Chapter V: Front Matter (5)

The principles and methods of surveying and position finding had by
this time become well advanced, and the most remarkable example of the
early application of these improvements is to be found in the survey
of China by Jesuit missionaries. They first prepared a map of the
country round Peking, which was submitted to the emperor Kang-hi, and,
being satisfied with the accuracy of the European method of surveying,
he resolved to have a survey made of the whole empire on the same
principles. This great work was begun in July 1708, and the completed
maps were presented to the emperor in 1718. The records preserved in
each city were examined, topographical information was diligently
collected, and the Jesuit fathers checked their triangulation by
meridian altitudes of the sun and pole star and by a system of
remeasurements. The result was a more accurate map of China than
existed, at that time, of any country in Europe. Kang-hi next ordered
a similar map to be made of Tibet, the survey being executed by two
lamas who were carefully trained as surveyors by the Jesuits at
Peking. From these surveys were constructed the well-known maps which
were forwarded to Duhalde, and which D'Anville utilized for his atlas.

The 18th century.

Asia.

Several European missionaries had previously found their way from
India to Tibet. Antonio Andrada, in 1624, was the first European to
enter Tibet since the visit of Friar Odoric in 1325. The next journey
was that of Fathers Grueber and Dorville about 1660, who succeeded in
passing from China, through Tibet, into India. In 1715 Fathers
Desideri and Freyre made their way from Agra, across the Himalayas, to
Lhasa, and the Capuchin Friar Orazio della Penna resided in that city
from 1735 until 1747. But the most remarkable journey in this
direction was performed by a Dutch traveller named Samuel van de
Putte. He left Holland in 1718, went by land through Persia to India,
and eventually made his way to Lhasa, where he resided for a long
time. He went thence to China, returned to Lhasa, and was in India in
time to be an eye-witness of the sack of Delhi by Nadir Shah in 1737.
In 1743 he left India and died at Batavia on the 27th of September
1745. The premature death of this illustrious traveller is the more to
be lamented because his vast knowledge died with him. Two English
missions sent by Warren Hastings to Tibet, one led by George Bogle in
1774, and the other by Captain Turner in 1783, complete Tibetan
exploration in the 18th century.

From Persia much new information was supplied by Jean Chardin, Jean
Tavernier, Charles Hamilton, Jean de Thevenot and Father Jude
Krusinski, and by English traders on the Caspian. In 1738 John Elton
traded between Astrakhan and the Persian port of Enzeli on the
Caspian, and undertook to build a fleet for Nadir Shah. Another
English merchant, named Jonas Hanway, arrived at Astrabad from Russia,
and travelled to the camp of Nadir at Kazvin. One lasting and valuable
result of Hanway's wanderings was a charming book of travels. In 1700
Guillaume Delisle published his map of the continents of the Old
World; and his successor D'Anville produced his map of India in 1752.
D'Anville's map contained all that was then known, but ten years
afterwards Major Rennell began his surveying labours, which extended
over the period from 1763 to 1782. His survey covered an area 900 m.
long by 300 wide, from the eastern confines of Bengal to Agra, and
from the Himalayas to Calpi. Rennell was indefatigable in collecting
geographical information; his Bengal atlas appeared in 1781, his
famous map of India in 1788 and the memoir in 1792. Surveys were also
made along the Indian coasts.

Arabia received very careful attention, in the 18th century, from the
Danish scientific mission, which included Carsten Niebuhr among its
members. Niebuhr landed at Loheia, on the coast of Yemen, in December
1762, and went by land to Sana. All the other members of the mission
died, but he proceeded from Mokha to Bombay. He then made a journey
through Persia and Syria to Constantinople, returning to Copenhagen in
1767. His valuable work, the _Description of Arabia_, was published in
1772, and was followed in 1774-1778 by two volumes of travels in Asia.
The great traveller survived until 1815, when he died at the age of
eighty-two.

Africa.

