stopped. He had hunted down, as he was accustomed to express it, an hypothesis, and found it erroneous. He had not yet discovered how the planet did move round the sun, but he had ascertained one other manner in which it did not. Transferring the sun to one of the foci, he resumed his calculations, comparing the positions of the planet, computed upon this supposition, with those obtained from observation; and then tracing the planet through half its revolution round the sun, he found the observed and computed positions to agree. Here, then, after long years of persevering toil, he had found in what kind of orbit the planet Mars did move. Hence the conjecture was natural that the other planets revolved round the sun in orbits of the same kind; and computing their motions on that supposition, the correctness of the theory was established. Hence was determined one of the most important propositions in astronomy, usually termed Kepler's first law, that all the planets move in ellipses, having the sun in a common focus. Kepler having been so signally rewarded by this great discovery, now turned his attention to an investigation of the first importance, one indeed which was indispensably necessary to render his first discovery available. As the planets were now known to revolve in ellipses, and as their motion was found by observation to be unequal in different parts of their orbits, it became a matter of the first consequence to ascertain some simple law, regulating the orbitual motion, and by means of which a planet might be readily followed, and its places computed. To detect this law, in whose existence Kepler seems to have entertained the most unwavering belief, a figure was drawn representing the orbit of Mars, the sun occupying one of the foci of the curve. On the circumference of this curve the places of the planet were marked down as observation had determined them; and here commenced a series of examinations which finally led to the knowledge of the second great law of the planetary motions, which may be thus announced. If a line be drawn from the centre of the sun, to any planet, this line as it is carried forward by the planet, will sweep over equal areas in equal portions of time. This law accorded in the most perfect manner with fact, and gave at once the power of following, and, from the mean motion, computing the place of any planet; a triumph which all the complexity of older systems had failed ever to accomplish. Any other mind less adventurous than that of Kepler, might have been satisfied with these two great discoveries. The precise curves described by the planets and a law regulating their motions in their orbits, sufficed to render all the phenomena of the heavenly bodies not only explicable, but susceptible of accurate prediction. There seemed nothing more to be added. Kepler did not think He conceived the idea that the solar system was not a mere assemblage of isolated planets 80. revolving about a common centre, but a great associated system, in which some common bond of union existed, which, once found, would present the solar system in a new and true light. This bond he believed existed in some hidden relation between the times occupied by the planets in describing their orbits, and their distances from the sun. There is an immense difference between the pursuit which resulted in the discovery of the first two laws of Kepler, and the third one. In seeking for the curve described by the planets, it was looking for that which must have an existence; but in seeking for a bond of union among the planetary periods and distances, it was a search for that which it was generally believed had no existence, except in the wild imagination of this extraordinary philosopher. After long and deliberately pondering this great problem, Kepler decided that the strongest probability suggested that the distances of the planets, and their periods of revolution, would in some way contain the mysterious bond of union. Here then did this daring mind concentrate its energies; and his purpose once fixed, he marched steadily forward in his research with a courage which no defeat could daunt, and a perseverance which knew no limit but success. After Kepler had exhausted all simple relations between the periods and distances of the planets, in no degree shaken in his lofty faith, he pro ceeded to try all possible relations between the squares of the periods and distances; but with as little success. Nothing daunted, he proceeded to investigate the possible relations between the cubes of the periods and distances. Here again he was foiled; no law exhibited itself. He returned ever fresh to the attack, and now commenced a series of trials involving the relations between the simple periods and the squares of the distances. Here a ray of hope broke in his dim and darkened path. upon No actual relation existed, yet there was a very distant approximation, enough to excite hope.He then tried simple multiples of the periods and the squares of the