THE USES OF ASTRONOMY.* HE telescope may be likened to a wondrous Cyclopean eye endued with superhuman power, by which the astronomer extends the reach of his vision to the further heavens and surveys galaxies and universes compared with which the solar system is but an atom floating in the air. The transit may be compared to a measuring-rod which he lays from planet to planet and from star to star to ascertain and mark off the heavenly spaces and transfer them to his notebook. The clock is the marvellous apparatus by which he equalizes and divides into nicely-measured parts a portion of that unconceived infinity of duration, without beginning and without end, in which all existence floats as on a shoreless and bottomless sea. In the contrivance and the execution of these instruments the utmost stretch of inventive skill and mechanical ingenuity has been put forth. To such perfection have they been carried that a single second of magnitude or space is rendered a distinctly visible and appreciable quantity. "The arc of a circle," says Sir J. Herschel, "subtended by one second, is less than the two hundred thousandth part of the radius; so that on a * From a discourse delivered at Albany on occasion of the inauguration of the Dudley Observatory, in that city, August 28, 1856. | circle of six feet in diameter it would occupy no greater linear extent than 70 part of an inch, a quantity requiring a powerful microscope to be discerned at all." The largest body in our system, the sun, whose real diameter is 882,000 miles, subtends, at a distance of 95,000,000 miles, but an angle of a little more than 32'; while so admirably are the best instruments constructed that both in Europe and America a satellite of Neptune, an object of comparatively inconsiderable diameter, has been discovered at a distance of 2,850,000,000 of miles. The object of an observatory erected and supplied with instruments of this admirable construction and at proportionate expense is to provide for an accurate and systematic survey of the heavenly bodies, with a view to a more correct and extensive acquaintance with those already known, and, as instrumental power and skill in using it increase, to the discovery of bodies hitherto invisible, and in both classes of objects to the determination of their distances, their time of passing the meridian, their relations to each other and the laws which govern their movements. Why should we wish to obtain this knowledge? What inducement is there to expend large sums of money in the erection of observatories, in furnishing them with costly instruments, and in the support of the men of science employed in making, discussing and recording, for successive generations, these minute observations of the heavenly bodies? In an exclusively scientific treatment of this subject, an inquiry into its utilitarian relations would be superfluouseven wearisome. But on an occasion like the present you will not, perhaps, think it out of place if I briefly answer the questions, What is the use of an astronomical observatory? and What benefit may be expected from the operations of such an establishment in a community like ours? In the first place, we derive from the observations of the heavenly bodies which are made at an observatory our only adequate measures of time and our only means of comparing the time of one place with the time of another. Our artificial timekeepers -clocks, watches and chronometers-however ingeniously contrived and admirably fabricated, are but a transcript, so to say, of the celestial motions, and would be of no value without the means of regulating them by observation. It is impossible for them, under any circumstances, to escape the imperfection of all machinery the work of human hands, and the moment we remove with our timekeeper east or west it fails us. It will keep home-time alone, like the fond traveller who leaves his heart behind him. The artificial instrument is of incalculable utility, but must itself be regulated by the eternal clockwork of the skies. This single consideration is sufficient to show how completely the daily business of life is affected and controlled by the heavenly bodies. It is they, and not our mainsprings, our expansion-balances and our compensationpendulums, which give us our time. To reverse the line of Pope, 'Tis with our watches as our judgments: none Go just alike, but each believes his own. But for all the kindreds and tribes and tongues of men, each upon their own meridian, from the Arctic pole to the equator, from the equator to the Antarctic pole, the eternal sun strikes twelve at noon, and the glorious constellations far up in the everlasting belfries of the skies chime twelve at midnight-twelve for the pale student over his flickering lamp, twelve amid the flaming wonders of Orion's belt if he crosses the meridian at that fated hour; twelve by the weary couch of languishing humanity, twelve in the star-paved courts of the empyrean; twelve for the heaving tides of the ocean; twelve for the weary arm of labor; twelve for the toiling brain; twelve for the watching, waking, broken heart; twelve for the meteor which blazes for a moment and expires; twelve for the comet whose period is measured by centuries; twelve for every substantial, for every imaginary, thing which exists in the sense, the intellect or the fancy, and which the speech or thought of man, at the given meridian, refers