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(hat about the hand and club of Orion; and found therein an astonishing multitude of stars, whose number he endeavonred to estimate, by counting many fields, and computing from a mean of these how many might be contained in a given portion of the milky-way. In the most vacant place to be met with in that neighbourhood, he found 63 stars ; other six fields contained 110, 60, 70, 90, 70, and 74 stars; a mean of all which gave 79 for the number of stars to each field; and thus he found, that by allowing 15 minutes for the diameter of his field of view, a belt of 15 degrees long and two broad, which he had often seen pass before his telescope in an hour's time, could not contain less than 50,000 stars, large enough to be distinctly numbered; besides which, he suspected twice as many more, which could be seen only now and then by faint glimpses, for want of sufficient light. The success he bad within the milky-way soon induced him to turn his telescope to the nebulous parts of the heavens, of which an accurate list had been published in the "Connoisance des Temps, for 1783 and 1784." Most of these yielded to a Newtonian reflector, of 20 feet focal distance, and 12 inches aperture; which plainly discovered them to be composed of stars, or at least to contain stars, and to show every other indication of its consisting of them entirely.
"The nebulae (says he) are arranged into strata, and run on to a great length, and some of them I have been able to pursue, and to guess pretty well at their form and direction. It is probable enough that they may surround the whole starry sphere of the heavens, not unlike the milky-way, which undoubtedly is nothing but a stratum of fixed stars: and as this latter immense starry bed is not of equal breadth or lustre in every part, nor runs on in one straight direction, but is curved, and even divided into two streams along a very considerable portion of it; we may likewise expect the greatest variety in the strata of the cluster of stars and nebuhe. One of these nebulous beds is so rich, that, in passing through a section of it in the time of only 36 minutes, I have detected no less than 31 nebulae, all distinctly visible upon a fine blue sky. Their situation and shape, as well as condition, seem to denote the greatest variety imaginable. In another stratum, or perhaps a different branch of the former, I have often seen double and treble nebulae variously arranged; large ones, with small
seeming attendants; narrow, but nrach-extended lucid nebulae or bright dashes; some of the shape of a fan, resembling an electric brush issuing from a lucid point; others of the cosmetic shape, with a seeming nucleus in the centre, or like cloudy stars, surrounded with a nebulous atmosphere: a different sort again, contain a nebnlosity of the milky kind, like that wonderful inexplicable phenomenon about Ononis; while others shine with a fainter mottled kind of light, which denotes their being resolvable into stars.
"It is very probable that the great stratum called the milky-way, is that in which the sun is placed, though perhaps not in the very centre of its thickness. We gather this from the appearance of the galaxy, which seems to encompass the whole heavens, as it certainly must do, if the sun is within the same: for, suppose a number of stars arranged between two parallel planes, indefinitely extended every way, but at a given considerable distance from one another, and calling this a sideral stratum, an eye placed somewhere within it, will see all the stars in the direction of the planes of the stratum projected into a great circle, which will appear lucid, on account of the accumulation of the stars, while the rest of the heavens, at the sides, will only seem to be scattered over with constellations, more or less crowded, according to the distance of the planes, or number of stars, contained in the thickness or sides of the stratum."
GALBANUM, in pharmacy, is obtained from the bubon galbanum, a plant found in Africa. By cutting the plant across, a milky juice flows out, which soon hardens, and constitutes galbanum. It is brought here from the Levant, in small pieces agglutinated together; its taste is acrid, and its smell strong; the specific gravity is 1.2. It is partly soluble in water and alcohol, and when distilled, it yields about half its weight of volatile oil, which is of a bluish colour.
GALBULA, the jacamar, in natural history, a genus of birds of the order Picas." Generic character: bill strait, "very long; quadrangular, and pointed ; nostrils situated near the base of the bill, and oval; tongue pointed and short; legs feathered before, down to the toes, feet formed for climbing. There are four species.
