It has been found no where but at Ytterby, in Sweden.

GÆRTNERA, in botany, in memory of Joseph Gartner, M. D. F. R. S. a genus of the Decandria Monogynia class and order. Essential character: calyx five-parted, the leaflets having on the outside a single marginal gland; corolla fivepetalled, somewhat unequal, tooth-letted, furnished with very short claws; seed vessel nearly globose, with four wings. There is but one species, viz. G. racemosa, a native of the East Indies, in the Circar mountains.

GAFF, in naval affairs, a sort of boom used in small ships, to extend the upper edge of the mizen, and employed for the same purpose on those sails, whose foremost edges are joined to the masts by hoops or lacings, and which are usually extended by a boom below; such are the main-sails of sloops, brigs, and schooners. Gaff top-sail, is a light quadrilateral sail, the head being extended on a small gaff, which hoists on the top-mast, and the foot spreading from the throat to the extent of the lower gaff.

GAGE, in the sea language. When one ship is to windward of another, she is said to have the weather-gage of her. They likewise call the number of feet that a vessel sinks in the water, the ship's gage this they find by driving a nail into a pike near the end, and putting it down beside the rudder till the nail catch hold under it; then as many feet as the pike is under water is the ship's gage.

GAGE, among letter-founders, a piece of box or other hard wood, variously notched; the use of which is to adjust the dimensions, slopes, &c. of the different sorts of letters.

GAGE, sliding, a tool used by mathematical instrument makers, for measuring and setting off distances. It is also of use in letter-cutting, and making of moulds.

GAHNIA, in botany, so named in honour of Henry Gahn, a genus of the Hexandria Monogynia class and order. Essential character: glume two valved, irregu

lar; nectary two-valved, involving the fi laments; stigma dichotomous. There are two species.

GAINAGE, in old law books, properly signifies the plough-tackle, or implements of husbandry; but is also used for the grain or crop of ploughed lands.

GALANTHUS, in botany, snow-drop, a genus of the Hexandria Monogynia class and order. Natural order of Spathacer, Narcissi, Jussieu. Essential character: petals three, concave; nectary of three small emarginate petals; stigma simple. There is but one species, viz. G. nivalis, snow-drop.

GALARDIA, in botany, a genus of the Syngenesia Polygamia Frustranea class and order. Natural order of Corymbiferæ. Essential character: receptacle chaffy; seed crowned with the five-leaved calycle; calyx of two rows of scales almost equal. There is only one species, viz, G. alterni-folia.

GALAX, in botany, a genus of the Pentandria Monogynia class and order. Essential character: calyx ten-leaved; corolla salver-shaped; capsule one-celled, two-valved, elastic. There is but one species, viz. G. aphylla.

GALAXIA, in botany, a genus of the Monadelphia Triandria class and order. Natural order of Ensatæ. Irides, Jussieu. Essential character: spathe one-valved; corolla one-petalled, six-cleft; tube capillary; stigma many-parted. There are two species, both natives of the Cape of Good Hope.

GALAXY, in astronomy. A very remarkable appearance in the heavens is that called the galaxy, or the milky-way. This is a broad circle, sometimes double, but for the most part single, surrounding the whole celestial concave. We perceive also in different parts of the heavens small white spots, which appear to be of the same nature with the milky-way. These spots are called nebulæ.

With a powerful telescope, Dr. Herschel first began to survey the via lactes, and found that it completely resolved the whitish appearance into stars, which the telescope he formerly used had not power enough to do. The portion he first observed was that about the hand and club of Orion; and found therein an astonishing multitude of stars, whose number he endeavoured 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 degress 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 had within the milky-way soon induced him to turn his telescope to the nebulous parts of the heavens, of with 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 nebula (says he) are arranged in 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 nebula. 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 nebula, 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 nebulæ variously arranged; large ones, with small seeming attendants; narrow, but much extended lucid nebula or bright dashes; some of the shape of a fan, resembling an electric brush issuing from a lucid point; others of the cometic shape, with a seeming nucleus in the centre, or like cloudy stars, surrounded with a nebulous atmosphere: a different sort, again, contain a nebulosity of the milky

kind, like that wonderful inexplicable phenomenon about Orion is; 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 solu ble 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 Picæ. 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 se questered 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 Diadelphia Decandria class and order. Natural order of Papilionacea, or Leguminosa. Essential character: calyx with subulate teeth, nearly equal; legume with oblique streaks between the seeds. There are nineteen species.

GALENIA, in botany, a genus of the Octandria Digynia class and order. Natural order of Succulenta. Attriplices, Jussieu. Essential character: calyx fourcleft; corolla none; capsule roundish, two-seeded. There are two species.

GALEOPSIS, in botany, a genus of the Didynamia Gymnospermia class and order. Natural order of Verticillatæ, or Labiatæ. 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 1564. The earliest subjects of his studies were, poetry, music, and drawing but his genius soon led him to the cultivation of sublimer sciences, by his proficiency in which he has immortalized 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 profits of 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 dissatisfied 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 prudently 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 master, held him out in the odious light of a visionary and dan gerous innovator. Becoming disgusted with the obstructions which their igno rance and bigotry threw in the way of his promoting just principles of science, in the year 1592 he resigned his profes sorship at Pisa, and accepted with plea sure of an invitation that was sent him to fill the mathematical chair in the university of Padua. In this seminary he continued for eighteen years, esteemed and cherished by the Paduans and Venetians, raising the credit of the university as a school of sound philosophy, and admired by all the learned, who had sufficient liberality and spirit to emanci pate 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 his "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

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 penitential 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 he was sent to the archi-episcopal 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 Ancetri, 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 philosophi cal 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 acuteness 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 showed 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 diurnal 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 showed 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 was made in it for almost 2000 years; but Galileo has given as fully the theory of equable motions, and of such as are uniformly accelerated or retarded, and of these two compound. ed 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 his pupil Torricelli. He in