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PUGILISM_PULCI.

pugilists, who never quitted the stage till one or most influential backers. The more distinguished other was defeated, the reward of each man being patrons of the ring gradually seceded; the · Pugidependent upon, and proportioned to, the receipts. listic Club,' which had been established in 1814, Broughton was for 18 years champion of England, and which included all the aristocratic patrons of and with him commences the first scientific era the ring, was broken up. The magistracy of the of pugilism. He propounded some rules for country set their faces against the lawless assemthe regulation of the ring, and these remained in blies of roughs' and pick pockets who latterly authority till 1838, when they were materially formed the greater part of the spectators at prizealtered. Rule 1 is, That a square of a yard be fights. The electric telegraph, and the establishchalked in the middle of a stage, and that in every ment of an efficient rural police, have given the fresh set-to after a fall, the seconds are to bring finishing touches to an already-expiring profession. their men to the side of the square, and to place Matches can now only be got up by stealth, and them opposite each other, and until this is done, it the place of meeting is kept a profound secret to is not lawful for one to strike the other. Rule 2, the last moment, for fear of interruption. A few That if either of the combatants is unable to be years ago, however, the international combat brought up to the square within 30 seconds after a between Tom Sayers the Englishman, and John fall and the close of a round, he' shall be deemed Heenan the American, revived for a moment public a beaten man. No man is permitted to hit his interest in the art; but apart from exceptional adversary when he is down, or to seize him by the matches, the popular feeling is that prize-fighting breeches, or below the waist, and a man on his knees should not be countenanced, and we may look for is to be reckoned down. These rules laid the foun- its gradual extinction. The art of boxing, as an dation of fair play, and robbed boxing of half its active and healthy exercise, is likely to be mainhorrors. To Broughton also is due the introduction tained; and the display of science between two of gloves for sparring-matches,' where lessons accomplished boxers is very işteresting, while it could be taken without injury. The greatest pro- is deprived of all the horrors of the prize-ring; fessor of the art was Jackson, who was champion in the rapidity of the blows, the facility with which 1795. He was not only the most scientific boxer of they are mostly guarded or avoided by moving his day, but he gave his art such a prestige and the head and arms; the trial of skill and manœuvre popularity that half the men of rank and fashion of to gain a trifling advantage in position, all give a the period were proud to call themselves his pupils. wonderful interest to the spectator, who can watch He opened rooms for the practice of boxing in Bond the perfection of the art devoid of the brutalities Street, and for years these were crowd by men of of the ring... The pugilists of the present day are note. His ‘principles of pugilism' were, that con- mostly publicans ; their friends and the patrons tempt of danger and confidence in one's self were of the fancy' meet at their houses for convivial the first and best qualities of a pugilist; that in evenings, sparring-matches, ratting, and the like. hitting, you must judge well your distances, for a It has constantly been urged in defence of pugi. blow delivered at all out of range, was like a spent lism, that were it abolished, the use of the knife shot, and valueless; that men should fight with their would increase, and Englishmen would lose their legs, using all possible agility, as well as with their present manly system of self-defence. This may be hands ; and that all stiffness of style and position true, if the use of the fist in self-defence depended was wrong. Jackson is still regarded as the best on the mercenary exhibition of pugilistic encounters, theorist on the 'noble art, and since his time, it which, however, is mere assumption.- The best has received no essential improvement. Shaw, the authority on the subject of pugilism is Fistiana, Life Guardsman, who immortalised himself at 24th ed. 1863, office of Bell's Life. Waterloo, was a pupil of his, and the prowess which PULCI, LUIGI, an Italian poet of distinguished he so brilliantly displayed on that occasion, was family, was born at Florence, 30 December 1431, owing as much to his scientific training, as to his and devoted his life to study and to literary comgreat strength. At this period, pugilism was position. He was one of the most intimate friends actively supported by many persons of high rank of Lorenzo de' Medici and of Poliziano, from the -the Dukes of York and Clarence, the Earls of latter of whom he derived no little assistance in the Albemarle, Sefton, &c., Lords Byron, Craven, Pom- composition of his poem Il Morgante Maggiore (Morfret. In 1814, when the allied sovereigns were in gante the Giant). This celebrated work, a burlesque England, among other entertainments, a sparring' epic (in 28 cantos), of which Roland is the hero, is display was provided under Jackson's management; a vivacious parody of the romances of Carlovingian and the distinguished foreigners expressed the chivalry, which had become (as P. thought) undegreat gratification they had experienced from the servedly popular in Italy. His mocking imagination exhibition of so much science and fine physical took a pleasure in turning into ridicule the combats development. Besides Jackson, Belcher, Gulley, with giants, the feats of magicians, and all the and Cribb were noted champions at this period. incredible adventures that form the material basis George IV. was a staunch patron of boxing in of the medieval epic; and he manages to do it with his youth, and although he discontinued by his a wonderfully pleasant and original naïveté. But presence to give countenance to the sport, fre- although the poem is essentially heroico-comic, it quent indications were observable of his desire occasionally contains passages of the finest pathos, for its promotion. At the time of the coronation, in which P. fortunately seems to forget his design when the popular feelings were much enlisted on of travestying the inventions of the trouvères, and behalf of Queen Caroline, who was excluded from comes out undisguisedly as a real poet. Moreover, the throne, a body of pugilists were employed to in the midst of the most extravagant buffooneries, preserve order; and so well did these men perform we come upon the truest and most natural pictures their duties, that the king presented each man with of manners—the vanity and inconstancy of women, a gold medal, to commemorate the event, and to the avarice and ambition of men. P. died in 1487. shew his satisfaction. This period may be termed The Morgante Maggiore is one of the most valuable the 'palmy days of the ring;' and from various sources for acquiring a knowledge of the early causes, its decline has since then been uninterrupted. Tuscan dialect, the niceties and idioms of which Among other causes, several cases occurred of prize. have been employed by P. with great skill. The fighters who were tempted to lose fights on which first edition appeared at Florence in 1488, and has large sums had been staked, and to deceive their since been frequently reprinted. Other works of

