The width of the approach to this region by the Atlantic Ocean, in its narrowest part, is 660 miles, from the Norwegian Islands of Lofoten to Cane Hodgson on the east coast of Greenland. The width of the approach by Davis Strait in the narrowest part, which is nearly on the Arctic Circle, is 165 miles; and the width of Behring Strait is 45 miles. Thus out of the whole ring of 8640 miles along which the Arctic Circle passes about 900 miles is over water. This great environment of land is an important feature in the physical condition of the north polar region. It influences the currents and the movements of ice, which are still further affected by the archipelagos lying to the northward of the fringing coast-lines. The larger opening into the north polar region by way of the Atlantic is divided from Davis Strait by the vast mass of Greenland, which, extending for an unknown distance to the north, crosses the Arctic Circle and ends in a point at Cape Farewell in 59° 48' N. lat. It was inevitable that the routes across the Arctic Circle by the Atlantic and Davis Strait should first become known, because these openings to the polar regions are nearest to the temperate regions inhabited by the exploring nations of Europe.

A rumour respecting Thule, an island on the Arctic Circle, first brought by Pytheas (g ’.f.), and afterwards doubted, was the extent of the knowledge of the north polar regions with which the ancients can be credited. But in the 9th century some Irish monks really appear to have visited Iceland. The monk Dicuil, writing about 825, says that he had information from brethren who had been at Thule during several months, and they reported that there was no darkness at the summer solstice.

King Alfred told the story of the first polar voyages undertaken for discovery and the acquisition of knowledge, in his very free translation of Orosius. In the first book he inserted the narrative of the voyages of Other and Wulfstan, related to him by the former explorer himself. The localities mentioned in the story cannot now be identified, but it seems probable that Other rounded the North Cape, and visited the coast of Lapland.

The Norsemen of the Scandinavian peninsula, after colonizing Iceland, were the first to make permanent settlements on the shores of Greenland, and to extend their voyages beyond the Arctic circle along the western coast of that vast glacier-covered land. See Greenland. The Norse colonies in Greenland at Brattelid and Einarsfjord did not extend farther north than 65°, but in the summer time the settlers carried on their seal hunting far beyond the Arctic circle. One of their runic stones was found in a cairn in latitude 73° N., the inscription showing that the date of its being left there was 1235. Another expedition is believed, on good grounds, to have reached a latitude of 75° 46' N. in Barrow Strait, about the year 1266. Their ordinary hunting grounds were in 73° N., to the north of the modern Danish settlement of Upernivik. For the visits of the Greenlanders to the American coasts see America, vol i. p. 706.

The last trace of communication between Greenland and Norway was in 1347. The black death broke out in Norway and the far off colony was forgotten; while the settlers were attacked by Skrellings or Eskimo, who overran the West Bygd in 1349. Ivar Bardsen, the steward to the bishopric of Gardar in the East Bygd, and a native of Greenland, was sent to convey help to the sister colony. A document, of which Ivar Bardsen was the author, has been preserved. It consists of sailing directions for reaching the colony from Iceland, and a chorography of the colony itself. It is the oldest work on arctic geography, and is still valuable iu the study of all questions relating to the early settlements in Greenland. From 1400 to 1448 there was some communication, at long intervals, with the Greenland settlers, but during the latter half of that century it entirely ceased. Here then the ancient portion of polar history comes to an end. The next period, comprised in the 16th and 17th centuries, was that in which expeditions were despatched across the Arctic Circle to discover a shorter route to India.

Sebastian Cabot, whose own northern voyages have been spoken of in the article Cabot, was the chief promoter of the expedition which sailed under Sir Hugh Willoughby and Richard Chancellor on the 20th May 1553, “for the search and discovery of the northern parts of the world, to open a way and passage to our men, for travel to new and unknown kingdoms.” Willoughby, after discovering Nova Zembla (Novaya Zemlya) by sighting the coast of Goose Land, resolved to winter in a harbour of Lapland, where he and all his men perished of starvation and cold. Chancellor reached the Bay of St Nicholas, and landed near Archangel, which was then only a castle. He undertook a journey to Moscow, made arrangements for commercial intercourse with Russia, and returned safely. His success proved the practical utility of polar voyages. It led to a charter being granted to the Association of Merchant Adventurers, of which Cabot was named governor for life, and gave fresh impulse to arctic discovery.

In the spring of 1556 Stephen Burrough, who had served with Chancellor, sailed in a small pinnace called the “Searchthrift,” and kept a careful journal of his voyage. He went to Archangel, and discovered the strait leading into the Kara Sea, between Nova Zembla and the island of Waigat. In May 1580 the company fitted out two vessels under Arthur Pet and Charles Jackman, with orders to pass through the strait discovered by Burrough, and thence to sail eastward beyond the mouth of the river Obi. Pet discovered the strait into the Kara Sea, between Waigat and the mainland, and made a persevering effort to push eastward, returning to England in safety. Jackman, after wintering in a Norwegian port, sailed homeward but was never heard of again.

In 1558 a narrative and map were published at Venice which profoundly affected the system of polar cartography for many years afterwards. The publication was the handiwork of a Venetian nobleman named Niccolö Zeno. Towards the close of the 14th century his ancestor, also named Niccolb, made a voyage into the northern seas, and entered the service of a chief named Zichnmi as pilot. He was eventually joined by his brother Antonio, and four years afterwards died in the country he called Frislanda. Antonio remained ten years longer in the service of Zichnmi, and then returned to Venice. The younger Niccolo found the mutilated letters of these brothers in the Zeni palace, with a map; and out of these materials he prepared the narrative and map which he published, adding what he considered improvements to the map. It was accepted at the time as a work of high authority, and the names on it continued to appear on subsequent maps for at least a century, puzzling both geographers at home and explorers in the field. After a very exhaustive study of the subject, Mr Major has identified the names on the Zeni map, as follows :—Engronelant, Greenland; Islanda, Iceland; Estland, Shetlands; Fr island, Faroe Isles; Markland, Nova Scotia; Estotiland, Newfoundland; Drogeo, coast of North America; Icaria, coast of Kerry in Ireland.

