of the final result; and better still, if this test be be reported to the Observatory, these sources of more rigorously applied by the transit instrument error may be eliminated. It will be a part of the whenever it is practicable. In addition to this, the daily business at the Observatory to observe the observation of the meridian passages of the moon's moon's place; and when its actual place upon any bright limb and of the stars near its path ought to day is compared with that given by the tables, the be made as frequently as possible while at a port, error in the latter becomes apparent, and may be the longitude of which has never been ascertained applied to the results of any calculation at sea, in by more correct methods. A mass of data would which the same tables were employed. It would thus be collected for the correction of our charts, be also the duty of the persons having charge of which would soon render these sufficiently accu- the Observatory to possess themselves of the rerate for the general purposes of navigation. But sults of the latest and best observations made by that the greatest advantage may be derived from the vessels of other countries and by scientific this system of observation, the original observa- travellers, and to embody in our charts such as tions themselves with every accompanying circum- might be deemed worthy of credit. stance ought to be deposited at the Observatory, that their relative importance may be judged of, and the most valuable of them reduced and calculated. Their reduction on ship board, at the time they are made, cannot be effected with sufficient accuracy, because, in the first place, the methods used for this purpose, as they are generally developed in treatises on Navigation, are designed to give results only approximately true. The survey of our own coast, which is so extensive and in some places so dangerous to approach, is certainly one of the most important works undertaken by the government. But as it has been connected with another department of the public service, it does not come properly within the scope of my present remarks; and yet the Observatory may be made to sustain a relation to that work which f will not pass by without a brief allusion. Mr. Hassler stated to the committee, appointed the several stations comprised in the primary triangulation. I was the more surprised at this because his triangulation lies in the vicinity of several cities and towns which I believe lay claim to the possession of Observatories of a grade at least sufficient to determine with a considerable degree of approximation their coördinates of position. It must be borne in mind, that after the geodetical distances between the several stations have been calculated, the latitude and longitude of at least one of the stations and the azimuth of one of the sides must be determined, in order to assign latitudes and longitudes to the other stations. But in a survey so extensive as that of the United States' coast, the latitude and longitude of but one station will not suffice. To give to the method, adopted for the survey, all of the accuracy of which it is susceptible, the figure of that portion of the earth over which the triangulation is spread, must be deduced. To do this, the triangulation must not only Take, for example, the very convenient method of working a "Lunar Distance" given by Dr. Bow-by the last Congress, on the Coast Survey, as the ditch in the first edition of his "Practical Navi- reason why charts, of those parts of the coast gator," and which he has farther improved by ad- which had been surveyed, had not been published, ditional tables in the last edition of that extremely that the geographical position of no point in the valuable work. The distance obtained, according United States had been sufficiently well determined to that method, is defective by reason of neglecting to deduce therefrom the latitudes and longitudes of several small corrections due, 1st. to the variations in the refractive power of the atmosphere; 2nd, to the spheroidal figure of the earth; 3rd, to the horizontal parallax of the moon when different from 57 minutes and 30 seconds. It is not thought necessary to introduce any such refinements into nautical calculations, as the observations upon which they are founded are generally made under circumstances but little favorable to a high degree of accuracy. But when peculiarly favorable circumstances are seized upon for making them, as may be done occasionally on deck and always on shore, the results should be obtained by more accurate methods, especially when they are to serve for the correction of charts. I speak from experience when I say, that with a well-constructed Reflecting Circle, and in a favorable position of the moon in respect to a star, their apparent distance may be measured with an accuracy which will warrant the reduction of the observation by a process more perfect than those usually employed at sea. But be conducted with all the precision of modern in the second place, if the methods used at sea were not defective in the particulars above stated, yet the tabular distance of the moon from the star is regarded as perfectly accurate, while in point of fact it is inaccurate by the whole amount of error in the Lunar Tables. In like manner the calculation of the longitude of a place founded upon Lunar culminations is affected by the errors of the Lunar Tables. But when the original observations shall science and art, and be verified by the measurement of several bases, but temporary Observatories must be erected at certain stations along the series