substances have occurred, such as pieces of wood and bark, sand, or amber. To purify it from these, it is commonly dissolved in proof spirit. By this means a larger quantity of resin is procured than was originally subjected to the solvent, owing to a hydrate being formed. Resin which has been so purified has lost nearly all acrimony; the resin is likewise adulterated with colophony; and it is said to be adulterated with the resin or gum of the manchineel-tree, a most culpable substitution, owing to its formidable powers.

According to Unverdorben, guaiac-resin consists of two distinct resins the one is easily soluble in aqua ammoniæ, which the alcoholic solution of acetate of copper precipitates; the other forms with ammonia a tarry combination, which is soluble in six thousand parts of water, and which the alcoholic solution of acetate of copper does not precipitate.

The resin of guaiac becomes blue by continued exposure to the air, and also when in contact with many organic substances: many vegetable substances, particularly several containing gum and starch, turn the tincture of guaiac blue; a point of importance, from the similar effect of iodine on starchy substances.

The acrid taste of guaiac-resin is owing to a peculiar bitter acrid, so-called extractive (or guaiacin), which is contained in much greater quantity in the bark than the wood. It is to this principle, according to Buchner, that guaiac-resin is indebted for its medicinal powers.

Guaiac possesses the property of stimulating the system generally, causing increased vascular action, augmented heat of the body, and promotes the secretions of the skin and lungs; but in large doses it produces nausea, anxiety, abdominal pains, and stupor. It is not prized now so highly as on its introduction into European practice in the 16th century, when it bore a most extravagant price, four ducats being often given for a pound of the wood. It is, however, a useful agent in certain forms and stages of gout and rheumatism, and in some cutaneous diseases, especially when in the first set of disorders it is combined with ammonia, and in the latter with mercurials and diaphoretics or antimonials, as in Plummer's pills.

Its insolubility in watery menstrua is an obstacle to its easy administration, and even its alcoholic solutions are precipitated on the addition of water. It is generally made into an emulsion, or given in pills; but a soap may be formed by means of heated aqua potassæ, in which the resin is to be dissolved, then evaporated, and a soft consistent mass is obtained, which may be formed into pills or a bolus. GUAIACYL (CH,O,), the theoretical base of the resin called guaiacum. If this resin is distilled, an oily liquid is obtained, which is regarded as a hydride of guaiacyl, C,,H,O,+H, although it has been named pyroguaiacic acid.

Another constituent of guaiacum resin is guaiacic acid (C12H,O), which crystallises in needles, and is freely soluble in water. By destructive distillation the resin also yields guaiacene (C,H,O,), a light volatile oil, which absorbs oxygen from the air, and forms a crystalline compound.

GUANINE (CN,H,O,), a compound discovered by Unger in guano. It resembles urea in its properties, forming crystallisable salts with hydrochloric, sulphuric, and nitric acids. It is a white powder, and insoluble in water. Its salts are all neutral or acid, none basic.

GUANO (from the Peruvian word huanu, which signifies dung) is the excrement of sea-fowl, and was used as a manure probably for ages before Peru was visited by the Spaniards. It is spoken of by Herrera in a work published at Madrid in 1601; by Garcilaso de la Vega, in his' Memoriales Reales,' published at Lisbon in 1609; and by Ulloa in his Voyage.' Garcilaso de la Vega says that "in the time of the Incas there was so much vigilance in guarding these birds (the seafowl), that during the rearing season no person was allowed to visit the islands which they frequented, under pain of death, in order that they might not be frightened and driven away from their nests. Neither was it allowed to kill them at any time, either on or off the islands, under the same penalty. Each district or territory had a portion of these islands allotted to it." Mr. Thairlwall, of Richmond, Yorkshire, who has visited the western coast of South America, describes a small island, about three miles in circumference, in 13° 44' S. lat., on which guano is deposited in a solid mass 200 feet in depth. The surface is coated over with a thick incrustation of almost pure muriate of ammonia; and when the bulk is disturbed, the ammonia given out is so strong as to affect respiration, and to cause an unpleasant sensation in the eyes. Peruvian guano is imported into England only by the agents of the Peruvian government, Messrs. A. Gibbs & Co. About the commencement of 1843 guano was discovered on the island of Ichaboe, about two miles and a half from the mainland of Africa, in 26° 13′ S. lat. and 14° 15′ E. long. The place soon attracted notice, and by the end of 1844 the whole of the guano had been carried away. As many as 350 ships have been anchored off the island at the same time. The guano was 35 to 38 feet in depth, and the deposit extended to a length of about 1100 feet, with an average width of 400 feet. Towards the close of 1844 another guano island (Malagas) was discovered at the entrance of Saldanha Bay. The guano covers an extent of about eight miles, and gradually increases in thickness from about 4 yards to 8 yards. It is obtained for shipment by a licence from the collector of customs at Cape Town. In October, 1845, a cargo of guano was brought to this country from Patagonia. It has been supposed

that the excrement of the sea-fowl which swarm on some parts of the coast of Great Britain might be used as a fertiliser with the same results as Peruvian or African guano; but the quantity which could be collected is comparatively small, as the annual accumulation is in most cases washed away by the rains, and the valuable properties of that which remains are dissipated by the changeable nature of our climate. In South America and Africa the dryness of the climate allows the guano deposits of successive years to accumulate, and the heat of the sun produces a coating of the surface which preserves its virtue as a manure. The superiority of the Peruvian over the African and other guanos is owing chiefly to the greater dryness of the climate. A guano has been found on the Koorya Moorya Islands off the southern coast of Arabia, and has been imported to some extent, but its composition is very inferior to that of the Peruvian in all that constitutes worth in a manure.