distances-all in vain. He finally abandoned the simple periods and distances, and rose to an examination of the relations between the squares of these same quantities. Gaining nothing here, he rose still higher, to the cubes of the periods and distances ;-no success; until finally he tried the proportion existing between the squares of the periods in which the planets perform their revolutions and the cubes of their distances from the sun. Here was the grand secret, but alas! in making his numerical computations, an error in the work vitiated the results, and with the greatest discovery which the mind ever achieved, in his very grasp, the heartsick and toil-worn philosopher turned away almost in despair from his endless research. Months rolled round, and yet his mind with a sort of keen instinct, would recur again and again to this last hypothesis. Returning again to his task, he detected the error in his former computation, and commenced his work anew. He made the proportion, as the square of the time in which Jupiter revolves round the sun, is tothe square of the time of Saturn's revolution, so is the cube of Jupiter's distance to a fourth number; and comparing that number with the cube of Saturn's distance, he found them the same. Fearing that he was deceived, he ran over the work again and again—he tried the proportion, the square of Jupiter's period to the square of Mars' period as the cube of Jupiter's distance to a fourth term, which he found to be the cube of the distance of Mars. Till finally, full conviction broke upon his mind: he had won the goal; the struggle of seventeen long years was ended; and the third of Kepler's laws was fairly established. More than two hundred years have rolled away since these discoveries were announced, and the labours of succeeding philosophers have served to confirm the laws of Kepler. From that time to this, they have been classed among the essential parts of astronomy; and before the end of the seventeenth century they were demonstrated upon physical principles, and placed among the propositions of Newton's great work, the mathematical principles of natural philosophy. For Friends' Review. ALFRED. ALFRED, a child of peculiar promise, and the centre of many hopes, "ceased to be mortal" 4th mo. 22d, 1849, aged 5 years. He was a bright and beautiful boy. His frame was slight, yet his activity was always remarkable. His mind, too, was active, yet marked by the gentleness and sweetness which were depicted in his countenance. His cheerful hilarity and intelligence attracted strangers, and endeared him to his friends, yet his tractable obedience was not less remarkable. Whilst yet too young to tell, in theologic phrase, the workings of the Good Spirit, by whom he was called to "awake to righteousness, and sin not;" he evinced that he had in degree experienced the victory only to be obtained through his power; and, infant as he was, he was clothed with that universal love to God and to all men, which is "the fulfilling of the law." Daily striving against the evil tendencies of his nature, when he was, through unwatchfulness, betrayed into any childish faults, his quick and tender feelings were easily affected by reproof, by reason, or persuasion: and even when his errors were, in the eyes of others, only supposed ones, his prompt confession and penitence afforded a salutary example to those in riper years, and furnished an instructive illustration of the Apostle's beautiful exhortation-"Be ye followers of God as dear childrer "" He had brothers and a gentle sister. The lat ter, who was younger than himself, was the object of his peculiar tenderness, and pure fraternal love. "Certainly," said one of his parents, "not more than three or four times in his life did he address to her an impatient expression; never was he known to strike her; but every wish that she could express, though perhaps unheard by others, was not so by him; and if in his power, he would immediately gratify it." When the language of authority was addressed to her, he was filled with concern, and he would plead excuses, and mention as a palliation, her childhood and want of knowledge. His toys and treasures, of whatever kind, were always yielded to her, not sullenly, but cheerfully, and with endearing epithets. To his brothers, whom he also loved tenderly, the same traits were exhibited, but not to so remarkable an extent. After this darling child had been taught at home to spell in two syllables, he received a present of a little book. Being deeply interested in it, he mastered it himself in one week, and thus he learned to read. His sense of the beautiful in nature was keen; he would gaze upon the shining orbs which spangle the firmament with eager questionings, and with a manifest mental reference to the "Great Original:" but flowers may be said to have constituted his greatest delight, and when, within a year of his death, he was sent to a day school, he said, in expressing his love for his Teacher, that she was "a very smart