest will, of course, in accordance with the principles already explained, have a tendency to make their vibrations in shorter periods; and those which are furthest, in longer periods. But all these particles are bound together firmly by the power of cohesion, and must move connectedly. They, therefore, come to an agreement to move at a mean rate--that is, between the two extremes. The top particles hurry on the middle ones; the bottom particles retard them in a like degree. Consequently, the whole of the weight moves as if its entire mass were concentered in the position of those middle particles; and the exact place of this central position in relation to the point of suspension, becomes the important condition which determines the time in which the instrument swings.

In pendulums of ordinary construction, this relation is by no means an unvarying one--changes of temperature alter the bulk of all kinds of bodies. A metal rod runs up and down under increase and diminution of heat, as certainly as the thread of mercury in the tube of the thermometer does. A hot day, therefore, lengthens the metallic suspending-rod of a pendulum, and carries the centre of its weight to a greater distance from the point of suspension. By this means, the period of each vibration is of necessity lengthened. An increase of temperature to the extent of ten of Fahrenheit's degrees, will make a second's pendulum with a brass rod lose five vibrations in a day. All substances do not, however, suffer the same amount of expansion under like increments of heat. If the rod of the pendulum be made of varnished or black-leaded wood, an addition of ten degrees of heat will not cause it to lose more than one vibration in a day. But even this small irregularity is too vast for the purposes of precise science, and accordingly ingenuity has been taxed to the utmost to find some means of removing the source of inaccuracy, to invent some plan whereby the pendulum may be made sensitive enough to discover and correct its own varying dimensions as different temperatures are brought to bear upon its material.

The first successful attempt to accomplish this useful purpose was made by George Graham in 1715. He replaced the solid weight at the bottom of the rod by a glass jar containing mercury. The rod he formed of steel of the usual length; and because mercury expands five times more than steel, he fixed the height of the column of mercury in the jar at only 6-1/2 inches. In this arrangement he found that additional heat carried up the mercury in the jar, as much as it carried down the jar by the elongation of the rod. Consequently, the motion of the one perfectly compensated the motion of the other, and the effective centre of the weight always remained at the same precise distance from the top of the rod. By the application of this compensating pendulum, clocks are now constructed that do not vary to the extent of a tenth of a second in a day.

Soon after the invention of Graham's mercurial pendulum, John Harrison--the same clever mechanician who received L.20,000 from government for making a chronometer that went to Jamaica in one year and returned in another with an accumulated error of only 1 minute and 54 seconds--hit upon another means of gaining the same end. He brought a steel rod down from the point of suspension, turned it up into a copper rod of less length; and from the top of this hung the weight. He fixed the lengths of the steel and copper rods, which expand unequally, in such a way that the steel carried the copper down exactly as much as the copper carried the weight up; and thus the centre of the weight was still kept at the same distance from the real point of suspension. Harrison's pendulum is generally seen in somewhat the form of a gridiron, because many parallel bars of copper and steel are used in its construction, for the sake of rendering it firm and unyielding in all its parts.

MAGIC IN INDIA.

A correspondent in India tells us that a military friend of his, on returning to England, and finding all astir there about mesmerism, writes to him that he had often had much cause to regret that, during his long residence of more than twenty-eight years in India, he was ignorant of the very name or existence of mesmerism; as he could recall to mind many instances of what he then deemed to be native superstitions, on which he now looked very differently, believing them to be the direct effects of mesmeric influence. These instances are daily and hourly exhibited in Indian dwellings, though either passing without notice, or ascribed to other causes. Children in India, especially European children, seldom go to sleep without being subjected to some such influence, either by the ayahs or the attendant bearers; and our military friend says, that he has himself repeatedly, in a few seconds, been the means of tranquillising a fractious, teething child, and throwing it into a profound sleep by the mere exercise of the will, quite ignorant that he was thus using, though in one of its simplest forms, a power at which he laughed heartily when displayed around him in some of its more hidden ramifications. We give the following in his own words:--

I shall now relate a circumstance, proving that the natives of India apply mesmeric power to the removal of diseases with the utmost success. I had in my establishment at Lucknow a _chuprassie_,[2] who was a martyr to the most deplorable chronic rheumatism. His hands, wrists, knees, and all his joints, were so greatly enlarged, and in a state so painful, that his duties had gradually become merely nominal. One day, he hobbled up, and begged my permission to remain at home for a few days, for the purpose of being cured of his agonising disease. I said: 'Certainly; get cured of your complaint, and let me see you when you return.' In a very few days, perhaps in four or five, to my great astonishment he returned, smiling and joyous, with his limbs as pliant and supple as my own.