The value of guano is to be estimated according to the proportions which it contains of-1, ammonia; 2, phosphates; 3, organic matter. The results of a number of analyses of Peruvian and African guano show the following variations in their composition :

The

Good Peruvian guano sells now at 13. per ton. The article is extensively adulterated, and instances have occurred in which the adulterated matter prevailed to the extent of 97 per cent. Umber, stone ground into a fine powder, various earths, old mortar, and partially decomposed saw-dust, are employed for this purpose. mixture is moistened with putrid urine and re-dried. Even genuine guano differs so frequently in quality, that it is never advisable to purchase it without a satisfactory analysis. Purchasers are often deluded with false analyses, and those who deal only with those who profess to be importers are not always safe. Dr. Ure advises the farmer before he buys to obtain an analysis from a competent chemist, and then to cork up a sample in a bottle, and in the event of his crops disappointing reasonable expectation he is in a better position for obtaining satisfaction for any fraud which may have been practised upon him. Farmers' clubs might retain a respectable chemist at a salary on condition that he should perform analyses for the members at a moderate fee. This is what in effect was done by the Agricultural Chemistry Association of Scotland, and the consequence was that scarcely a single sample of adulterated guano was offered for sale in that country.

The easiest test of the purity of guano is its weight. It may vary from 69 to 73 lbs. a bushel, and the lighter the better, provided on throwing it into water some of it floats. If heavier than 73 lbs. per bushel, it has been adulterated with earth. The following are the common chemical tests of its genuineness, as given by Mr. Nesbitt :(1). Procure from any druggist a common wide-mouthed 6-oz. bottle, with a solid glass stopper. Let this bottle be filled with ordinary water, the stopper inserted, and the exterior well dried. The scales to be used ought to turn well with a couple of grains. In one pan of the scales place the bottle, and exactly counterpoise it in the other by shot, sand, or gravel. Remove the bottle from the scale, pour out two-thirds of the water, and put in 4 oz. avoirdupois of the guano to be tested. Agitate the bottle, adding now and then a little more water; let it rest a couple of minutes, and fill with water so that all the froth escapes from the bottle. Insert the stopper carefully, wipe dry, and place the bottle in the same scale from which it was taken. Add now to the counterpoised scale 14 oz. avoirdupois and a fourpenny piece; and if the bottle prove the heavier, the guano is in all probability adulterated. (2.) Place 10 grains of the guano in a platinum capsule, which is held by the tongs in the flame of a spirit lamp for several minutes, until the greater part of the organic matter is burnt away. It is allowed to cool for a short time, and a few drops of a strong solution of nitrate of ammonia is added, to assist in consuming the carbon in the residue. The capsule is again gently heated (taking care to prevent, its boiling over or losing any of the ash), until the moisture is quite evaporated. A full red heat must then be given it, when, if the guano be pure, the ash will be pearly white, and will not exceed 3 grains in weight. If adulterated with sand, marl, &c., the ash will always be coloured, and will weigh more than 34 grains. (3). Dissolve in a quart of water as much common salt as it will take up, and strain the solution. Pour a quantity of it into a saucer or basin, and sprinkle on the surface the guano to be tested. Good guano sinks almost immediately, leaving only a very slight scum. The adulterated leaves the light materials floating on the water. (4.) If chalk or ground limestone has been used in adulterating guano, it may be shown by pouring strong vinegar over a tea-spoonful of the sample placed in a

wine-glass. On stirring, effervescence shows its presence. Genuine guano, under the same circumstances, merely allows the escape of a few air bubbles. We add here the method suggested by Dr. Cameron in his recently published lecture on agricultural chemistry, for the detection of spurious guano. By drying and burning, Peruvian guano should lose from 55 to 60 per cent. of its weight. Its ash should be white, and should dissolve readily, and without effervescence, in dilute muriatic acid, leaving insoluble residue, which should not amount to more than 2 per cent. of the weight of the guano. Mixed with quicklime it should give a strong ammoniacal odour. A bushel of guano if pure weighs almost exactly 70 lbs.; if adulterated with clay, marl, sand, &c., the weight will be materially increased, and so far as this test applies gross adulterations will be easily detected.

The great cost of guano has materially checked its consumption, and it will be seen from the following table how much during the past year its consumption has fallen off. The fact is, that at the price of 13. per ton many other manures are cheaper.

The following is a table of the imports since its first introduction:

apply cwt. of nitrate of soda and 1 cwt. of Peruvian guano per acre broadcast, in showery weather if possible.

On the application of guano to the soil, Mr. Nesbit gives the following instructions:

(1.) Guano is best applied in damp or showery weather.

(2.) Guano should not generally be put on grass land in the spring later than April.

(3.) When guano is applied to arable land, it should immediately be mixed with the soil, either by harrowing or otherwise.

(4.) When wheat is sown very early in the autumn, a less than usual amount of guano must at that time be applied, and the rest in the spring. The wheat otherwise might become too luxuriant, and be injured by subsequent frosts.

(5.) Guano, and artificial manures in general, should be put on the land only in quantities sufficient for the particular crop intended to be grown, and not with the intention of assisting the succeeding one. Each crop should be separately manured.