G. alcedo, is about the size of a lark, and is of a most elegant and brilliant plumage. It is found in the damp places of the woods of Guiana and Brazil, feeding on insects, and is of very solitary and sequestered habits, continuing motionless on its perch during the whole night, and often also a considerable part of the day, and but rarely seen otherwise than alone. Naturalists are but imperfectly acquainted with the jacamar genus, and know nothing of its nest and ■eggs.
GALEGA, in botany, a genus of the Diadelptua Decandria class and order. Natural order of Papilionacea', or Lesuminosa'. Essential character: calyx with subulate teeth, nearly equal; Limine with oblique streaks between the seeds. There are uiueteen species.
GALEMA, in botany, a genus of the Octandria Digynta class and order. Natural order cf Succulents. Atriplices, Jus•sieu. Essential character: calyx four-cleft; corolla none; capsule roundish, two-seeded. There are two species.
GALEOPSIS, in botany, a genus of the Didynamia Gyutnospermia class aud order. Natural order of Vei ticillatse, or Labial J>. Essential character: corolla upper-lip notched a little, vaulted; lower has two teeth above. There are four species, with several varieties.
GALILEI, or Galileo, in biography, a most excellent philosopher, mathematician and astronomer, was the son of a Florentine nobleman, and born at Pisa, in the year 1664. The earliest subjects of his studies were poetry, music, and drawing; but his genius soon led him to the cultivation of subiimer sciences, by his proficiency in which he has immortalised his name. His father, though a noble, possessed but a limited fortune, and was therefore desirous of educating him a physician, that he might secure greater means of independence from, the proritsof his profession, than he could derive from his paternal estate. With this view he entered him as a student in philosophy and medicine at the university of Pisa; but Galileo became soon dissatisCed with the obscurity of the Aristotelian system, then taught in the schools, and conceived an unconquerable dislike to medical studies.
He now betook himself to the study of The mathematics, and, without the assistance of a tutor, made a rapid progress in those sciences, commencing with Euclid, and afterwards making himself master of the works of Archimedes, and of other ancient mathematicians. When his father perceived which way his inclination tended, and that his improvement indicated uncommon talents for mathematical pursuits, he
prttdently suffered him to follow the natural bias of his mind without any restraint. So great was the reputation he acquired as a mathematician, that in the year 1589, the Duke of Tuscany appointed him to the mathematical chair in the University of Pisa. He discharged the duties of this appointment, for about three years, with the applause and admiration of the liberal and more enlightened; but not without exciting the jealousy and opposition of the violent Aristotelians, who, because he ventured to question some of the hypothetical maxims of their piaster, held him out in the odious light of a vi-ionary and dangerous innovator. Becoming disgusted with the obstructions which their ignorance and bigotry threw in the way of his promoting just principles of science, in the year H9> he resigned his professorship at Pisa, and accepted with pleasure of an invitation that was sent him to fill the maUiematic.il chair in the university of Padua. In this seminary he continued for eighteen years, esteemed and cherished by the Papuans and Venetians, raising the credit *ef the university as a school of sound philosophy, and admired by all the learned, who had sufficient liberality and spirit to emancipate themselves from the fetters of ancient prejudices.
By degrees Tuscany felt an increasing ardour for improvement, and no sooner was it known that Galileo's patriotism inclined him to devote his services to his native country, than Cosmo II, Grand Duke, sent for him to Pisa in the year 1611, where he made him professor of mathematics, with a very considerable stipend. Afterwards he invited him to Florence, and gave him the title of principal mathematician and philosopher to his highness, continuing to him the salary annexed to his professorship, without any obligation to a residence at Pisa. With the study of mathematics, Galileo united that of physics, particularly the doctrines of mechanics and optics. Before he had settled at Padua, he had written Ids " Mechanics," or treatise on the benefits derived from that science, and its instruments; and also his " Balance," for finding the proportion of alloy or mixed metals. These he had introduced into his lectures at that university.
