ence, every lover of wisdom, with a satisfaction the most perfect and entire. May this society still prosper! Like the tree, deep-rooted and well watered, may it still flourish; perfuming the air with its fragrance, adorning the earth with its verdure, and benefiting the world by its fruit! May it never want the beams of a vivifying sun, nor the refreshing breezes, nor the fruitful showers of heaven! May it continue the seat of all that is noble and elegant; of all that is entertaining and instructive in learning and philosophy; the boast and ornament of these towns, to the end of time! Such are the wishes of a stranger; a stranger, whom the members of this society have received with the attention and kindness of a brother! Such the desires of one who is willing to contribute what lies in his power to the welfare of this institution: The best proof of which he now proceeds to submit. Definition of Astronomy.-Astronomy is the science which teaches the knowledge of the heavenly bodies; their magnitudes, distances, motions, periods, eclipses, and order. ; History of the Science. Josephus informs us, that Astronomy was understood among the antediluvians and that it was particularly studied by the patriarch Seth, and his posterity. Unless we can credit this account of Josephus, the ancient Chaldeans must be acknowledged as the fathers of Astronomy. The lofty summit of the tower of Babel; the extensive and level plains of that country; the refreshing coolness of the night, after the oppressive heats of the day; an unbroken horizon; a pure and serene sky-all conspired to engage that people to contemplate the extent of the heavens, and to observe the motions and phenomena of the stars. From Chaldea, Astronomy passed into Egypt, and from Egypt into Phoenecia; and as the Phoenicians applied it to the purposes of navigation, they soon became masters of commerce, and of the sea. Thales, the chief of the seven sages of Greece, who flourished about 600 years before the Christian era, is said to have brought the science of the stars from Phoenicia into Greece; and to have taught the reason of the length and shortness of the days, the causes of eclipses, and other astronomical phænomena. In the hands of the Greeks, the science was cultivated with assiduity and success; and the names of Pythagoras, Anaximander, Meton, Pythias, Ar famed in the annals of the stars. The Romans, the Arabian princes, and at last the princes of Europe, became the patrons and promoters of Astronomy. Importance of the Science.-Whether we consider the objects which Astronomy sets before us; or, the accuracy and precision of most of its proofs and calculations; or, the service which, in various ways, it renders to the na-chimedes, Aristotle, and others, are tions of the earth, it is, and ever must remain, the most valuable, interesting, and sublime science, which can possibly engage the attention of man. This noble science, not only deserves our regard, as a matter of curiosity, or rather of astonishment and wonder; and as answering the most important purposes for the good of civil society; but still more so, as it opens a scene, which impresses the mind with the most exalted, and consequently, the most just and correct ideas, of that eternal and omnipotent Being, who contrived, made, and still upholds, the whole! When surveying those stupendous works, which move with such order and harmony through the immeasurable fields of space, we are led to exclaim, But it is from the sixteenth century to the present time; from the days of Copernicus to those of Herschel and Olbers, that this sublime science has continued to advance towards perfection, with a steadiness and glory so peculiar to itself. And in all that interval, if we except the very days in which the immortal Newton sketched the laws of the universe, perhaps Astronomy, perhaps science of no kind, has ever witnessed a more bril *In the first volume of the Imperial Magazine, we gave, through several numbers, the "These are thy glorious works, Parent of History of Astronomy at large, which would good, Almighty! thine this universal frame Thus wondrous fair! thyself how wondrous then! seem to supersede the necessity of this. But as the lecture would be incomplete were this historical sketch omitted, it is retained, that order and uniformity may be preserved. liant period, than that, in which it is our honour and happiness to live. Systems. Although there have been many schemes and hypotheses concerning the heavenly bodies, yet there have been only four which have attained to any thing like authority and permanence in the world. The first of these is the Ptolemaic system, so called from Claudius Ptolemy, a native of Pelusium, in Egypt, who made his last astronomical observation, on Wednesday the 2d of February, 141. The system which is distinguished by his name, is contained in his celebrated book, called "The Great Syntaxis;" which book reduces to order the observations of the ancient astronomers, and is, I believe, the first book which ever set forth regular tables of the sun, moon, planets, and fixed stars. The Ptolemaic system supposes the earth to be at rest in the centre, and that the heavens, solid and incorruptible, revolve round it from east to west, carrying along with them all the planets and fixed stars. The diverse motion of the planets, this system accounts for, by assigning to each of them its