'What!' said I, 'are you come back already?'

'Yes, sir, by your favour, I am perfectly cured.'

'What! entirely cured?'

'Yes, sir; perfectly cured.'

'Well, then, tell me what medicine you took.'

'I took no medicine; I called in two women, _zadoo walees_ (dealers in magic) from the bazaar, and gave them four pice apiece (about twopence each), and they cured me.'

'But how--what did they do?'

'They put me on a _charpaee_ (a low bed), and one sat at each side of me, and both passed their hands over my body so (describing long mesmeric passes), and thus they set me to sleep, and I slept soundly: when I awoke, I was free from rheumatism, and am now perfectly well.'

The master made no investigation of the matter; the man was laughed at, and told to return to his duties, which he continued thenceforth to perform with all his former zeal. Now, this was not regarded by the patient or the other servants as a strange thing, for they took it quite as a matter of course; and there is indeed no reason to doubt, that the natives of India frequently have recourse to _jhar phoonk_, or mesmerism, for the cure of rheumatism; but many interesting things arc carefully concealed from the English, because we invariably ridicule or sneer at native customs--a mode of treatment peculiarly distasteful to the inhabitants of the East.

But though willing to make use of these mysterious powers in their beneficent and curative forms, there exist all over Hindostan abundant proofs of the dread of 'zadoo,' or witchcraft, among all classes, Moslems as well as Hindoos, when it appears to threaten them with evil. If a cultivator has transplanted his tobacco or other valuable plant, he collects old cracked earthen cooking-pots, and places a spot of limestone whiting on the well-blackened bottom of each. They are then fixed on stakes driven into the ground, so that the white spots may be seen by all passers-by. This ingenious process is meant to neutralise the influence of the 'evil eye' of the envious. The talismans worn by the natives, said to be always the same, consist of an oblong cylinder, with a couple of rings for a string to pass through to fasten them, and would appear to have been originally impregnated with the electric fluid. Children are invariably provided with such amulets to avert the 'evil eye;' and should any one praise their beauty, the parent spits on the ground, and declares them to be perfect frights.

The inhabitants of the mountainous regions east of Bengal--the Bhooteeas, and others--accuse all those of Bengal of being great sorcerers; and when seized with fever in the low malarious tracts, which they must pass through on descending from the mountains and entering that province, for the purpose of bathing in the holy Ganges, or visiting one of the numerous shrines in the plains, the disease is invariably imputed to the incantations of the Bengalees.

Nor tree, nor plant Grows here, but what is fed with magic juice, All full of human souls.

Our military friend gives two other instances in which the effects produced were really and truly mesmeric, though of course ascribed to magic. He vouches for the facts, but leaves every one to form his own opinion:--

The wife of one of my grooms, a robust woman, and the mother of a large family, all living within my grounds, was bitten by a poisonous serpent, most probably a cobra, or coluber maja, and quickly felt the deadly effects of its venom. When the woman's powers were rapidly sinking, the servants came to my wife, to request that the civil surgeon of the station might be called in to save her life. He immediately attended, and exerted his utmost skill, but in vain. In the usual time, the woman appeared to be lifeless, and he therefore left her, acknowledging that he could not be of any further service. On his reaching my bungalow, some of my servants stated, that in the neighbourhood a fakir, or wandering mendicant, resided, who could charm away the bites of snakes; and begged, if the doctor had no objection, that they might be permitted to send for him. He answered: 'Yes, of course: if the poor people would feel any consolation by his coming, they could bring him; but the woman is dead.'

After a considerable lapse of time, the magician arrived, and began his magical incantations. I was not present at the scene, but it occurred in my park, within a couple of hundred yards of my bungalow; and I am quite confident that any attempt to use medicines would have been quite useless, as the woman's powers were utterly exhausted, though her body was still warm. The fakir sat down at her side, and began to wave his arm over her body, at the same time muttering a charm; and he continued this process until she awoke from her insensibility, which was within a quarter of an hour.

