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their knowledge was very imperfect. An early toes. One plant will produce three or four treatise on refraction, in nine books, was written large roots. The skin of these roots is pretty by J. Baptista Porta; but Kepler was the first thick, rough, unequal, covered with many stringy who elucidated this subject in any great degree, fibres or filaments, and of a violet color, aphaving demonstrated the properties of spherical proaching to black. The inside is white and of lenses very accurately, in a treatise published the consistence of red beet. It resembles the anno 1611. After Kepler, Galileo introduced potatoe in its mealiness, but is of a closer texture. the doctrine into his Leiters; as also an Exami- When raw, the yams are viscous and clammy; nation of the Preface of Johannes Pena upon when roasted, or boiled, they afford very nouEuclid's Optics, concerning the use of Optics in rishing food; and are often preferred to bread astronomy. Des Cartes also wrote a treatise on by the inhabitants of the West Indies, on account Dioptrics, commonly annexed to his Principles of their lightness and facility of digestion. When of Philosophy, one of his best works : in which first dug out of the ground, the roots are placed the true doctrine of vision is more distinctly ex- in the sun to dry; after which, they are either plained than by any former writer, and in which put in sand, dry garrets, or casks; where, if kept is contained the law of refraction, discovered by from moisture, they may be preserved whole Snell, though the name of the inventor is sup- years without being spoiled or diminished in pressed. Here are also laid down the properties their goodness. The root commonly weighs two of elliptical and hyperbolical lenses, with the or three pounds; though some yams have been practice of grinding glasses. Dr. Barrow has found upwards of twenty pounds weight. treated on Dioptrics in a brief but very elegant DIOSCORIDES, a physician of Anazarba, in manner, in his Optical Lectures, read at Cam- Cilicia, who lived in the reign of Nero. He was bridge. There are also Huygens's Dioptrics, an originally a soldier; but afterwards he applied excellent work of its kind. Molyneur's Diop- himself to study, and wrote a book upon Meditrics, a heavy and dull work. Hartsoeker's cinal Herbs. See BOTANY. Essai de Dioptrique, Cherubin's Dioptrique DIOSCURI, in antiquity, a name given to Oculaire, et De Vision Parfaite, David Gregory's Castor and Pollux, as kovpor, Elements of Dioptrics, Traber's Nervus Opticus, the children, Alos, of Jupiter. and Zahn's Oculus Artificialis Teledioptricus. They are often borne on the Dr. Smith's Optics is a complete work of its medals of the Roman consuls, kind. Wolfius's Dioptrics are contained in his and generally appear, as in Elementa Matheseos Universalis. Harris's Op- the annexed diagram, on tics, Bouguer's Optics, and the second volume horse-back, armed with spears, of Haüy's Natural Philosophy, may also be ad- and with helmets surmounted vantageously consulted. The Treatise on Optics, with stars. and the Optical Lectures of Newton, contain an DIOSCURIA, Jiookovpla, in antiquity, a fesaccount of inestimable experiments and reason- tival in honor of Castor and Pollux. It was ings in this science: and Mr. Dollond's disco- observed by the Cyreneans, but more especially very of achromatic glasses, by which colors are by the people of Sparta, the birth-place of these obviated in refracting telescopes, has been of heroes. The solemnity was full of mirth, being great importance to this branch of optics. See at a time wherein they shared plentifully of the Optics.

gifts of Bacchus, and diverted themselves with DIORTHOʻSIS, n.s. Gr. diopowois, of diopoour sports, of which wrestling matches made a part. to make straight. A chirurgical operation, by DIOSMA, African spiræa, a genus of the which crooked or distorted members are restored monogynia order and pentandria class of plants : to their primitive and regular shape.