of triangles, and the geographical positions of such stations independently obtained by the best methods and with the utmost care. In the final elimination of the errors in the latitudes and longitudes of the stations as deduced by calculation, the Observatory, if it be made one of the stations in the primitive triangulation, will afford very essential service. Its instrumental resources will be such, it is to be presumed, as will admit of the last degree of accuracy in the determination of its position. And as such, it may, and doubtless will be, one of the most important fundamental points in the survey. ralty" of Great Britain, or the "Bureau des Longitudes" of France, for the means of navigating the high seas with safety. And is it not discreditable to the science and enterprise of our country that it should be so? There is not an original Ephemeris published in America. Blunt's, of New-York, which is so much used by our commercial vessels, If this degree of precision be not given to the is merely a reprint of the most useful parts of the Coast Survey, it will loose its scientific character, British Nautical Almanac; and this epitome, or and very imperfectly fulfil the end it is intended to some other, or the British Almanac itself, or the accomplish. If its results are not founded upon "Connaissance des Temps," will be found on board the determination of the special configuration of of all our vessels of war. This service to our the surface over which it extends, I would not be commerce and Navy may be performed at Washdisposed to place as much confidence in them, as I ington as well as at Greenwich, or Paris, and would in latitudes independently determined by not only the interest, but the honor of the counTroughton's Zenith Sector and longitudes by sig-try requires that it should be done. nals of fire. But furthermore, the Observatory may be organized upon such a scale as to enable it to con tribute its share to the advancement of Astronomy, which is the oldest of the sciences, which, perhaps, has, more than any other, contributed to the progress of civilization and refinement throughout the world, and which must depend for its successful prosecution, so far as instrumental results are concerned, upon the countenance and munificence of governments. And it is gratifying to see to what extent this noble science has been fostered by the civil powers of Europe. There are not less than forty public Observatories, established in Europe and its colonies, of which the most celebrated and useful are those at Greenwich, Dublin, Cape of Good Hope, Paramatta, Paris, Turin, Altona, Bremen, Königsburg, Berlin, Gotha, Göttingen and Dorpat. I will dismiss this subject, unexpectedly alluded to at all, with but one other remark. That the original observations, with all the attendant circumstances, ought to be reported without an erasure, without the suppression even of those known at the time to be defective. The observer ought not himself to be at liberty to reject any instrumental result, however discordant it may seem to be with those formerly obtained. He may state his reasons why he has not confidence in any particular observation, but should not have authority to exelude it from the result. It is only in this way that a correct judgment can be formed of the probable instrumental and personal errors which are inseparable, to some extent, from observations of this sort. The observations ought to be committed to a separate commission, or bureau, by which the calculations and reductions should be made with But while the governments of Europe have the utmost exactness. I am aware, that from mo- seemed to vie with each other in the number and tives of economy those who make observations in character of their public Observatories, there is the summer, calculate the results during the suc- not one, so far as I know, in this country which eeeding winter;—but it is worth while to inquire deserves to be ranked among them. It surely must whether observations cannot be pushed forward in be a narrow and prejudiced mind, that would arthe South during winter, so as to expedite the rest the progress of a science because every step progress of the work to a very considerable extent. of it has not a palpable and immediate relation to And if it is contemplated, as I hear, to carry the the ordinary business of life. We cannot always primary triangulation as far into the interior as the foresee in what manner precisely our more abstract mountains, unless the work be pushed forward more and refined speculations will bear upon the common energetically, our children's children will not live interests of mankind; and yet assuredly, if we are to see the benefits resulting from its completion; in the pursuit of Truth, its attainment will prove and, in the meanwhile, the loss of life and pro- highly useful to the improvement and happiness of perty may greatly exceed the additional expense our species. Our present subject furnishes an apt which its more vigorous prosecution will require. illustration of the propriety of this remark. WithThe objects already noticed, as they bear a most out the high speculations of Geometers upon ceobvious and immediate relation to the interests of lestial mechanics, the method of Lunar Distances, the Navy, were probably the only ones had in con- so valuable at sea for determining longitudes, templation in the establishment of the Observatory. could never have been realized. The possibility But there are others no less important which may of applying the method depends upon the accube accomplished by a very trifling addition to the