The last instance we shall give occurred at Bombay. The writer says: On visiting Bombay in 1822, I was greatly diverted by a circumstance told to me by an old friend in the artillery there. He stated that he had had a _kulashee_, or tent-pitcher, in his service for many years; that he was a most faithful and active man; but that he had all of a sudden, and without any visible cause, become very greatly emaciated, feeble, and ghastly. His master had sent him to the hospital, to have the benefit of the skill of the regimental surgeon; but after the lapse of some time, he was sent back, with the intimation that the surgeon could not discover any specific disease, and that he, therefore, could make nothing of his case. On bringing back this information, my friend began to cross-question his servant, who would not at first acknowledge the cause of his disease; but at last, after much persuasion, he candidly avowed to his master, in confidence, that he was labouring under the effect of witchcraft. 'And do you know,' said my friend, 'that the fellow actually believed it himself.' And we both laughed most heartily. His master continued his examination, until the kulashee confessed that a certain Brahmin, officiating at a large tank close to the fortress of Bombay, had threatened him with his revenge, and was now actually eating up his liver, by which process he would shortly be destroyed. 'I will tell you what I did: I no sooner got the Brahmin's name, than I ordered my buggy, and quickly drove down to the tank. On reaching it, I inquired for the magician; and on his arrival, I leaped down, seized him by the arm, and horsewhipped him within an inch of his life, now and then roaring out: "I'll teach you to bewitch my kulashee, you villain!" "How dare you injure my servant, you rascal?" and so forth. In a very few minutes, the liver-eating Brahmin declared that he would instantly release the kulashee from the spell; that, on reaching home, I would find him recovered; and ultimately he was perfectly released. And, believe me,' said my friend laughing, 'that the fellow mended from that hour, and is now a capital servant.'

In a series of interesting papers in the _Dublin University Magazine_, called 'Waren, or the Divine Afflatus of the Hindoos,' the writer gives a lengthened description of that strange possession (which he calls _daimoniac_, preferring that word to _demoniac_--the latter being exclusively evil or devilish, while the former implies a superhuman power for good as well as evil), with all its varied manifestations. This faith, if it may be so called, prevails over the whole of Western India, its greatest stronghold being the province of Concan, not far from Bombay. There are three kinds of waren: the hereditary or family waren; the transmitted or tribe waren; and that which is summoned by a variety of spells and incantations, called the village waren; the last being, of course, the most widely spread, as almost every village has a temple dedicated to Devee, the frightful goddess who presides over and is consulted on every calamity, giving her responses in the person of some waren selected for the purpose. In the hereditary and tribe waren, the visitation continues at intervals through life in the person once influenced, and it is always regarded as a proof of divine favour, being seldom exercised but for beneficent purposes. Its approach is made known by sundry sudden changes and tremblings, _and always_ by a nodding of the head. After heavings, pantings, gurglings, and moanings, composure returns, and the possessed begins his utterances, and always in the name of some divinity or other waren, speaking of himself as a distinct person, by the name of _Majhen Jhad_, _my tree_, whom he reproves, admonishes, and advises, in such terms as '_My tree_ has broken such a vow'--'If _my tree_ acts thus,' &c. This phrase has been variously explained, as the spirit of the root-man or family ancestor, speaking of his descendant waren as _my tree_, or as a simple allusion to his motionless condition.

The hereditary waren is the oracle of the household, as the village waren is of the entire neighbourhood, often usurping the functions of judge and jury, causing sometimes the innocent to suffer for the guilty, but also, by his prophecies, being the means of recovering stolen property. There are many other kinds of waren: a cholera waren, a sanitary waren, a necromantic waren; and so forth. The last named not only discovers the state of affairs of those who die suddenly, or disappear mysteriously, but pretends to raise the dead; and a story is recorded of an impudent impostor, taking advantage of the belief of the people in the identity of the persons thus raised, and personating so well a prince slain in battle some years before, that not only did his brother swear to his identity, but the widow actually threw off her weeds, and went to live with him!