broken-down parishioner, and requesting his nephew | which amuse his fancy in the nursery fire, but to make his adieux to the ladies, and to young Sum- the philosopher reads in them the suggestive ner, he hurried off in quest of the Bribeworth coach, leaving his nephew to look over some important papers, and to expect very anxiously the return of Mr. Gribe. THOUGHTS ON THE PENDULUM. To many persons there is something impressive in the monotonous beat of a pendulum. Through day and night, amid scenes chequered by the varieties of life, or deepened into solemn gloom by death, we still hear its dull, scarcely audible, but emphatic movement. hints of nature as she mightily works in her circle of wonders. If a simple spark can thus instruct us in the laws of electricity, so may the pendulum enlighten us respecting other great facts. Before proceeding to these particulars we must take a short survey of the history of the pendulum itself, and explain the events which led to the discovery and improvement of this time-measurer. 'The Dutch mathematician Huyghens was probably the first who adapted the pendulum to the clock, and thus laid a foundation for all subsequent experiments. The peasant's wife who regulates the affairs of her household by the clock behind her cottage door, little suspects the laborious experiments to which men of the keenest intellects have subjected the pendulum. Huyghens himself turned aside from the excitements and honours of statesmanship, open to him by his position,' to speculations on the pendulum, from which not even the fascinations of geometry and optics could keep his busy intel How this melancholy repetition of sound impresses us in the deep quiet of midnight with a feeling which prepares the mind for supernatural impressions. Whilst the faint night-light burns dimly, as if oppressed by some unseen presence, and the surrounding silence is broken by those unaccountable crackings and creakings heard only in old houses, the pendulum's measured tick seems as if muttering|lect. untranslatable mysteries to the spirit of the night. Thus some may feel or think, at times, about the pendulum; investing the common-place dutchclock with a poetry wild and wonderful as the strains of Southey or Coleridge. But others may be inclined, though with little reason. perhaps, to ridicule such sentiments, deeming them but romance. What useful facts, or scientific principles, are connected with the pendulum? these may inquire.-What can it teach, or how is it useful except to keep the old eight-day-clock moving? Some readers may be surprised to hear that many of the most refined problems in physical science are connected with the motions of a common pendulum. The shape of the globe on which we live can be ascertained by a skilful observation of this vibrating instrument; and the variations of so mysterious a power as attraction are noted by the same means. The reader may not, at present, see the mode in which this is done; but we trust the whole matter will be comprehended when we have concluded this article. That the sublimities of the laws which rule the material universe should be inter The preted by the vibrations of a piece of metal, seems at first too startling to be true; but it is nevertheless one of the grand facts which are so often made plain to our view, by their connexion with the simplest phenomena. great is thus often understood through the little, as the nature of the lightning is made evident by means of the sparks produced from an electrical machine. The child sees little, if any, difference, between such sparks and those The This man, therefore, who forms the important link between the starry Galileo and the philosophic Newton, gave to the vibrations of the pendulum the earnest attention of his subtle and exact understanding. applicability of this oscillating power to keep a clock in motion is supposed to have occurred to Huyghens in the year 1656, before which time, however, we must admit that other men of high genius had made experiments on the pendulum. Amongst these was the great Galileo himself, who died when Huyghens was but thirteen years old.2 These previous discoveries do not, however, diminish the fame of the Dutch philosopher, who must doubtless be regarded as the inventor of the clock-pendulum. Before his time a weight was used to set the time-keeping machinery in motion; but henceforth the principle of the oscillating rod was universally adopted. The swinging of the lamps in the cathedral of Pisa suggested to Galileo some general notions of pendulum oscillation, and the ideas of this profound student of nature may have easily become known to Huyghens, and thus the structure of a common clock might be traced to two apparently accidental circumstances. The first being the vibration of the lamps in the Italian cathedral-a common occurrence whenever the lights were trimmedand the second the presence of a young student in the building at that precise time. To follow all the experiments made on the pendulum since the days of Galileo and Huyghens to this and his brother was