own house, suspected that his papers might contain dangerous heresies, and therefore committed them to the flames.

Sir John Finch, in a letter to Thomas Salisbury, attributes the destruction of Ga-` lileo's MSS. to his widow's devotion, and the fanaticism of her confessor; but the best authorities maintain that our philosopher was never married. His son Vincenzo Galilei, who, as we have already seen, honourably supported his father's reputation, by first applying his invention of the pendulum to clock-work, was of illegitimate birth.

GALIUM, in botany, a genus of the Tetrandria Monogynia class and order. Natural order of Stellatæ. Rubiacea, Jussien. Essential character: corolla one-petalled, flat; seeds two, roundish. There are forty. eight species.

perty depends the art of making our writing-ink, as also a great deal of those of dyeing and dressing leather, and other manufactures. See INK, &c.

GALL bladder, called vesicula, is usually of the shape of a pear, and of the size of a small hen's egg. It is situated in the concave side of the liver, and lies upon the colon, part of which it tinges with its own colour. The use of the gall-bladder is to collect the bile, first secreted in the liver, and mixing it with its own peculiar produce to perfect it farther, to retain it together a certain time, and then to expel it.

GALL fly. See CYNIPS.

GALL stone. See CALCULI biliary.

GALLEON, in naval affairs, a sort of ships employed in the commerce of the West Indies. The Spaniards send annually two fleets; the one for Mexico, which

GALL, in natural history, denotes any protuberance or tumour, produced by the puncture of the insects on plants and trees of different kinds. Galls are of various forms and sizes, and no less different with regard to their internal structure. Some have only one cavity, and others a number of small cells communicating with each other: some of them are as hard as the wood of the tree they grow on, whilst others are soft and spongy; the first being termed gall-nuts, and the latter berry-galls, or apple-galls.

The general history of galls is this: an insect of the fly-kind (see CYNIPS), ishstructed by nature to take care for the safety of her young, by lodging her eggs in a woody substance, where they will be defended from all injuries: she for this purpose wounds the branches or leaves of a tree, and the lacerated vessels, discharging their contents, soon form tumours about the holes thus made. The hole in each of these tumours, through which the fly has made its way, may for the most part be found; and when it is not, the maggot-inhabitant or its remains, are sure to be found within, on breaking the gall. It is to be observed, however, that in those galls which contain several cells, there may be insects found in some of them, though there is a hole by which the inhabitant of another cell has escaped. Oak-galls, put in a very small quantity into a solution of vitriol in water, though but a very weak one, give it a pur ple or vitriol colour, which, as it grows stronger, becomes black; and on this pro

By a general regulation, made in Spain, it has been established, that there should be twelve men of war, and five tenders, annually fitted out for the armada or galleons; eight ships of six hundred tons burden each, and three tenders, one of an hundred tons, for the island Margarita, and two of eighty each, to follow the armada; for the New Spain fleet, two ships of six hundred tons each, and two tenders of eighty each; and for the Honduras fleet, two ships of five hundred tons each: and, in case no fleet happened to sail any year, three galleons and a tender should be sent to New Spain for the plate. They were formerly appointed to sail from Cadiz, in January, that they might arrive at PortoBello about the middle of April, where the fair being over, they might take aboard the plate, and be at Havanna with it about the middle of June, where they were joined by the flota, that they might return to Spain with the greater safety. For this purpose, the viceroy of Peru was to take care that the plate should be at Panama by the middle of March. The plate is fifteen days removing from Potosi to Arica, eight days generally from thence by sea to Callao, and from that place to Pauama twenty days, taking in by the way the plate at Paita and Truxillo. It has, however, been found by experience, that the month of September is the fittest for the fleet to sail: they are about two years in the whole voyage.

The galleons bring annually of gold about two or three millions of crowns, and the

flota one. Of silver, the galleons bring eighteen or twenty thousand crowns, and and the flota ten or twelve. Of precious stones the galleons bring quantities to an immense value; besides fine wool, leather, and Campeachy wood.

GALLERY, in fortification, a covered walk across the ditch of a town, made of strong beams, covered over head with planks, and loaded with earth: sometimes it is covered with raw hides to defend it from the artificial fires of the besieged. Its sides should be musquet proof.

GALLERY of a mine, is a narrow passage, or branch of a mine carried on underground to a work designed to be blown up. Both the besiegers and the besieged also, carry on galleries in search of each others mines, and these sometimes meet and destroy each other.

GALLERY, in ship-building, a balcony, projecting from the stern or quarter of a ship of war, or of a large merchantman: the stern-gallery is wholly at the stern of the ship, and is usually decorated with a balustrade extending from one side of the ship to the other; the fore-part is limited by a partition, in which are framed the cabin windows, and the roof of it is formed by a sort of vault termed the cove, which is frequently ornamented with sculpture. Quarter-gallery is that part which projects on each quarter, and is generally fitted up as a water closet. Ships of twenty-guns and upwards, on one deck have quarter galleries, but no stern gallery; two and three deckers have quarter galleries, with their proper conveniences, and one or two stern galleries.