racy of the Lunar Tables; and these never could appropriations which will be necessary for the have attained their present degree of perfection, former. without the labors, purely geometrical, to which I Our Navy has always been and is yet dependent have referred. Indeed, Astronomy is one conapon the "Lords Commissioners of the Admi- tinued illustration of the truth of the remark, that the satisfaction of our commonest wants frequently | In Stellar Astronomy our knowledge is still more demands scientific speculations of a character the imperfect. We do not as yet know the distances most sublime. Whether we consider the perfec- of the fixed stars from us, which is the simplest tion of its scientific character, the generality of element that can enter into our researches conits laws, or the importance of its results, Astrono- cerning them; unless, indeed, 61st Cygni be an my must confessedly stand the first of the natural exception, to which Bessel thinks his observations sciences. It furnishes us with all our measures of assign an annual parallax of 0. 3136 of a second. time-with all our knowledge in respect to the It must still, however, be admitted to be doubtful figure and dimensions of the planet which we in- whether this, or any other star has an appreciable habit-with the means of determining positions parallax. The accurate observation of binary stars upon its surface, and of directing our course along is likely to prove the most fertile source of discoits pathless waters-and with our best and only very in respect to these distant bodies. It already invariable units of linear measure. Surely it be- seems to be quite probable, that their dynaminal comes the United States, as a great commercial and relations to each other, may be adequately exnavigating nation, to extend a fostering care to a plained upon the hypothesis, that they circulate department of human knowledge which is so iden- about their common centre of gravity, by virtue of tified with its interests and honor. a force identical in its laws with gravitation. I And though Astronomy has, in many points of think farther observation necessary to warrant this view, attained a degree of perfection to which no extraordinary extension of gravitation, although other science can lay claim, yet it must not be the analogical argument in favor of it is very strong. supposed that the establishment of an Observatory of proper rank can contribute nothing to its future progress. In respect to our solar system there are several interesting and delicate questions which are yet to be solved. More accurate observation will show whether something is still wanting to the solar theory, as is suspected by Bessel and Airy. The planets are yet to be more nicely weighed, and the tables of their motions more perfectly constructed. In such delicate observations, is it yet certain whether the one star describes an elliptic orbit about the other placed at the focus or the centre, or at any intermediate point? As long as doubt exists in regard to the relative position of the latter, we should not be hasty in drawing our conclusions in respect to the law of attraction subsisting between the bodies. I regret that I have not seen the most recent papers upon this interesting subject by Sir J. F. Herschell. They are said to be replete with valuable information, and I regret yet more that I have not as yet been able to obtain his Astronomers already feel the absolute necessity method communicated to the Astronomical Soof investigating more minutely the refraction which ciety, for the calculation and construction of the rays of light undergo in traversing the atmosphere, elements of the orbits of binary stars, which deand of applying with greater accuracy the correc-pends exclusively upon the observed angles of tions due to variations in temperature, density and position. humidity. The errors which exist in our best tables of refraction, are unfortunately involved in many of our most important and delicate researches, such as the determination of the Obliquity of the Ecliptic, the place of the equinox, the positions of the stars and many others. The constants of nutation and aberration are still in From the difference of the observed times which the revolving star requires to describe the two portions of its orbit symmetrical to the Axis Major, Savary has proposed to determine its distance from the earth. The idea is ingenious, but it remains for future observations to establish its practicability. In this hasty sketch of the objects to be accomdoubt to a small extent; and, in a word, there is plished by the establishment of an Observatory, I no instrumental result employed in Astronomy, must not forget that magnetism is to receive the which may not undergo a modification, greater or special attention of those who have the charge of less, when better instruments shall be constructed it. And I perceive that a separate building has and improved methods of observation employed. very properly been erected for this purpose, and Cometary Astronomy is yet in its infancy. We that it is the intention of the government to supply have determined, with tolerable precision, the or-it with the best instruments. bits of only three or four of the many hundreds To a maritime nation the subject of Magnetism which belong to our system. In respect to their is one of much importance. All Marine Charts physical constitution, we may be said to be pro- must show the variation of the Magnetic from the foundly ignorant. But though we know so little of true meridian, at least approximately, in every them, yet important results have