secretary to our William III. 1 His father was the intimate friend of three princes of Orange, 2 Galileo died 1642; Huyghens was born 1629. year 1848 would require an elaborate treatise, | of one substance might be checked by uniting and a discussion of some of the most difficult it with another of less expansibility. Our problems in science. It must, therefore, suffice countryman Harrison thus produced, in the if we indicate one class of such researches, and the results to which they have led. year 1726, what is justly called the compensation pendulum, composed of nine distinct bars, five being made of steel and four of brass. The term compensation was significantly expressive of the important property possessed by this pendulum, which retained the same length through all changes of temperature; the unequal expansion of the brass and steel preventing, by a careful arrangement, those deviations so fatal to astronomical observation. Some persons call these gridiron pendulums, a name which is only applicable to the visible form, and not to the qualities of the instrument. The reader is doubtless aware that most substances expand by heat, and contract by cold; and he will therefore suppose that a strip of metal, or three feet of wire, will not remain of the same length under all temperatures. The variation may be small, but it must be something. The pendulum of a clock will therefore alter its length in different climates: one three feet long at the pole becoming more than thirty-six inches in length at the equator. Such a result must inevitably follow from the laws of expansibility; and what is the consequence? That the clock The inventor found his patient experiments will vary its rate of going with these changes in this department of science rewarded by the in the pendulum; going faster when it is short-discovery of a chronometer, or time-piece, ened, and losing as it becomes longer. The keeping time so truly that the captain of a ship derangements in the rate of going may be too small to cause inconvenience in our ordinary business, but are most important when the clock is employed in astronomical observations, when a small error may produce results of the most mischievous character. at sea could, by having one of these clocks on board, find the longitude within a few miles of the exact position. This procured for Harrison 20,000l. from the Government, being the highest of the rewards offered to him who should discover a method for finding the longitude at sea. To pursue the long series of experiments which have developed the various properties of the pendulum, would, perhaps, be tedious and uninstructive to the general reader, who may be satisfied with the view already given of the origin of this instrument, and its subsequent improvements. We therefore omit all reference to the mercurial and other pendulums which have brought the chronometers to such perfection, that the best do not vary more than a quarter of a second from the exact time in twenty-four hours. How shall these deviations from uniform movement be prevented? This was the problem proposed to the philosophy of Europe, and long was the struggle, and almost numberless the experiments, before the solution was obtained. Nor is this surprising, when we remember that the fixed laws of nature seemed against men in this attempt. The Creator had so formed metallic and other bodies, and so adapted the agencies of heat, that when the latter power acted upon substances, they expanded. Such is the chemistry of the universe, or of that part called the earth. To alter such arrangements Having thus shortly viewed the history of was clearly beyond human powers, which can this vibrating machine, let us consider its imonly collect, combine, and adapt-not create-portance as an auxiliary to science. The shape natural agencies. of the globe can be determined from the motions of the pendulum; a statement which will excite no surprise in the minds of some, whilst others What, then, can be done? cried puzzled Science from her halls of experiment, whilst her disciples looked in bewilderment at obstinate pen-may gaze upon its oscillations and ask, “What dulums, and varying chronometers. Science, however, when thoughtfully working in her appointed circle, has a keen and wide eye, which after long vigils seldom fails to read aright the characters written on some key-fact, which being understood opens a pathway to brilliant discoveries. In the present case the results may seem of a less striking character, but they solved the problem, and that was sufficient. The expansibility of bodies under heat created the difficulty, yet by this very property itself was the difficulty overcome. Science, after much pondering, and deep questioning, on this said expansibility, heard a voice suggesting that all bodies might not expand alike. The hint was enough for patient thought to work upon; and it was soon found that the too great lengthening connexion can possibly exist between these movements and the form of our planet?" Not that the question would be a wise one, for the falling