GALLEY, in naval affairs, a low-built vessel, using both sails and oars, and commonly carrying only a main-mast and foremast, which may be struck or lowered at pleasure. Such vessels are much used in the Mediterranean.

These vessels are of a long standing, though it is probable the construction of those in modern times is very different from that formerly adopted. Galleys are of a finer and slenderer make than ships. Galley is the name also of an open boat, rowing six or eight oars, and used on the Thames by Custom-house officers, press-gangs, and also for pleasure. The same word denotes the kitchen of a ship of war, or the place where the grates are put up, fires lighted, and the victuals generally dressed.

GALLEY slave, a person condeinned, in

France, to work at the oar on board a galley, being chained to the deck.

GALLIC-acid, in chemistry, exists in nut-galls, and is obtained by boiling together for some time carbonate of barytes, and a solution of gall-nuts. This affords a bluish green liquid, which consists of a solution of gallic acid and barytes. It is now to be filtered and saturated with diluted sulphuric acid. Sulphate of barytes is deposited in the state of insoluble powder, and a colourless solution of gallic acid remains behind. This is the method given by Mr. Davy, others have been suggested by almost every practical chemist. Gallicacid, pure, is in the form of transparent plates or octahedrons. Its taste is acid, and somewhat astringent, and when heated has rather an unpleasant aromatic odour. It is soluble in about twelve parts of cold water, and in three parts of alcohol: it is soluble in ether. It combines with alkaline bodies, making with them compounds called gallates. It occasions a precipitate when poured into solutions of glucina, yttria, and zircon in acids, which distinguishes these from the other earths, none of which are precipitated from their solutions by gallic acid. Upon the metallic solutions gallic acid acts with great energy, changing the colour, and producing precipitates in many of them. Hence it is frequently used as a re-agent to detect the presence of metallic bodies. It is composed of oxygen, carbon, and hydrogen, but the proportions of each have not been accurately ascertained.

GALLIOT, a small galley designed only for chase, carrying only one mast, and two or three pattereroes; it can both sail and row, and has sixteen or twenty oars. All the seamen on board are soldiers, and each has a musket by him on quitting his oar.

GALLON, a measure of capacity both for dry and liquid things, containing four quarts; but these quarts, and consequently the gallon itself, are different, according to the quality of the thing measured: for instance, the wine gallon contains 231 cubic inches, and holds eight pounds averdupois of pure water: the beer and ale gallons contain 282 solid inches, and holds ten pounds three ounces and a quarter averdupois, of water: and the gallon for corn, meal, &c. 2724 cubic inches, and holds nine pounds thirteen ounces of pure water.

GALLOON, in commerce, a narrow thick kind of ferret, or lace, used to edge

GALLY, in printing, a frame into which the compositor empties the lines out of his composing-stick, and in which he ties up the page when it is completed. The gally is formed of an oblong square board, with a ledge on three sides, and a grove to admit a false-bottom, called a gally

slice.

GALOPINA in botany, a genus of the Tetrandria Digynia class and order. Natural order of Rubiaceæ, Jussieu. Essential character: calyx none; corolla four-cleft; seeds two, naked. There is one species, viz. G. circæoides, a native of the Cape of Good Hope.

GALVANI (LEWIS) a modern physiologist, who has had the honour of giving his name to a supposed new principle in nature, was born in 1737, at Bologna, where several of his relations had distinguished themselves in jurisprudence and theology. From his early youth he was much disposed to the greatest austerities of the Catholic religion, and particularly frequented a convent, the monks of which attached themselves to the solemn duty of visiting the dying. He shewed an inclination to enter into this order, but was diverted from it by one of the fraternity. Thenceforth he devoted himself to the study of medicine in its different branches. His masters were the Doctors Beccari, Jacconi, Galli, and especially the Professor Galeazzi, who received him into his house, and gave him his daughter in marriage. In 1762, he sustained with reputation an inaugural thesis "De Ossibus," and was then created public lecturer in the University of Pologna, and appointed reader in anatomy to the in. stitute in that city. His excellent method of lecturing drew a crowd of auditors; and he employed his leisure in experiments and in the study of comparative anatomy. He made a number of curious observations on the urinary organs, and on the organ of hearing in birds, which were published in the Memoirs of the Institute. His reputation, as an anatomist and physiologist, was established in the schools of Italy, when accident gave birth to the discovery which has immortalised his name. His beloved wife, with whom he lived many years in the tenderest union, was at this time in a declining state of health. As a restorative, she made use of a soup of frogs; and some of these animals, skinned for the purpose, happened to lie upon a table in her hus