COR. pentapetalous; nectarium crown-shaped, DIOSCOREA, in botany, a genus of the above the germen : Caps. five, coalited : SEEDS hexandria order and diæcia class of plants; hooded. There are nine species, of which the Datural order eleventh, sarmentaceæ. Male cal. most remarkable are, sexpartite : CoR. none. Female Cal. sexpartite : 1. D. hirsuta, with narrow hairy leaves; a STYL. three: CAPs. trilocular and compressed ; very handsome shrub, growing to the height of and there are two membranaceous seeds. There five or six feet. The stalks are of a fine coral are fifteen species, of which the only remarkable color, the leaves come out alternately on every one is the D. bulbifera, or the yam. It is side of the branches; the flowers are produced triangular winged stalks, which trail upon the in small clusters at the end of the shoots, and ground, extend far, and frequently put out routs are of a white color. They are succeeded by from their joints as they lie upon the ground, starry seed-vessels, having five corners ; in each by which the plants are multiplied. The roots of which corners is a cell, containing one smooth, are eaten by the inhabitants of both the Indies; shining, oblong, black seed; these seed-vessels and, in the West India islands, make the abound with a resin which emits a grateful greatest part of the negroes' food. The plant is scent, as does also the whole plant. supposed to have been brought from the East to 2. D. oppositifolia, with leaves in the form of the West Indies; for it has never been observed a cross. It rises to the height of three or four to grow wild in any part of America; but, in feet; the branches are slender, and produced, the island of Ceylon, and on the coast of Ma- from the stem very irregularly; the flowers are labar, it grows in the woods, and there are in produced at the ends of the branches, between those places many different species. It is pro- ihe leaves; the plants continue long in flower, pagated by cutting the root pieces, observing

make a

fine appearance, intermixed with to preserve an eye in each, as in planting pota- other exotics in the open air.

DIOS NOMBRE DE, a town of Mexico, on In Richard's time, I doubt, he was a little dipt in the road from the mines of Sombrerete to Du- the rebellion of the commons. Dryden. Fables. rango. It contains 6800 inhabitants.

Be careful still of the main chance, my son ; DIOSZEGH, a large market town of Hun

Put out the principal in trusty hands, gary, in the county of Bihar, thirty miles S.S. W Live on the use, and never dip thy lands of Zathmar.

Id. Persius. DIOSPOLITES Nomos, a division of The

When men are once dipt, what with the encouragebais, or the Higher Egypt, to distinguish it from

ments of sense, custom, facility, and shame of deanother of the Lower Egypt, or the Delta; south parting from what they have given themselves up tn, of the Nomos Thinites, on the west side of the they go on till they are stified. L'Estranje. Nile. DIOSPYROS, the Indian date-plum, a genus

So fishes, rising from the main,

Can soar with moistened wings on high ; of the diæcia order and polygamia class of

The moisture dried, they sink again, plants; natural order eighteenth, dicornes . Cal.

And dip their wings again to fly. Swift. hermaphrodite and quadrifid: cor. urceolated

The kindred arts shall in their praise conspire, and quadrifid; stam. eight: STYL. quadrifid: One dip the pencil, and one string the lyre.' Pope. BERRY octospermous. There are two species, viz.

1. D. lotus, which is supposed to be a native The vulture dipping in Prometheus' side, of Africa, from whence it was transplanted into

His bloody beak with his torn liver dyed.

Granville. several parts of Italy, and also into the south of France. The fruit of this tree is supposed to be

The persons to be baptised may be dipped in water; the lotus with which Ulysses and his compa: thrice, according to the canon.

and such an immersion or dipping ought to be made

Ayliffe's Parergon. nions were said to have been enchanted, and which made those who eat of it forget their country Unclasped their sandals, and their zones untied,

Crowd round her baths, and, bending o'er the side, and relations. In the warm parts of Europe Dip with gay fear the shuddering foot undressed, this tree grows to the height of thirty feet.