(6.) Guano, before application, should be mixed with at least from five to six times its weight of ashes, charcoal, salt, or fine soil. (7.) Guano should on no account be allowed to come in direct contact with the seed.

An artificial guano may be easily compounded by an admixture of the constituents of natural guano, all of which, with the exception of bone-dust, may be procured of any druggist. Professor Johnston gives the following recipe for an artificial manure which will produce an effect about equal to 1 cwt. of natural guano :-78 lbs. bone-dust, 25 lbs. sulphate of ammonia, 1 lb. of pearlash, 25 lbs. common salt, 24 lbs. dry sulphate of soda; total, 132 lbs. The following artificial substitute for guano has been successfully used, at the rate of 5 cwts. per acre:

Bones, dissolved in spirits of salt instead of oil of vitriol 18 lbs.
Charcoal powder

Anderson.

Nitrate of soda (cubic petre)

28

20 0

1 0 0 1 0 0

1 0

about

about 18

9

Alkaline salts Organic matters

These are the prices at which these several ingredients are purchased in guano at present prices. Can they be procured elsewhere at a cheaper rate? The ammoniacal liquor of the gas works, after having been once distilled, can be obtained containing 20 per cent. of ammonia at a price which gives that substance at from 3d. to 31d. per lb., or about 281. per ton. The objection to its use is, that the ammonia exists there chiefly as carbonate, and in that state is peculiarly liable to loss by evaporation. It is clear, however, that if concentrated gas liquor were applied to the soil, the farmer could afford to lose onethird of it, and still have his ammonia cheaper than in the state of sulphate. The application should be of 2 to 3 cwts. per acre on grain crops, both alone and mixed with a certain quantity of bone ash, and the land should be made up in ridges, and the solution, diluted to a proper extent, poured into the bottom of the furrows, while the plough, immediately following the application, should be made to divide the ridge and cover the ammonia. This should be done several days before sowing, for it would not answer to put the seed near the strong ammoniacal fluid, and a few days should be allowed for it to disseminate itself through the soil. One hundredweight and a half of the ammoniacal fluid, and the same quantity of bone ash, might also be tried on turnips, and should these applications prove successful, it will be possible to make a mixture as good as Peruvian guano at a cost of not more than 87. per ton.

Mr. Finnie, of Swanstone, has recently called attention to the existing wastefulness in the use of guano. His advice included the following particulars :-Government should investigate every source from which a supply of guano can be obtained; we should encourage manufacturers by making trial of other portable manures; we should turn our attention more than ever to the dung heap at home; and, lastly, instead of employing guano by itself as formerly, for turnips and barley, on the lighter and weaker description of soils, let farmers use along with it an admixture of other manures, such as bone meal, dissolved bones, or even guano of a secondary class; and for turnips and potatoes on the heavier character of soils, employ along with guano some other nitrogenous manure, such as rape dust, blood manure, &c. Thus-Superphosphate, along with farm-yard manure, is quite a sufficient substitute for guano for Swedes. Apply 3 cwt. per acre, along with 10 or 12 tons of dung. Nitrate of soda, 1 or 14 cwt., is better applied to corn crops, if used in place of guano. 1 or 2 cwt. of sulphate of ammonia per acre is a good dressing for an acre of wheat. If you can buy good soot at 6d. to 8d. a bushel, you can find no cheaper dressing than 40 bushels of that per acre. If you cannot get that,

ARTS AND SCI. DIV. VOL. IV.

Sulphate of soda (Glauber salts)

Sulphate of magnesia (Epsom salts)

Experiments have indeed been made, the results of which showed that 3 cwts. of good Peruvian guano were equal in their immediate effect to 20 tons of good farm-yard dung; but much is required to be known of the composition of a soil, and of the crops which it is to yield, before the exact value of any manure for that soil and crop can be fully settled; and this can only be ascertained by extensive experiments under every variety of local circumstances. The question may also arise, whether guano and other stimulating fertilisers do not exhaust the land while they produce great immediate results. They may, by supplying ingredients in which the soil is deficient, enable the plant so to use up others present in the land, that the soil shall be poorer after the crop has been removed than it was before the manure was applied. In this way it is that certain "artificial" fertilisers are called stimulating, and that farm-yard dung is alone a complete manure.

For various crops the guano answers best after vegetation has commenced; and it is useful in some cases to apportion the quantity intended to be used per acre into two or three portions for sowing at intervals, but the intervals most favourable are not fully determined. For small allotments or gardens it is often most convenient to use guano in a liquid state, in which case 4 lbs. of guano may be mixed with 12 gallons of water, and used after it has stood twelve hours, and the proportion per acre may be from a half to one cwt. of guano to 160 gallons of water.

GUARANINE (C1N,HO,), a substance identical with theine and caffeine, and found in the Guarana officinalis. [CAFFEINE.]

GUARD is a detachment of troops appointed to watch a position to prevent surprise, or to take care of stores, baggage, &c.

GUARDIAN, one who has the care of a person and his property, who, by reason of his imbecility or want of understanding, is in law considered incapable of acting for his own interest. Guardians in the English law are appointed only to infants, though under the civil law

NN

they were also assigned to idiots, lunatics, women, and sometimes prodigals. The laws of England indeed provide for the protection of idiots and lunatics, but the rules relating to them will be more conveniently considered under those heads, and therefore we shall here confine our remarks to guardians of infants. The guardian under the civil law was either a tutor or a curator. [CURATOR.] Guardians were appointed either by the will of the father, by the disposition of the law, or by the magistrate; and accordingly, with reference to its origin, the guardianship was styled testamentaria, legitima, or dativa. The nature of guardianship under the civil law is fully explained in the 'System des Pandekten-Rechts' of Thibaut, i., p. 377.

