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POLAR EXPLORATION

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number of search-parties which it occasioned. His object was to penetrate to Behring Strait from Lancaster Sound (see FRANKLIN, SIR JOHN). 70° N. lat., 98° 30' W. long., on the west side of King William's Land, the ships were beset, and Franklin died June 1847. The survivors abandoned the ships, and all perished. Many search-expeditions were sent out. One of these, under Collinson and M'Clure, sailed from Plymouth to Behring Strait in 1850. Fixed in the ice on its eastward voyage, M'Clure's ship was rescued next spring

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by Sir Edward Belcher, about 60 miles west of Barrow Strait. Belcher now returned towards the Atlantic, and thus M'Clure with his crew reached England in 1854 after actually traversing the North-west Passage from ocean to ocean. He therefore received the honour of knighthood, and a sum of £10,000 was voted by parliament to him and the crew. One of the last search-expeditions was that in the Fox, under Captain (now Sir) Leopold M'Clintock, sent out by Lady Franklin in 1857. M'Clintock obtained many relics from the

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Eskimo of Boothia, and in a cairn in Point Victory | found the record which told the story of the expedition. Perhaps we should here note the fact that afterwards, 1879-80, one of the United States search-expeditions, under Lieutenant Schwatka, found evidence that Franklin had really completed the discovery of the North-west Passage. Owing to the different Franklin expeditions from Great Britain and the United States the whole Arctic coast of North America was explored almost ex

haustively, so that several routes are now completely mapped between Davis Strait and Behring Strait. For commercial purposes, however, the North-west Passage is of no value whatever.

And now to return to the North-east Passage. In 1827 Parry sailed to Spitzbergen, and after much toilsome effort reached 82° 40′ N. After that little was done in this region till Sweden began to take an active interest in the exploration, under the active guidance of Professor (afterwards Baron)

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Nordenskiöld, who in 1858-72 did much exploring work in the Spitzbergen islands and seas. In two voyages he reached the Gulf of Obi. At last, in 1878, he rounded Cape Chelyuskin, 77° 41' N., and after wintering near Behring Strait sailed into the Pacific and reached Yokohama, 2d September 1879. Thus, three and a quarter centuries after the attempt of Willoughby, the North-east Passage was at last completed. Before that date an Austrian expedition under Lieutenants Payer and Weyprecht had been singularly successful, having discovered an island about 200 miles north of Nova Zembla, as large apparently as Spitzbergen. This new country, Franz-Josef Land, extends from 80° N. to about 83°. At a later date (1880) this land was still farther explored to the north-west by Mr Leigh Smith; and in the winter of 1881-82 Mr Leigh Smith wintered at Franz-Josef Land, he and his companions having great difficulty in escaping.

The more recent exploration to the north of America has added little to our geographical knowledge, however interesting in certain scientific aspects. The expedition of Kane and Hayes in 1853-55 reached in sledges Cape Constitution in 82° 27' N., and saw what appeared to be an open polar sea. Hayes again (1860-61) reached 81° 35' N. In 1871 the Polaris, under Captain C. F. Hall, sailed from New London, U.S., and reached the latitude 82° 16', which was surpassed in 1876 by the English expedition under Captain Nares; Captain A. H. Markham, by means of sledges, reaching 83° 20′ N. At the same time Aldrich explored the north shore of Grinnell Land. More famous and more disastrous was the 'Lady Franklin Bay Expedition,' 1881-84, conducted by Lieutenant Greely; the relief party sent in the summer of 1883, being unfortunately entrusted to military men, failed to reach the explorers, who were, therefore, compelled to abandon their ships and find their way southwards through almost impassable ice. In October 1883 Greely and his brave companions landed at Cape Sabine, the bleakest spot probably in all the Arctic regions; and there in June 1884 Commander Schley found the six men who still survived. Greely and his assistants took scientific observations up to the day of their release. In the early part of Greely's exploration, when in Grinnell Land, one of his party, Lieutenant Lockwood, succeeded in reach ing 83° 23-8' N. lat., on the coast of Greenland, which is a few miles nearer the pole than the point reached by Markham. The Greely expedition also explored the interior and the west coast of Grinnell Land. In 1869-70 Captain Koldewey's expedition reached 77° N. on the east coast of Greenland, the highest latitude yet attained on that coast. The Jeannette expedition under Commander De Long, sent out by the New York Herald in 1879 to push north by Behring Strait, ended in disaster. The vessel was crushed in the ice in June 1882 in 77° N., 155 E. The crew made their way over the ice by the New Siberian Islands to the mouth of the Lena. De Long and many of his men perished. Lieutenant Berry, sent out to search for the Jeannette, explored Wrangel Land. The icy plateau which covers the archipelago of Greenland was in 1888 crossed from east to west by Nansen, a feat not to be accomplished without great energy, skill, and endurance. Nansen has planned an expedition for 1892 to reach the North Pole by way of Behring Strait and the New Siberian Islands.