We now come to the voyages of Frobisher, undertaken to obtain the means for equipping an expedition for the discovery of a shorter route to India by the north-west. Aided by Michael Lok, an influential merchant and diligent student of geography, Frobisher sailed, in the spring of 1576, with two small vessels of 20 to 25 tons, called the “Gabriel’’and “Michael.” But the “Michael” parted company in the Atlantic, the voyage being continued in the “Gabriel” alone. On 20th July Frobisher sighted high land, which he called Queen Elizabeth’s Foreland; and the next day he entered the strait to which he gave his own name, calling the land “Meta Incognita.” On his return in the autumn, with various specimens of plants and stones, the “goldfinders” in London took it into their heads that a glittering piece of mica-schist contained gold ore. This caused great excitement, and much larger expeditions were fitted out, in the two following years, to collect these precious ores. As many as fifteen vessels formed the third expedition of 1578, and one of them, a busse (small ship) of Bridgwater, called the “Emma,” reported that on her voyage home she had sighted land in the Atlantic and sailed along it for three days. It was never seen again, and may have been only a large ice-field; but it soon found its place on maps and charts under the name of Busse Island, and afterwards as “sunken land of Busse.” For a long time Frobisher Strait was supposed to pass through Greenland, and, the map of the Zeni adding to the confusion, the land to the south was called Frislanda. It is now clear that Frobisher never saw Greenland, and that his strait and “Meta Incognita” are on the American side of Davis Strait. What Frobisher really did was to establish the fact that there were two or more wide openings leading to the westward, between latitudes 60° and 63°, on the American coast.

John Davis, who made the next attempt to discover a north-west passage, was one of the most scientific seamen of that age. He made three voyages in three successive years, aided and fitted out by William Sanderson and other merchants. Sailing from Dartmouth on the 7th June 1585, he was the first to visit the west coast of Greenland subsequent to the abandonment of the Norse colonies. He called it “The Land of Desolation.” He discovered Gilbert’s Sound in 64° 10' (where now stands the Danish settlement of Godthaab) and then, crossing the strait which bears his name, he traced a portion of its western shore. In the second voyage Davis noted what he calls “a furious overfall,” which was the tide flowing into Hudson Strait; and in his third voyage, in 1587, he advanced far up his own strait, and reached a lofty granite island in 72° 41' N. which he named Sanderson’s Hope. He considered that there was good hope of advancing farther, and reported “no ice towards the north, but a great sea, free, large, very salt and blue, and of an unsearchable depth.” The results of his discoveries are shown on the Molyneux globe which is now in the library of the Middle Temple; but he found it impossible to reconcile his work with that of Frobisher, and with the Zeni map. In 1595 Davis published a tract entitled The Worlds Hydrographical Description, in which he ably states the arguments in favour of the discovery of a northwest passage.

The Dutch also saw the importance of a northern route to China and India, especially as the routes by the Cape of Good Hope and Magellan’s Strait were jealously guarded by Spaniards and Portuguese. Their plan was to proceed by the north-east along the coast of Asia. As early as 1578 Dutch merchants had opened a trade with Kola and Archangel, but it was Peter Plancius, the learned cosmographer of Amsterdam, who conceived the idea of discovering a north-east passage. In 1594 the Amsterdam merchants fitted out a vessel of 100 tons, under the command of Willem Barents. The coast of Nova Zembla was sighted on the 4th July, and from that date until the 3rd of August Barents continued perseveringly to seek a way through the ice-floes, and discovered the whole western coast as far as Cape Nassau and the Orange Islands at the north-west extremity. The second voyage in which Barents Was engaged merely made an unsuccessful attempt to enter the Kara Sea. The third was more important. Two vessels sailed from Amsterdam on May 13, 1596, under the command of Jacob van Heemskerck and Corneliszoon Rijp. Barents accompanied Heemskerck as pilot, and Gerrit de Veer, the historian of the voyage, was on board as mate. The masses of ice in the straits leading to the Sea of Kara, and the impenetrable nature of the pack near Nova Zembla, had suggested the advisability of avoiding the land and, by keeping a northerly course, of seeking a passage in the open sea. They sailed northwards and on 9th June discovered Bear Island. Continuing on the same course they sighted the north-western extreme of Spitzbergen, soon afterwards being stopped by the polar pack ice. This important discovery was named “Nieue Land,” and was believed to be a part of Greenland. Arriving at Bear Island.again on 1st July, Rijp parted company, while Heemskerck and Barents proceeded eastward, intending to pass round the northern extreme of Nova Zembla. On the 26th August they reached Ice Haven, after rounding the northern extremity of the land. Here they wintered in a house built out of driftwood and planks from the wrecked vessel. In the spring they made their way in boats to the Lapland coast; but Barents died during the voyage. This was the first time that an arctic winter was successfully faced. The voyages of Barents stand in the first rank among the polar enterprises of the 16th century. They led directly to the flourishing whale and seal fisheries which long enriched the Netherlands.

The English enterprises were continued by the Muscovy Company, and by associations of patriotic merchants of London; and even the East India Company sent an expedition under Captain Waymouth in 1602 to seek for a passage by the opening seen by Davis, but it had no success.

The best servant of the Muscovy Company in the work of polar discovery was Henry Hudson. His first voyage was undertaken in 1607, when he discovered the most northern known point of the east coast of Greenland in 73° N. named “Hold with Hope,” and examined the edge of the ice between Greenland and Spitzbergen, reaching a latitude of 80° 23' N. On his way home he discovered the island now called Jan Mayen, which he named “Hudson’s Tutches.” In his second expedition, during the season of 1608, Hudson examined the edge of the ice between Spitzbergen and Nova Zembla. In his third voyage he was employed by the Dutch East India Company, and he explored the coasts of North America, discovering the Hudson river. In 1610 he discovered Hudson’s Strait, and the great bay which bears and immortalizes his name (see Hudson, vol. xii. p. 332).