And quick retract it to the fringed vest. Darwin. 2. D. Virginiana, pinshamin, persimon, or pichumon pluin, is a native of America, but

In nautical observations it is necessary to know the particularly of Virginia and Carolina. The depression or dip of the sea, to correct the apparent

Dr. A. Res. seeds

of this sort have been frequently imported altitude of an observed object. into Britain, and the trees are common in many

DIPETALOUS. adj. Δις and πεταλον. . nurseries about London. It rises to twelve or Having two flower leaves. fourteen feet; bul generally divides into many DIPIIT'HONG, n. s. Fr. diphthongue ; Ital. irregular trunks near the ground, so that it is and Span. diftongo; Lat. diphthongus; Gr. very rare to see a handsome trec of this sort. deqOoyyos, from ois, double, and pooyyn, a sound. Though plenty of fruit is produced on these trees, it never comes to perfection in this

We see how many disputes the simple and ambigucountry. In America the inhabitants preserve and now it has begut the mistake concerning diph

ous nature of vowels created among grammarians, the fruit till it is rotten, as is practised with thongs; all that are properly so are syllables, and not medlars in England, when they are esteemed diphthongs, as is intended to be signified by that very pleasant. Both species are propagated by word.

Holder's Elements of Speech. seeds, and the plants require to be treated tenderly while young; but when theyare grown up, of their being two syllables, and the objection is vone.

Make a diphthong of th.c second eta and iota, instead they resist the greatest cold of this country.

Pope. DIP, v..., v. n. & n.s. ) Goth.doppen ; Sax. Dip'cuck, n. S.

Diphthongs are distinguished by some au| dopen; Dutch doopene; Teut. tauffen; Hindoo duba, from Gr. thors into those that regard the eye, and those 'YUTTW. To imnierse; put into a liquid; wet; tion was long ago made by that eminent gram

that regard the ear; but a more accurate distincand, figuratively, to be deeply involved in affair, and to engage as a pledge. As a neuter marian, Mr. Ruddiman, "into proper and imverb to sink; enter; immerge: as a substantive proper. A third class, however, seems to exist it is applied by miners to the direction of coal

in the English language, which may be styled shafts and minerals (see p. 268), and by scientific wherein only one of the vowels is sounded, the

neutral. 1. Improper diphthongs, are those men to the depression of a part of the horizon, the needle of the compass, &c.

other being sunk; as de and æ in the Latin,

Dip-chick the example explains.

and ea, ei, eo, ie, ou, oe, ue, and ui, in the

English language. The Latins pronounced the Who, dipping all his faults in their affection,

two vowels in their diphthongs ae or æ, oe or æ, Work like the spring that turneth wood to stone,

much as we do; only that the one was heard Convert his gyves to graces.

Shakspeare.

much weaker than the other, though the division Dipchick is so named of his diving and littleness. was made with all the delicacy imaginable. 2.

Carcu.

Neutral diphthongs are those combinations of And though not mortal, yet a cold shuddering vowels, wherein either a new sound, different

from that of both, takes place, or neither of them Dips me all o'er, as when the wrath of Jove is sounded; for instance, the sound of eo in Speaks thunder.

Milton.

people, is quite different from that of eo in jeo To be baptized, is to be dipped in water; mctapho- pardy, or of either of the vowels separate; and ricall to be plunged in afiictions.

diphthong, or diphthong of the Poole's Continuators, eye, as others style it, ue, in rogue, vogue, &c.

dew

the appare

is sunk altogether. Among the former of these Ægyptiacum, and which were pasted one over classes may be ranked ee and oo, wherein the the other with the slime of the Nile, and were original sound of the vowels, instead of being pressed and polished with a pumice stone. lengthened, like that of aa, is changed to that This paper was very scarce; and it was of vaof i and u.