At the suggestion of Lieutenant Weyprecht, an international series of polar observatories was established around the north polar area, for the purpose of taking a complete year's observations, beginning with August 1882. The stations selected were the following: Bossekop, in Lapland (Norwegians); Ice Fjörd, Spitzbergen (Swedes); Lena

Mouth, Siberia, and Möller Bay, Nova Zembla (Russians); Dickson Harbour, mouth of the Yenisei (Dutch, but the expedition failed to reach its destination); Great Slave Lake (English); Point Barrow on north coast of America, east of Behring Strait, and Lady Franklin Bay, in Grinnell Land (the United States, the latter being Greely's expedition); Cumberland Bay, Davis Strait (Germans); Jan Mayen Island (Austrians); Godthaab, Greenland (Danes). The Germans had also a station on South Georgia Island, on the verge of the Antarctic, and the French on the south coast of Patagonia. The result was a series of observations of high value on the physics, meteorology, and natural history of the polar, especially the Arctic regions. The Russian expedition at the mouth of the Lena was continued for some years under Bunge and Toll, who not only explored the mainland, but made a thorough investigation of the New Siberian Islands.

It only now remains to survey shortly the polar explorations of the mighty Southern or Antarctic Ocean. Some of the earlier navigators of the 16th and 17th century were drifted south as far as South Georgia and South Shetland. Cook was the first to undertake a systematic exploration of the region, sailing all round at a high latitude, and so disprov ing the existence of the Great Southern Continent' to be found on old maps. Cook reached 71° 15′ S., in 106° 50′ W. In 1821 the Russian Bellinghausen discovered the islands named Alexander Land and Peter Land. Weddell afterwards sailed south to 74° 15', and in 1831 Biscoe discovered Enderby Land, 65° 57′ S., and Graham Land, 67° S. The French expedition, 1838, under D'Urville, found its advance to the pole blocked by a bank extending east and west for 300 miles; La Terre Adèle, in 140° E., was first named in this voyage. In 1840 the United States expedition under Captain Wilkes discovered a long coast-line, apparently extending from Enderby Land eastwards to Ringold's Knoll, but the only part of this which has since been found was discovered by Balleny in 1839. The most important results obtained in the Antarctic region are due to Sir James Clarke Ross, who made three Voyages in 1839-43, discovering Victoria Land, with a lofty range containing the volcanoes Erebus and Terror. He traced the coast from 71° S. to 78° 10', the highest latitude yet reached in the Antarctic, after passing some ice-floes which were 1000 miles broad. These southern expeditions of Ross, like those of all the chief polar explorers, have supplied valuable information for students of magnetism, meteorology, geology, and natural history, besides extending the bounds of geographical science. The Challenger expedition only just crossed the Antarctic circle.

The general result of all the exploring work is that in the north polar regions the unknown has been pushed back to within 80° N. lat.; while in the Greenland and the Nova Zembla regions exploration has been carried to within about 400 miles from the North Pole. On the other side, with the exception of patches here and there, the south polar region is a great blank within the Antarctic Circle. The Australians have been making efforts within the past few years to take up Antarctic exploration afresh, but nothing has yet been done, although Baron Oscar Dickson, a wealthy Swede, has offered to defray the bulk of the expense, and has secured the services of Baron Nordenskiöld as leader.

regions is largely treated at ARCTIC OCEAN, ANTARCTIC The physical geography of the north and south polar OCEAN. See also GEOGRAPHY, GEOGRAPHICAL DISTRIBUTION, GREENLAND, SPITZBERGEN, NOVA ZEMBLA, FRANZ-JOSEF LAND, SIBERIA, NEW SIBERIAN ISLANDS, OB, GLACIER, ICE, and the articles on Hudson, Cook,

POLARISATION

Franklin, Ross, Parry, M'Clure, M'Clintock, Hall, Nordenskiöld, Greely, and other Arctic and Antarctic explorers; Barrow's History of Voyages to the Arctic Regions (2 vols. 1818 and 1846); C. R. Markham's Threshold of the Unknown Region; A. R. Markham's Life of Franklin; Edinburgh Review, April 1891; Journal and Proceedings, Roy. Geo. Soc.; and the published narratives of the various Arctic and Antarctic explorations.