woman, and beautiful as a flower." In his later weeks, his mind expanded rapidly, to the admiration and delight of his friends; and his remarks were characterized by beauty, shrewdness, and gentle and winning goodness. Trained (so far as was fitting his extreme youth) in a knowledge of the truths of the Bible, they fastened upon his mind, and were blessed by the Divine Spirit in making him "wise unto salvation." On one occasion, standing silently beside his mother, he thoughtfully exclaimed, "He that covereth his sins shall not prosper," and proceeded to say that he did not cover his, "because," said he, in childish phrase, "the Good Man knows every thing." Awaking one morning, a short time before he was taken with his final sickness, he said that he had seen an angel in his dream; and then he seriously observed, "None would be afraid to die if they were good-I am not, because I love everybody." He was taken ill 4th mo. 17th, with scarlet fever and croup; and throughout his sickness, which was a painful one, not a murmur or complaint escaped him. His patience and sweet acquiescence under medical treatment were beautiful and touching to behold-never objecting to severe applications, and taking unpleasant doses with perfect willingness; so that an elderly and experienced Christian, who was under heavy affliction, on hearing of his behaviour, was affected to tears, as the example of this "babe in Christ" tion, brought to her mind her Lord and Master's ex- | And the tender recollection, the endearing retrospecclamation-"The which cup my heavenly Father hath given me, shall I not drink it?" When his fever was raging, and his end approaching, his self-denying thoughtfulness and love did not abate. His sister having been attacked with a similar disease, he once called, "Father, tell Annie, if she will take her medicine like a good girl, she shall have my ice cream." This delicacy constituting almost his sole nourishment, it will be seen that his offer evinced decided self-denial and generosity. Many touching expressions fell from him, which it would not suit the intended brevity of this notice to record. Nothing having been said to convey to him the idea that he was sinking, he called to his father about 11 o'clock the morning previous to his death, with difficulty of utterance, and with an expression of countenance never to be forgotten-"Father, I feel as if I was going to die." To the query whether he feared to die, he replied, "No!" and he manifested sweet composure in the assurance that he would be "joined to the Lord," and be eternally happy. Expressing emphatically, a few hours before his close, his love to his father and his mother, and others, he added, "but I love God more!" Being asked if he would rather live or die, he declared that he "would rather go to Heaven, and be with God." Being asked if he wanted any thing, he said, "nothing, but to go to Heaven." He expressed in juvenile, but sweet language, his conceptions of the surpassing beauty of the blessed realm for which he panted; and in which he who said, "Suffer little children to come unto me," had prepared for him a mansion, "for of such," declared he, "is the kingdom of Heaven." Uncomplaining to the last, when asked if he suffered, he would say no, but he felt "tired." And his weariness increased, as his perfect rest drew nigh: but the moment of deliverance arrived, and an angelic smile irradiated his placid countenance, and making a deep inspiration, he fell asleep in Jesus. He "languished into life" before day-break, on the 22d of 4th month, 1849, and his bereaved friends wept with chastened sorrow, pouring out their tears before the Lord. The feelings of the parents are supposed to be embodied (though imperfectly) in the following lines: Of each grace and sweet perfection, 'twere an "aching void" to miss And we would not change the sorrow, and the tears our cheeks which furrow, And the anguish, like an arrow in our hearts, for Grief's surcease Pleasure's well For a draught from Lethe's waters—for a home by swell. Till our warfare be accomplished, and our summons home be given. RE-VACCINATION. W. J. A. 1st. Every individual is susceptible of vaccination; 2d, re-vaccination is not necessary before maturity; 3d, the system undergoes a change at maturity, and re-vaccination is then necessary; 4th, vaccination is a sure preventive of small-pox; 5th, re-vaccination is a sure preventive of varioloid; 6th, the third vaccination is inert; 7th, the system is susceptible of varioloid after matu rity, whenever the individual is exposed to small- | on the floor. In a tropical climate, what must be pox, without re-vaccination; 8th, re-vaccination the condition of such a company? is not necessary if the first operation was perform- The question then naturally arises, what can be ed since maturity; 9th, those who disregard done to check this barbarous traffic? This quesvaccination are always liable to small-pox, when- tion may be answered in what is sometimes termed ever exposed to the influence of that dreadful the true Quaker style, that is, by asking another. disease; 10, if every individual were vaccinated before maturity, and re-vaccinated at that revolution of the system, there would be no such disease existing as small-pox.