to the lapse of time. Not only do we resort to the observation of the heavenly bodies for the means of regulating and rectifying our clocks, but the great. divisions of day and month and year are derived from the same source. By the constitution of our nature the elements of our existence are closely connected with the celestial times. Partly by his physical organization, partly by the habit-second nature— of the race from the dawn of creation, man as he is and the times and seasons of the heavenly bodies are part and parcel of one system. The first great division of time, the day-night (nytchthemerum, for which we have no precise synonym in our language), with its primal alternation of waking and sleeping, of labor and rest, is a vital condition of the existence of such a creature as man. The revolution of the year, with its various incidents of summer and winter and seedtime and harvest, is not less involved in all our social, material and moral progress. It is true that at the poles and on the equator the effects of these revolutions are variously modified or wholly disappear, but, as the necessary consequence, human life is extinguished at the poles, and on the equator attains only a languid or feverish development. Those latitudes only in which the great motions and cardinal positions of the earth exert a mean influence exhibit man in the harmonious expansion of his powers. The lunar period, which lies at the foundation of the month, is less vitally connected with human existence and development, but is proved by the experience of every age and race to be eminently conducive to the progress of civilization and culture. but in our ignorance of that harmony their practical adjustment to each other is a work of difficulty. The great embarrassment which, attended the reformation of the calendar after the error of the Julian period had in the lapse of centuries reached ten (or rather twelve) days sufficiently illustrates this remark. It is most true that scientific difficulties did not form the chief obstacle. Having been proposed under the auspices of the Roman pontiff, the Protestant world for a century or more rejected the new style. It was in various places the subject of controversy, collision and bloodshed. It was not adopted in England till nearly two centuries after its introduction at Rome, and in the country of the Struves and the Pulkova equatorial they persist at the present day, for civil purposes, in adding eleven minutes and twelve seconds to the length of the tropical year. Connected with the use of astronomy in all determinations of time is its application to the purposes of history and chronology. The want of reliable historical eras has involved many portions of ancient history, But indispensable as are these heavenly especially Oriental history, in the greatest measures of time to our life and progress, confusion. Almost the only events in very and obvious as are the phenomena on which remote times of which the date can be ascerthey rest, yet, owing to the circumstance that tained with precision are those which can be in the economy of nature the day, the month referred to eclipses. Thus, the battle between and the year are not exactly commensurable, the Lydian and the Median armies narrated some of the most difficult questions in prac- by Herodotus is by the eclipse of the sun tical astronomy are those by which an ac- supposed to have been predicted by Thales curate division of time applicable to the vari- ascertained to have happened on the 30th of ous uses of man is derived from the observa- September, 610 в. C. The delay of Nicias to tion of the heavenly bodies. I have no doubt embark from Sicily—a delay which proved that to the supreme Intelligence which cre- a sentence of death to the Athenian army" ated and rules the universe there is a har-was caused by an eclipse of the moon on mony, hidden to us, in the numerical rela- the 27th of August, 413 B. c., and the date tion to each other of days, months and years, of Alexander's passage of the Tigris, before the mighty battle of Arbela, is determined by a similar eclipse of the moon on the 20th of September, 331 B. C. These dates are ascertained by modern astronomy with as much precision as if they had happened yesterday, and without its aid no event in profane Oriental history as ancient as the seventh century before our Saviour could be fixed within a generation. The second great practical use of an astronomical observatory is connected with the science of geography. The first page of the history of our continent illustrates this connection. Profound meditation on the sphericity of the earth was one of the main reasons which led Columbus to undertake his momentous voyage, and his thorough acquaintance with the astronomical science of that day was, in his own judgment, what enabled him to overcome the almost innumerable obstacles which attended its prosecution. In return, I find that Copernicus in the very commencement of his immortal work appeals to the discovery of America as completing the demonstration of the sphericity of the earth. Much of our knowledge of the figure, size, density and position of the earth as a member of the solar system is derived from this science, and it furnishes us the means of performing the most important operations of practical geography. Latitude and longitude, which lie at the basis of all descriptive geography, are