Polarisation. (1) Of Light.-An ordinary narrow beam of sunlight has no sides, and is always divided into two equal beams by a crystal of Iceland spar; but if it has once been reflected from glass or water, it will then be found in general that different results, as regards the intensities of these two beams, are produced by turning the crystal of Iceland spar round the axis of the beam into different successive positions. The beam is no longer the same all round, but has acquired sides. On the vibratory or undulatory theory of Light (q.v.) this shows that the vibrations must be transverse to the direction of propagation (see POLARITY). Suppose a long cord, fixed to a distant wall, to be held in the hand; apply a sharp up-and-down movement; an up-and-down wave will run along the cord to the wall; this illustrates the mode of vibration in a beam of plane polarised light. Make the hand move in a circle, in a direction contrary to that of the hands of a clock; a wave will run along in the form of a screw; this screw will have the form, and will advance after the fashion, of a corkscrew; this illustrates the mode of vibration in a right-handed circularly polarised beam of light. Make the hand move in a circle clockwise; the wave-screw advances in a lefthanded fashion; this illustrates left-handed circularly polarised light. Make the hand move in an ellipse; an elliptical disturbance travels, screwfashion, right or left-handed as the case may be; this represents elliptically polarised light. Communicate a series of disturbances of the greatest irregularity in which no one direction, up or down, right or left, has on the whole any predominance; the irregular succession of transverse disturbances which will travel along the cord will represent the vibration in a beam of common or natural light. Assume that while communicating these irregular disturbances the hand is hampered but not disabled with reference to any particular direction, say up and down; the vibrations in that direction are on the whole less than those from right to left; and the whole complex of irregular disturbances would, if they wrote their own path, tend to fill up an ellipse with their trace-marking rather than to fill up a circle, as the vibrations in common light would tend to do; this would represent the nature of the vibrations in partially polarised light. Now suppose a slot in a board, which will allow the cord to swing from end to end of the slot, but will not allow the cord to swing athwart the slot; all those oscillations or components of oscillation which are parallel to the slot will be able to traverse the slot; but those which are at right angles to these will not be allowed to pass. On endeavouring to transmit through the slot the complex of oscillations which illustrate the vibrations of common or natural light, it will be found that no motion at right angles to the slot is transmitted, and that what does pass through is a complex of irregular oscillations restricted to the plane of the slot. A second slot, at right angles to the first, will cut off the whole of what passes through the first; and the propagation of transverse oscillations along a cord may thus be entirely checked. If, however, the second slot be parallel to the first, all the oscillations transmitted by the first may pass through it also; and if it lie in an intermediate direction, the second slot will allow a proportion to pass, which depends upon the angle between the two slots,

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being proportional to cos e, where is that angle. The first slot illustrates the functions of a polariser; the second illustrates those of a second polariser or analyser. A polariser reduces incident common light to a plane polarised condition, and an analyser at right angles to the polariser will quench it altogether.

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The phenomena of polarised light were first observed in sunlight reflected from water or glass. Common or natural light so reflected is always, except when it retraces its path by direct reflection, more or less partially polarised by reflection." The polarisation is more or less complete according to the angle of incidence. At one particular angle of incidence the reflected light is as nearly plane polarised as the particular reflecting substance employed can make it. At this angle, the socalled angle of complete polarisation,' the reflected and the refracted rays are (or tend to be) at right angles to one another, and tan i = μ, where i is the angle between the incident ray and the normal, and a is the index of refraction (see REFRACTION). Metal reflectors have no angle of complete, but only of maximum, polarisation; and even among such substances as glass, which are usually said to have an angle of complete polarisation by reflection, it is only those whose index of refraction 1:46 which can completely polarise common light by a single reflection. In that case the intensity of the reflected plane polarised beam is to that of the original incident beam of common light as 6:52 to 100, or 6.52 per cent. The intensity of light polarised by one reflection is therefore a good deal less than the 50 per cent. which might be secured by any contrivance which effectually acted in a way analogous to the first slot above mentioned. The intensity of light polarised by reflection is greatly improved by using, instead of a single reflecting plate, a pile of plates. A crystal of tourmaline or of iodo-sulphate of quinine will, on the whole, allow only light polarised in one particular plane to pass through; but then it darkens it and colours it. Advantage is accordingly taken of the property of a doubly-refracting transparent crystal, such as Iceland spar, of dividing an incident beam of common light into two equal beams, which are, when they travel in principal sections of the crystal (see REFRACTION, DOUBLE), polarised in planes at right angles to one another, and each of which possesses (absorption apart) half the intensity of the original beam. As these two beams diverge from one another it is comparatively easy to arrange that one of them shall remain parallel to the axis of the incident beam and of the apparatus, while the other is allowed to wander away laterally and this is the basis of the construction of the prisms of Nicol, Foucault, Wollas ton, Rochon, and others, which receive incident ordinary light and transmit plane polarised light.

