53 7

galvanism.

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farm water by combustion: and if the process be continued forsome time, the apparatus being exposed to the atmosphere, the'eater, in the oxygen-giving tube, will become impregnated withan acid (apparently the nitrous'); whilst that in the hydrogen-giving tube will be found to hold in solution a fixed alkali, I.ettile glass-vessel A, fig, 26, have the two tubes, Z and C, groundtnto its two necks. At the ends, Z and C, of the tubes, are tiedbit s of bladder, so that any liquid in the tubes may have no ten- IJeucy to enter the vessel A. The vessel being previously filledwith some liquid, the tubes are so inserted that no air may exhtbetween the ends of the tubes; the tubes are also provided with*Wo small caps of ivory or wood, through which the platina-wires,Pp, are passed, reaching the bottom so near as not to pierce thebladders. The tubes being filled with water, and the wire fromthe zinc-end of the battery connected with the w ire of the tube Z,while that of the copper is attached to that of the lube C, the decom-position of water will speedilv commence, the wire in Z affording°xygen gas, while that of C affords hydrogen gas. In a very shortdine, the liquid of the tube Z, will be found to contain muriatica cid; or rather, the oxy-muriatic; and the tube C, will at the jsmile lime be found to contain a fixed alkali. If the tubes be till-°d with infusion of cabbage, the signs of alkali and acid are verysoon observed, from the liquid of Z becoming red, and that of Cgreen. If the connection be reversed, the liquids repass to theblue colour, and if the process he continued, that of Z becomes jRreeii, and C red. From some experiments it would appear pro- !babie, that the quantities of hydrogen, produced in series, are |small, and the quantities of alkali great, in proportion as the sur- i^sces of contact of the least oxidable metals with the water aref*>ore extended. All the oxygenated solutions of bodies possess-ln g less aflinity for oxygen than nascent hydrogen, are decompos-ed when exposed to the action of the metal occupying the place !

the least oxidable part of the series in the compound circle. }* bus, sulphur may be produced from sulphuric acid ; and copper ja ml other metals precipitated in the metallic form from theirSolvents. It is well known that hydrogen gas, in its nascent state,re duces the oxides of metals. Accordingly when the tube, fig. |

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22 or 23, is tilled with a solution of acetite of lead in diddledwater, and a communication is made with the battery as abovedescribed, no gas is perceived to issue front the wire which pro-j ceeds from the negative end of the battery ; but, in a few minutesj beautiful metallic needles are perceived on the extremity of thisi wire ; these soon increase, and assume the form of a fern or othervegetable. The lead thus separated is in its perfect metallic stale,and very brilliant. When a solution of sulphate of copper is em-ployed, the copper is precipitated in its metallic stale ; hut insteadof appearing in crystals, it forms a kind of button, which adheres(irmly to the end of the wire. On making the experiment with asolution of nitrate of silver, the silver is precipitated in the formof a beautiful metallic brush, the metal shooting into tine needic-. like crystals, If iron be immersed in a solution of sulphate of! copper, the latter metal will be precipitated into a metallic form,j and will adhere to the surface of the tormer. Upon silver merelyi immersed in the same solution, no such effect is produced ; but asj soon as the two metals, viz. the silver and the copper, are broughti into contact, the silver receives a coating of copper. A measureof the intensity of the power in Galvanic batteries, producing che-mical changes, may be derived from the quantity of gas it is ca-pable of evolving from water in a given time. By the powerful actionof a large Galvanic battery, the illustrious Mr. Davy, professor ati the itoyal Institution, effected the decomposition of the fixed al-kalis, which had hitherto been attempted in vain, A small bit ofalkali is laid on a plate of platina connected with one end of thebattery, and bringing another piece of platina connected with theother end of the battery into contact with it. A portion of blackmatter is soon formed, in which is found imbedded small metallicglobules; which substance is found to be the base of tire alkali,apd has been deprived of its oxygen by the Galvanic agency.This base is found to be a metal: that obtained from potass is de-nominated potasium, and that which constitutes the base of soda iscalled sodium. These metals are very inflammable, and decom-pose Water, with a bright Hash and slight explosion. The same in-genious philosopher has also in some degree succeeded in decomposing the alkaline earths.