of a drop of rain, and the size of a dewdrop, are affected by the bulk of the globe, or even by its shape. How does the pendulum furnish us with any suggestions on such a subject? Let us now state the facts belonging to the subject, and the causes on which the phenomena depend. Suppose a pendulum is at this moment beating sixty times a minute in the reader's room, what will happen if this same pendulum be removed to the equator, or towards the pole? In the former case it will beat more slowly, and therefore lose time, but in the latter its oscillations will be quickened. What occasions this? It is clear that the pendulum beats language, a great physical truth, and illus- It may now be desirable to state some of the facts connected with this subject. Those who have heard that the pendulum beats more slowly at the equator than at the poles, may wish to know the difference between the vibrations in those parts. Some idea of this may be gained if we remember that a seconds pendu more slowly at the equator than at the poles, that is, it falls more slowly in its sweep in that part of the world. This decrease in its rate of falling is, of course, produced by a diminution in the earth's attraction, or, in other words, the pendulum is drawn downwards with less force than before; this of course accounts for the slower swing. But why has attraction diminished at the equator; does that universal principle vary, being stronger here and weaker there? Let the reader bear in mind the fact, that attraction must diminish the further we depart from the centre of the earth; if, then, one part of the surface of the globe is further from the centre than another, bodies at that point will not be so strongly drawn downwards as those which are placed in portions nearer the central part in other words, substances will weigh less when far from the attracting point than when near it; and will therefore lum, beating at Cayenne made 148 oscillations fall towards the earth with a diminished velocity. This is exactly the case with the pendulum, which, at the equator, oscillates more slowly, that is, descends with less velocity than at a part of the earth near the poles. Why is this? The fact is one which must interest the speculations of thoughtful men, and there is but one satisfactory explanation. The surface of the globe at the equatorial parts must be farther from the centre than that in the polar regions, for the pendulum falls more slowly in the former than in the latter parts of the earth. The shape of the globe cannot, therefore, be a circle, but must be a spheroid. If it were a circle the pendulum would beat at the same rate in all parts, for every point of the earth's surface would, in that case, be at the same distance from the centre, and attraction would act with the same force in every part of the globe. A dozen persons sitting round a candle at equal distances from it, will have the same degree of light; but far otherwise will it be if some are placed sixteen feet from the light, whilst others remain within a radius of four or six feet. The influence of attraction diminishes also in proportion as we recede from the point towards which bodies fall. Now, as the pendulum falls faster at a station near the north or south pole, than at a place on the equator, the inference must be that a man, when standing near or on the line, is farther from the centre of the globe than an inhabitant of the arctic regions. The conclusion, therefore, is, that the equatorial portions of the earth bulge out, and the parts near the poles have a flattened shape. The above course of reasoning is suggested by every pendulum which we see vibrating, whether it belongs to the Dutch clock in the poor man's house, or to the highly-finished time-keeper in the rooms of our philosophical institutions. The oscillations of a slip of metal may, therefore, utter, though in a peculiar less in twenty-four hours than a similar pen- This may be stated at 39 139 inches; increasing, of course, as we approach the poles. If such a pendulum were removed to the equator, it must be made shorter to prevent the vibrations from becoming too slow, but if taken to the pole, it must be lengthened to correct the tendency of the oscillations to become quicker. Some readers may have imagined that the pendulum which beats so regularly in the cases of their English clocks, would preserve the same uniformity of motion in all parts of the globe. Such must henceforth remember that this delicate instrument always declares to the intelligent observer, whether its distance from the centre of the earth has been altered. The pendulum therefore speaks to the ear of the scientific in a language most emphatic. This variation in the lengths and vibrations of pendulums will not, perhaps, surprise those who know that a clock near the equator is about sixteen miles further from the earth's centre than one stationed near the pole. That the attraction should be as different in such distinct circumstances, was to have been expected. But the pendulum will of course always remain the same length under