The diphthong oe, in shoe, also rious qualities, forms, and prices, wbich they belongs to this class, with many others. 3. distinguished by the names of charta hieratica, Proper diphthongs, are such as include the luria, augusta, amphitheatrica, saitica, tanirica, sound of both the component vowels, though still emporetica, &c. They cut it into square leaves, in one syllable; such as au, eu, and ei, in which they pasted one to the other, in order to Latin; and ai, au, ay, eu, ey, oi, and ou, in make rolls of them; from whence an entire English.

book was called volumen, from volvendo; and DIPLOE, n. s. The inner plate or lamina the leaves of which it consisted, paginæ. Someof the skull.

times, also, they pasted the leaves all together by Diploe, in anatomy, the soft meditullium, one of their extremities, as is now practised in or medullary substance, which lies between the binding; by this method they formed the back two laminæ of the bones of the cranium. of a book, and these the learned called codices. DIPLOMA, n. s.

Fr. diplome ; from Gr. They rolled the volume round a stick, which diriwwa. See the article following.

they named umbilicus; and the two ends which In 1728 he received from Edinburgh and Aberdeen written on parchment, in purple characters, was

came out beyond the paper, cornua. The title, an unsolicited diploma. Academical honours would have more value, if they were always bestowed with joined to the last sheet, and served it as a cover. equal judgment. Johnson's Life of Watts.

They made use of all sorts of strings or ribands,

and even sometimes of locks, to close the book ; Diploma is peculiarly used for an instrument sometimes, also, it was put into a case It is or licence, given by colleges, societies, &c., to easy for those, who apply themselves to this clergymen or physicians, to exercise their re- study, to distinguish the parchment of the anspective professions, after passing examination, cients from that of the moderns, as well as their and being admitted to a degree.

ink and various exterior characters; but that DIPLOMATICS, the science of diplomas, which best distinguishes the original from the or of ancient literary monuments, public docu- counterfeit, is the writing or character itself; ments, &c. It does not, however, nor can it, which is, in most cases, very distinctly different absolutely extend its researches to antiquity; but from one century to another. There are two is chiefly confined to the middle age, and the works which furnish the best lights on this first centuries of modern times. For though matter, and which may serve as sure guides in the ancients were accustomed to reduce their judging of what are called ancient diplomas. contracts and treaties into writing, yet they The one is the celebrated Treatise on the Diplograved them on tables, or covered them over matic, by F. Mabillon; and the other, the first with wax, or brass, copper, stone, or wood, &c. volume of the Chronicon Gotvicense. We shall And all that in the first ages were not traced on here only add, that all the diplomas are written brass or marble, have perished by the length of in Latin, and consequently the letters and chatime, and the destructive events, that have taken ractèrs have a resemblance to each other; but place. The word diploma signifies, properly, there are certain strokes of the pen which disa letter, or epistle, folded in the middle, and tinguish not only the ages, but also the different not open. But, in more modern times, the nations; as the writings of the Lombards, French, title has been given to all ancient epistles, let- Saxons, &c. The letters in the diplomas are ters, literary monuments, and public documents, usually longer, and not so strong as those of and to all those pieces of writing which the an- MSS. There has been also introduced a kind cients called syngrapha, chirographa, codicilli, of court hand, of a very disproportionate length, &c. In the middle age, and in the diplomas and the letters of which are called, Exiles litthemselves, these writings are called literæ, teræ, crispæ ac protractiores. The first line of præcepta, placita, chartæ indiculæ, sigilla, and the diploma, the signature of the sovereign, that bullæ ; as also panchartæ, pantochartæ, tracto- of the chancellor, notary, &c., are usually written riæ, descriptiones, &c. The originals of these in this character. The signature of the diploma pieces are named exemplaria, or autographa, consists either of the sign of the cross, or of a chartæ authentica, originalia, &c.; and the co- monogram, or cipher, composed of the letters of pies, apographa, copiæ, particulæ, &c. The the names of those who subscribed it. The collections that have been made of them, are initial letters of the name, and sometimes also called chartariæ and chartı'æ. The place where the titles, were placed about this cross. By these papers and documents were kept, the an- degrees, the custom changed, and they invented cients damed scrinia, tabularium, or ærarium, other marks. They sometimes added also the words that were derived from the tables of brass, date and epoch of the signature, the feasts of the and, according to the Greek idiom, archeium, or church, the days of the kalendar, &c. The sucarchivum. To understand the nature of these cessive corruption of the Latin language, the ancient papers, diplomas, and MSS., and to style, and orthography of each age, as well as distinguish the authentic from the counterfeit, their different titles and forms; the abbreviations, it is necessary to observe, that the paper of the accentuations, and punctuation, and the various ancients came from Egypt, and was formed of methods of writing the diphthongs; all these thin leaves, or membranes, taken from the matters united, form so many characters and branches of a tree named Papyrus, or Biblum marks, by which the authenticity of a diploma