PULEX-PULLEY.

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P. are a series of sonnets (often grossly indecent), the block of the next pulley, with the exception of La Beca du Dicomano (a parody of a pastoral poem the last cord, which passes round a fixed pulley by Lorenzo de' Medici); Confessione a la San Ver. above, and is attached to the counterpoise P. The gine, a novel; and some letters.-BERNARDO PULCI, tension of a string being the same in all its parts, elder brother of Luigi, wrote an elegy on the death the tension of every part of the string marked (1) of Simonetta, mistress of Julian de' Medici; and a in fig. 3 is that which is poem on the passion of Christ, and also executed produced by the weight of P, the first translation of the Eclogues of Virgil.- consequently, as the last move Loca Pulci, another brother, achieved some literary able pulley is supported on reputation too by his Giostra di Lorenzo de' Medici, both sides by a string hav

poem in honour of the success won by Lorenzo ing a tension P, the tension in a tournament; n Ciriffo Calvaneo, à metrical applied in its support is 2P. romance of chivalry; Driadeo d'Ancore, a pastoral The tension of the string poem; and Epistole Eroide.

marked (2) is therefore 2P, PU'LEX. See FLEA.

and the second movable

pulley is supported by a force PULKO'VA, a village of Russia, in the govern. equal to 4P. It may similarly ment of St Petersburg, about 9 miles south of be shewn that the force the capital, contains a population of 600. It applied by the strings marked stands on a ridge called the Pulkova Hills, (4) in support of the last which command å splendid view of St Peters- pulley (which is attached to burg, and is noted for its magnificent observatory, W), is SP. Hence we see, that built by the Czar Nicholas, and placed under the according to this arrange

Fig. 3. direction of M. Friedrich Struve. For an interest- ment, 1 lb. can support 4 lbs., if two movable pulleys ing description of the observatory, see Professor C. Piazzi Smyth's Three Cities in Russia (2 vols., Ibs., if there are 4 movable pulleys; and if there are

are used ; 8 lbs., if there are 3 movable pulleys ; 16 Lond. 1862).

n movable pulleys, 1 lb. can support 21 lbs. It PU'LLEY, one of the Mechanical Powers (q. v.), must be noticed, hewever, that consists of a wheel, with a groove cut all round its in practice, the weight of the circumference, and movable on an axis ; the wheel, cords, and of the pulleys, and the which is commonly called a sheave, is often placed friction of the cord on the pulleys, inside a hollow oblong mass of wood called a block, must allowed for; and the fact, and to the sides of this block the extremities of thé that in this system all of these

sheaves axle are fixed for sup- resist the action of the power P,
port; the cord which passes over and that to a large extent, has
the circumference of the sheave rendered it of little use in practice.
is called the tackle. Pulleys may |---The second system is much in.
be used either singly or in com- ferior in producing a mechanical
bination ; in the former case, advantage, but it is found to be

they are either fixed or movable. much more convenient in practice, PO

The fixed pulley (fig. 1) gives no and is modified according to the

mechanical advantage; it merely purpose for which it is to be used ; Ow changes the direction in which a two prevalent forms are given in

force would naturally be applied figs. 4 and 5. In this system, ono Fig. 1.