the same condi (1) Or about thirty-nine inches and one-eighth. tions; and this fact leads us to another important remark. This instrument is capable of becoming a standard of measures, so that all our feet, yards, and furlongs, can be rectified by it. It has long been the desire of philosophers to discover an invariable standard, by which to test and connect all measures. This is supplied by the pendulum. Let us suppose that a pendulum, beating in London, when the thermometer stands at 60%. and the barometer at 30o. is exactly measured in the year 1848; its length will form a standard to which all other measures are referrible. The foot would be a fraction of such a standard, which would be contained a certain number of times in a furlong, or a mile. Now, if 1000 years afterwards, all our measures should be lost, the standard could be again recovered by another examination of the pendulum, under the same circumstances as at first. Both experiments, that in the year 1848, and that in 2848, would give the same length of the standard, nor would the case be different in the year 10,000, if we dare suppose the earth existing at such a distant epoch. A ROBBER-CHIEF IN THE EIGHTEENTH AMONG the remarkable personages of the last century, was the celebrated (or shall we not rather say the notorious) Cartouche, or Robber-Chief, who, at the head of his daring band of followers, filled all France with his deeds of violence, and carried terror even into the streets of Paris. His reckless audacity was mixed with a degree of gallantry and of devotion which softened the harsher features of his character, and invested him with a certain kind of popularity even among those who were held in constant terror by his name. Monsieur Argenson was an incomparable Lieutenant General of Police, but in defiance of all his vigilance, Cartouche appeared in the midst of Paris; and at this unwelcome apparition, many families who had not the resource of a courtly residence at Versailles, prepared to take refuge in their country châteaux, although the severity of the winter made such a removal both disagreeable and inconvenient. They soon found, however, that safety was not to be secured by flight, for Cartouche, at the head of forty or fifty men, attacked the Car The possession of such a perfect standard of measure is naturally an object of interest to scientific men, who, from the time of Huy-dinal of Gèvres as he was passing through the ghens to the present age, have devoted their attention to the subject. The French mathematicians rejected this mode of fixing the standard for reasons which are not deemed very strong, and adopted the ten-millionth part of the line between the pole and the equator, which part they call a mitre. The standard in England is, however, the pendulum, which is made the test of all other measures by Act of Parliament. Such is the importance stamped on a slip of metal by science. We trust all our readers will from this time regard the pendulum with a higher interest, looking upon it as an expounder of great laws, and an illustrator of important facts in the constitution of the globe. If we have appeared, during our brief discussion of this subject, to verge a little on the borders of the dry (that horror of horrors to some readers), we must shelter ourselves behind the remark that all things cannot be arrayed in flowers, nor are the grand truths of science better understood or appreciated when expressed in fanciful prettinesses. We, however, trust that few will feel disposed to complain of dryness when the importance of all facts relating to the pendulum are considered. W. D. Ir is not the pleasure of curiosity, nor the quiet of resolution, nor the raising of the spirit, nor victory of wit, nor faculty of speech, nor lucre of profession, nor ambition of honour or fame, or inablement for business, that are the true ends of knowledge-Lord Bacon. outlets of Paris on his way to Bourges. It is true that he dealt gently with the cardinal, having deprived him only of his episcopal cross and pontifical ring, together with ten louis d'or which were found in his purse; a pasty of robin-red-breasts, and two flagons of Tokay, which he had won from a friend at picquet. We may observe here, by way of parenthesis, that this worthy cardinal, although prodigiously scrupulous, was somewhat addicted to good living: he would on no account play for money, lest he might lose that which rightfully belonged to the poor; neither would he indulge himself by purchasing expensive food or wine; but his conscience was quite at ease when he played at picquet for some recherché dish, or for a flagon of Schiraz which cost twelve or fifteen louis. If he was so unlucky as to lose, he paid his debt of honour by giving a volume of his ecclesiastical mandates and pastoral instructions, of which he always carried about with him forty or fifty copies superbly bound and illuminated. These little self-deceptions were thoroughly understood among his friends, who readily fell in with his humours, because he was not only the most dainty, but also the