stone.

is to be known. The seal annexed to a diploma and yet, which is rare, they may meet all together was anciently of white wax, and artfully im- in one hatch, as it were a knot, and so separate printed on the parchment itself. It was after- again, and keep their former distances. wards pendent from the paper, and enclosed in The DIPPING NEEDLE, or INCLINATORY a box or case, which they called bulla. There NEEDLE, is defined, by Dr. Hutton, “a magare some also that are stamped on metal, and netical needle, so hung, as that, instead of playeven on pure gold.

ing horizontally, and pointing out N. and s., DIPONDIUS, a coin, of very little value, one end dips or inclines to the horizon, and the mentioned by St Luke, xii. 6. Our translation other points to a certain degree of elevation of the passage is, Are not five sparrows sold for ahove it. It is used for observing the quantity two farthings? In St. Matthew, x. 29, it runs, of inclination towards the earth assumed by the Are not two sparrows sold for a farthing? The magnetic needle. The inventor of the dipping Greek has assarion instead of as, which some needle was Robert Norman, a compass-maker, say was worth half an as, i.e. four French de- at Ratcliffe, about 1580. This is not only tesniers and one-eighth; and, according to others, tified by his own account, in his New Attractive, two deniers and five-sixteenths. Dipondius but also by Mr. Whiston, Dr. Gilbert, Mr. Wilscems rather to signify half an as.—Calmet. liam Burrowes, Mr. Henry Bond, and other Dr. Arbuthnot, however, says, that this coin was writers of that period. The occasion of the disat first libralis, or of a pound weight; and, even covery he himself relates, viz. that it being his when diminished, it retained the name of lihella; custom to finish, and haug the needles of his so that dipondius denotes two asses.

compasses, before he touched them, he always DIPPEL (John Conrad), a German physician, found that, immediately after the touch, the N. born at Darmstadt in 1672. He studied theo- point would dip or decline downwards, pointing logy at Giessen, and afterwards read medical in a direction under the horizon; so that, to balance lcctures at Strasburgh, but took his doctor's de- the needle again, he was always forced to put a gree at Leyden in 1711. He was much addicted piece of wax on the S. end, as a counterpoise. to the study of alchemy, and, among other secrets, The constancy of this effect led him at length to pretended to have discovered the philosopher's observe the precise quantity of the dip, or to