respective orb ; and the outermost orb, the primum mobile of the ancients, was supposed to communicate motion to all the rest. Although philosophers of the present day smile at this system as absurd and impossible; yet it should be remembered, that the world was content with it for many ages; and that it was once looked upon as founded on invincible demonstration, and as placed beyond the reach of controversy and the fluctuations of opinion: a circumstance this, which calls for a degree of modesty and hesitation, about much, very much, of our knowledge. embarrassed and perplexed, that few persons have embraced it; and no wonder, if, as some of the biographers of Tycho intimate, his vanity to become the founder of a system, had too large a share in its production. The third system is denominated the Cartesian, from its author Des Cartes, a French philosopher, of the seventeenth century; and a man of a speculative, bold, prodigious genius. His reputation in foreign nations appears on his monument, which consists of four faces, inscribed with so many encomiums. It was erected at Stockholm, where he died in the year 1650. The system of Des Cartes, though very artfully contrived, yet carries with it more of the air of a ROMANCE, than of a just and solid philosophy. It supposes the planets to be driven round the sun, in a vortex or whirlpool of subtile matter; and that the vast regions of space being full of this subtile matter, there is an infinite number of planetary vortices, every fixed star being the centre of its distinct vortex. That this whirlpool scheme of the Cartesians is a mere fiction, is evident from the following considerations. 1. That comets, which pass very freely in the heavenly spaces, taking their prodigious journeys to and from all parts, move in orbits which intersect the orbits of the planets at all angles. So that if the comets move in a vortex, as well as the planets, there would be two vortices, moving in different, perhaps in opposite directions, in one and the same place, at one and the same time; which is absurd. 2. According to the laws of mechanics, it is evident, that if matter of any kind move in a vortex, which is Ty-elliptical, it must move the swiftest in that part of the ellipse which is the most strait, narrow, and compressed. But according to the laws of Astronomy, the planets which move in elliptical orbits, when in that part of their orbits which is the most contracted and compressed, viz. in aphelion, then move the slowest. The second system is called the Tychonic system, from its inventor, cho Brahe, a noble Dane, who acquired great celebrity as an Astronomer, in the latter half of the sixteenth century. In this system there are supposed to be two centres; the earth, the centre of the universe or firmament of stars, around which they revolve in 24 hours; and the sun, the centre of the orbits of Mercury, Venus, Mars, Jupiter, and Saturn; around which they are carried in their respective periods, the same as the sun is supposed to be carried round the earth in its solar year. This hypothesis was so 3. This doctrine of vortices is not supported by any phenomena of nature, with which we are acquainted. "If," says Sir Isaac Newton, "three equal round vessels be filled, the one with water, the other with oil, the third with molten pitch, and the liquors be stirred about till they have alike acquired a vorticle motion; the pitch by its tenacity will lose its motion quickly; the oil, being less tenacious, will keep it longer; and the water, being least tenacious of the three, will keep it longest, but yet will soon lose it. Whence it is easy to understand, that if many contiguous vortices of molten pitch were each of them as large as those which are supposed by some to revolve around the sun and fixed stars; yet these and all their parts, would, by their stiffness | and tenacity, communicate their motion one to another, until they all rested among themselves. Vortices of oil, or water, or some more fluid matter, might continue longer in motion; but unless the matter were destitute of tenacity, and attrition of parts, and communication of motion, (which is not to be supposed,) the motion would constantly decay, till finally there would be an universal rest." It would have been a waste of time thus to combat the Cartesian hypothesis, but for the very recent attempts which have been made to revive it. The temerity with which Sir Richard Philips has discarded the Newtonian philosophy, and substituted that of Des Cartes, has led some to doubt whether the philosophic knight-errant be in reality sincere. But whether Sir Richard, and the rest of the Cartesian astronomers, be sincere or insincere, it is manifest their situation calls for our philosophic commiseration: the poor fellows having got into a whirlpool, from which they cannot get out, are carried round and round a centre of absurdity, in a vortex of nonsense! is The fourth system, which we do not hesitate to pronounce the true one, that theory of Astronomy which now almost universally prevails, and which is certainly destined to be received as the rule of the sun, moon, and stars, as long as sun, and moon, and stars, endure. This system has sometimes been classically denominated the Pythagorean system, because it was understood and taught by Pythagoras, an ancient Greek philosopher. It is a remarkable fact in the history of science, that