most charitable of prelates-the most candid and good hearted of men. To return to his adventure with Cartouche. The bandits refused to take any thing from the Abbé de Cervette, the cardinal's secretary; saying that he was too handsome a youth to be robbed, and that they had not audacity enough to commit so great a crime. "Since you are so very kind and courteous to Monsieur l'Abbé," said his Eminence, "you ought, at least, to leave him half the pasty, and one flagon of this Hungary wine." "Most gladly will I share them with M. l'Abbé," replied Cartouche; "if he will do us the honour to join our party, and to partake." But the Abbé hastened to offer his excuses for declining so polite an invitation; and there on followed mutual compliments and regrets, which doubtless were more amusing to the bandits than to those whom they were despoiling and who longed for their departure. One of the robbers pretended to suspect the Abbé was a fair lady disguised in a cassock. "Rash and unhappy being!" exclaimed the Cardinal; "do you not know that such a concealment would be an act of sacrilege on my part? And how do you dare to take me for a guilty debauchee ?" Cartouche gave his comrade so furious a blow, that he struck him to the ground. "There! that will teach thee to treat our prelates disrespectfully;" said he, reddening with anger. "See how this rascal presumes to attack the Cardinal of Bourges; knowest thou not that he refuses tythes from those that are in distress?" continued Cartouche, foaming with rage, and kicking the poor wretch who lay sprawling on the ground!.. So full of terror were the good people of Paris at this time, that no one ventured out at night, without being accompanied by five or six well-armed men; and those whose attendants were either few or cowardly, attached themselves to the better appointed equipages of their friends. The Parisian police were continually on the qui vive; and while their indefatigable chief was on his nightly patrole, Cartouche entered his house, and rifled it so thoroughly of every article of value, that the worthy officer was obliged to eat his soup with a pewter spoon. The major of the French guards did not know which way to turn, so numerous and pressing were the applications made to him for sentinels and escorts, many of which he was obliged to refuse. In short, since the days of the Fronde, Paris had not been filled with such perplexity and fear. While this extraordinary man was thus baffling the vigilance of some, and defying the authority of others, it was affirmed that the influence of one lady's name was all-powerful with Cartouche and his myrmidons. The Marquise de Bauffremont distributed passes which were always respected by the bandits, and the secret of her power soon became known. She had returned home one morning at half past two o'clock, and as soon as her waiting women had undressed her, she dismissed them according to her usual custom, and sat down by her fireside to write her journal, which, unhappily, has since been lost; for she was a woman of great talent, and so full of observation that nothing passed unnoticed before her eyes. She was enjoying her busy solitude, when her attention was suddenly attracted by a confused noise in the chimney; and a moment afterwards there appeared from amid a tumbling mass of soot, plaster, and swallows' nests, a man armed to the teeth. His precipitate descent having impelled the burning logs into the !! centre of her apartment, his first act was to seize the tongs and deliberately to replace the wood in its former position on the hearth. Some glowing cinders having fallen upon the carpet, he gently removed them with his foot; and then turning to the marquise, made her a low bow. "Madam, may I presume to inquire who it is I have the honour of addressing ?" "Sir, I am Madame de Bauffremont; but as you have the appearance and manners of a gentleman, rather than of a robber, I cannot divine why you have come down the chimney at this very unseasonable hour into my apartment." 'Speak lower, Sir; for heaven's sake, speak lower!" said the terrified woman. "The Marquis de Bauffremont may overhear you." "Pray, Madam, put on your mantle, for it is excessively cold, and you may suffer from going out in your dressing-gown." His orders were implicitly obeyed, and Madame de Bauffremont was so overcome with fear, that as soon as she had seen her redoubtable visitor fairly outside the house, she was obliged to sit down a moment in the porter's lodge. A loud tap was heard at the window which overlooked the street. "Monsieur le Suisse, I have travelled a couple of leagues to-night over the roofs of houses, being pursued by informers. Do not let your master suppose that I have been here on an affair of gallantry, or that I am Madame de Bauffremont's lover; you will have to do with Cartouche, so take care what you are about. But they shall hear from me by post." Madame de Bauffremont returned to her apartment, more dead than alive, and awaking the marquis, related to him what had passed. He declared it was only a nightmare, and that |