Being informed at Venice, in the year 1609, that Jansen, a Dutchman, had invented a glass, by means of which distant objects appeared as if they were near, he turned his attention to this subject, and from the imperfect accounts he had received, and his own reflections on the nature of refraction, discovered the construction of that instrument. The next day, after he had solved the problem of its construction, he made such an instrument, and by the attention which he paid to its perfection and improvement, may justly be considered as the second inventor of the telescope. He now turned his instrument towards the heavens, and discovered unheard of wonders. He perceived the surface of the moon not to be smooth, but rough, and full of prominences and cavities. The milky way he found to be an assemblage of fixed stars invisible to the naked eye. Venus he found to vary in its phases like the moon. The figure of Saturn he observed to be oblong, and imagined that it consisted of three distinct parts, one spherical in the midst, and two lesser ones on the sides, which afterwards appeared to be only the ansae, or extreme parts of Saturn's ring. Jupiter he saw surrounded with four moons, which in honor of the Duke de Medici he called Medic.TM stars, and soon perceived that by means of their frequent eclipses, geographical longitudes might be found. On the sun's disk he perceived spots, from the motion of which he inferred that the sun revolved on its axis.
It was while he was pursuing these discoveries, that he was invited to Florence, where, as we have seen, he had leisure afforded him to devote himself to his mathematical and philosophical studies, without being obliged to attend to the duties of his professorship. In a very few years, however, his tranquillity was disturbed by the ignorant and bigoted clergy, on account of the zeal which he discovered for illustrating and confirming the truth of the Copernican system. That system they maintained to be false and heretical, as being contrary to the plain and express language of the scriptures; and by their complaints against him to the Inquisition at Rome, rendered it necessary for him, in the year 1615, to appear in that city to justify himself. According to letters written from Rome, by the learned Anthony Quezenghi, Galileo did not lose his courage on this occasion, but in numerous companies of men of letters and others, defended the Copernican doctrine with a force of argument which persuaded many of its truth and reasonableness, and silenced the objections of others who would not be convinced. When he attended the Inquisition, however, he was not suffered to enter into any
explanations, but was directly accused of heresy for maintaining the two propositions, that the sun is the centre of the world, and immovable by a local motion, and that the earth is not the centre of the world, nor immoveable, but moves with a diurnal motion. These propositions he was ordered by a decree of the Inquisitors to renounce, and not to defend them either in conversation or writing, or even to insinuate them into the minds of any persons whomsoever. Most accounts concur in stating, that, on this occasion, he was committed to the prison of the Holy Office, where he was confined for about five months; but according to other accounts, he was treated with greater mildness, and only threatened with imprisonment if he proved refractory. Be that as it may, he was not permitted to quit Rome until he had promised to conform himself to the decree of the Inquisition; and it is probable that his sentence would have been more severe, had not the Grand Duke of Tuscany warmly interested himself on his behalf, as well as some persons of high rank and influence at the papal court.
Galileo now returned to his studies, in which his astronomical observations, and other happy discoveries served to establish most completely and satisfactorily the truth of his obnoxious opinions. From time to time he laid before the public an account of his discoveries, with such remarks and inferences as tended to point out the natural conclusions to be drawn from them. At length, in the year 1632, he ventured to publish at Florence, his famous " Dialogues on the two greatest systems of the World, the Ptolemaic and Copernican;" in which he produced the strongest arguments in favour of both systems, without expressing a decided opinion which of them was the true one, but not without such insinuations in favor of the Copernican as sufficiently indicated its superior reasonableness and his own belief in it. These dialogues, likewise, contain some keen strokes of raillery against the Aristotelians, for their bigoted and servile attachment to every hypothesis of their master.