-Substance of a paper in the Boston Medical and Surgical Jour. FRIENDS' REVIEW. PHILADELPHIA, SIXTH MONTH 23, 1849. The article headed Alfred, is a true narrative, of recent occurrence; and though the name is withheld from motives of delicacy, it has been furnished to the Editor, with the late residence of the deceased child. Such instances of youthful piety, conclusively show that the spirit of truth often manifests itself to the human mind, at a very early period of life. There are probably none who, when in mature age they review the thoughts and impressions of their childish years, cannot recall among their earliest reminiscences, the tendering visitations of divine love; gently inclining them to the paths of piety and peace. Authentic narratives of the lives and happy exits of those who have wisely yielded to those gracious invitations, are well calculated to stimulate and encourage their youthful readers to go and do likewise. The brief notice which we have extracted from a public paper of the capture of a slaver, with 550 human beings, crowded into a vessel of little more than 100 tons, may well awaken feelings of commiseration, not only for the victims of this horrid traffic, but also for those who are themselves such slaves to avarice as to engage in so iniquitous and dangerous an employment. Probably most readers, upon seeing it stated that 550 slaves were contained in a vessel of about 100 tons, would form no other conception of the case than that they must be greatly crowded, but the degree of crowding would be altogether in the dark. When Sir William Dolben prepared his bill regulating the number of slaves to te carried in the British vessels, he allowed, in vessels not exceeding 150 tons, having five feet between the decks, five men to every three tons; and yet on this plan, they were stowed so closely as to touch each other, when they were all lying down at the same time. Supposing the slaves in the recently captured vessel to have been all men, 166 would have been the number admissible under Sir William's regulation. Hence we perceive that more than three slaves must have been stowe I into the space which one man would occupy when stretched What is it that supports the slave trade? A little Socratic reasoning can hardly fail to bring us to the conclusion, that we can do something towards checking a trade which we all sincerely profess to abhor. The Editor has been kindly furnished, by one of his friends, with a pamphlet printed within the current year, containing Testimonies respecting a number of deceased Friends, formerly members of New England Yearly Meeting; one of which was copied into our last week's number; and another appears in the present one. The labours of Keplar, which we have extracted partly from Mitchel's Planetary and Stellar World, and partly from Brewster's Martyrs of Science, but without entirely adhering to the language of either, furnish one of the most remarkable instances of perseverance that has ever been known. It is asserted that his calculations respecting the planet Mars, filled between seven and eight reams of paper; or more than thirteen thousand pages of manuscript. Yet in these laborious computations, he was seeking what he might certainly and rationally believe had an existence. He could not doubt that each planet revolved in some regular curve round a fixed point; and what he wished to discover was, the nature of that curve and the position of the point. He then had before him a definite object, and he had only to search, among the possible curves, and the possible positions of a fixed point, till he found one of each which would solve the phenomena of the planetary motions. But when he set out in the search which ended with the discovery of his third law, he could have no assurance beyond the suggestion of an ardent imagination, that the object of his search had any existence. No previous discovery suggested the idea, that the times in which the different planets revolved round the sun, and their respective distances from that luminary, bore any relation to each other which numbers could express. And yet to the pursuit of this supposed relation, he gave the labour, not constantly, but occasionally, of seventeen years. We need not then be surprised, that when he ascertained that he had been chasing a reality and not a shadow, he declared he did not care whether the book containing this discovery was read in that age or by posterity. He could willingly wait a century for a reader, since the Author of nature had waited so long for an interpreter. Although the selections which we have copied | Meeting was adopted, strongly expressive of unity into this week's number, from the speeches deliver- and sympathy, together with the desire that they ed at a