The usual division of guardians, according to the English law, and therefore the most convenient order in which to explain their office, is-1. Guardians by the common law. 2. Guardians by custom. 3. Guardians by statute.

I. Guardians by the common law were of four kinds : guardians in chivalry, in socage, by nature, and for nurture.

Guardianship in chivalry is now abolished by the statute of 12 Car. II., c. 24, which extinguished the onerous portions of the feudal system. This guardianship arose wholly out of the principles of tenure, and it could only take place where the estate vested in the infant by descent. All tenants by knights' service, being males under 21, or females under 14, at the ancestor's death, were liable to it; and it continued over males till 21, over females till 16 or marriage. It extended over the estate as well as the person of the infant, and entitled the lord to make sale of the marriage of the infant under the restriction of not making it a marriage of disparagement, and to levy forfeitures if the infant refused the marriage, or married, after tender of an alliance by the lord, against his consent. The lord was bound to maintain the infant, but subject to this obligation he was entitled to the profits of the estate for his own benefit. This guardianship, being considered more an interest in the guardian, than a trust for the ward, was saleable; and if not disposed of, passed at the lord's death to his personal representatives.

2. Guardian in Socage.-This also, like the former, is a consequence of tenure, and takes place only where lands of socage-tenure descend upon an infant under the age of 14. Upon attaining that age, the guardianship in socage ends, and the infant may appoint his own guardian. The title to this guardianship is in such of the infant's next of blood as cannot have the estate by descent in respect of which the guardianship arises, lest, it is said, the lamb should be delivered to the wolf to be devoured. This precaution springs perhaps from too great a mistrust of human nature, and it seems that in the early period of the Roman republic no such distinction was made. No provision upon the subject exists in the laws of the Twelve Tables--the lawgiver did not imagine that the life of the heir was in danger, though it was put in the hands of the person who would reap a benefit by his death. (Montesq., b. 19, c. 24.) And even at a subsequent period no such rule was known to the civil law; and indeed such a rule could have no place in the Roman system of succession. By the laws of Solon, no one could be a guardian who was to enjoy the estate of the ward after his death, and such it has been shown is the law of England with regard to guardians in socage. The laws of Scotland and the old laws of France prescribe a middle course: the estate is entrusted to the next in succession, because he is most interested in preserving it from waste, but he is excluded from the custody of the person of the ward. This is the principle upon which the Court of Chancery proceeds in its management of lunatics and their estates. [LUNACY.] The Code Civil of France, b. 1, tit. x., ch. 1, 2, 3, has many provisions relating to guardianships, too numerous to mention here. The guardian in socage is entitled not only to the custody of the person and socage estates of the infant, but also to his hereditaments not lying in tenure, and even his copyhold estates, where no custom to the contrary exists in the manor of which they are held, and also his personal property. The guardianship in socage is regarded as a trust wholly for the infant's benefit, and is not saleable, or transmissible, but in the event of the death of the guardian the wardship devolves on the person next in degree of kindred to the infant, not being inheritable to him, and the guardian is accountable to the infant for the profits of his

estate.

Guardianship in socage is, however, superseded both as to the person and estate of the infant, if the father appoints a guardian according to the statute, as will shortly be mentioned.

3. Guardian by Nature.-This species of guardianship has no connection with the rules of tenure. It extends only to the custody of the infant's person, and lasts till he attains 21. Any ancestor of the infant may be such a guardian, the first right being in the father, the next in the mother, and if they be dead the ancestor to whom the infant is heir has a right to the custody of his person. Until 14, it seems the guardian in socage is entitled to the custody of the person, and after that age the guardian by nature.

4. Guardians for nurture are the father and mother of the infant; in default of father or mother, the Ordinary, it is said, may appoint some person to take care of the infant's personal estate and to provide for his maintenance and education, though this has been doubted. This species of guardianship extends only to the age of 14, in males and females. Both these last descriptions of guardianship are also superseded by the appointment of a guardian by statute.

Where an infant is without a guardian the Court of Chancery has power to appoint one, and this jurisdiction seems to have vested in the king, in his Court of Chancery, as Parens Patriæ, upon the abolition of the Court of Wards. [CHANCELLOR.] And where a proper case exists for the jurisdiction of this court, it will, treating all guardians as trustees for their wards, interfere not only with the property of the infant, but also with the custody of his person, and will, in case of any misbehaviour, remove a guardian, however he may have been appointed or constituted, and will appoint a proper guardian to the infant in his room. Of this jurisdiction an instance is afforded by the case of the Duke of Beaufort v. Wellesley-where, the father being alive, Lord Eldon upon moral grounds deprived him of the custody of his children and this power of the Court of Chancery is now firmly established. And though the infant may have elected and appointed a guardian, this will not exclude the jurisdiction of the Court of Chancery, but upon the case being brought before the court it will order an inquiry as to the fitness of the guardian appointed. All courts also have power to appoint a guardian ad litem, that is, to defend a prosecution or suit instituted by or against an infant. (Co. Litt.,' 88 b, Hargr. note.)

II. Guardians by Custom.-By the custom of the city of London the guardianship of orphans under age and unmarried belongs to the city; and in many manors particular customs exist relating to the guardianship of infants; but in the absence of any such, the like rules prevail as before mentioned of guardians in socage.