The voyages of Hudson led immediately to the Spitzbergen whale fishery. From 1609 to 1612 Jonas Poole made four voyages for the prosecution of this lucrative business, and he was followed by Fotherby, Baffin, Joseph, and Edge. These bold seamen, while in the pursuit of whales, added considerably to the knowledge of the archipelago of islands known under the name of Spitzbergen, and in 1617 Captain Edge discovered a large island to the eastward, which he named Wyche’s Land.

At about the same period the kings of Denmark began to send expeditions for the rediscovery of the lost Greenland colony. In 1605 Christian IV. sent out three ships, under the Englishmen Cunningham and Hall, and a Dane named Lindenov, which reached the western coast of Greenland and had much intercourse with the Eskimo. Other expeditions followed in 1606-7.

Meanwhile the merchant adventurers of London continued to push forward the western discovery. Sir Thomas Button, in command of two ships, the “Resolution” and “Discovery,” sailed from England in May 1612. He entered Hudson’s Bay, crossed to its western shore, and wintered at the mouth of a river in 57° 10' N. which was named Nelson’s river after the master of the ship, who died and was buried there. Next year Button explored the shore of Southampton Island as far as 65° N., and returned home in the autumn of 1613. An expedition under Captain Gibbons, despatched in 1614, was a miserable failure; but in 1615 Robert By lot as master and William Baffin as pilot and navigator in the “Discovery” examined the coasts of Hudson’s Strait, and Baffin, who was the equal of Davis as a scientific seaman, made many valuable observations. In 1616 Bylot and Baffin again set out in the “Discovery.” Sailing up Davis Strait they passed that navigator’s farthest point at Sanderson’s Hope, and sailed round the great channel with smaller channels leading from it which has been known ever since as Baffin’s Bay. Baffin named the most northern opening Smith Sound, after the first governor of the East India Company, and the munificent promoter of the voyage, Sir Thomas Smith. Wolstenholme Sound, Cape Dudley Digges, Hakluyt Island, Lancaster Sound, Jones Sound, and the Cary Islands were named after other promoters and friends of the voyage. The fame of Baffin mainly rests upon the discovery of the great channel extending north from Davis Strait; but it was unjustly dimmed for many years, owing to the omission of Purchas to publish the skilful navigator’s tabulated journal and map in his great collection of voyages. It may be mentioned, as an illustration of the value of these early voyages to modern science, that Professor Hansteen of Christiania made use of Baffin’s magnetic observations in the compilation of his series of magnetic maps.

In 1631 two expeditions were despatched, one by the merchants of London, the others by those of Bristol. In the London ship “Charles” Luke Fox explored the western side of Hudson’s Bay as far as the place called “Sir Thomas Roe’s Welcome.” In August he encountered Captain James and the Bristol ship “Maria” in the middle of Hudson’s Bay, and went north until he reached “North-west Fox his furthest,” in 66° 47' N. He then returned home and wrote the most entertaining of all the polar narratives. Captain James was obliged to winter off Charlton Island, in the southern extreme of Baffin’s Bay, and did not return until October 1632. Another English voyager, Captain Wood, attempted, without success, to discover a north-east passage in 1676.

The 16th and 17th centuries were periods of discovery and daring enterprise, and the results gained by the gallant seamen of those times are marvellous when we consider their insignificant resources and the small size of their vessels. Hudson’s Strait and Bay, Davis Strait, and Baffin’s Bay, the icy seas from Greenland to Spitzbergen and from Spitzbergen to Nova Zembla, had all been discovered. The following century was rather a period of reaping the results of former efforts than of discovery. It saw the settlement of the Hudson's Bay Territory and of Greenland, and the development of the whale and seal fisheries.

The Hudson’s Bay Company was incorporated in 1670, and Prince Rupert sent out Zachariah Gillan, who wintered at Rupert’s river. At first very slow progress was made. A voyage undertaken by Mr Knight, who had been appointed governor of the factory at Nelson river, was unfortunate, as his two ships were lost and the crews perished. This was in 1719. In 1722 John Scroggs was sent from Churchill river in search of the missing ships, but merely entered Sir Thomas Roe’s Welcome and returned. His reports were believed to offer decisive proofs of the existence of a passage into the Pacific; and a naval expedition was despatched under the command of Captain Christopher Middleton, consisting of the “Discovery” pink and the “Furnace” bomb. Wintering in Churchill river, Middleton started in July 1742 and discovered Wager river and Repulse Bay. In 1746 Captain W. Moor made another voyage in the same direction, and explored the Wager Inlet. Captain Coats, who was in the service of the company 1727-51, wrote a useful account of the geography of Hudson’s Bay. Later in the century the Hudson’s Bay Company’s servants made some important land journeys to discover the shores of the American polar ocean. From 1769 to 1772 Samuel Hearne descended the Coppermine river to the polar...

A I abcabc dbc ∣ B, where A and B are poles and a, b, c particles of three different kinds. Of course the same may occur with a more complicated constitution, the condition being that the cyclical order read from A to B is different from that read from B to A. Even with particles all of the same kind we can imagine this sort of polarity produced by such an arrangement as

A I αα a a a aa a a a aa a a a∣B, where the density varies periodically as we pass along the axis, but so that the order of variation is different in passing from A to B and from B to A. There is another sort of polarity produced also by an arrangement such as that described above, but here not along the axis but about it. As we took a cat’s tail as an example of the one, so we may take a sable muff as an example of the other. As we stroke the tail in one direction along the axis, so we stroke the muff in one sense about the axis. This arrangement also produces polarity, for there is a real difference between the two ends of the muff. The one is that into which we put our right hand, the other that into which we put our left hand if the fur is to lie downwards in front. If we reverse the ends we find the fur sticking up in front, and we have thus as little difficulty in distinguishing the two poles from one another in this as in the former sort of polarity.