already flowed sea and place visited by our commercial and naval from the attention which astronomers have paid to these mysterious bodies. By means of them we have arrived at the interesting fact of the existence of a resisting medium. vessels. The needle is essential to direct the vessel upon any designated course, and therefore the laws by which its indications are controlled should be carefully investigated. There is but little doubt It should of course be put under the direction of one having every qualification to conduct the business of it in the best manner possible. It should be furnished with Astronomical and Magnetical instruments, as powerful and as perfect as art can render them. The number of assistants should be sufficient to keep up a continued series of observations in the Magnetic Observatory, and also in the Astronomical, when the weather permits. All of the observations with every accompany that the Magnetic forces of the earth are subjec- Having consumed so much of the space allotted ted to laws which may be discovered, and from to this letter, in treating of the objects to be acwhich, if they were known, the courses and varia-complished by the establishment of an Observatory, tions of the isoclinal and isodynamic lines might I must be very brief on the subject of its organibe deduced by calculation. We feel in this depart-zation. ment of science as if the conception of some great and fundamental truth was just about to burst upon us, not unlike that which opened up before the vision of the philosopher of Samos when he uttered the rapturous "c'úpnka." But already is theory in advance of observation, particularly observation of that continued and delicate character, which alone can conduct to definite and certain results. Europe has recently taken up this subject with becoming interest and zeal. The methods of observation devised and practised in Germany have ing circumstance should be published; and the extended to other countries. Magnetical Observa-same properly reduced. It is not enough that obtories have been established in various quarters of servations be skilfully made; they should be rethe globe, as at St. Helena, the Cape of Good Hope, Van Dieman's Land, Canada, India, &c., in which observations are prosecuted, strictly in concert with the Observatories in Europe. It is therefore with pride and pleasure that I hail the estab-and mental resources find the fullest scope. lishment of such an Observatory in the City of Washington, which may be made to play an important part in that grand system of concerted observation which has been undertaken by the principal nations of the earth; and every American must desire to see it organized and conducted in a manner worthy of science and of our country. It must not be forgotten that a Magnetical Observatory is essential to give value to the individual contributions which the scientific men of our country are continually making to our stock of Magnetical information. The differential dip, variation and intensity are more readily and accurately found than the absolute; and therefore the Observatory That estimate did not include a Magnetic Obat Washington will be a fundamental point of com-servatory, which will require an additional obserparison for all observations made by individual en-ver, and probably two. It should be recollected terprise. The instruments used in Magnetic Surveys, whether on land or sea, ought to be examined at the Observatory both before and after their use, and this should be a service required of the Observatory, independently of the observations proper to itself. duced in the most rigid and exact manner. It is the least part of an Astronomer's business to make an observation. The results are to be exhibited and compared with theory, and here all his talents Many of the observations of Bradley and Maskalyne remain to this day almost useless for the want of reduction, and England ingloriously suffered the Astronomers of the continent to profit chiefly by the instrumental results of her most accomplished observers, by neglecting this very essential part of the work of an Observatory. As to the actual expense of establishing and conducting an Observatory on the scale contemplated in the foregoing remarks, the estimate made by Mr. Adams, in his "Report on the Smithsonian Bequest," seems to be founded on satisfactory data, and to that I beg leave to refer you. that the expense for buildings and instruments has And while on ship board observations cannot be the Magnetic Charts now in common use. It would With sentiments of the highest regard, I am your obedient servant, EDITOR'S TABLE. SAWYER'S LIFE OF RANDOLPH. "The Lion was dead that received the kick." No man ever lived whose biography was more likely to excite a general interest and to be well received by the public than Randolph of Roanoke. The profound silence of the press on that subject is a curious fact. It is understood that considerations of delicacy may have restrained his near relations pending the controversy arising out of his will. The question of his sanity is one on which it would have been wrong to preoccupy the public mind; and no biographer could, in justice to him, have been silent on that subject. His other near friends may be supposed to have been restrained by the same consideration. guage of indictments as a "false, scandalous and malicious libel." Let us take a few examples. At p. 26 Mr. R.'s change of political position is said to have grown out of a certain presidential message of January 17, 1806. Now there was neither then, nor at any time, any such message as is there