III. Guardians by Statute.-At common law no person could appoint a guardian, because the law appointed one in every case. The statute 4 and 5 Phil. and Mary, c. 8, seems to have given some powers to the fathers of infants to appoint guardians; but guardians by statute are now appointed by virtue of 12 Ch. II., c. 24. Under this statute fathers, whether under age or of full age, may, by deed or will attested by two witnesses, appoint any person or persons (except Popish recusants) guardians of their unmarried children until they attain 21, or for any less period. A guardian appointed under this statute supersedes all other guardians, except those by the custom of London, or any city or corporate town in favour of which an exception is made, and is entitled to the custody of the infant's person, and his estate, real and personal. If two or more persons are appointed guardians under the provisions of this statute, the guardianship remains to the survivor. By the wording of the statute a father alone is empowered to appoint a guardian, and consequently, though the omission was probably unintentional, it has been decided that neither a mother, nor grandfather, nor any other relation, can make such an appointment. Neither can a father appoint a guardian to his natural child: but in all these cases the Court of Chancery will appoint the persons named to be guardians if they appear to be fit persons to exercise the trust reposed in them.

Guardians are rarely now appointed by infants themselves, the jurisdiction of the Court of Chancery providing far safer and more effectual means for the management and control of their property; and since in many cases the Court will interfere by petition without the institution of a suit, a cheap and speedy mode of procuring its interference is afforded. The guardian is considered as a trustee for his ward, and is accountable for the due management of the infant's property, and is answerable not only for fraud, but for negligence or omission.

Guardian of the Spiritualities is the person to whom the spiritual jurisdiction of any diocese is committed during the vacancy of the see.

Guardian of the Temporalities is he to whom the temporal jurisdiction and the profits of the see are committed during the like period. The words guardian and warden are of the same signification: indeed, they were formerly used indifferently. Thus the warden of the Cinque Ports was styled guardian, or in the old French, gardeyn, and churchwardens, gardeyns del Eglise. The Welsh word qward is the same as the English guard.

GUELPHS and GHIBELLINES, the names of two great political parties which divided Italy and Germany during the middle ages, became first known as the watchwords of their respective adherents at the battle of Winsberg, in Suabia, between two rivals for the Imperial throne, Conrad, duke of Franconia, and Henry the Lion, duke of Saxony, of the house of Guelph, Welf, or Wölf. Welf, who was young Henry's uncle, fought on behalf of his nephew, and his name was the war-cry of his followers; whilst those of Conrad took for their rallying word the name of Waiblingen, a town of Würtemberg, and the patrimonial seat of the Hohenstaufen family, to which Conrad belonged. [CONRAD III. in BIOG. DIV.] In course of time the name of Guelphs was given to all who were disaffected to the Emperor, and that of Ghibellines (which the Italians had formed from the German Waiblingen) to the supporters of the Imperial authority; and as the popes, reviving their old rivalry with the empire, encouraged and supported the disaffected Guelphs, they became at last the leaders of that party, and the Italian cities were divided between the adherents of the popes and those of the emperors. The names of Guelphs and Ghibellines were not however generally adopted in Italy till the reign of Frederic II., when Italy was divided, as it were, into two camps; some cities, such as Florence, Milan, Bologna, ranging themselves on the Guelph side, while Pisa, Arezzo, Verona, and others, remained

Ghibelline. The Ghibellines adopted as a symbol a white rose or a red lily; the Guelphs chose the eagle, already the arms of the Guelph family. But in the long struggle that ensued many alternate changes took place in each city, where sometimes the Guelphs, and sometimes the Ghibellines, gained the upper hand. [FLORENCE; GENOA, HISTORY OF, in GEOG. Div.] Most of the powerful nobles in Northern Italy, the Visconti, Doria, Della Scala, Pelavicino, were Ghibellines; the Anjou dynasty, which the popes had called to the throne of Naples, were the main support of the Guelphs. As the emperors, engrossed by their German affairs, neglected and dropped their hold upon Italy, the names of Guelph and Ghibelline lost their original meaning, and the struggle became one of personal or municipal ambition among the Italians themselves, the Ghibellines being for the most part animated by a spirit of aristocracy, the Guelphs professing to be favourers of a popular form of government. [DANTE, in BIOG. DIV.] But even this distinction was often belied by facts, and the leaders of the Guelphs in some towns tyrannised over their countrymen; whilst in some instances, as at Genoa, the Ghibellines formed really the popular party. In the 15th century the names of Guelphs and Ghibellines had become a mere traditional shadow, and at last the popes themselves united with the emperor in extinguishing the independence of the Italian republics, without distinction of parties. (Sismondi, History of the Italian Republics; Raumer, Geschichte der Hohenstaufen.)

The House of Guelph, originating in Italy, settled in Germany in the 11th century, and very shortly acquired large territorial possessions. From this family has proceeded both the lines of Brunswick-Oels and Luneburg; it gave emperors to Germany, dukes to Saxony, Carinthia, and Bavaria; one branch became also Dukes of Este in Italy, and the House of Hanover claims descent from both branches. [BRUNSWICK, HISTORY OF, in GEOG. DIV.; ESTE, in BIOG. Div.] GUERITE is the term applied in fortification to the projecting masonry sentry boxes to be seen in many old fortresses, at the salient angles of works on the top of the revetment. They are provided with loop-holes, so as to enable a few men in them thoroughly to command the foot of the escarp along the whole extent of the face. They have, however, the disadvantage of enabling an enemy the more easily to take up the prolongation of works to place his enfilade batteries, by giving well marked points at the extremities of the faces: they have, therefore, not been much used of late years.