James Bruce of Kinnaird, the contemporary of Niebuhr, was equally
devoted to Eastern travel; and his principal geographical work was the
tracing of the Blue Nile from its source to its junction with the
White Nile. Before the death of Bruce an African Association was
formed, in 1788, for collecting information respecting the interior of
that continent, with Major Rennell and Sir Joseph Banks as leading
members. The association first employed John Ledyard (who had
previously made an extraordinary journey into Siberia) to cross Africa
from east to west on the parallel of the Niger, and William Lucas to
cross the Sahara to Fezzan. Lucas went from Tripoli to Mesurata,
obtained some information respecting Fezzan and returned in 1789. One
of the chief problems the association wished to solve was that of the
existence and course of the river Niger, which was believed by some
authorities to be identical with the Congo. Mungo Park, then an
assistant surgeon of an Indiaman, volunteered his services, which were
accepted by the association, and in 1795 he succeeded in reaching the
town of Segu on the Niger, but was prevented from continuing his
journey to Timbuktu. Five years later he accepted an offer from the
government to command an expedition into the interior of Africa, the
plan being to cross from the Gambia to the Niger and descend the
latter river to the sea. After losing most of his companions he
himself and the rest perished in a rapid on the Niger at Busa, having
been attacked from the shore by order of a chief who thought he had
not received suitable presents. His work, however, had established the
fact that the Niger was not identical with the Congo.

While the British were at work in the direction of the Niger, the
Portuguese were not unmindful of their old exploring fame. In 1798 Dr
F.J.M. de Lacerda, an accomplished astronomer, was appointed to
command a scientific expedition of discovery to the north of the
Zambesi. He started in July, crossed the Muchenja Mountains, and
reached the capital of the Cazembe, where he died of fever. Lacerda
left a valuable record of his adventurous journey; but with Mungo Park
and Lacerda the history of African exploration in the 18th century
closes.

South America.

In South America scientific exploration was active during this period.
The great geographical event of the century, as regards that
continent, was the measurement of an arc of the meridian. The
undertaking was proposed by the French Academy as part of an
investigation with the object of ascertaining the length of the degree
near the equator and near the pole respectively so as to determine the
figure of the earth. A commission left Paris in 1735, consisting of
Charles Marie de la Condamine, Pierre Bouguer, Louis Godin and Joseph
de Jussieu the naturalist. Spain appointed two accomplished naval
officers, the brothers Ulloa, as coadjutors. The operations were
carried on during eight years on a plain to the south of Quito; and,
in addition to his memoir on this memorable measurement, La Condamine
collected much valuable geographical information during a voyage down
the Amazon. The arc measured was 3 deg. 7' 3" in length; and the work
consisted of two measured bases connected by a series of triangles,
one north and the other south of the equator, on the meridian of
Quito. Contemporaneously, in 1738, Pierre Louis Moreau de Maupertuis,
Alexis Claude Clairaut, Charles Etienne Louis Camus, Pierre Charles
Lemonnier and the Swedish physicist Celsius measured an arc of the
meridian in Lapland.

The Pacific Ocean.

The British and French governments despatched several expeditions of
discovery into the Pacific and round the world during the 18th
century. They were preceded by the wonderful and romantic voyages of
the buccaneers. The narratives of such men as Woodes Rogers, Edward
Davis, George Shelvocke, Clipperton and William Dampier, can never
fail to interest, while they are not without geographical value. The
works of Dampier are especially valuable, and the narratives of
William Funnell and Lionel Wafer furnished the best accounts then
extant of the Isthmus of Darien. Dampier's literary ability eventually
secured for him a commission in the king's service; and he was sent on
a voyage of discovery, during which he explored part of the coasts of
Australia and New Guinea, and discovered the strait which bears his
name between New Guinea and New Britain, returning in 1701. In 1721
Jacob Roggewein was despatched on a voyage of some importance across
the Pacific by the Dutch West India Company, during which he
discovered Easter Island on the 6th of April 1722.