an electrical machine. One of the assistants in his experiments chanced carelessly to bring the point of a scalpel near the crural nerves of a frog, lying not far from the conductor. Instantly the muscles of the limb were agitated with strong convulsions. Madame Galvani, a woman of quick understanding, and a scientific turn, was present, and, struck with the phenomenon, she immediately went to inform her husband of it. He came and repeated the experiment; and soon found that the convulsion only took place when a spark was drawn from the conductor, at the time the scalpel was in contact with the nerve. It is unnecessary in this place to mention the series of experiments by which he proceeded to investigate the law of nature, of which accident had thus given him a glimpse, for which our article GALVANISM must be consulted.

In conjunction with these enquiries, his duties as a professor, and his employment as a surgeon and accoucheur, in which branches he was very eminent, gave full occupation to his industry. He drew up various memoirs upon professional topics, which have remained inedited; and regularly held learned conversations with a few literary friends, in which new works were read and commented upon. He was a man of an amiable character in private life, and possessed of great sensibility, which he had the misfortune of being called to display on the death of his wife in 1790, an event which threw him into a profound melancholy. He rarely suffered a day to pass without visiting her tomb in the nunnery of St. Catherine, and pouring out his prayers and lamentations over her remains. He was always, indeed, punctual in practising the minutest rites of his religion, the early strong impressions of which never left him, and this attachment to religion was probably the cause of steadily refusing to take the civic oath exacted by the new constitution of the Cisalpine Republic, in consequence of which he incurred the deprivation of his posts and dignities. A prey to melancholy, and reduced almost to indigence, he retired to the house of his brother James, a man of very respectable character,and there fell into a state of languor and almost imbecility. The republican governors, probably ashamed of their conduct towards such a man, passed a decree for his restoration to his professional chair and its emoluments; but it then was too late. He died on November

5, 1798, at the age of sixty, amid the tears of his friends and the public regret.

GALVANISM, this surprizing branch of philosophy has been denominated galvanism, from Galvani, an Italian professor, whose experiments led to its discovery.

In 1789, some time before he made the most important discovery, he was by ac cident led to the fact, of electricity having the property of exciting contractions in the muscles of animals. Stimulated by the then prevailing idea of electricity being a principle inherent in animals, which acting upon the muscular susceptibility, was the immediate cause of muscular motion, he was induced to persevere in the inquiry, during the prosecution of which, he brought to light other facts, which laid the foundation of this valuable scientific acquisition.

After having observed that common electricity, even that of lightening, produced vivid convulsions in the limbs of recently killed animals, he ascertained that metallic substances, by mere contact,under particular circumstances, excited similar commotions.

He found, that it was essential, that the forces of metals employed should be of different kinds. He applied one piece of metal to the nerve of the part, and the other to the muscle, and afterwards connected the metals, either by bringing them together, or by connecting them by an arch of a metallic substance; every time this connection was formed the convulsions took place. The diversity in the metals employed in these experiments appeared, in the very early stages of this enquiry, to be connected with their respective degrees of oxydability, the one being possessed of that property in a great degree, and the other little liable to the change. Hence zinc, and silver, or gold, was found to produce the greatest muscular contractions.

The experiments of Galvani were confirmed by many able philosophers, by whom they were repeated. Those who particularly distinguished themselves by their la bours on the subject were Valli, Volta, Drs. Monro and Fowler.

Galvani had theorised upon the phenomena which he had observed to a considerable extent. He conceived, that the convulsions were produced by a disturbance of the electricity inherent in animals, which was identical with the nervous fluid, and that the metallic substances employed had not any other effect, than that of transmitting the electricity from the nerve to the muscles producing the contractions in question.

Simon Volta with much labour and ingenuity successfully opposed the hypothesis of Galvani. He had recourse to those valuable experiments made by Bennet, by, which to explain the phenomena observed by Galvani. Bennet had some time before observed, when plates of different metals were brought in contact, that one of the metals transmitted a portion of its electricity to the other, each of which, when separated, being at the same time insulated, evinced signs of contrary states of electricity. When the plates, for instance, were one of copper and the other zinc; the former, while the two were in contact, gave a portion of its electricity to the latter. Hence, when they were separated, and thus presented to the electrometer, the copper exhibited signs of negative electricity, and the zinc that of positive.

On this ground it was that Volta objected to the hypothesis of Galvani, and established the more plausible idea, that the electricity was furnished by the disturbance of that fluid, arising from the contact of the different metals, and that the conyulsions were excited by the stimulating effect of that active agent. It was in the investigation of this experiment, that this truly ingenious philosopher was led to the discovery of the pile, which from its inventor has been called the Voltaic pile. This apparatus consisted, in combining the effects of a number of pairs of the different metals, and by that means constituting a battery in galvanism, similar in effect to the Leyden vial in common electricity.