We can easily imagine the particles of a compound substance to be arranged so as to produce this polarity. To take a simple case,—the molecules of the substance may be formed of three atoms a, b, and c, arranged a 0 with c the planes of the molecules all at right angles to the axis, so that on turning the substance about the axis in one sense the atoms in every molecule follow each other in the order abc, and of course in the opposite order when the rotation is reversed.

In these examples the polarity is due to an arrangement of the matter at rest, but both kinds of polarity may be produced by motion. Thus a rotating body has polarity of the second kind; the axis is the axis of rotation, and the two poles differ from each other as the two ends of a muff do. A wire along which a current of electricity is passing has polarity of the first kind; and a magnet, in which currents of electricity may be supposed to circulate about the axis, has polarity of the second kind.

There is an important difference between these two kinds of polarity. We have seen that they depend on two different conditions—the one on an arrangement of matter or motion along the axis, the other on a similar arrangement about the axis. This gives rise to a difference in their relation to their mirror image.

If we hang up a cat’s tail by one end, say the A end, in front of a mirror, we see in the mirror the image of a cat’s tail hanging by its A end. But if we hang up a muff by one end, say the right-hand end, before a mirror, we see in the mirror the image of a muff hanging by its left-hand end. If we put our hands into the muff in the usual way and stand before the mirror we see a person with his hands in a muff in the usual way. But his right and left hands correspond to our left and right hands respectively, and the right and left ends of the muff in the mirror are the images of the left and right ends respectively of the real muff. Thus the mirror image of a body having polarity of the second kind has its polarity reversed.

But the muff and its image are not truly enantiomorph. They differ in position but in nothing else. Turn the one round and it will fit the other.

Magnetic and electric polarity having been already discussed under Electricity and Magnetism, we shall here consider some cases of crystalline polarity.

Both kinds of polarity occur in crystals.

We have no direct means of ascertaining how the ultimate particles of a crystal are arranged, but it seems reasonable to suppose that there is a relation between the form of the crystal and the structure of its smallest parts; and, when we find the crystals of particular substances always showing polarity of the one or the other kind, we naturally suspect that this is the external indication of such an arrangement of the particles as has been shown above to be capable of producing structural polarity. Of crystalline polarity of the first kind the most striking instances are tourmaline and electric calamine (hydrated silicate of zinc), forms of which are shown in figs. 1 and 2, in which it will be seen that the crystals are not similarly terminated at the two ends. It is this kind of crystalline polarity (often called “hemimorphism”) which (as was first observed by Haiiy and more fully investigated by Gustav Rose and by Hankel) is associated with pyroelectricity (see Mineralogy, vol. xvi. p. 376). It is worthy of note that the crystalline polarity and the physical (electric) polarity occurring in the same substances are both of the kind not inverted by reflexion in a mirror.

As an instance of the same kind of crystalline polarity of a somewhat more complicated character, also associated with pyroelectricity, we may take boracite. The crystals of this mineral exhibit combinations of the cube, the rhombic dodecahedron, and the tetrahedron, as shown in fig. 3. If four lines are drawn corresponding to the four diagonals of the cube, it will be observed that at the two ends of each of these axes the crystal is differently developed. (In the figure one of these axes is indicated by the dotted line.) These axes, therefore, resemble the single axis in tourmaline and electric calamine, and are also axes of pyroelectricity, the end at which the tetrahedral face is situated being the antilogous pole.

Scheelite, apatite, ilmenite, and fergusonite are examples of crystalline polarity of the second kind. Figs. 4, 5, and 6 are representations of forms of ilmeni te, apatite, and fergusonite.

Crystalline polarity of both kinds no doubt depends on the arrangement of the molecules and on their structure; it manifests itself by the occurrence of hemihedral or hemimorphic forms. A crystal may have a polar structure although these external marks of polarity are absent, just as the faces parallel to planes of cleavage do not appear on every crystal.

Another kind of contrast between the two complementary hemihedral forms of the same substance may be mentioned here.

Marbach observed that different specimens of iron pyrites (and also of cobalt glance) have very different thermoelectric characters, differing indeed from one another more than bismuth and antimony. Gustav Rose showed that these thermoelectrically opposite kinds are also crystallographically opposite. There is indeed no geometrical difference between two opposite hemihedral forms in the regular system, but Rose detected a difference in the lustre and striation of the faces of the two kinds, and by examining the rare cases in which the two opposite pentagonal dodecahedra or tetragonal icositetrahedra occur on the same crystal proved that the one surface character belongs to the one, the other surface character to the other of the two complementary hemihedra.

Enantiomorphism..— A figure having polarity of the first kind gives a mirror image resembling itself in form and in position; a figure having polarity of the second kind gives a mirror image resembling itself in form but not in position—the poles being inverted. A figure the axis of which has both kinds of polarity will therefore give a mirror image not superposable to the figure itself, because the polarity of the second kind is reversed while that of the first kind remains unchanged. The figure and its mirror image are enantiomorph, as well as polar. We can construct a figure which is enantiomorph to its mirror image but not polar. Imagine a muff so made that in one half the fur lies the one way, and the opposite way in the other half (fig. 7, where the arrow-heads indicate the lie of the fur). In whichever way we put our hands into this muff one end will be wrong; the muff in the figure has, in fact, two righthand ends. It has therefore no polarity; the two ends are exactly alike. But there are two ways in which such a non-polar muff could be made—with two right-hand ends as in the figure, or with two left-hand ends, and these two forms are enantiomorph. A helix or screw has similar properties (compare fig. 8 with fig. 7); if uniform it is non-polar, but is either rightor left-handed. Hence the property which each of two enantiomorph bodies possesses has been called by Sir William Thomson “hélicoïdal asymmetry.”

As we have crystals exhibiting polarity of both kinds, so we have also enantiomorph crystals, indeed the word enantiomorph was first used by Naumann to express the relation between such crystals. The crystallographic theory of enantiomorph crystals has been very fully worked out. We may divide them into two groups— (1) those in which the hélicoïdal asymmetry depends on the presence of tetartohedral forms of the regular or of the hexagonal system, and (*2) those in which it depends on the presence of hemihedral forms of the rhombic system or hemimorphic forms of the monoclinic system.