late meeting at Boston, on the subject of may be favoured with best assistance in their dePeace, may probably furnish but little that is new liberations. A copy of this minute was also directed to the readers of Friends' Review, yet it must be to be transmitted to the conference at Baltimore. encouraging to find the principles, in relation to war, for which our Society has always contended, so far recognized by men of influence among other denominations. Several of the speakers on that occasion appear to belong to the clerical order; a class of men who unquestionably exercise a greater influence than any other, over the opinions of the community on questions connected with religion and morals. Bad as the world is, it can hardly be questioned that public opinion in relation to religion and morals is, in great measure influenced, if not absolutely moulded, by the opinions of those who are, or profess to be, the religious part of the community. The Meeting for Sufferings has prepared an interesting document, addressed to all the foreign. governments, and people professing the christian religion, on the subject of slavery and the slave trade; which document was adopted by the Yearly Meeting. Our beloved Friend William Forster expressing a concern to offer himself as the bearer of this communication to the different powers of Europe, the offer was cordially accepted, and a minute was made which is to be furnished to him as a certificate where it may be useful. NEW ENGLAND YEARLY MEETING.-Several communications from Friends who attended that Meet The Meeting of Ministers and Elders convened on Seventh day, the 9th inst., at which a number of Friends from other Yearly Meetings were present. That meeting is stated to have been a humbling and baptizing season. It is sometimes declared, that as civil society is ing have been received, from which the following now constituted, wars are unavoidable. If so, the summary is collected. great object must be so to remodel the habits and sentiments of the community as to introduce an improved state of society. Reformation must spring from the people, and not from the governments. If those who take on themselves the responsible task of preaching the gospel, could be induced to The Yearly Meeting commenced on Second day, unite their influence in the maintenance of inviola- the 11th inst., at 9 o'clock, A. M., when certificates ble peace-if they would unitedly pronounce the or minutes for Ministers from other Yearly Meetprosecution of wars, offensive and defensive, incomings then in attendance were produced, viz., for patible with the doctrines of the gospel, we might then hope that the day was near in which nation should no longer lift up sword against nation; and the sound of the trumpet, the alarm of war, be silenced forever. George Carter, Eleazer Beales, Enos Pray and Cornelius Douglass, from Indiana; Zebulon Weaver, Nathaniel Sands, John Thorn and Abigail Cornell, from New York, several of whom were very acceptably engaged in religious service. B. Seebohm and R. Lindsey, were also in attendance. LONDON YEARLY MEETING.-In our last number Besides the general printed epistle from London, a brief notice of the commencement of that Meet-epistles in manuscript were received from London, ing was given. Letters received by the last Dublin, New York, Baltimore, North Carolina, and steamer enable us to continue our information to Indiana, which being read, a committee was sepathe evening of the 31st ult., the meeting being ex-rated to prepare essays in return to these acceptpected to close on the evening of the following day. able communications. We are informed that the members in attendance had been about equal to what usually appear; and that the various sittings had been characterized by a remarkable degree of unity and brotherly concord. The proposition from New York Yearly Meeting relative to a conference at Baltimore, obtained the deliberate and weighty consideration of the Meeting; during which much sympathy with Friends on this side of the Atlantic, was expressed, with desires that the proposed conference may be promotive of true gospel unity among us. But Friends were unitedly of the judgment that it would not be best for that meeting to send delegates to the conference. A minute addressed to New York Yearly In the afternoon, the circumstance of no epistle having been received from the Yearly Meetings of Philadelphia and Ohio was brought, in a feeling manner before the view of the meeting. After a time of deliberation, in which, we are informed, that much brotherly regard for those meetings was manifested, a large committee was appointed to take the subject into their solid consideration, and if way should open, they were requested to prepare and produce to a future sitting, essays of epistles to those meetings. Subsequently the clerk informed the meeting that he had received a communication from William Evans, addressed to him individually, requesting him to lay an accompanying document, from Phila |