GAMBIA, a great river of Africa , which, running from E. to”. falls into the Atlantic ocean, S. of Cape Verb. It oversowsan nuully like the Nile , and is navigable for ships of 130 tons, 300fl, iles from its mouth.

GAMBEZON, or GAMBA, in antiquity, a kind of soft quilt-ed waistcoat, worn under the coat pf mail to prevent its hurtingBie bodv. It is made of wool or cotton, qmlted between twostuffs, and was also called counterpoint.

GAMBOGE, a concreted vegetable juice, partly of a gummy,partly of a resinous, nature. It is brought to us either in form°l orbicular masses, or of cylindrical rolls of various sizes, and isa dense, compact, and firm texture, and of a beautiful yellow,u is chiefly brought to us from Cambaja, in the East Indies, call-ed also Cambodja and Cambogia; and thence it has obtained itsbanies of cambadium, cambogium, and gambogumi. It is ob-huned from the stalagmites cambogioides, a tree ot the East Indies,b y wounding the slioot. It is a very rough and strong purge ; itoperates both t>y vomit and stool, and both ways with much vio-•ei'ce, almost in the instant in which it is swallowed, but yet wilh-v ' ut griping. It requires caution and judgement in administering .l . 1 ' hut those who know how to give it properly, find it an excel-ktU remedy in dropsies, cachexies, jaundice, asthmas, catarrhs,iilJ d in the. worst cutaneous eruptions. Its dose is from two or|kree grains to six,. eight, or ten: four grains generally operatebriskly without vomiting, and eight or ten grains usually vomit■briskly, and afterwards purge downwards. It is at present muchbiorc esteemed by painters in water-colours titan by physicians,

, DAME, ill law, signifies birds, or prey, taken or killed bybaling or hunting. r l he property of such animals fertc natural as,lr e known under the denomination of game, with the right of pur- ;iU ' n g, taking, and'destroying them, is vested in the king alone, :a,l d ivoin him derived to such of his subjects as have received thepunts of a chace, a park, or free warren. By the law of nature,‘‘deed, every man, from the prince to the peasant, lias an equalv ol. ii.—no. £>1.

rigiit of pursuing, and taking to his own use, all such creatures asare feral naturx, and therefore the property of nobody, but liableto be seized by the first occupant. But it follows, "(savs Black-stone,) from the very end ami constitution of society, tluit this na-tural rigid, as well as many others belonging to man as an indivi-dual, may be restrained by positive laws enacted for reasons ofstate, or for the supposed benefit of the community. This restric-tion maybe either with respect to the place in'which this rightmay, or may not, lie exercised; with respect to the animals thatare the subjects of this right; or with respect to the persons allow-ed or forbidden to exercise it. And, in consequence of this au-thority, we find, that the municipal laws of many nations have ex-erted such power of restraint; have in general*forbidden the en-tering on another man’s grounds, for any cause, without the owner’s leave; have extended their protection to such particular ani-mals as are usually the objects of pursuit; and have invested t-lieprerogative of hunting and takmg such animals in the sovereign ofthe stale only, and such as be shall authorise. Many reasons haveconcurred for making these constitutions: as, 1. For the encou-ragement of agriculture and improvement of lands, bv giving everyman an exclusive dominion over his own soil. 2. For the preser-vation of the several species of these animals, which would soon beextirpated by a general liberty. 3. For prevention of idleness amidissipation in husbandmen, artificers, and others of lower rank-which would be the unavoidable consequence of universal licence''4. For prevention of popular insurrections and resistance to thegovernment, by disarming the hulk of the people; which last is areason oftener meant than avowed, by the makers of forest orgame laws. Nor, certainly, in these prohibitions is there any na-tural injustice, assume have weakly enough supposed: since, asl’uffendorf observes, the law does not hereby tike from any manhis present property, or what was already has own; but ibuiyhabridges him of one means of acquiring a future property, that ofoccupancy ; which indeed the law of nature would allow him, but