determined by observation. No map deserves the name on which the position of important points has not been astronomically determined. Some even of our most important political and administrative arrangements depend upon the co-operation of this science. Among these I may mention the land-system of the United The States and the determination of the boundaries of the country. I believe that till it was done by the federal government a uniform system of mathematical survey had never in any country been applied to an extensive territory. Large grants and sales of public land took place before the Revolution and in the interval between the peace and the adoption of the Constitution, but the limits of these grants and sales were ascertained by sensible objects-by trees, streams, rocks, hills-and by reference to adjacent portions of territory previously surveyed. uncertainty of boundaries thus defined was a never-failing source of litigation. Large tracts of land in the Western country granted by Virginia under this old system of special and local survey were covered with conflicting claims, and the controversies to which they gave rise formed no small part of the business of the federal courts after their organization. But the adoption of the present land-system brought order out of chaos. The entire public domain is now scientifically surveyed before it is offered for sale; it is laid off into ranges, townships, sections and smaller divisions with unerring accuracy, resting on the foundation of base and meridian lines; and I have been informed that under this system scarce a case of contested location and boundary has ever presented itself in court. The general land-office contains maps and plans in which every quarter-section of the public land is laid down with mathematical precision. The superficies of half a continent is thus transferred in miniature to the bureaus at Washington, while the local landoffices contain transcripts of these plans, copies of which are furnished to the individual purchaser. When we consider the tide of domain and the immense importance of its efficient and economical administration, the utility of this application of astronomy will be duly estimated. will population annually flowing into the public | the unsuccessful attempt to recreate the highlands which this strange doctrine had annihilated, and just as the two countries were on the verge of a war the controversy was settled by compromise. Had the boundary been accurately described by lines of latitude and longitude, no dispute could have arisen. No dispute arose as to the boundary between the United States and Spain and her successor, Mexico, where it runs through untrodden deserts and over pathless mountains along the forty-second degree of latitude. The identity of rivers may be disputed, as in the case of the St. Croix; the course of mountainchains is too broad for a dividing-line; the division of streams, as experience has shown, is uncertain; but a degree of latitude is written on the heavenly sphere, and nothing but an observation is required to read the record. I will here venture to repeat an anecdote which I heard lately from a son of the late Hon. Timothy Pickering. Mr. Octavius Pickering, on behalf of his father, had applied to Mr. David Putnam of Marietta to act as his legal adviser with respect to certain land-claims in the Virginia military district in the State of Ohio. Mr. Putnam declined the agency. He had had much to do with business of that kind, and found it beset with endless litigation. "I have never," he adds, “succeeded but in a single case, and that was a location and survey made by General Washington before the Revolution, and I am not acquainted with any surveys, except those made by him, but what have been litigated." Astronomical observation furnishes by far the best means of defining the boundaries of states when the lines are of great length and run through unsettled countries. Natural indications like rivers and mountains, however distinct in appearance, are in practice subject to unavoidable error. By the treaty of 1783 a boundary was established between the United States and Great Britain depending partly on the course of rivers and upon the highlands dividing the waters which flow into the Atlantic Ocean from those which flow into the St. Lawrence. It took twenty years to find out which river was the true St. Croix, that being the starting-point. England then having made the extraordinary discovery that the Bay of Fundy is not a part of the Atlantic Ocean, forty years more were passed in But the scientific element, like sharp instruments, must be handled with care. A part of our boundary between the British provinces ran upon the forty-fifth degree of latitude, and about forty years ago an expensive fortress was commenced by the government of the United States at Rouse's Point, on Lake Champlain, on a spot intended to be just within our limits. When the line came to be more carefully surveyed, the fortress turned out to be on the wrong side: we had been building a fortification. for our neighbor. But in the general compromises of the Treaty of Washington by the Webster and Ashburton treaty of the 9th of August, 1842, the fortress was left within our limits. Errors still more serious had nearly resulted a few years since in a war with Mexico. By the Treaty of Guadalupe Hidalgo, of the 2d of February, 1848, the boun |