The voyage of Lord Anson to the Pacific in 1740-1744 was of a
predatory character, and he lost more than half his men from scurvy;
while it is not pleasant to reflect that at the very time when the
French and Spaniards were measuring an arc of the meridian at Quito,
the British under Anson were pillaging along the coast of the Pacific
and burning the town of Payta. But a romantic interest attaches to the
wreck of the "Wager," one of Anson's fleet, on a desert island near
Chiloe, for it bore fruit in the charming narrative of Captain John
Byron, which will endure for all time. In 1764 Byron himself was sent
on a voyage of discovery round the world, which led immediately after
his return to the despatch of another to complete his work, under the
command of Captain Samuel Wallis.

The expedition, consisting of the "Dolphin" commanded by Wallis, and
the "Swallow" under Captain Philip Carteret, sailed in September 1766,
but the ships were separated on entering the Pacific from the Strait
of Magellan. Wallis discovered Tahiti on the 19th of June 1767, and he
gave a detailed account of that island. He returned to England in May
1768. Carteret discovered the Charlotte and Gloucester Islands, and
Pitcairn Island on the 2nd of July 1767; revisited the Santa Cruz
group, which was discovered by Mendana and Quiros; and discovered the
strait separating New Britain from New Ireland. He reached Spithead
again in February 1769. Wallis and Carteret were followed very closely
by the French expedition of Bougainville, which sailed from Nantes in
November 1766. Bougainville had first to perform the unpleasant task
of delivering up the Falkland Islands, where he had encouraged the
formation of a French settlement, to the Spaniards. He then entered
the Pacific, and reached Tahiti in April 1768. Passing through the New
Hebrides group he touched at Batavia, and arrived at St Malo after an
absence of two years and four months.

Captain Cook.

The three voyages of Captain James Cook form an era in the history of
geographical discovery. In 1767 he sailed for Tahiti, with the object
of observing the transit of Venus, accompanied by two naturalists, Sir
Joseph Banks and Dr Solander, a pupil of Linnaeus, as well as by two
astronomers. The transit was observed on the 3rd of June 1769. After
exploring Tahiti and the Society group, Cook spent six months
surveying New Zealand, which he discovered to be an island, and the
coast of New South Wales from latitude 38 deg. S. to the northern
extremity. The belief in a vast Antarctic continent stretching far
into the temperate zone had never been abandoned, and was vehemently
asserted by Charles Dalrymple, a disappointed candidate nominated by
the Royal Society for the command of the Transit expedition of 1769.
In 1772 the French explorer Yves Kerguelen de Tremarec had discovered
the land that bears his name in the South Indian Ocean without
recognizing it to be an island, and naturally believed it to be part
of the southern continent.

Cook's second voyage was mainly intended to settle the question of the
existence of such a continent once for all, and to define the limits
of any land that might exist in navigable seas towards the Antarctic
circle. James Cook at his first attempt reached a south latitude of 57
deg. 15'. On a second cruise from the Society Islands, in 1773, he,
first of all men, crossed the Antarctic circle, and was stopped by ice
in 71 deg. 10' S. During the second voyage Cook visited Easter Island,
discovered several islands of the New Hebrides and New Caledonia; and
on his way home by Cape Horn, in March 1774, he discovered the
Sandwich Island group and described South Georgia. He proved
conclusively that any southern continent that might exist lay under
the polar ice. The third voyage was intended to attempt the passage
from the Pacific to the Atlantic by the north-east. The "Resolution"
and "Discovery" sailed in 1776, and Cook again took the route by the
Cape of Good Hope. On reaching the North American coast, he proceeded
northward, fixed the position of the western extremity of America and
surveyed Bering Strait. He was stopped by the ice in 70 deg. 41' N.,
and named the farthest visible point on the American shore Icy Cape.
He then visited the Asiatic shore and discovered Cape North. Returning
to Hawaii, Cook was murdered by the natives. On the 14th of February
1779, his second, Captain Edward Clerke, took command, and proceeding
to Petropavlovsk in the following summer, he again examined the edge
of the ice, but only got as far as 70 deg. 33' N. The ships returned
to England in October 1780.