GUILDS. [MUNICIPAL CORPORATIONS.] GUILLOTINE, an instrument for the infliction of capital punishment, proposed to the National Assembly of France by Joseph Ignace Guillotin, a physician, a native of Xaintes, and a member of the Assembly; and which from him took its name. It was adopted by a decree of the 20th of March, 1792, and used for the first time on April 25th.

This instrument, under other names, had existed as a means of public execution long before, in Germany, Bohemia, Italy, Scotland, England, and even in Persia and India.

Crusius in his Annales Suevici,' fol. 1595-6, tom. ii., p. 296, says, Antiquis autem temporibus, in Germania etiam, decollatio non gladio fiebat, sed querno ligno, habente scindens acutissimè ferrum. Addit Widemannus, se vidisse tale instrumentum Halæ in vetere Nosodocheo (Siechaus) priusquam id destrueretur: et hodiernum ibi ædificaretur. Efferebatur inde illa machina, si quis plectendus esset: supplicioque peracto, eodem referebatur."-" Postea usus gladii successit."

In German this instrument was called der Planke der Deil (the plank of wood), and in older language Falbeil (the falling hatchet). In Bohemia it was called Hagec, something akin to the plank. In Italy it was known by the name of Mannaia, and an engraving of it may be seen in Achillis Bocchii Bonon. Symbolicarum Questionum,' lib. v., 8vo., Bonon, 1555, p. 36. There is a very beautiful engraving of the German instrument in a representation of the beheading of the son of Titus Manlius, by Henry Aldegrevers, dated 1553. Evelyn, in his ‹ Memoirs,' vol. i., p. 170, states that he saw a similar instrument at Naples. Pennecuik, in his 'Description of Tweeddale,' pp. 16, 17, speaking of the Regent Morton of Scotland, says: "This mighty earl, for the pleasure of the place and the salubrity of the air, designed here a noble recess and retirement from worldly business, but was prevented by his unfortunate and inexorable death, three years after, anno 1581, being accused, condemned, and executed by the Maiden at the Cross of Edinburgh, as art and part of the murder of King Henry, earl of Darnley, father to King James VI., which fatal instrument, at least the pattern thereof, the cruel Regent had brought from abroad to behead the Laird of Pennecuik of that ilk, who notwithstanding died in his bed, and the unfortunate earl was the first himself that handselled that merciless Maiden, who proved so soon after his own executioner."

In England, what has been since called the Guillotine was used only at Halifax in Yorkshire, and confined even there to the punishment of felonies committed within the forest of Hardwick. Its use at Halifax is traced as far back as the time of Edward III. It was in 1650 that the last malefactors there suffered by it. (Watson's' Hist. of Halifax,' p. 214-239.)

Joseph Ignace Guillotin, who revived the use of this instrument, in France, is supposed, by many, to have perished at a later period of the Revolution, like the Regent Morton, by his own invention. But this is

not correct. He died a natural death, 26th May, 1814, at the age of 76. (Biogr. Universelle.') GUINEA. [MONEY.]

GUITAR, a musical instrument which, in various shapes, may be traced to the remotest periods of antiquity. The word is derived from the Greek kitapa, and comes immediately to us through the French Guitare, though it is nearly the same in the Italian, Spanish, and German languages. The terms Cittern and Gittern, used by the old English poets, are but corruptions of the primitive word.

The English and French guitar of the last century was wide and thin in body, short in the neck, and strung with wire. The modern guitar, which is of the Spanish kind, and differing little from the lute, consists of a body from seventeen to eighteen inches in length, four in depth, and of a neck of about sixteen inches, the latter carrying a finger-board divided by seventeen frets. It has six strings, three being of silk covered with silvered wire, and three of catgut.

The compass of this elegant instrument is from E below the base staff, to A above the treble staff, including all the intermediate tones and semitones. The best and cheapest guitars are made in Germany, and may be purchased in London at a moderate price.

GUM is a proximate principle of vegetables, of more universal occurrence than any other secretion by plants. It is in reality the material generally prepared by them for their own growth and nourishment, and is at first always in a state of solution, in which condition it mostly remains so long as it is contained in the internal tissues of plants; but when it escapes to the exterior of the bark it frequently becomes thickened, and even solid and pulverisable. It is probable that it never escapes to the surface unless some wound of the bark has been made, either by disease, the punctures of insects, the agency of fungi, by the knife, or by the more rapid growth of the inner wood, producing by its distension a rupture of the bark. The escape of the gum terned cerasin from plum and cherry trees may always be regarded as an indication of unhealthiness; the immediate cause of escape is the presence of a small corkscrew-like fungus termed Namaspora crocea.

Gum is known in commerce only in the solid state; the term is often erroneously applied to substances which are a mixture of gum with resins, and which are properly gum-resins, such as ammoniacum, asafoetida, and the like, and even to substances which contain no portion of gum, such as euphorbium.