In the first group the asymmetry seems to be produced by the manner in which the molecules, themselves symmetrical, are arranged in the crystal. In the second group the molecules themselves appear to have hélicoïdal asymmetry. This is shown by the action of these substances on polarized light. We shall take examples from each group. If we allow a solution of sodium chlorate to crystallize we find that the crystals, which belong to the regular system, are of two kinds enantiomorph to each other. These are represented in fig. 9. The enantiomorphism depends on the combination of the tetrahedron and the pentagonal dodecahedron. Now when a ray of plane polarized light is passed through one of these crystals the plane of polarization is rotated, the amount of rotation being proportional to the length of the path in the crystal. The crystals having the form a rotate to the right, those having the form b to the left. They are therefore optically as well as crystallographically enantiomorph. But a solution of sodium chlorate is without action on the plane of polarization, even if the solution be made by dissolving only right-handed or only left-handed crystals, and if a crystal be fused the fused mass is optically inactive, so that it would seem that the optical activity depends on the arrangement of the molecules in the crystal and not on any enantiomorphism in the molecules. The enantiomorphism of quartz crystals is indicated by the presence of faces of a tetartohedral form (vol. xvi. p. 389). The two kinds of crystals rotate the plane of polarization equally, but in opposite senses, when a plane polarized ray is passed through a section cut at right angles to the axis of the crystal. Here also the optical activity ceases when crystalline structure is destroyed by fusion or solution.

Right-handed and left-handed tartaric acids crystallize in enantiomorph forms (fig. 10). Their solutions are optic ally active, the amount of the rotation for the same strength of solution and the same length of path in it being the same in both acids, but the sense of the rotation is right-handed in the one and left-handed in the other. It iε clear that here we have to do with enantiomorph molecules. In ordinary physical properties such as density, solubility, refracting power—in short, in everything not involving rightor left-handedness— the acids are identical. When mixed in equal proportions they unite and form racemic acid which is optically inactive, and from racemic acid we can by various means recover unchanged the right and left-handed tartaric acids. We now know a considerable number of cases where, as in that of the two tartaric acids, both enantiomorphs have been discovered, and many where only one has as yet been found.

It is natural that we should ask what peculiarity of constitution can give a molecule this hélicoïdal asymmetry? Λ very ingenious answer to this question was given simultaneously and independently by the French chemist Le Bel and the Dutch chemist Van ’ t Hoff. We shall give a short statement of the essential points of this interesting theory.

All the known substances which are optically active in solution are compounds of carbon, and may be regarded as derived from marsh gas, a compound of one atom of carbon and four of hydrogen, by the replacement of hydrogen by other elements or compound radicals. Now we do not know how the atoms of hydrogen are actually arranged relatively to each other and to the atom of carbon in the molecule of marsh gas, but, if we may make a supposition on the subject, the most simple is to imagine the four hydrogen atoms at the apices of a regular tetrahedron in the centre of which is the carbon atom as in the diagrams (fig. 11), where C represents the position of the carbon atom and α, β, γ, δ that of the four atoms of hydrogen.

If these hydrogen atoms are replaced by atoms of other elements or by compound radicals we should expect a change of form of the tetrahedron. If two or more of the atoms or radicals united to the carbon atom are similar there is only one way of arranging them, but if they are all different there are two ways in which they may be arranged, as indicated in the figures. It will be seen that these two arrangements are enantiomorph. In the figures the tetrahedron is represented as regular, but if the distance from C depends on the nature of the atom, the tetrahedron, when a, β, γ, and δ are all different, will not be symmetrical, but its two forms will be enantiomorph. A carbon atom combined with four different atoms or compound radicals may therefore be called an asymmetric carbon atom.

Now all substances of ascertained constitution, the solutions of which are optically active, contain an asymmetric carbon atom, and their molecules should therefore, on the above hypothesis, have hélicoïdal asymmetry.

The converse is not generally true. Many substances contain an asymmetric carbon atom but are optically inactive. It is easy to reconcile this with the theory; indeed, a little consideration will show that it is a necessary consequence of it.

Let us suppose that we have the symmetrical combination of C with a, a, β, γ and that we treat the substance in such a way that one a is replaced by δ. The new arrangement is asymmetrical, and will be right or left as the one or the other α is replaced. But the chances for the two are equal, and therefore, as the number of molecules in any quantity we can deal with is very great, the ratio of the number of right-handed molecules in the new substance to the number of left-handed ones will be sensibly that of unity. It is therefore evident that by ordinary chemical processes we cannot expect to produce optically active from optically inactive substances; all that we can get is an inactive mixture of equal quantities of the two oppositely active substances.

As these two substances have identical properties in every respect where rightor left-handedness is not involved, the problem of separating them is a difficult one. We may note three distinct ways in which the separation can be effected.

(1) By crystallization. For example, the right and left double tartrates of soda and ammonia crystallize in enantiomorph forms (fig. 12) and are less soluble in water than the double racemate formed by their union. If therefore racemic acid (the optically inactive compound of equal quantities of right and left tartaric acids) is half neutralized with soda and half with ammonia, we obtain an optically inactive solution containing a mixture of the two double salts. If this solution is allowed to crystallize each salt crystallizes independently, and the crystals can be separated by picking them out. Further, a supersaturated solution of the one double salt is not made to crystallize by contact with a crystal of the other, so that if we make a supersaturated solution of the inactive mixture and drop into the vessel, at different places, two crystals one of the right the other of the left salt, crystallization occurs at each place, at the one of the one kind and at the other of the other.

(2) By the action of another optically active substance. While the salts of the two opposite tartaric acids with an inactive base are precisely alike in solubility, density, and other physical characters, and, if they crystallize, crystallize in the same form (or in enantiomorph forms), it is not at all so when the base is optically active; thus right tartaric acid forms a crystalline salt with left asparagine, while with the same base left tartaric acid gives an uncrystallizable compound.