to one more convenient-thus, string passes round all the pulleys,

W can be raised without lifting and as the tension in every part it directly by merely pulling P down. The single of it is that produced by the weight movable pulley, with parallel cords, gives a of P, the whole force applied to Fig. 4 mechapical advantage = 2 (fig. 2), for a little con elevate the lower block with its sideration will shew that as the weight, W, is attached weight, W, is the weight P multiplied

supported by two strings, the by the number of strings attached to the lower
strain on each string is 4 W, and block; in fig. 4, W = 4P, and in fig. 5, W = 6P,
the strain on the one being sup- the pulleys in the upper block
ported by the hook A, the being only of use in changing the
power, P, requires merely to direction of the pulling force. This
support the strain on the other system is the one in common use
string, which passes round C. in architecture, in dockyards, and
The fixed pulley, C, is only of on board ship, and various modi.
service in changing the natu- fications of it-such as White's
rally upward direction of the pulley, Smeaton's pulley, &c., have
power into a downward one. been introduced; but the simpler
If the strings in the single mov- forms shewn above have been
able pulley are not parallel, found to answer best. -The third
there is a diminution of mecha- system (fig. 6) is merely the first

nical advantage—i. e., P must be system inverted, and it is a little more than half of W to produce an exact coun- more powerful, besides having the terpoise ; if the angle made by the strings is 120°, weight of the pulleys to support P must be equal to W; and if the angle be greater the power, instead of acting in than this, there is a mechanical disadvantage, or opposition to it, as in the former P must be greater than W. The following are

case. By this time, it will have examples of different combinations of pulleys, gener been evident to the reader that Fig. 5. ally known as the first, second, and third systems the mechanical advantage is not of pulleys. In the first system, one end of each cord produced by the pulleys, but by the strings, and is fastened to a fixed support above ; each cord that the pulleys are merely useful in keeping the descends, passes round a pulley (to the lowest of strings in a certain position, changing with as little

and which the weight, W, is fastened), and is fastened to friction as possible the direction of the pullo

B

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W

Fig. 2.

PULMONATA-PULSE

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affording a convenient means of attaching the subjects. . The pulpit (in Arabic, mimber) forms weight. Theoretically, the larger the number of

movable pulleys in one combin-
ation, the greater is the mecha-
nical advantage afforded; but
the enormous friction produced,
and the want of perfect flexi-
bility in the ropes, prevent any

great increase in the number of

pulleys.

PULMONATA, an order of

gasteropodous molluscs, having, α

for the purpose of respiration, a
vascular air-sac or lung, which
opens by a hole under the mar.

gin of the mantle, capable of
a
a 앞

being contracted or dilated at
pleasure. Some are terrestrial,

some aquatic. Slugs and snails Pi

are familiar examples of the

former; water-snails, or pond. WIB

snails (Limnæa, Planorbis, &c.),

of the latter. Most of the P. Fig. 6. are protected by a shell; in

some, as slugs, the shell is internal and rudimental.

PULNEYS, a range of hills in the Madura district of the Madras Presidency of India. The average height of this range is about 7500 feet above the level of the sea. It possesses pecu. liar advantages for the establishment of sanitarium. The climate is one of the most equable anywhere to be found, the variation of the thermometer during twelve months in a closed room without a fire being observed to be Pulpit (Fotheringhay, Northamptonshire, 1440 A. D.) no greater than between 58o and 62o. At present,

(From Parker's Glossary.) there are only a few European residences built on these hills.

one of the scanty appliances of Mohammedan

worship PU'LO-PENANG. See PRINCE OF WALES' ISLAND.