In 1785 the French government carefully fitted out an expedition of
discovery at Brest, which was placed under the command of Francois La
Perouse, an accomplished and experienced officer. After touching at
Concepcion in Chile and at Easter Island, La Perouse proceeded to
Hawaii and thence to the coast of California, of which he has given a
very interesting account. He then crossed the Pacific to Macao, and in
July 1787 he proceeded to explore the Gulf of Tartary and the shores
of Sakhalin, remaining some time at Castries Bay, so named after the
French minister of marine. Thence he went to the Kurile Islands and
Kamchatka, and sailed from the far north down the meridian to the
Navigator and Friendly Islands. He was in Botany Bay in January 1788;
and sailing thence, the explorer, his ship and crew were never seen
again. Their fate was long uncertain. In September 1791 Captain
Antoine d'Entrecasteaux sailed from Brest with two vessels to seek for
tidings. He visited the New Hebrides, Santa Cruz, New Caledonia and
Solomon Islands, and made careful though rough surveys of the
Louisiade Archipelago, islands north of New Britain and part of New
Guinea. D'Entrecasteaux died on board his ship on the 20th of July
1793, without ascertaining the fate of La Perouse. Captain Peter
Dillon at length ascertained, in 1828, that the ships of La Perouse
had been wrecked on the island of Vanikoro during a hurricane.

The work of Captain Cook bore fruit in many ways. His master, Captain
William Bligh, was sent in the "Bounty" to convey breadfruit plants
from Tahiti to the West Indies. He reached Tahiti in October 1788, and
in April 1789 a mutiny broke out, and he, with several officers and
men, was thrust into an open boat in mid-ocean. During the remarkable
voyage he then made to Timor, Bligh passed amongst the northern
islands of the New Hebrides, which he named the Banks Group, and made
several running surveys. He reached England in March 1790. The
"Pandora," under Captain Edwards, was sent out in search of the
"Bounty," and discovered the islands of Cherry and Mitre, east of the
Santa Cruz group, but she was eventually lost on a reef in Torres
Strait. In 1796-1797 Captain Wilson, in the missionary ship "Duff,"
discovered the Gambier and other islands, and rediscovered the islands
known to and seen by Quiros, but since called the Duff Group. Another
result of Captain Cook's work was the colonization of Australia. On
the 18th of January 1788 Admiral Phillip and Captain Hunter arrived in
Botany Bay in the "Supply" and "Sirius," followed by six transports,
and established a colony at Port Jackson. Surveys were then undertaken
in several directions. In 1795 and 1796 Matthew Flinders and George
Bass were engaged on exploring work in a small boat called the "Tom
Thumb." In 1797 Bass, who had been a surgeon, made an expedition
southwards, continued the work of Cook from Ram Head, and explored the
strait which bears his name, and in 1798 he and Flinders were
surveying on the east coast of Van Diemen's land.

Yet another outcome of Captain Cook's work was the voyage of George
Vancouver, who had served as a midshipman in Cook's second and third
voyages. The Spaniards under Quadra had begun a survey of
north-western America and occupied Nootka Sound, which their
government eventually agreed to surrender. Captain Vancouver was sent
out to receive the cession, and to survey the coast from Cape
Mendocino northwards. He commanded the old "Discovery," and was at
work during the seasons of 1792, 1793 and 1794, wintering at Hawaii.
Returning home in 1795, he completed his narrative and a valuable
series of charts.

Arctic regions.