(3) By the action of living ferments. The minute fungi which act as ferments do not show any rightor left-handedness as far as their obvious anatomical structure is concerned, but Pasteur has shown that some of them are, if we may use the expression, physiologically asymmetrical. As an example we may give the very interesting case of mandelic acid. This acid, which stands to benzoic aldehyde (bitter almond oil) in the same relation as lactic acid does to common aldehyde, contains one asymmetric carbon atom in its molecule. It is optically inactive, and therefore, if Le Bel and Van ’ t Hoff’s theory is true, it must be a mixture of two oppositely active acids. Now Lewko-witsch found that when Penicilium, glaucum, is cultivated in a solution of mandelic acid fermentation takes place. This goes on until exactly half of the acid is decomposed, and what remains has all the properties of mandelic acid, but is optically active; it is the right-handed component of the mixture, the growing fungus having consumed the other.

There is an interesting peculiarity of tartaric acid discovered by Pasteur (to whom we owe nearly all our knowledge of the relations between optical activity and crystalline form in tartaric acid) which is of importance in connexion with the theory we have just been explaining.

We have not only right and left tartaric acid and racemic acid, the inactive compound of the two, but also a kind of tartaric acid which is inactive but incapable of being separated into the two oppositely...

The width of the approach to this region by the Atlantic Ocean, in its narrowest part, is 660 miles, from the Norwegian Islands of Lofoten to Cane Hodgson on the east coast of Greenland. The width of the approach by Davis Strait in the narrowest part, which is nearly on the Arctic Circle, is 165 miles; and the width of Behring Strait is 45 miles. Thus out of the whole ring of 8640 miles along which the Arctic Circle passes about 900 miles is over water. This great environment of land is an important feature in the physical condition of the north polar region. It influences the currents and the movements of ice, which are still further affected by the archipelagos lying to the northward of the fringing coast-lines. The larger opening into the north polar region by way of the Atlantic is divided from Davis Strait by the vast mass of Greenland, which, extending for an unknown distance to the north, crosses the Arctic Circle and ends in a point at Cape Farewell in 59° 48' N. lat. It was inevitable that the routes across the Arctic Circle by the Atlantic and Davis Strait should first become known, because these openings to the polar regions are nearest to the temperate regions inhabited by the exploring nations of Europe.

A rumour respecting Thule, an island on the Arctic Circle, first brought by Pytheas (g ’.f.), and afterwards doubted, was the extent of the knowledge of the north polar regions with which the ancients can be credited. But in the 9th century some Irish monks really appear to have visited Iceland. The monk Dicuil, writing about 825, says that he had information from brethren who had been at Thule during several months, and they reported that there was no darkness at the summer solstice.

King Alfred told the story of the first polar voyages undertaken for discovery and the acquisition of knowledge, in his very free translation of Orosius. In the first book he inserted the narrative of the voyages of Other and Wulfstan, related to him by the former explorer himself. The localities mentioned in the story cannot now be identified, but it seems probable that Other rounded the North Cape, and visited the coast of Lapland.

The Norsemen of the Scandinavian peninsula, after colonizing Iceland, were the first to make permanent settlements on the shores of Greenland, and to extend their voyages beyond the Arctic circle along the western coast of that vast glacier-covered land. See Greenland. The Norse colonies in Greenland at Brattelid and Einarsfjord did not extend farther north than 65°, but in the summer time the settlers carried on their seal hunting far beyond the Arctic circle. One of their runic stones was found in a cairn in latitude 73° N., the inscription showing that the date of its being left there was 1235. Another expedition is believed, on good grounds, to have reached a latitude of 75° 46' N. in Barrow Strait, about the year 1266. Their ordinary hunting grounds were in 73° N., to the north of the modern Danish settlement of Upernivik. For the visits of the Greenlanders to the American coasts see America, vol i. p. 706.

The last trace of communication between Greenland and Norway was in 1347. The black death broke out in Norway and the far off colony was forgotten; while the settlers were attacked by Skrellings or Eskimo, who overran the West Bygd in 1349. Ivar Bardsen, the steward to the bishopric of Gardar in the East Bygd, and a native of Greenland, was sent to convey help to the sister colony. A document, of which Ivar Bardsen was the author, has been preserved. It consists of sailing directions for reaching the colony from Iceland, and a chorography of the colony itself. It is the oldest work on arctic geography, and is still valuable iu the study of all questions relating to the early settlements in Greenland. From 1400 to 1448 there was some communication, at long intervals, with the Greenland settlers, but during the latter half of that century it entirely ceased. Here then the ancient portion of polar history comes to an end. The next period, comprised in the 16th and 17th centuries, was that in which expeditions were despatched across the Arctic Circle to discover a shorter route to India.

Sebastian Cabot, whose own northern voyages have been spoken of in the article Cabot, was the chief promoter of the expedition which sailed under Sir Hugh Willoughby and Richard Chancellor on the 20th May 1553, “for the search and discovery of the northern parts of the world, to open a way and passage to our men, for travel to new and unknown kingdoms.” Willoughby, after discovering Nova Zembla (Novaya Zemlya) by sighting the coast of Goose Land, resolved to winter in a harbour of Lapland, where he and all his men perished of starvation and cold. Chancellor reached the Bay of St Nicholas, and landed near Archangel, which was then only a castle. He undertook a journey to Moscow, made arrangements for commercial intercourse with Russia, and returned safely. His success proved the practical utility of polar voyages. It led to a charter being granted to the Association of Merchant Adventurers, of which Cabot was named governor for life, and gave fresh impulse to arctic discovery.

In the spring of 1556 Stephen Burrough, who had served with Chancellor, sailed in a small pinnace called the “Searchthrift,” and kept a careful journal of his voyage. He went to Archangel, and discovered the strait leading into the Kara Sea, between Nova Zembla and the island of Waigat. In May 1580 the company fitted out two vessels under Arthur Pet and Charles Jackman, with orders to pass through the strait discovered by Burrough, and thence to sail eastward beyond the mouth of the river Obi. Pet discovered the strait into the Kara Sea, between Waigat and the mainland, and made a persevering effort to push eastward, returning to England in safety. Jackman, after wintering in a Norwegian port, sailed homeward but was never heard of again.