the true scheme of the universe should have been known and published by Pythagoras, more than 500 years before the Christian æra; and then that it should slumber and | be superseded for two thousand years. The true theory of the heavens was revived in the sixteenth century, by Nicholas Copernicus, a prebend of Thorn, in Poland; and hence is called the Copernican system. Copernicus died in the year 1543: he was an excellent classical scholar; a profound mathematician; and a most acute and laborious observer of celestial phenomena. His book, "De orbium cælestium revolutionibus," which contains his theory, was a work of long and arduous toil; it was printed under the management of two of his philosophical friends, and a copy of it was put into his hands just before he expired. But the denominating terms, Pythagorean and Copernican, are now giving place to the more Anglicized, and perhaps more significant appellative, Newtonian. In the latter part of the seventeenth century, it pleased the Almighty, in pity to the darkness of mankind, and to throw a stronger light upon his own matchless and amazing works, to visit our hemisphere with that bright and steady luminary, the great Sir Isaac Newton. Endowed with a compass of soul, high, and vast, and profound ;-with a penetration which could look through nature, and scan her mighty laws ;—with an intellectual industry equal to the most gigantic enterprise-with a temper calm, tranquil, and devout,—the immortal Newton rose far above the common level, even of learned and scientific men; and by his single power, reared a fabric of mathematical and experimental philosophy, which must for ever stand the boast of true wisdom, and the terror of idleness, ignorance, and pride. (To be concluded in our next.) ADVANTAGES OF CONCESSION. IN great matters of public moment, where both parties are at a stand, and both are punctilious, slight condescensions cost little, but are worth much. He that yields them is wise, inasmuch as he purchases guineas with farthings. A few drops of oil will set the political machine at work, when a tun of vinegar would only corrode the wheels, and canker the movements. CHEMICAL ESSAYS,-BY 8TUDIOSUS. MR. EDITOR, Sir,—If you think the following Essay on Oxygen, worthy a place in the columns of your valuable miscellany, for which it has been purposely written, an early insertion will gratify. Should it meet your approbation, it shall be followed by a second, on Nitrogen, and a third on Atmospheric Air. I am Sir, With the most profound respect, Essay 1st.-Oxygen. THE word Oxygen is of Greek extraction, and signifies to generate acidity. Oxygen Gas was first discovered by Dr. Priestley, in 1774, who called it dephlogisticated air. In 1775, it was discovered by Mr. Sheelc, without any previous knowledge of the discovery of Dr. Priestley. Mr. Sheele gave it the name of empireal air. It first received the name of vital air from Condorcet, and that of Oxygen Gas from Lavoisier. We are acquainted with many substances, from which Oxygen Gas may be obtained. Amongst others, it may be procured from the green leaves of vegetabies, from the oxydes of manganese, lead, or mercury, from the hyperoxymuriate of soda, or potass. 1st. From the fresh leaves of vegetables. Fill a large receiver, or bell glas, with water, and invert it on a broad dish, which is to be likewise filled with that fluid; introduce fresh gathered leaves; expose the whole to the rays of the sun, and pure Oxygen will be disengaged, which will gradually displace all the water, and occupy its place. 2d. From the black oxyde of manganese. Put into a retort of glass any quantity of the black oxyde of manganese, add as much sulphuric acid as will form the whole into a thin paste, apply the heat of a lamp, and Oxygen Gas, sufficiently pure for all common purposes, will be liberated. | If we are wishful to obtain it on a more extensive scale, the following process will be preferable. Procure an iron retort, and having introduced a sufficient quantity of the black oxyde of manganese, expose the retort to a red heat, and Oxygen Gas will be evolved in abundance, which may be No. 36.-VOL. IV. collected over water in the following manner. The pneumato-chemical, or pneumatic apparatus, was first invented by Dr. Priestley, which consisted of nothing more than a common tub, with a shelf in it. He afterwards used a most elegant apparatus, which the Duke of Rochefoucault sent him. This trough may be made of any size, but should not be less than a foot in depth; the shelf is to be placed on one side only, and about three inches from the top. Having filled the whole with water, for at least an inch above the shelf, we are next to fill a jar or glass receiver with common water; and having placed the open end of it upon the shelf, we are to introduce the beak of the retort into the pneumato-chemical, immediately under the open end of the receiver, when airbubbles will be seen to arise through the water into the receiver, and displace the water. In this way we may proceed till we have obtained a sufficiency for use. 3d. From the Hyperoxymuriate of soda, or potass. Put into a retort any quantity of either of these salts, apply the heat of a lamp, and Oxygen, in the greatest purity, will be liberated, which may be collected over water, as previously described. Nitrate of potass is another substance which is frequently used for