PULQUE, a favourite beverage of the Mexicans

and of the inhabitants of Central America, and PULP, a term employed to describe those very some parts of South America ; made from the juice soft and succulent parts of plants, almost exclu- of different species of Agave (q.v.), which is col. sively of fruits, which consist of cellular tissue lected by cutting out the flowering-stem from the with much juice. The pulp of a fruit is sometimes midst of the leaves in the beginning of its growth, found in one part of it, sometimes in another; and scooping a hole for the juice. From this cavity, thus, in the peach, plum, and other drupes, it is large quantities of juice are removed daily for the mesocarp; in the grape and gooseberry, it is months. The juice is an agreeable drink when developed from the placentas, and the seeds are fresh, but is more generally used after fermentation, embedded in it.

when it has a very pleasant taste, but a putrid

smell, disgusting to those unaccustomed to it. PU'LPIT (Lat. pulpitum), an elevated tribune or Pulque is retailed in Mexico in open sheds called desk, from which sermons, lectures, and other solemn Pulquerias, which also serve for dancing-rooms. religious addresses are delivered. In great churches, When mixed with water and sugar, and allowed to the pulpit is commonly placed against the wall, or ferment for a few hours, it forms a beverage called in juxtaposition with a pillar or buttress. Originally Tepache. A kind of spirit is also prepared from it. it would appear to have been used chiefly for the singing, chanting, or recitation which form part of

PULSE (Lat. puls), a name for the edible seeds the public service, and was a kind of stage suffi- of leguminous plants, as corn is the name for the ciently large to accommodate two or even more edible seeds of grasses. Peas and beans are the most chanters. For the convenience of the hearers, this common and important of all kinds of pulse; next to

them stage began to be used by the bishop, priest, or

may be ranked kidney-beans, lentils, chick. deacon, for the delivery of the homily; and thus by peas, pigeon-peas, &c. Legumine (q. v.), a very degrees a tribune expressly suited to the latter use nitrogenous principle, abounds in all kinds of pulse. alone came to be introduced. In some of the older Legumine forms a thick coagulum with salts of churches, the ambo or pulpitum is still used for the lime, wherefore all kinds of pulse remain hard if chanting of the Gospel and Epistles. In Catholic boiled in spring-water containing lime. The best churches, the pulpit is generally distinguished by kinds of pulse are very nutritious, but not easy of some religious emblems, especially by the crucifix; digestion, and very apt to produce flatulence. and the pulpits of the Low Countries and of PULSE (Lat. pulsus, a pushing or beating). The Germany are often masterpieces of wood-carving, phenomenon known as the arterial pulse or arterial the preaching place in some of them forming part pulsation is due to the distention of the arteries conof a great artistic group, as of the Conversion of sequent upon the intermittent injection of blood into St Paul, the Vocation of Peter and Andrew, the their trunks, and the subsequent contraction which Temptation of Adam and Eve, and other similar results from the elasticity of their walls. It is

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PULTOWA-PULU.

perceptible to the touch in all excepting very minute importance of ascertaining the various meanings of arteries, and in exposed positions, is visible to the eye. this symptom. This pulsation,' says Dr Carpenter, involves an The pulse is said to be full when the volume of augmentation of the capacity of that portion of the the pulsation is greater than usual, and it is called artery in which it is observed; and it would seem small or contracted under the opposite condition. to the touch as if this were chiefly effected by an A full pulse may depend upon general plethora, on increase of diameter. It seems fully proved, how- a prolonged and forcible contraction of the left venever, that the increased capacity is chiefly given by tricle of the heart, and possibly, to a certain extent, the elongation of the artery, which is lifted from on relaxation of the arterial coats ; while a smali its bed at each pulsation, and when previously pulse results from general deficiency of blood, straight, becomes curved; the impression made upon from feeble action of the heart, from congestion of the finger by such displacement not being distin. the venous system, or from exposure to the action guishable from that which would result from the of cold. When very small, it is termed thread-like. dilatation of the tube in diameter. A very obvious The tension of the pulse is the property by which example of this upheaval is seen in the prominent it resists compression, and may be regarded as temporal artery of an old person.'—Principles of synonymous with hardness. A hard pulse can Human Physiology, 4th ed., p. 492. The number of scarcely, be stopped by any degree of pressure of pulsations is usually counted at the radial artery the finger. It occurs in many forms of inflammaat the wrist, the advantages of that position being tion, and its presence is commonly regarded as one that the artery is very superficial at that spot, and of the best; indications of the necessity of venethat it is easily compressed against the bone. In section. A soft or compressible pulse is indicative some cases, it is preferable to count the number of of general weakness. contractions of the heart itself.