The 18th century saw the Arctic coast of North America reached at two
points, as well as the first scientific attempt to reach the North
Pole. The Hudson Bay Company had been incorporated in 1670, and its
servants soon extended their operations over a wide area to the north
and west of Canada. In 1741 Captain Christopher Middleton was ordered
to solve the question of a passage from Hudson Bay to the westward.
Leaving Fort Churchill in July 1742, he discovered the Wager river and
Repulse Bay. He was followed by Captain W. Moor in 1746, and Captain
Coats in 1751, who examined the Wager Inlet up to the end. In November
1769 Samuel Hearne was sent by the Hudson Bay Company to discover the
sea on the north side of America, but was obliged to return. In
February 1770 he set out again from Fort Prince of Wales; but, after
great hardships, he was again forced to return to the fort. He started
once more in December 1771, and at length reached the Coppermine
river, which he surveyed to its mouth, but his observations are
unreliable. With the same object Alexander Mackenzie, with a party of
Canadians, set out from Fort Chippewyan on the 3rd of June 1789, and
descending the great river which now bears the explorer's name reached
the Arctic sea.

In February 1773 the Royal Society submitted a proposal to the king
for an expedition towards the North Pole. The expedition was fitted
out under Captains Constantine Phipps and Skeffington Lutwidge, and
the highest latitude reached was 80 deg. 48' N., but no opening was
discovered in the heavy Polar pack. The most important Arctic work in
the 18th century was performed by the Russians, for they succeeded in
delineating the whole of the northern coast of Siberia. Some of this
work was possibly done at a still earlier date. The Cossack Simon
Dezhneff is thought to have made a voyage, in the summer of 1648, from
the river Kolyma, through Bering Strait (which was rediscovered by
Vitus Bering in 1728) to Anadyr. Between 1738 and 1750 Manin and
Sterlegoff made their way in small sloops from the mouth of the
Yenesei as far north as 75 deg. 15' N. The land from Taimyr to Cape
Chelyuskin, the most northern extremity of Siberia, was mapped in many
years of patient exploration by Chelyuskin, who reached the extreme
point (77 deg. 34' N.) in May 1742. To the east of Cape Chelyuskin the
Russians encountered greater difficulties. They built small vessels at
Yakutsk on the Lena, 900 m. from its mouth, whence the first
expedition was despatched under Lieut. Prontschichev in 1735. He
sailed from the mouth of the Lena to the mouth of the Olonek, where he
wintered, and on the 1st of September 1736 he got as far as 77 deg.
29' N., within 5 m. of Cape Chelyuskin. Both he and his young wife
died of scurvy, and the vessel returned. A second expedition, under
Lieut. Laptyev, started from the Lena in 1739, but encountered masses
of drift ice in Chatanga bay, and with this ended the voyages to the
westward of the Lena. Several attempts were also made to navigate the
sea from the Lena to the Kolyma. In 1736 Lieut. Laptyev sailed, but
was stopped by the drift ice in August, and in 1739, during another
trial, he reached the mouth of the Indigirka, where he wintered. In
the season of 1740 he continued his voyage to beyond the Kolyma,
wintering at Nizhni Kolymsk. In September 1740 Vitus Bering sailed
from Okhotsk on a second Arctic voyage with George William Steller on
board as naturalist. In June 1741 he named the magnificent peak on the
coast of North America Mount St Elias and explored the Aleutian
Islands. In November the ship was wrecked on Bering Island; and the
gallant Dane, worn out with scurvy, died there on the 8th of December
1741. In March 1770 a merchant named Liakhov saw a large herd of
reindeer coming from the north to the Siberian coast, which induced
him to start in a sledge in the direction whence they came. Thus he
reached the New Siberian or Liakhov Islands, and for years afterwards
the seekers for fossil ivory resorted to them. The Russian Captain
Vassili Chitschakov in 1765 and 1766 made two persevering attempts to
penetrate the ice north of Spitsbergen, and reached 80 deg. 30' N.,
while Russian parties twice wintered at Bell Sound.

Geographical societies.