Scarcely had this work made its appearance before the cry of heresy was raised more loudly than ever against Galileo, and he was again cited to appear before the tribunal of the Inquisition, in the year 1633. Though now seventy years of age, he was obliged to submit to the persecuting mandate, and on bis arrival at Rome was first committed prisoner to the apartments of the Fiscal of the Holy Office. Afterwards, through the intercession of the Grand Duke, he was permitted to reside in the honse of his embassador, while the process was carrying on against him. After his trial had lasted about two months, he was brought up to receive sentence in full congregation; when he was ordered, in the most solemn manner, to abjure and condemn the Copernican system, as contrary to the Scriptures, and to bind himself, by oath, no longer to teach or support it, either directly or indirectly. As a punishment for having disobeyed the former decree of the court, he was condemned to be detained in the prisons of the Holy Office during the pleasure of the Cardinal Inquisitors, and enjoined, as a saving penance, for three years to come, to repeat, once a week, the seven penetential psalms, the court reserving to themselves the power of moderating, changing, and taking away altogether, or in part, the above-mentioned punishment and penance. His Dialogues were also censured, prohibited, and ordered to be burnt at Rome.
Pope Urban VIII. who at that time sat on the Pontifical throne, lessened the rigour of his sentence, by confining him for a time to the palace and garden de Medici at Rome ; after which be was sent to the archiepiscopal palace at Sienna, where the air was more favourable to his state of health; and in the course of the year, 1634, he was permitted to reside at his country house, at Alice11 i, in the vicinity of Florence.
In this place he spent the remainder of his days, visited and esteemed by the most distinguished characters in Florence, and diligently applying himself to his celestial observations. By his continual use of the telescope, however, and the injuries which his eyes received from the nocturnal air, his sight was gradually impaired, till he became entirely blind about three years before his death. This calamity he bore with a truly philosophical resignation, employing himself in constant meditation and enquiry, the result of which he intended to communicate to the world. He had digested much matter, and had begun to dictate his conceptions, when he was attacked by a distemper which terminated in his death, in 1642, when he was in the seventy-eighth year of his age.
Galileo was small in stature, but of a venerable aspect, and of a vigorous constitution. His learning was very extensive; and he possessed in a high degree, a clearness
and acutencss of wit. In company he was free and affable, and full of pleasantry.
He took great delight in Architecture and Painting, and designed extremely well; and he also played on the lute with great skill and taste. Whenever he spent any of his time in the country, he took great pleasure in husbandry. From the time of Archimedes, as M. Leibnitz observes, there had been nothing done in mechanical geometry, till Galileo, who possessing an excellent judgment, and great skill in the most abstruse points of geometry, first extended the boundaries of that science, and began to reduce the resistance of solid bodies to its laws. We shall follow the example of Dr. Hutton, in giving a summary sketch of his discoveries and improvements, chiefly in the language of the judicious Colin Maclaurin. "He made the evidence of the Copernican system more sensible, when he shewed from the phases of Venus, like to the monthly phases of the moon, that Venus actually revolves about the sun. He proved the revolution of the sun on his axis, from his spots; and thence the diumal rotation of the earth became more credible. The four satellites that attended Jupiter, in his revolution about the sun, represented, in Jupiter's lesser system, a just image of the great solar system, and rendered it more easy to conceive how the moon might attend the earth, as a satellite, in her annual revolution. By discovering hills and cavities in the moon, and spots in the sun constantly varying, he ■ shewed that there was not so great a difference between celestial and sublunary bodies as the philosophers had vainly imagined.
"He rendered no less service to science by treating, in a clear and geometrical manner, the doctrine of motion, which has been justly called the key of nature. The rational part of mechanics had been so much neglected, that scarcely any improvement wa3 made in it for almost 2000 years; but Galileo has given us fully the theory of equable motions, and of such as are uniformly accelerated or retarded, and of these two compounded together. He first demonstrated, that the spaces described by heavy bodies from the beginning of their descent, are as the squares of the times; and that a body, projected in any direction that is not perpendicular to the horizon, describes a parabola. These were the beginnings of the doctrine of the motion of heavy bodies, which has been since carried to so great a height by Sir Isaac Newton. In geometry, he invented the cycloid, or trochoid, though the properties of it were afterwards chiefly demonstrated by bis pupil Torricelli. He invented the simple pendulum, and made use of it in his astronomical experiments: he had also thoughts of applying it to clocks, bnt did not execute that design. The glory of that invention was reserved for his son Vinceuzo, who made the experiment at Venice in 1649; and Huygens afterwards carried the invention to perfection. Of Galileo's invention also was the machine with which the Venetians render their laguna fluid and navigable.