The strength of the pulse depends chiefly on the The qualities which are chiefly attended to in the force with which the blood is driven from the heart, pulse are its frequency, its regularity, its fulness, its but partly also upon the tonicity of the artery itself tension, and its force.

and the volume of the blood. A strong pulse is The frequency of the pulse varies greatly with the correctly regarded as a sign of a vigorous state of age. In the fætus in utero, the pulsations vary the system; it may, however, arise from hyperfrom 140 to 150 in the minute; in the newly-born trophy of the left ventricle of the heart, and remain infant, from 130 to 140; in the 2d year, from 100 as a persistent symptom even when the general to 115; from the 7th to the 14th year, from 80 to powers are failing. As strength of the pulse usually 90; from the 14th to the 21st year, from 75 to 85; indicates vigour, so weakness of the pulse indicates and from the 21st to the 60th year, 70 to 75. After debility. There may, however, be cases in which this period, the pulse is generally supposed to fall weakness of the pulse may occur in association with in frequency, but the most opposite assertions have undiminished energy of the system at large. For been made on this subject. There are many excep- example, active congestion of the lungs may so far tions to the preceding statement; young persons impede the passage of the blood through these being often met with having a pulse below 60, and organs that it cannot reach the heart in due quancases not unfrequently occurring in which the pulse tity; the necessary result is a weak and feeble habitually reached 100, or did not exceed 40 in the pulse, which will rapidly increase in strength if minute, without apparent disease. The numbers the congestion is relieved by free blood-lettings. which have been given are taken from an equal Various expressive adjectives have been attached number of males and females, and the pulsations to special conditions of the pulse, into the consitaken in the sitting position. The influence of sex deration of which our space will not permit us to is very considerable, especially in adult age, the enter. Thus, we read of the jerking pulse, the pulse of the adult female exceeding in frequency hobbling pulse, the corded pulse, the wiry pulse, that of the male of the same age by from 10 to 14 the thrilling pulse, the rebounding pulse, &c. beats in the minute. The effect of muscular exertion

PULTOWA. See POLTAVA. in raising the pulse is well known; and it has been found by Dr Guy that posture materially influences

PU'LTUSK, a town of Poland, in the govern. the number of pulsations. Thus, in healthy males ment of Plock, is situated in a thickly-wooded of the mean age of 27 years, the average frequency district on the Narew, 35 miles north-north-east of of the pulse was, when standing, 81, when sitting, Warsaw. It contains numerous churches and a 71, and when lying, 66, per minute ; while in very large bishop's palace. Pop. 4772. Here, on healthy females of the same age the

averages were

December 26, 1806, was fought one of the battles standing, 91; sitting, 84; and lying, 79. During of the campaign of Eylau, between the Russians sleep, the pulse is usually considerably slower than

and the French. The field was most obstinately in the waking state. In disease (acute hydro- contested, but the victory, which, however, was cephalus, for example), the pulse may reach 150 or claimed by both armies, inclined in favour of the even 200 beats ; or, on the other hand (as in

French. apoplexy and in certain organic affections of the PUʻLU, a beautiful substance, resembling fine heart), it may be as slow as between 30 and 20. silk, of a rich brown colour and satin lustre, used

Irregularity of the pulse is another condition largely as a styptic by the medical practitioners of requiring notice. There are two varieties of irre. Holland, and lately introduced into this country gular pulse : in one, the motions of the artery are for the same purpose. It consists of the fine hairs unequal in number and force, a few beats being from the stipes of one or more species of tree-fern, from time to time more rapid and feeble than the referrible, without doubt, to the genus Cibotium. rest; in the other variety, a pulsation is from time It was first imported into this country in 1844 to time entirely left out, constituting intermission from Owhyhee under the name of Pulu, or vegeof the pulse. These varieties often concur in the table silk, and was proposed as a substitute for same person, but they may exist independently of silk in the manufacture of hats, but could not be each other. Irregularity of the pulse is natural applied. In 1856, it was again imported from to some persons; in others, it is the mere result Singapore under the Malay names of Penghaof debility; but it may be caused by the most war Djambi and Pakoe Kidang, and was said to serious disorders, as by disease of the brain, or by have been used in Dutch pharmacy for a long period organic disease of the heart; and hence the practical l as a styptic. Several importations have since taken

PUMA-PUMPS.

place, and it has been successfully used. It acts action. Of these, as the most important, we shall mechanically by its great absorbent powers. describe in detail the following: 1. The Lift or

PU’MA, or COUGAR (Felis concolor, Leopardus Suction Pump; 2. The Lift and Force Pump; 3. concolor, or Puma concolor), one of the largest of The Chain-pump; 4. The Centrifugal Pump; 5. the American Felida, rivalled only by the jaguar.