Two beams of plane polarised light can interfere with one another (see INTERFERENCE) when their vibrations are wholly or partly in the same direction, but not if they be at right angles to one another; and a beam of light polarised in any way can give rise to the phenomena of Diffraction (q.v.).

On interposing in the path of a plane polarised beam of light an analyser, so placed as to allow none of that light to be transmitted, and then placing in the course of the plane polarised beam before it reaches the analyser a thin film of a doubly-refracting substance, such as mica, the field of view may become filled with light. The doublyrefracting film generally breaks the incident plane polarised beam into two plane polarised beams, which are, after emergence from the film, parallel to one another and on the whole coincident if of sufficient breadth. These two beams are differently retarded in the mica; and, according to the amount

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of this relative retardation and to the position of the principal plane of the interposed film, their resultant, that which reaches the analyser, may be a beam plane polarised in the original plane, plane polarised in another plane, elliptically polarised, or circularly polarised. In all these cases except the first, the analyser lets some light through. If we substitute for the analyser a doubly-refracting crystal, there will in general be two images seen on looking through; but as this crystal itself introduces relative retardations, the result of which depends on the wave-lengths-i.e. on the coloursthe different wave-lengths may give different relative intensities in the two images: some wavelengths may predominate in the one image, the rest in the other; the two images may thus be coloured; and when coloured they will be complementarily coloured. The phenomena of colour produced by the reaction of polarised light upon various doubly-refracting crystals and films, &c.all which colour-phenomena are due to varying relative retardations of ordinary and extraordinary rays in doubly-refracting media, and are either uniform all over the resultant wave-front or vary with respect to particular parts of it-are of great variety and extreme beauty. For an account of these we refer to Thomas Preston's Theory of Light (Lond. 1890).

POLARITY

the consequences of the vibration being at right angles to this plane, and arrived (on the assumption that the density of the ether in two media, at whose bounding surface reflection takes place, is different in the two media, while its elasticity is the same in both) at consequences consistent with experiment. Neumann and MacCullagh, from a contrary hypothesis as to the elasticity and density of the ether, and on the hypothesis that the vibrations are parallel to the plane of polarisation, arrived at optical conclusions which, so far as it is possible to test them by experiment, are equally consistent with observation. Clerk-Maxwell's electric or electro-magnetic theory of light, confirmed by Hertz's researches (see MAGNETISM), requires that there should be an undulatory propagation of electric disturbances at right angles to the plane of polarisation, and of magnetic disturbances parallel to that plane.

Polarisation of light is useful in several ways. A polariser can be made to cut off the glare from the surface of water while we look into its depths; or to cut off a large portion of the light which is reflected from haze and obscures our view of landscape; or it may be used in examining the light of the sky, which is partly polarised, because due to reflection (see SKY). A polariser and analyser are of use in examining the strained condition of glass A beam of plane polarised light may be recognised which, when heated or bent, &c., or too suddenly by means of a crystal of Iceland spar. Paste a piece cooled, will give rise between crossed prisms to of paper with a pinhole in it on one end of the phenomena analogous to those produced by a crystal; look through, turning the crystal round; doubly-refracting crystal; and they are also of use each of the two images waxes and wanes and dis- in low-power microscopic work for the examination appears alternately with the other. In partially or identification of crystals and of many organic polarised ordinary light, and in elliptically polarised structures. Crossed prisms have also been used to light, the two images wax and wane alternately reduce the intensity of a beam of light to any with one another, but do not disappear. In required percentage for photometric purposes. circularly polarised and in ordinary light the two images remain equal to one another, and present no variation of intensity. Circularly or elliptically polarised light is converted by a plate of mica of proper thickness into plane polarised light; natural liglit, unpolarised or partially unpolarised, is not so affected by the same plate of mica. These criteria enable the character of a given beam of light to be readily recognised.