"He also discovered the gravity of the air, and endeavoured to compare it with that of water; and opened several other inquiries in natural philosophy. He was not esteemed and followed by philosophers only; but was honoured by persons of the greatest distinction of all nations. Galileo had scholars worthy of so great a master, by whom the gravitation of the atmosphere was fully established, and its varying pressure accurately and conveniently measured, by the column of quicksilver of equal weight sustained by it in the barometrical tube. The elasticity of the air, by which it perpetually endeavours to expaud itself, and while* it admits of condensation, resists in proportion to its density, was a phenomenon <>(' a new kind, (the common fluids having no such property), and of the utmost importance to philosophy. These principles opened a vast field of new and useful knowledge, and explained a great variety of phenomena, which had been accounted for in an absurd manner before that time. It seemed as if the air, the fluid in which men lived lioin the beginning, had been then first discovered. Philosophers were every ■where busy, enquiring into the various properties and their effects; and valuable discoveries rewarded their industry. Of the great number who distinguished themselves on this occasion, we cannot but mention Torricelli and Viviani, in Italy; Pascal, in France; Otto Guricke, in Germany; and Boyle, in England."
Galileo wrote a number of treatises, of which the principal published during his life-time: besides his " Mechanics," "Balance," and " Dialogues," already mentioned, were, "The Operations of the Compass, geometrical and military," 1606 ; " A Discourse, addressed to the Most Serene Cosmo II. Grand Duke of Tuscany, concerning the swimming of Bodies upon, and their submersion in,Water," 1612; "Nuncius
Siderous," 1610, of which a " Continuation" or " An Essay on the History of Galileo's last Observations on Saturn, Mars, Venus, and the Sun, &c." was afterwards collected from letters between Galileo and his correspondents; "A Letter concerning the Trepidation of the Moon, lately discovered, inscribed to Alpbonso Antonini, with Antonini's Answer," 1638 ; "A Discourse of the Solar Spots, See. with Predictions and Ephemeridcs of the Medicean Planets," 1613; the famous Italian piece, entitled, "11 Saggiatore," written in defence of Guidiicci's "Discourse on Comet-," and containing a complete account of the physiology and astronomy of our author, printed in 1623; "A Letter to Prince Leopold of Tuscany, examining the fiftieth chapter of Licetus's Letheosphoros j" "A Letter to Christopher Greiubergerus, concerning the Montuosity of the Moon," 1611, " Mathematical Discourses and Demonstration* concerning two new Sciences, relating to Mechanics and local Motions, together with an Appendix concerning the Centre of Gravity in some Solids," 1638, &c.
The preceding articles, together with some oilier treatises, written either by Galileo, or by some of bis disciples, in defence of his doctrines and observations, were collected and published by Meuolessi, in 16S6, under the title of " L'Opere de Galileo Galilei Lynceo, nobile Fiorentiuo,'' »\c. in two volumes quarto. Several of these pieces were translated into English, and published by Thomas Salisbury, in his "Mathematical Collections," in two vols, folio.
A volume also of his " Letters" to several learned men, and solutions of a variety of problems, was published at Bologna, in quarto. His last disciple Vinceuzo Viviani, who proved a very eminent mathematician, methodised a piece of his master's, and published it under the title of " Quinto Libro dc gli Elementi d'Euclid,'' Sue. 1674, quarto j and he also published some other pieces of Galileo, including extracts from his "Letters to a learned Frenchman," in which the author gives an account of the works which he intended to have published, and an extract of a letter to John Camillo, a mathematician of Naples, concerning the angle of contact. Many other of Galileo's writings were unfortunately lost to the world, owing to the superstition of one of his ignorant' nephews; who, considering that his uncle died a prisoner of the holy office, though permitted to reside in his