In 1558 a narrative and map were published at Venice which profoundly affected the system of polar cartography for many years afterwards. The publication was the handiwork of a Venetian nobleman named Niccolö Zeno. Towards the close of the 14th century his ancestor, also named Niccolb, made a voyage into the northern seas, and entered the service of a chief named Zichnmi as pilot. He was eventually joined by his brother Antonio, and four years afterwards died in the country he called Frislanda. Antonio remained ten years longer in the service of Zichnmi, and then returned to Venice. The younger Niccolo found the mutilated letters of these brothers in the Zeni palace, with a map; and out of these materials he prepared the narrative and map which he published, adding what he considered improvements to the map. It was accepted at the time as a work of high authority, and the names on it continued to appear on subsequent maps for at least a century, puzzling both geographers at home and explorers in the field. After a very exhaustive study of the subject, Mr Major has identified the names on the Zeni map, as follows :—Engronelant, Greenland; Islanda, Iceland; Estland, Shetlands; Fr island, Faroe Isles; Markland, Nova Scotia; Estotiland, Newfoundland; Drogeo, coast of North America; Icaria, coast of Kerry in Ireland.

We now come to the voyages of Frobisher, undertaken to obtain the means for equipping an expedition for the discovery of a shorter route to India by the north-west. Aided by Michael Lok, an influential merchant and diligent student of geography, Frobisher sailed, in the spring of 1576, with two small vessels of 20 to 25 tons, called the “Gabriel’’and “Michael.” But the “Michael” parted company in the Atlantic, the voyage being continued in the “Gabriel” alone. On 20th July Frobisher sighted high land, which he called Queen Elizabeth’s Foreland; and the next day he entered the strait to which he gave his own name, calling the land “Meta Incognita.” On his return in the autumn, with various specimens of plants and stones, the “goldfinders” in London took it into their heads that a glittering piece of mica-schist contained gold ore. This caused great excitement, and much larger expeditions were fitted out, in the two following years, to collect these precious ores. As many as fifteen vessels formed the third expedition of 1578, and one of them, a busse (small ship) of Bridgwater, called the “Emma,” reported that on her voyage home she had sighted land in the Atlantic and sailed along it for three days. It was never seen again, and may have been only a large ice-field; but it soon found its place on maps and charts under the name of Busse Island, and afterwards as “sunken land of Busse.” For a long time Frobisher Strait was supposed to pass through Greenland, and, the map of the Zeni adding to the confusion, the land to the south was called Frislanda. It is now clear that Frobisher never saw Greenland, and that his strait and “Meta Incognita” are on the American side of Davis Strait. What Frobisher really did was to establish the fact that there were two or more wide openings leading to the westward, between latitudes 60° and 63°, on the American coast.

John Davis, who made the next attempt to discover a north-west passage, was one of the most scientific seamen of that age. He made three voyages in three successive years, aided and fitted out by William Sanderson and other merchants. Sailing from Dartmouth on the 7th June 1585, he was the first to visit the west coast of Greenland subsequent to the abandonment of the Norse colonies. He called it “The Land of Desolation.” He discovered Gilbert’s Sound in 64° 10' (where now stands the Danish settlement of Godthaab) and then, crossing the strait which bears his name, he traced a portion of its western shore. In the second voyage Davis noted what he calls “a furious overfall,” which was the tide flowing into Hudson Strait; and in his third voyage, in 1587, he advanced far up his own strait, and reached a lofty granite island in 72° 41' N. which he named Sanderson’s Hope. He considered that there was good hope of advancing farther, and reported “no ice towards the north, but a great sea, free, large, very salt and blue, and of an unsearchable depth.” The results of his discoveries are shown on the Molyneux globe which is now in the library of the Middle Temple; but he found it impossible to reconcile his work with that of Frobisher, and with the Zeni map. In 1595 Davis published a tract entitled The Worlds Hydrographical Description, in which he ably states the arguments in favour of the discovery of a northwest passage.

The Dutch also saw the importance of a northern route to China and India, especially as the routes by the Cape of Good Hope and Magellan’s Strait were jealously guarded by Spaniards and Portuguese. Their plan was to proceed by the north-east along the coast of Asia. As early as 1578 Dutch merchants had opened a trade with Kola and Archangel, but it was Peter Plancius, the learned cosmographer of Amsterdam, who conceived the idea of discovering a north-east passage. In 1594 the Amsterdam merchants fitted out a vessel of 100 tons, under the command of Willem Barents. The coast of Nova Zembla was sighted on the 4th July, and from that date until the 3rd of August Barents continued perseveringly to seek a way through the ice-floes, and discovered the whole western coast as far as Cape Nassau and the Orange Islands at the north-west extremity. The second voyage in which Barents Was engaged merely made an unsuccessful attempt to enter the Kara Sea. The third was more important. Two vessels sailed from Amsterdam on May 13, 1596, under the command of Jacob van Heemskerck and Corneliszoon Rijp. Barents accompanied Heemskerck as pilot, and Gerrit de Veer, the historian of the voyage, was on board as mate. The masses of ice in the straits leading to the Sea of Kara, and the impenetrable nature of the pack near Nova Zembla, had suggested the advisability of avoiding the land and, by keeping a northerly course, of seeking a passage in the open sea. They sailed northwards and on 9th June discovered Bear Island. Continuing on the same course they sighted the north-western extreme of Spitzbergen, soon afterwards being stopped by the polar pack ice. This important discovery was named “Nieue Land,” and was believed to be a part of Greenland. Arriving at Bear Island.again on 1st July, Rijp parted company, while Heemskerck and Barents proceeded eastward, intending to pass round the northern extreme of Nova Zembla. On the 26th August they reached Ice Haven, after rounding the northern extremity of the land. Here they wintered in a house built out of driftwood and planks from the wrecked vessel. In the spring they made their way in boats to the Lapland coast; but Barents died during the voyage. This was the first time that an arctic winter was successfully faced. The voyages of Barents stand in the first rank among the polar enterprises of the 16th century. They led directly to the flourishing whale and seal fisheries which long enriched the Netherlands.