The name of Rotatory Polarisation is given to the phenomenon observed when a beam of plane polarised light is sent through a slice of quartz cut parallel to the axis. The plane of polarisation is found to have been rotated, and that into a different position for each component colour; so that, with white light incident, a crystal of Iceland spar gives two images complementarily coloured, and varying in colour on rotation of the prism. This property of rotation is shared by many substances even in solution cane-sugar, grape-sugar, camphor act like quartz, rotating the plane of polarisation to the right (dextro-rotatory); fruit-sugar and starch rotate the plane to the left (laevo-rotatory). Upon this property are based various instruments for the quantitative estimation of saccharine solutions, called saccharimeters. If the light whose plane has been rotated be reflected back through the plane-rotating medium, the rotation is reversed, and the light emerges polarised in the original plane. A somewhat similar phenomenon, though much less pronounced, is observed on passing a beam of light through heavy glass in a strong magnetic field; but here, if the path of the light be reversed by reflection, the rotation of the plane is not reversed but doubled.

As to the direction of vibration in a plane polarised ray, a ray polarised by reflection is said to be polarised in the plane of incidence-i.e. in a plane containing both incident and reflected rays: the question is whether the vibration is in this plane or at right angles to it. Fresnel worked out

(2) Polarisation of Dielectric.-The condition of the dielectric or medium between two opposite charges of electricity: a condition of stress.

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(3) Polarisation of a Galvanic Cell.-Production of a reverse electromotive force' by the deposi tion of elements of the electrolyte upon, or their combination with, the plates of the cell.

(4) Polarisation of Electrodes.-An entirely similar phenomenon in an electrolytic cell. When the battery is taken off, a reverse current flows from the electrolytic cell; this is the basis of the gas battery and of the modern accumulator (see ELECTRICITY).

Polarity, in physical science, a word of various application; but in all its uses there is present the idea of a directed quantity or Vector (q.v.). A sphere, situated in space, is a perfect type of all-sidedness, presenting the same aspect in every direction. Let this sphere, however, begin to rotate about some diameter, and at once it becomes a polar body; it becomes possessed of polarity (see POLES). Looked at from one end, it appears rotating clockwise; looked at from the other, it appears rotating counter-clockwise. A similar polarity is acquired by a body of any shape when it is set spinning about some axis. Hence we may take rotation as a very perfect illustration of kinematic polarity.

Perhaps the most familiar example in physics of a polar body is the magnet. Its polarity is a forcepolarity, the ends or poles of one magnet having a selective action upon the ends or poles of another. This particular action is, however, only one of a host of manifestations of what is known as Magnetism (q.v.); and the general tendency in modern theory is to explain all magnetic phenomena as being essentially rotational. Thus, again, from a physical or dynamic point of view, we conceive of rotation as a true type of polarity. The phenomena of statical electricity have also been discussed as analogous to certain phenomena in vortex motion.

POLAR LIGHTS

In electrolytic polarisation, however, it is difficult to see any rotational analogy. Here the electrodes which bring and carry away again the electric current flowing through the decomposing liquid acquire new properties and functions which have distinct directive relations to the current that produced them. See ELECTRICITY, INDUCTION, MAGNETISM.

In all the cases so far mentioned the polarity or polarisation involved is of such a nature as that originally typified by the sphere's rotation; there are two ends which in some respects have opposite characteristics. In polarisation of Light (q.v.), however, this condition is no longer always fulfilled. For instance, a plane polarised ray of light which is stopped by a Nicol prism passes more or less completely as soon as the prism is rotated round an axis codirectional with the ray. The ray has, in fact, peculiarities as regards its sides-its 'polarity' is strictly speaking lateral, not polar. On the other hand, in a circularly polarised ray we have, according to the ordinary theory, a true kinematic polarity of a rotational kind, so that, looking along the ray, we are able to distinguish right-handed and left-handed circular polarisations. It may be mentioned as a final illustration that the rotation of the plane of polarisation by means of quartz or a saccharine solution is not a real polar phenomenon, the rotation being for any one substance always in the same sense relatively to the travelling ray; but that the rotation of the plane of polarisation in a magnetic field is a true polar phenomenon, changing sign with the direction of the field.