As silver and zinc had been found in the minor experiments to produce the greatest effect, these metals were employed by Volta in the construction of his battery. The silver plates generally consisted of coins; and the zinc plates were of the same size, being frequently cast in moulds made with the silver. The same number of pieces of cloth, pasteboard, or leather, of the same size, and steeped in solution of common salt, were also provided. The above substances were formed into a pile, in the following order: zinc, silver, wet cloth; zinc, silver, wet cloth; and so on, in the same order, till the pile became sufficiently high. If it were to be elevated to any considerable height, it was usual to support it on the sides with three pillars of glass, or varnished wood.

The pile, thus formed, was found to unite the effects of as many pairs of plates as might be employed. Previously to

this no other effect had been produced than what resulted from the energy of a single pair of plates. A pile of 50 pairs of plates, with as many corresponding pieces of wet cloth, was found to give a pretty smart shock, similar to an electric shock, every time that a communication was made between the top and bottom of the pile. It was found, however, that little or no shock was perceived, when the hands, or other parts applied, were not previously moistened. It was also observed, that the effect was increased when a larger surface was exposed to the action of the pile. If the communication were made by touching the pile with the tip of each finger merely, the effect was not perceived beyond the joint of the knuckle; but if a spoon, or other metallic substance, were grasped in moistened hands, the effect was felt up to the shoulder. If the communication be formed between any part of the face, particularly near the eyes, and another part of the body, a vivid flash of light is perceived before the eyes, corresponding with the shock. This phenomenon may be more faintly observed, by placing a piece of silver, as a shilling, between the upper lip and the gum, and laying a piece of zinc at the same time upon the tongue: upon bringing the two metals in contact, a faint flash of light is perceived. It is singular, that this light is equally vivid in the dark with the strongest light, and whether the eyes be shut or open.

Another variety of galvanic battery was also contrived by Volta. The pairs of plates were soldered to each end of a bit of wire, which was afterwards bent into an arch, so that the plates became parallel to each other. A number of glass cups were also provided, and filled with a solution of culinary salt. The glasses being arranged side by side, the metallic ares were so placed, that the silver plate was immersed in one glass, and the zinc in another; and also that a silver and zinc plate of different arcs should be placed in each glass. This arrangement was found to be similar to the pile, the water in the cups being substituted for the disks of cloth.

Soon after the discovery of the pile, in 1800, it was communicated by Vol'a himself to the Royal Society, London. The first experiments made in this country upon the Voltaic pile, were made jointly by Messrs. Nicholson and Car'isle. After observing the phenomena already described by Volta, they observed an impo fact which had escaped the notice of that acute philosopher.

:

When bringing the wire from the bottom of the pi'e, in contact with a drop of water at the top, they observed the disengagement of some gaseous substance, which had the smell of hydrogen. Supposing this effect to arise from the decomposition of the water, they caused the ends of two brass wires, coming from the two ends of the pile, to be immersed in water, so that a portion of that liquid might be exposed between the wires. A disengagement of gas immediately took place from one of the wires, while the other became as quickly tarnished, and oxydated. The former appearance took place at the silver end of the pile, the latter at the zinc end. They ascertained that the effect would not take place when the wires were placed far asunder, and that the effect diminished gradually with the distance. They observed also, that when the tincture of litmus was used, instead of water, the liquid in the vicinity of the oxydated wire, being that connected with the zinc end, became red. When they made use of wire of platina instead of brass, they observed that the wire from the zinc end of the pile, which when of brass became oxydated, now gave out bubbles of gas, which they found to be oxygen. In short, they determined that the gases evolved were oxygen and hydrogen, and in proportions fit to constitute water. These discoveries established the chemical nature of the galvanic action in England; and they soon spread over all Europe.

The above experiments were repeated by Mr. Cruickshank, of Woolwich. He employed a glass tube filled with water, having a cork at each end, through which wires of silver were passed, the points of which were separated from each other by a stratum of the liquid. Upon the wires being communicated with the two ends of the piles, the same appearances took place which were observed by Messrs. Nicholson and Carlisle : the silver wire, however, connected with the zinc end of the pile, became oxydated, the oxide forming a white cloud round the wire: he also, instead of water, introduced into the tube an infusion of Brazil-wood. During the galvanic action, the colour in the vicinity of the wire of the zinc-end, became very pale, while that about the wire of the silver-end of the pile, appeared of a purple colour. When a metallic solution was placed in the tube, Mr. Cruickshank observed, that, instead of hydrogen gas being evolved from the wire, which connected the silver-end of the pile,