After rambling from place to place, he at measure the greatest angle which the needle last settled at Hamburgh ; but having used some would make with the horizon. This, in 1576, indiscreet freedoms with the administration of he found at London to be 71° 50. Denmark, he was given up to the government of It is not quite certain, however, whether the that country, by whom he was sentenced to per- dip varies, as well as the horizontal direction, in petual imprisonment in the island of Bornholm. the same place. Mr. Graham made many expeHe, however, obtained his liberty at the end of riments with the dipping needle in 1723, and seven years; and about the same time was in- found the dip between 74° and 75°. Mr. Naime, vited to Sweden, to attend the king, who was in 1772, found it somewhat above 72o. And, dangerously ill, but through the intluence of the by many observations made since that time at clergy, whom he had ridiculed, he was obliged the Royal Society, the medium quantity is 721°. to leave the kingdom in 1727. Ile afterwards The trifling difference between the first observawent to Germany, and in 1733 gave out pub- tions of Norman, and the last of Mr. Nairne and licly that he should not die till 1808, but next the Royal Society, has led some philosophers to year he was found dead in his bed. He denied the opinion that the dip is unalterable ; and yet the inspiration of the Scriptures, and wrote a it may be difficult to account for the great difnumber of wild enthusiastic books, under the ference between these and Mr. Graham's pumname of Christianus Democritus. His works bers, considering the well-known accuracy of were published in 5 vols. 4to. 1747. We are in- that ingenions gen:leman. Philosophical Transdebted to him for the discovery of the Prussian actions, vol. xlv. p. 279; vol. Ixii. p. 476; vol. blue, and he invented a useful oil, which is lxix. lxx. lxxi. From a comparison of Mr. called after him.

Gilpin's observations of the dip in August, 1805, Dipping, among miners, signifies the inter- when he found it 70° 20', with those of Mr. Caruption, or breaking off the veins of ore; an vendish, in 1775, its annual decrease, on a mean, accident that gives them a great deal of trouble appears to have been 4.3°; and its progressive before they can discover the ore again. A great anual decrease, on a mean, in the above-menpart of the skill of the miners consists in the tioned period of thirty years, to have been 1.4'. understanding of this dipping of the veins. In It is certain, from many experiments and obserCornwall they have this general rule to guide vations, that the dip is different in different latithem in this respect : most of their tin-loads, tudes, and that it increases in going northward. which run from east to west, constantly dip to- It appears from a table of observations, made wards the north. Sometimes they underlie; that with a marine dipping needle of Mr. Nairne's, in is, they slope dowi towards the north three feet a voyage towards the north pole in 1773, that in height perpendicular. This must carefully in lat. 60° 18' the dip was 75° 0', be observed by the miners, that they may ex in lat. 70° 45' the dip was 77° 52', actly know where to make their air-shafts when in lat. 80° 12' the dip was 81° 52', and occasion requires; yet, in the higher mountains in lat. 80° 27' the dip was 82° 21'. of Dartmaer, there are some considerable loads See Phipps's Voyage, p. 122. See also the Obwhich run north and south; these always underlie servatious of Mr. Hutchins, made in Hudson's towards the east. Four or five loads may run Bay aud Straits, Philosophical Transactions, vol. nearly parallel to cach ther in the same hill; lxv. p. 129. Messrs Burrowes, Gilbert, Ridley,

Bond, &c. endeavoured to apply this discovery countable. Of all those who have attempted the of the dip to the finding of the latitude; and investigation of this obscure subject, none have Bond first proposed finding the longitude by it; been more successful than M. Cavallo, who, in his but for want of observations and experiments, he Treatise on Magnetism, has given particular attencould not conduct his reasoning to any length. tion to all the phenomena, and accounts for them Mr. Whiston, being furnished with the farther upon plain and rational principles, in the followobservations of colonel Windham, Dr. Halley, ing manner :--The dip of the magnetical needle, Mr. Pound, Mr. Cunningham, M. Noel, M. in general, may be understood from the following Feuille, and his own, made great improvements easy experiment: Lay an oblong magnet horizonin the doctrine and use of the dipping needle, tally upon a table, and over it suspend another brought it to more certain rules, and endeavoured smaller magnet (a sewing needle to which the to find the longitude by it. For this purpose, he magnetic virtue has been communicated will observes: 1. That the true tendency of the N. answer the purpose), in such a manner as to reor S. end of every magnetic needle is not to that main in an horizontal position when not dispoint of the horizon to which the horizontal turbed by another magnet. Now, if this last needle points, but towards another directly under small magnet or sewing needle, suspended by the it, in the same vertical, and in different degrees middle, be brought just over the middle of the under it, in different ages, and at different places. large one, it will turn itself in such a manner that 2. That the power by which the horizontal the south pole of the small magnet will point needle is governed, and all our navigation usually towards the north pole of the large one; and if at directed, it is proved, is only one quarter of the an equal distance from both, will remain in an power by which the dipping needle is moved; horizontal position. But if we move it nearer to which should render the latter by far the more one of the poles than the other, it will be readily effectual and accurate instrument. 3. That a understood that the corresponding end of the dipping needle of a foot long will plainly show needle will be attracted by the pole to which it an alteration of the angle of inclination, in these approaches, and of consequence inclined downparts of the world, in one-eighth of a degree, or wards; the contrary end being proportionably seren and a half geographical miles; and a elevated. It is likewise evident, that this inclinaneedle of four feet, in two or three miles; i. e. tion will be greater or less according to the dissupposing these distances taken along, or near a tance at which the small magnet is placed from meridian. 4. A dipping needle four feet long, in the pole of the large one; the attraction of the these parts of the world, will show an equal alter- nearest pole having always the greatest effect upon ation along a parallel, as another of a foot long will it. And it is equally plain that, when brought show along a meridian, i. e. that will