In reviewing the progress of geographical discovery thus far, it has
been possible to keep fairly closely to a chronological order. But in
the 19th century and after exploring work was so generally and
steadily maintained in all directions, and was in so many cases
narrowed down from long journeys to detailed surveys within relatively
small areas, that it becomes desirable to cover the whole period at
one view for certain great divisions of the world. (See AFRICA; ASIA;
AUSTRALIA; POLAR REGIONS; &c.) Here, however, may be noticed the
development of geographical societies devoted to the encouragement of
exploration and research. The first of the existing geographical
societies was that of Paris, founded in 1825 under the title of La
Societe de Geographie. The Berlin Geographical Society (Gesellschaft
fur Erdkunde) is second in order of seniority, having been founded in
1827. The Royal Geographical Society, which was founded in London in
1830, comes third on the list; but it may be viewed as a direct result
of the earlier African Association founded in 1788. Sir John Barrow,
Sir John Cam Hobhouse (Lord Broughton), Sir Roderick Murchison, Mr
Robert Brown and Mr Bartle Frere formed the foundation committee of
the Royal Geographical Society, and the first president was Lord
Goderich. The action of the society in supplying practical instruction
to intending travellers, in astronomy, surveying and the various
branches of science useful to collectors, has had much to do with
advancement of discovery. Since the war of 1870 many geographical
societies have been established on the continent of Europe. At the
close of the 19th century there were upwards of 100 such societies in
the world, with more than 50,000 members, and over 150 journals were
devoted entirely to geographical subjects.[11] The great development
of photography has been a notable aid to explorers, not only by
placing at their disposal a faithful and ready means of recording the
features of a country and the types of inhabitants, but by supplying a
method of quick and accurate topographical surveying.

THE PRINCIPLES OF GEOGRAPHY

As regards the scope of geography, the order of the various
departments and their inter-relation, there is little difference of
opinion, and the principles of geography[12] are now generally
accepted by modern geographers. The order in which the various
subjects are treated in the following sketch is the natural succession
from fundamental to dependent facts, which corresponds also to the
evolution of the diversities of the earth's crust and of its
inhabitants.

Mathematical geography.

The fundamental geographical conceptions are mathematical, the
relations of space and form. The figure and dimensions of the earth
are the first of these. They are ascertained by a combination of
actual measurement of the highest precision on the surface and angular
observations of the positions of the heavenly bodies. The science of
geodesy is part of mathematical geography, of which the arts of
surveying and cartography are applications. The motions of the earth
as a planet must be taken into account, as they render possible the
determination of position and direction by observations of the
heavenly bodies. The diurnal rotation of the earth furnishes two fixed
points or poles, the axis joining which is fixed or nearly so in its
direction in space. The rotation of the earth thus fixes the
directions of north and south and defines those of east and west. The
angle which the earth's axis makes with the plane in which the planet
revolves round the sun determines the varying seasonal distribution of
solar radiation over the surface and the mathematical zones of
climate. Another important consequence of rotation is the deviation
produced in moving bodies relatively to the surface. In the form known
as Ferrell's Law this runs: "If a body moves in any direction on the
earth's surface, there is a deflecting force which arises from the
earth's rotation which tends to deflect it to the right in the
northern hemisphere but to the left in the southern hemisphere." The
deviation is of importance in the movement of air, of ocean currents,
and to some extent of rivers.[13]

Physical geography.

In popular usage the words "physical geography" have come to mean
geography viewed from a particular standpoint rather than any special
department of the subject. The popular meaning is better conveyed by
the word physiography, a term which appears to have been introduced by
Linnaeus, and was reinvented as a substitute for the cosmography of
the middle ages by Professor Huxley. Although the term has since been
limited by some writers to one particular part of the subject, it
seems best to maintain the original and literal meaning. In the
stricter sense, physical geography is that part of geography which
involves the processes of contemporary change in the crust and the
circulation of the fluid envelopes. It thus draws upon physics for the
explanation of the phenomena with the space-relations of which it is
specially concerned. Physical geography naturally falls into three
divisions, dealing respectively with the surface of the
lithosphere--geomorphology; the hydrosphere--oceanography; and the
atmosphere--climatology. All these rest upon the facts of mathematical
geography, and the three are so closely inter-related that they cannot
be rigidly separated in any discussion.