Arranging the gums according to the facility with which they are acted upon by water, we have at one end of the list gum-acacia, or gum-arabic as it is most usually called, and at the other end gumtragacanth. Gum-arabic forms a perfect solution with even cold water, and to this variety of gum the term arabin is given; gum-tragacanth on the other hand, though swelling up immensely when digested in water, and at first sight appearing to form a solution, does not really dissolve, but forms a thick mucilage, and to this modification of gum the term bassorin is applied. The derivation of the name arabin is obvious, that of bassorin is obtained from bassora gum, a variety of tragacanth that comes from Bassora, and which contains scarcely a trace of arabin. Other members of the series of true gums are mixtures in variable proportions of these two gum modifications.

Arabin (CH,,O11) is colourless, tasteless, and inodorous. Specific gravity, from 13 to 15. It is uncrystallisable. Its solution slightly reddens litmus-paper, and rotates to the left a polarised ray. Dilute sulphuric acid converts it first into dextrin and then into grape-sugar; strong sulphuric acid carbonises it: nitric acid converts it into mucic and oxalic acids. It forms soluble compounds with the alkalies and alkaline earths. It is precipitated from solution by persalts of iron, proto-salts of mercury, and subsalts of lead. The reaction with persalt of iron is characteristic of arabin: if the solutions are strong, a brown gelatinous precipitate is formed, soluble with difficulty in boiling water; if the solutions are weak, a yellowish precipitate is produced only after the lapse of some time; thus one part of gumarabic in 100 parts of water gives a precipitate with persulphate of iron after the mixture has stood for twenty-four hours.

Bassorin is soluble in dilute acids or alkalies, and by very long boiling even in water, but in each case it is probably converted into arabin. Like arabin it is insoluble in alcohol or ether, and is oxidised by nitric acid to mucic and oxalic acids. The presence of bassorin gives the peculiar mucilaginous or viscous consistence to the decoctions of linseed, quince-seed, marsh-mallow root, &c.

Most of the commercial gums are obtained by incisions made in the bark of several species of acacia growing in Arabia, India, Upper Egypt, Senegal, &c. The specimens differ considerably in colour, even when obtained from the same species. Genuine gum-arabic occurs in pieces from the size of a pea to that of a walnut, or larger, which are irregular in shape, or roundish or angular; either white, yellowish, or dark wine yellow; scarcely any odour; taste mawkish, glutinous. Sp. gr. 1316 to 1:482. It breaks easily into small irregular pieces; fracture uneven, vitreous; dissolves almost completely in water; 100 parts of water at 212° of Fahr. take up 19 parts of gum. The solution is almost transparent when made with cold water. Gum, when in powder, is often adulterated with starch, the presence of which is detected by tincture of iodine; or when cold water is used for the solution of the gum, the starch will remain undissolved. The inucilage made with cold water is not only purer, but keeps better, and for all

purposes for which it can be used is preferable to that made with warm water, which is the common method.

This

Gum is not very easily digested when taken alone, and will often pass through the stomach nearly unchanged, if not associated with some bitter or astringent principle. Hence the advantage of some bitter extractive or astringent principle, either in the grasses themselves or in other plants, such as tormentil or lesser centaury, interspersed in the pasture lands of cattle. (See Davy,Agricultural Chemistry;' or Sinclair, 'Hortus Gramineus Woburnensis.') property, however, renders it demulcent in affections both of the throat and also of the intestines, by sheathing the membrane from air or the irritation of acrid secretions. Hence allowing a portion to dissolve slowly is often useful in common colds. Mucilage is also used to suspend many insoluble matters in water. Its agglutinating properties render it valuable in many of the arts. GUM-RESINS are secretions of plants which are produced in the greatest quantity, and most perfectly elaborated, in warm countries. They are obtained chiefly from trees and shrubs of particular tribes of plants, rarely from herbaceous plants, except the large herbaceous Umbellifera, which yield the foetid gum-resins. They either exude spontaneously, or are procured by incisions of the stem and branches. When they first escape to the surface they are fluid, and of a light colour, but gradually harden, and become of a deeper hue, either by the evaporation of some of their volatile oil, or by the absorption of oxygen from the air, and the conversion of the oil into a resin. Some remain in a semi-liquid, viscid state, such as sagapenum and galbanum, which are only pulverisable in winter. Most gum-resins possess a strong odour, which in many instances is disagreeable, such as that of asafoetida, with a warm acrid taste, and by application to the skin for any considerable time they cause redness and inflammation. Owing to their composition being a mixture of gum and resin, they are not completely soluble either in water or absolute alcohol, but are perfectly dissolved in proof-spirit, which is much employed to prepare tinctures of this class of substances. The gum being soluble in water is capable for a time of holding the resinous portion suspended in water, thereby forming an emulsion,-a state which permits of their administration, if used soon after being prepared; for by rest they separate. Many of them are soluble to a certain extent in acetic acid, especially when assisted by heat. The strong mineral acids char them and produce chemical changes. Many gum-resins are popularly termed balsams, a designation to which they have no title, as they do not contain benzoic acid. Gum-resins are with difficulty soluble in the animal juices, yet, as they must be assimilated before they produce their characteristic effects, they require to be used for some time before the secretions of the body acquire their peculiar odour. They influence the secretory and excretory processes, which they rouse to continued action. They also act upon the skin as sudorifics, and more permanently than the volatile oils. They manifest their beneficial effects chiefly when the skin is cool, pale, and in a state of atony; and they can even check profuse perspiration, when this is caused by the lax state of the cutaneous tissues. They are likewise possessed of considerable antispasmodic powers, and hence are much used in nervous complaints. They greatly promote digestion when the stomach is feeble, owing to a defective supply of nervous energy. Their utility in the treatment of hysterical and other paroxysms is very much increased by administering them in a state which admits of ready solution in the gastric fluids; hence the acetous preparations of them are much more potent than any other form. They may be administered either by the mouth, or, in case of spasm closing the teeth, or the patient being refractory, in the form of clyster, the dose being doubled in the latter instance. Gum-resins are likewise applied externally, owing to their rubefacient powers, in the form of liniments or plasters, in spasmodic and rheumatic affections, and also to assist in dispersing indolent tumours. Gum-resins should be kept in cool well-closed places, to prevent the evaporation of their volatile principles.