spoken of. At p. 47 there is a most indecent anecdote, in telling which Mr. S. affects accuracy, and corrects some other writer. Here he introduces a female name. It is well for him, that, as no such thing ever happened, there was no such lady as he speaks of. If there were, and she had a relation in the world with the spirit of a man, Mr. S. would be most deservedly punished. lar favor after his defeat in 1813, by Mr. Eppes, At p. 41 Mr. R. is represented as courting popuand the arts used by him are detailed. Every man, woman and child in Mr. R.'s district knows that his demeanor was never so high and haughty as at that time; that there was no such partizan as is there mentioned; that his deportment toward all to whom the description could apply was absolutely repulsive; and that the disgusting hypocrisy of frequenting Baptist meeting houses to conciliate that sect, and making a display of religious zeal was never heard of there. But why was not his life written by others? Lord Byron was hardly dead before the Dallas's and Leigh Hunts, &c., &c., were seeking to make a profit of the little intercourse with him which he had unadvisedly permitted. Why did nothing of the sort happen in this case? The answer is to be found in the delicacy which always has distinguished Virginians. They felt that it was due to Mr. R.'s friends to decide whether the veil should We instance these things as not resting on pribe drawn aside from his private life. Of the hun-vate knowledge, but on notoriety. They manifest dreds, therefore, who might have made entertain- a reckless disregard of truth, which makes it supering books of reminiscences from the conversations fluous to contradict calumnies, the refutation of of a man whose words were, by turns, prophecy, which must depend on testimony of a more precise poetry and epigram, not one has published a line. and personal character. A Mr. Jacob Harvey, an Irishman, entertained the Mr. S.'s disregard to truth is strikingly manipublic with such scraps as a short acquaintance fested in his neglect to inform himself of particu enabled him to collect. His account is probably lars which he might have learned from the most as faithful as he knew how to make it. But Mr. authentic sources. Mr. Randolph's brothers, Dr. H. had not the faculty to preserve the very words Brockenbrough and the Messrs. Leigh are known of Mr. R., and many of his anecdotes are, therefore, deficient in accuracy in this important point. There was a tone in his style of conversation as well known to his friends as his voice, and, missing that, they always know that the very words imputed to him, were never spoken by him. With this exception, and that of a small volume of his letters, nothing concerning him has ever, until now, been given to the public. In Virginia nothing at all. It remained for a citizen of another State, a stranger and an enemy, to interrupt, with his idle gossip, this funereal silence, and to make a market What we have said, founded on no particular of his pretended knowledge of Mr. R. by vending knowledge, but on a notoriety so great, that each it at a distance from those who could have told his point we have touched on is probably known to bookseller that he knew nothing of his subject. 10,000 persons, as certainly as man can know that His means of knowledge are paraded on the title of which he was not an eye witness, is enough to page, where he announces that he was for sixteen satisfy the public that in purchasing the work in years the associate of Mr. R. in Congress. But question, they may get gossip for their money, they he presently makes known that he was politically may get calumny, but they will certainly not get opposed to him; and all who know Mr. R. know an authentic biography of John Randolph. that to be so, at that time, was to be cut off from all intercourse with him. Hence, Mr. S. himself men, and Mr. S. could have reached either by letter. Had he done this, would he have called Mr. R. the nephew of Edmund Randolph, and represented him as a member of his family, as at p. 10! Would he have represented Mr. R.'s mother, at p. 9, as removing to Williamsburg with her husband. when she was already dead? These are things of small consequence in themselves. But to speak of them without resorting to the means of knowledge at hand, shows an utter disregard to the first duty of an historian. sudo Tucker THE ORATION OF DEMOSTHENES on the Crown; with notes, by J. T. Champlin, Professor of Greek and Latin in Waterville College. Boston: James Monroe & Co., 1843. This volume ought to have received an earlier attention from us. There is one comfort, however, in the matter. tells no more of his own personal knowledge than what passed at their first meeting. Giving him credit for intending to tell the truth, this fact may be taken, as he tells it, for what it is worth and this is precisely as much as the public can safely it is just as good now as it was the day it came from the take on the authority of Mr. Sawyer. The rest of the work is made up of a very unskilful digest of the contents of the papers of the day, and a collection of idle tales, of which not one in ten has any foundation in truth. In many passages the work may be truly characterised in the lan press. There is nothing ephemeral about it. It is not ole of that kind of works that must be praised the month, or the year in which they come out, or be praised too late. The object of its preparation is excellent, and carried out with distinguished skill. We are much mistaken, if any thing with the same design appear for a long time that can in justice supplant it. |