The Jet-pump: It is sometimes called the American Lion, although

1. The Lift or Suction Pump.—The diagrams it is more allied to the leopard, notwithstanding figs. 1 and 2 represent the ordinary suction pump. its want of spots and stripes. It is from 4 to 48 A is a cylinder, which is called the barrel ; with it is feet in length from the nose to the root of the tail, connected at the bottom a pipe, B, which communi. and the tail about 2 feet or 24. The fur is thick cates with the water to be raised; and at its top is and close, reddish-brown above, lighter on the sides, another pipe, C, which receives the water raised. and reddish-white on the belly; the muzzle, chin, In the barrel are placed two valves, D and E. D is throat, and insides of the legs grayish-white, the fixed in position at the bottom of the barrel; E is breast almost

pure white. Young pumas have darkbrown spots in three rows on the back, and scattered markings elsewhere, exhibiting the relation to the leopards. The long tail of the P. is covered with thick fur, and is generally coiled up, as if it were prehensile, which it does not seem to be, although the P. climbs trees very well, and often descends on its prey from among their branches. The P. was formerly found in all except the coldest parts of America, but is now rare in most parts of North America, having been expelled by man. It rarely attacks man, but is very ready to prey on domestic animals, and seems to have a thirst for blood beyond that of other Felidæ, one P. having

F been known to kill 50 sheep in a night, drinking a little of the blood of each; a very sufficient reason for the anxiety which all American farmers shew for its destruction. Yet it is easily tamed, and when tamed, a very gentle creature, urring like a cat, and shewing equal love of attentions. The geographical range of the P. extends far south

B wards in Patagonia, and northwards even to the state of New York, although it is now very rare in all long-settled parts of North America. It is the Painter (Panther) of North American farmers. It sometimes issues from the forests, and roams over prairies and pampas, and is not unfrequently

H caught by the lasso of South American hunters. A BLACK P. (Felis nigra of some naturalists), a doubtful species, and probably only a variety of the common P., is found in some parts of South America. PU'MICE, a mineral found in volcanic countries,

Fig. 1. generally with obsidian and porphyries. In cheinical composition, it agrees with obsidian, of which attached to, and forms part of the piston F, which it may be regarded as a peculiar form, rapidly

moves up and down the barrel when motive-power cooled from a melted and boiling state. It is of a is applied to the rod G. The piston, or bucket, white or gray colour, more rarely yellow, brown, consists of a cylindrical piece of wood or metal, or black ; and so vesicular, that in mass, it is which fits exactly the barrel in which it moves, lighter than water, and swims in it. The vesicles, or cells, are often of a much elongated shape. P. ference and the sides of the cylinder. This tight

so that no water or air can pass between its circumoften exhibits more or less of a filainentous structure; and it is said to be most filamentous them with a leather ring; and in those of metal, by

fitting is attained in wooden pistons by surrounding when silica is most abundant in its composition. hemp or other packing, which is wrapped round a It is very hard and very brittle. It is much used for polishing wood, ivory, metals, glass, slates, interior of the piston is closed at the top by the

groove made in their outer surface. The hollow marble, lithographic stones, &c., and in the pre: valve E, which is a kind of door opening on a hinge, paration of vellum, parchment, and some kinds of at one side of it, in an upward direction, on the leather. Among other purposes to which it is applied is the rubbing away of corns and callosities. application of pressure, and shutting on to its seat Great quantities are exported from the Lipari Isles on the piston when the pressure is removed. When to Britain and all parts of Europe. The Lipari opened, water, or air can pass through it to the

upper side of the piston; but when shut, none can Isles are in great part composed of P., which there, pass from one side of the piston to the other. The as in some other places, occurs as a rock. P. is the other valve, D, is similar to it in all respects, except chief product of some volcanic eruptions ; but in that, as before stated, it is fixed in the bottom of some eruptions, none is produced. It is found also the barrel ; it also can only open upwards. in regions where there are now no active volcanoes,

To describe the action of the pump, we shall as at Andernach on the Rhine.

suppose the piston to be at the bottom of the barrel, PUMPKIN. See GOURD.

and the pump to contain nothing but air. On PUMPS are machines for raising water and moving the piston up the barrel—the valve in it other tluids to a higher level. They are divided being shut, and kept so by the atmospheric pressure into several classes according to their mode of | above it- no air can pass from above it into the

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