GUMS AND GUM-TRADE. Professor Solly, in a paper on the subject of Gums, read before the Society of Arts, recommended to drug-brokers the adoption of a more exact classification than at present prevails, between gums, resins, and gum-resins. Dealers and brokers know very well what they mean; but they are not so precise as chemists in the nomenclature adopted. The distinctions recommended are as follow. Gums to comprise those natural vegetable exudations which soften or dissolve in water, and yield a more or less perfect mucilage, but which are wholly insoluble in spirit; resins to comprise those fusible and combustible vegetable substances which are quite insoluble in water, but which soften and dissolve in spirit, ether, or essential oil; and gum-resins to comprise those natural products which are intermediate in properties, and partake of the nature both of gums and resins, being partially and imperfectly soluble both in water and in spirit.

which was obtained from the mimosa tree, and which was sent to England for the use of calico printers, calenderers, envelope makers, &c.; the trade afterwards fell off, through the invention or discovery of British yum, presently to be described. The east and west shores of the Red Sea are the chief sources for gum arabic (which scarcely differs from gum senegal); from two to three hundred tons pass annually through the Custom House of Aden alone. Large quantities are collected by persons in the employ of the Egyptian government, and brought in caravans to Cairo to be warehoused; in recent years, the quantity has averaged about 20,000 packages of 78 lbs. each. The produce of Morocco is packed in very large leather sacks, and conveyed on the backs of camels and bullocks to the ports, where it is sold to English and French merchants; during the whole time, from the collecting to the sale, including the land journey, the natives live almost wholly on the gum, a few ounces being sufficient to support a man for twenty-four hours. A gum exuding from the Macarang or Indica in Travancore, is occasionally used for taking impressions of leaves, coins, medallions, &c.; when this gum is pure and carefully prepared, the transparent casts are as sharp as those of sulphur, without its brittleness.

The gums proper are most largely used in the stiffening of textile materials; the resins proper are, for the most part, used in the making of varnishes and lacquers, in dyeing, in paper-making, and in making sealing-wax. The gum-resins are mostly used in medicine. Many of these substances are of sufficient importance to occupy separate articles in this division of the Cyclopædia; while the general character of the uses of others can be inferred from the observations just made.

For some delicate processes in the arts, gum arabic and gum senegal require to be purified. The following is one mode, patented a few years ago, for effecting this:-A solution of purified sulphurous acid gas being prepared, the gum is dissolved in it, with exclusion of atmospheric air. The earthy and ligneous impurities fall to the bottom; the colouring matters combine with the gas; and the carbonic acid is driven off by the application of heat. Carbonate of baryta, or some other solidifiable base, is added; this combines with the sulphurous acid and forms a neutral salt. The solution is then filtered through a pure gelatinous hydrate of alumina; and is finally dried by heat, either in the open air or in vacuum pans.

Mention was made above of British gum, as a substance which has lessened the use of foreign gums in this country. According to an account given by Mr. Simmonds, a fire on one occasion broke out in a potato-starch manufactory in Dublin. The burning building was deluged with water by the fire-engines, and the starch was washed about in every direction. One of the workmen fell down, and had his clothes soaked with the calcined starch and water. He thought no more of it till the next morning; when, upon dressing himself, he found the sleeves of his coat, the legs of his trousers, and the linings of his pockets, glued up so that he could with difficulty open them. On revisiting the scene of the fire, he discovered that the glutinous properties were possessed by the potato starch; and by a few simple experiments, a discovery was completed which has resulted in large profits. Under the names of British gum, dextrine, and gum-substitute, a new substance appeared in commerce, and became largely employed in the arts. It is nearly equal to gum arabic in adhesiveness, less affected by climate, and less than one-fourth of the price. It forms the main ingredient in the adhesive composition for envelopes and postage-stamps. For the chemical qualities of this substance, see DEXTRINE.

It is not easy to state the quantity and value of gums, resins, and gum-resins imported into this country, and mostly used here in manufactures and in medicine. They are scattered about under so many headings in the official lists, and are entered under such different forms, that they can scarcely be recorded collectively. The Liverpool importation amounted, a few years ago, to 2200 tons annually, including the heavy items of turpentine, resin, caoutchouc, and gutta-percha; but the importation of the last two substances has since prodigiously increased. [CAOUTCHOUC; GUTTA-PERCHA.] Four of the most costly substances in the above list, those which present the most value in the smallest space, were imported into the United Kingdom in the following quantities and values in 1856:—

Many varieties of gum are included in the official entry, Gum arabic.

GUN is a term now generally applied to the larger description of fire-arm, but as a description of the principal varieties of fire-arms, both large and small, with notices respecting the dates of their inven tion, is given under ARMS and ARTILLERY, and under CANNON is an account of the manufacture of great guns, we shall here supply a notice of the manufacture of the smaller kinds of fire-arms, to which the names of musket or musquet, fowling-piece, &c. are applied.