obtaining Oxygen Gas; but trusting that the foregoing processes will be found sufficient, we will now proceed to investigate its properties. Oxygen Gas is invisible, and colourless, like common air. Like common air, it is also highly elastic, and capable of indefinite expansion and compression. Its specific gravity is 135, it is therefore 740 times lighter than the same bulk of atmospheric air. Its weight to that of atmospheric air being as 1103 to 1000. It is not sensibly absorbed by water, though left in contact with that fluid for a great length of time. It is entirely absorbable by the combustible bodies, which, in consequence of disengaging its caloric and light, produce heat and flame. If combustible bodies be burnt in Oxygen Gas, and the experiments are conducted with accuracy, we shall find the product increased in weight just the quantity of Oxygen consumed. By experiments, which shall be noticed in a following Essay, it hath been proved that Oxygen constitutes about 22 in every 100 parts of atmospheric C air, or, if the calculation be made by weight, 23 parts. It has also been proved beyond a doubt, that no animal whatever can live for a moment, in air previously deprived of all its Oxygen; and that animals will live six times as long in the same quantity of Oxygen Gas, as in common atmospheric air. Oxygen is therefore necessary to animal life. the atmosphere, passes from its original yellow colour, through several different shades, till it assumes that of a dark purple; this I have had shewn me several times by an intelligent dyer, of Manchester; and it is a well known fact, that when woollen goods are taken out of an indigo vat, they are generally of a beautiful green, but in the course of one or two minutes they have absorbed a sufficient dose of Oxygen, to convert them into a dark blue. Germination. That germination does not depend upon the seed alone, but requires some external cause to effect it, is now generally acknowledged. Seeds will not germinate, unless a certain degree of heat and moisture have access to them; nor will they then germinate, unless atmospheric air be present. It has been proved by well-conducted experiments, that seeds will not germinate in the vacu Oxygen necessary to combustion.-Introduce into a glass jar, or receiver, filled with Oxygen Gas, a lighted taper, and it will burn with great brightness, and produce a much greater degree of heat than if burnt in atmospheric air. Blow the taper out, reintroduce it, and the flame will be instantly rekindled. If we introduce a lighted taper into a well-closed jar of common air, it will be almost immediately extinguished; if we repeat the experiment, substituting Oxygen Gas, we shall find it to burn some time. We have said that Oxy-um of an air-pump, but as soon as gen is not absorbed by water; but, by atmospheric air is admitted, they bemeans of strong pressure, however, gin to germinate. Hence the wellit may be made to take up half its known fact, that seeds will not gerown bulk, which it will retain in solu- minate if placed at too great a depth tion. Though water thus impregnated below the earth's surface. The expedoes not essentially differ from com- riments of Sheele, Gouch, Archand, mon water, in either taste or smell, &c. fully prove that seeds will not yet it has been administered in several germinate unless oxygen be present, diseases with decided success. Dr. and that it is not atmospheric air, but Higgins caused a young man to the Oxygen it contains, which is nebreathe Oxygen Gas for several mi-cessary to the process, for seeds will nutes, when his pulse, which was at 64, soon rose to 120 beats in a minute. It is upon this principle that pure Oxygen has been used with such success in suspended animation. Effect of Oxygen upon the blood.— The blood when it has arrived at the lungs is of a dark purple colour, which is owing to the superabundance of carbon which it has received in its course of circulation through the body; it here becomes converted into a red oxyde, by the great quantities of Oxygen it is continually receiving through the agency of the lungs, and becomes of a bright and florid red. Put a little blood into a small vessel of Oxygen Gas, shake the vessel, and the gas will have become partly absorbed by the blood, which will assume a bright scarlet colour. Lavoisier has shewn that a man consumes, in the space of 24 hours, not less than 32 ounces, troy, of Oxygen Gas. Effect upon colours. The liquor made from Whelk, upon exposure to not germinate in either azote, carbonic acid, or hydrogen gas. Dr. Humbolt found that seeds which do not commonly germinate in our climate, even in our hot-houses, were capable of germinating after a few days immersion in weak oxymuriate acid. Oxygen combines with all the known metals, with every combustible substance, and with the greater number of substances of which the animal and vegetable kingdoms consist. When by this combination they become oxydes, they are said to be oxydized; when converted into acids, oxyginized. When speaking of atmospheric air, I shall say more on this important subject. (To be continued.) [We shall feel ourselves obliged if STUDIOSUS will forward the continuation of his Essays as soon as possible, that our arrangements may not be thrown into disorder. We beg all our other Correspondents, whose articles are announced to be continued, to take this hint.] EDITOR. |