The English enterprises were continued by the Muscovy Company, and by associations of patriotic merchants of London; and even the East India Company sent an expedition under Captain Waymouth in 1602 to seek for a passage by the opening seen by Davis, but it had no success.

The best servant of the Muscovy Company in the work of polar discovery was Henry Hudson. His first voyage was undertaken in 1607, when he discovered the most northern known point of the east coast of Greenland in 73° N. named “Hold with Hope,” and examined the edge of the ice between Greenland and Spitzbergen, reaching a latitude of 80° 23' N. On his way home he discovered the island now called Jan Mayen, which he named “Hudson’s Tutches.” In his second expedition, during the season of 1608, Hudson examined the edge of the ice between Spitzbergen and Nova Zembla. In his third voyage he was employed by the Dutch East India Company, and he explored the coasts of North America, discovering the Hudson river. In 1610 he discovered Hudson’s Strait, and the great bay which bears and immortalizes his name (see Hudson, vol. xii. p. 332).

The voyages of Hudson led immediately to the Spitzbergen whale fishery. From 1609 to 1612 Jonas Poole made four voyages for the prosecution of this lucrative business, and he was followed by Fotherby, Baffin, Joseph, and Edge. These bold seamen, while in the pursuit of whales, added considerably to the knowledge of the archipelago of islands known under the name of Spitzbergen, and in 1617 Captain Edge discovered a large island to the eastward, which he named Wyche’s Land.

At about the same period the kings of Denmark began to send expeditions for the rediscovery of the lost Greenland colony. In 1605 Christian IV. sent out three ships, under the Englishmen Cunningham and Hall, and a Dane named Lindenov, which reached the western coast of Greenland and had much intercourse with the Eskimo. Other expeditions followed in 1606-7.

Meanwhile the merchant adventurers of London continued to push forward the western discovery. Sir Thomas Button, in command of two ships, the “Resolution” and “Discovery,” sailed from England in May 1612. He entered Hudson’s Bay, crossed to its western shore, and wintered at the mouth of a river in 57° 10' N. which was named Nelson’s river after the master of the ship, who died and was buried there. Next year Button explored the shore of Southampton Island as far as 65° N., and returned home in the autumn of 1613. An expedition under Captain Gibbons, despatched in 1614, was a miserable failure; but in 1615 Robert By lot as master and William Baffin as pilot and navigator in the “Discovery” examined the coasts of Hudson’s Strait, and Baffin, who was the equal of Davis as a scientific seaman, made many valuable observations. In 1616 Bylot and Baffin again set out in the “Discovery.” Sailing up Davis Strait they passed that navigator’s farthest point at Sanderson’s Hope, and sailed round the great channel with smaller channels leading from it which has been known ever since as Baffin’s Bay. Baffin named the most northern opening Smith Sound, after the first governor of the East India Company, and the munificent promoter of the voyage, Sir Thomas Smith. Wolstenholme Sound, Cape Dudley Digges, Hakluyt Island, Lancaster Sound, Jones Sound, and the Cary Islands were named after other promoters and friends of the voyage. The fame of Baffin mainly rests upon the discovery of the great channel extending north from Davis Strait; but it was unjustly dimmed for many years, owing to the omission of Purchas to publish the skilful navigator’s tabulated journal and map in his great collection of voyages. It may be mentioned, as an illustration of the value of these early voyages to modern science, that Professor Hansteen of Christiania made use of Baffin’s magnetic observations in the compilation of his series of magnetic maps.

In 1631 two expeditions were despatched, one by the merchants of London, the others by those of Bristol. In the London ship “Charles” Luke Fox explored the western side of Hudson’s Bay as far as the place called “Sir Thomas Roe’s Welcome.” In August he encountered Captain James and the Bristol ship “Maria” in the middle of Hudson’s Bay, and went north until he reached “North-west Fox his furthest,” in 66° 47' N. He then returned home and wrote the most entertaining of all the polar narratives. Captain James was obliged to winter off Charlton Island, in the southern extreme of Baffin’s Bay, and did not return until October 1632. Another English voyager, Captain Wood, attempted, without success, to discover a north-east passage in 1676.

The 16th and 17th centuries were periods of discovery and daring enterprise, and the results gained by the gallant seamen of those times are marvellous when we consider their insignificant resources and the small size of their vessels. Hudson’s Strait and Bay, Davis Strait, and Baffin’s Bay, the icy seas from Greenland to Spitzbergen and from Spitzbergen to Nova Zembla, had all been discovered. The following century was rather a period of reaping the results of former efforts than of discovery. It saw the settlement of the Hudson's Bay Territory and of Greenland, and the development of the whale and seal fisheries.

The Hudson’s Bay Company was incorporated in 1670, and Prince Rupert sent out Zachariah Gillan, who wintered at Rupert’s river. At first very slow progress was made. A voyage undertaken by Mr Knight, who had been appointed governor of the factory at Nelson river, was unfortunate, as his two ships were lost and the crews perished. This was in 1719. In 1722 John Scroggs was sent from Churchill river in search of the missing ships, but merely entered Sir Thomas Roe’s Welcome and returned. His reports were believed to offer decisive proofs of the existence of a passage into the Pacific; and a naval expedition was despatched under the command of Captain Christopher Middleton, consisting of the “Discovery” pink and the “Furnace” bomb. Wintering in Churchill river, Middleton started in July 1742 and discovered Wager river and Repulse Bay. In 1746 Captain W. Moor made another voyage in the same direction, and explored the Wager Inlet. Captain Coats, who was in the service of the company 1727-51, wrote a useful account of the geography of Hudson’s Bay. Later in the century the Hudson’s Bay Company’s servants made some important land journeys to discover the shores of the American polar ocean. From 1769 to 1772 Samuel Hearne descended the Coppermine river to the polar...