, with equal directly over one of the poles of the large magexactness, show the longitude, as this the latitude. net, it will turn its own contrary one directly 10This depends on the position of the lines of equal wards it, and thus lie exactly in the axis of the dip, in these parts of the world, which, it is found, large one. The application of this experiment do lie about 14° or 15° from the parallels. Ilence to the phenomena of the dipping needle is obhe argues, that as we can have needles of five, vious, as nothing more is requisite for solving the six, seven, eight, or more feet long, which will whole mystery, than to suppose the earth itself move with strength sufficient for exact observa- to be the large magnet, and the magnetic needle, tion; and since microscopes may be applied for or any other magnetic body, the small magnet in viewing the smallest divisions of degrees on the the experiments: for admitting that the north limb of the instrument, it is evident that the pole of the earth possesses a south magnetism, longitude at land may thus be found to be less than and that the opposite pole is possessed of a-north four miles. And as there have been many ob- magnetical polarity; it appears, and the theory servations made at sea with the same instrument is confirmed by experiment, that when a magnet by Noel, Feuille, &c., which have determined the is suspended properly in the equatorial parts of dip usually within a degree, sometimes within a the world, it must remain in an horizontal posihalf, or one-third of a degree, and this with small tion; but when removed nearer to one of the poles, needles of five or six, or, at the most, nine inches it must incline one of its extremities, viz. that which long; it is inferred that the longitude may be is possessed of the contrary magnetic polarity; found even at sea, within less than one-eighth of and that this inclination must increase in propora degree.

tion as the magnet or magnetic needle recedes The phenomena of the dipping needle are:- from the equator of the earth; and, lastly, when That about the equatorial parts of the earth it brought exactly upon either of the poles of the remains in an horizontal position, but depresses earth, it must stand perpendicular to the ground, one end as we recede from these; the north end, or in the same direction with the axis of the if we go towards the north, and the south end, earth. The only difficulty in this explanation if we proceed towards the south pole. The arises from the attributing a south magnetism to farther north or south that we go, the inclination the north pole of the earth; but by this our becomes the greater; but there is no place of the author means only that its magnetism is contrary globe hitherto discovered where it points directly to that end of the magnetic needle which turns downwards, though it is supposed that it would towards it; and in the same sense it must be do so in some part of it very near the pole. Its understood, that the south pole of the earth has a inclination is likewise found to vary very consider- north magnetic polarity. "If the extremities of ably at different times in different places of the the axis of the earth, or the poles about which it earth, and by some changes of situation, in such performs its diurnal revolution, coincided with 1 manner as must appear at first sight very unac its magnetic poles, or even if the magnetic poles

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