Polar Lights. See AURORA BOREALIS. Polder, in the Netherlands, is land below the level of the sea or nearest river, which, originally a morass or lake, has been drained and brought under cultivation. An embankment, forming a canal of sufficient height to command a run towards the sea or river, is made, and when carried quite round, as in the case of the Haarlem Lake, it is called the Ring vaart. At one or more points on the embankment apparatus for lifting water is placed, and worked by wind or steam power. If the lake deepens towards the centre, several embankments and canals are necessary, the one within the other, formed at different levels as the water-surface becomes lessened, a connection being maintained with the outer canal, which secures a run for the drainage water. In the Schermer polder in North Holland are four canal levels, the land between forming long parallelograms. The water from the inner space is lifted into the first canal; that again, with the drainage of the second section, is thrown into the second, and so on until the outer canal is reached, and a fall obtained. The polders in the Netherlands are very numerous, the most important being the Haarlem Lake (q.v.), possibly to be surpassed by that of the Zuider Zee (q.v.). See also HOLLAND, Vol. V. p.

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Pole. See ROD.

Pole, DE LA, a family descended from William de la Pole, a Hull merchant, whose son Michael in 1383 became chancellor under Richard II., in 1385 was made Earl of Suffolk, and in 1389 died an exile in France. His grandson William (1396-1450) was the year before his death raised from Earl to be Duke of Suffolk, having since 1445 been practically prime-minister. His administration was a disastrous one; and he was on his way to a five years' banish ment in Flanders, when he was captured by a ship sent after him, and beheaded. John de la Pole, Duke of Suffolk (died 1491), married Elizabeth, sister to Edward IV. and Richard III.; and from this marriage sprang John, Earl of Lincoln (died 1487), Edmund, Earl of Suffolk (executed by Henry VIII, 1513), two churchmen, four daughters, and

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Pole, REGINALD, 'Cardinal of England,' was the son of Sir Richard Pole, and Margaret, Countess of Salisbury, the daughter of the Duke of Clarence and niece of Edward IV. He was born in Staffordshire, March 1500. He received the rudiments of his education from the Carthusians at West Sheen, and at twelve years of age he was sent to Magdalen College, Oxford. His relationship to the crown made him an important person, and being destined for the church, he was presented at an early age with several benefices. At nineteen he went to Italy with a pension from the king to finish his studies at Padua. He returned to England in 1525. He was then high in Henry's favour, while Queen Catharine was much attached to his mother. Pole's position, when the question of the king's divorce was raised, became a difficult one. appeared at first disposed to take the king's side. In 1530 we find him in Paris endeavouring to obtain from the university a decision favourable to the divorce, but shortly afterwards he became disgusted with the policy of Cromwell, refused the archbishopric of York which was offered to him on the death of Wolsey, and remonstrated with the king upon the course he was pursuing. Henry, however, made no open quarrel with him; and Pole left England in 1532, and after a short stay at Avignon took up his residence in Italy. Here he formed intimate friendships with a number of men of learning and piety-Sadoleto, Contarini, Morone, Flaminio, Priuli, and others--who were urgent for an internal reformation of the church, and whose views on justification by faith as a rule approximated closely to the doctrine of Luther. Pole still retained his English ecclesiastical reHenry, but in 1535 he entered into a political venues, and made no hostile demonstrations against correspondence with the Emperor Charles V. Pole which he did in a violent letter addressed to the was now compelled by Henry to declare himself, king, afterwards famous in its revised form as the treatise De Unitate Ecclesiastica. The king withdrew Pole's pension and preferments. Paul III., on the other hand, made him a cardinal (22d December 1536), and sent him as legate to the Low Countries to confer there with agents of the

English malcontents. Henry retaliated by causing a bill of attainder to be passed against him, and by setting a price on his head. His mother, with other relatives, was thrown into the Tower the cardinal, and subsequently beheaded. Pole's on the ground of treasonable correspondence with diplomatic career was not, however, a brilliant one. His several attempts to procure the invasion of England were not successful. From 1539 to 1542 he acted as governor of the 'Patrimony of St Peter,' of which Viterbo was the capital. He took an active part in the discussions on the Interim, and when the Council of Trent was opened in 1545, he was one of the three cardinals who acted as legatepresidents. In the conclave which followed on the death of Paul III. in 1549, Pole was at one moment on the point of being elected pope; after the election of Del Monte, as Julius III., he lived in retirement at a Benedictine monastery at Maguzzano on the lake of Garda, until the death of Edward VI., when he was at once commissioned to proceed to England as legate à latere, to assist Queen Mary in the reconciliation of the kingdom to the Church of Rome.

Pole was still only in deacon's orders, and had not abandoned the idea which he had apparently entertained from his youth, of marrying Mary Tudor. The queen for a moment considered the project of obtaining a dispensation for this union with favour, but the influence of Charles V. pre

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