Geomorphology.

Geomorphology is the part of geography which deals with terrestrial
relief, including the submarine as well as the subaerial portions of
the crust. The history of the origin of the various forms belongs to
geology, and can be completely studied only by geological methods. But
the relief of the crust is not a finished piece of sculpture; the
forms are for the most part transitional, owing their characteristic
outlines to the process by which they are produced; therefore the
geographer must, for strictly geographical purposes, take some account
of the processes which are now in action modifying the forms of the
crust. Opinion still differs as to the extent to which the
geographer's work should overlap that of the geologist.

The primary distinction of the forms of the crust is that between
elevations and depressions. Granting that the geoid or mean surface of
the ocean is a uniform spheroid, the distribution of land and water
approximately indicates a division of the surface of the globe into
two areas, one of elevation and one of depression. The increasing
number of measurements of the height of land in all continents and
islands, and the very detailed levellings in those countries which
have been thoroughly surveyed, enable the average elevation of the
land above sea-level to be fairly estimated, although many vast gaps
in accurate knowledge remain, and the estimate is not an exact one.
The only part of the sea-bed the configuration of which is at all well
known is the zone bordering the coasts where the depth is less than
about 100 fathoms or 200 metres, i.e. those parts which sailors speak
of as "in soundings." Actual or projected routes for telegraph cables
across the deep sea have also been sounded with extreme accuracy in
many cases; but beyond these lines of sounding the vast spaces of the
ocean remain unplumbed save for the rare researches of scientific
expeditions, such as those of the "Challenger," the "Valdivia," the
"Albatross" and the "Scotia." Thus the best approximation to the
average depth of the ocean is little more than an expert guess; yet a
fair approximation is probable for the features of sub-oceanic relief
are so much more uniform than those of the land that a smaller number
of fixed points is required to determine them.

Crustal relief.

The chief element of uncertainty as to the largest features of the
relief of the earth's crust is due to the unexplored area in the
Arctic region and the larger regions of the Antarctic, of which we
know nothing. We know that the earth's surface if unveiled of water
would exhibit a great region of elevation arranged with a certain
rough radiate symmetry round the north pole, and extending southwards
in three unequal arms which taper to points in the south. A depression
surrounds the little-known south polar region in a continuous ring and
extends northwards in three vast hollows lying between the arms of the
elevated area. So far only is it possible to speak with certainty, but
it is permissible to take a few steps into the twilight of dawning
knowledge and indicate the chief subdivisions which are likely to be
established in the great crust-hollow and the great crust-heap. The
boundary between these should obviously be the mean surface of the
sphere.

Sir John Murray deduced the mean height of the land of the globe as
about 2250 ft. above sea-level, and the mean depth of the oceans as
2080 fathoms or 12,480 ft. below sea-level.[14] Calculating the area
of the land at 55,000,000 sq. m. (or 28.6% of the surface), and that
of the oceans as 137,200,000 sq. m. (or 71.4% of the surface), he
found that the volume of the land above sea-level was 23,450,000 cub.
m., the volume of water below sea-level 323,800,000, and the total
volume of the water equal to about 1/666th of the volume of the whole
globe. From these data, as revised by A. Supan,[15] H.R. Mill
calculated the position of mean sphere-level at about 10,000 ft. or
1700 fathoms below sea-level. He showed that an imaginary spheroidal
shell, concentric with the earth and cutting the slope between the
elevated and depressed areas at the contour-line of 1700 fathoms,
would not only leave above it a volume of the crust equal to the
volume of the hollow left below it, but would also divide the surface
of the earth so that the area of the elevated region was equal to that
of the depressed region.[16]

Areas of the crust according to Murray.

A similar observation was made almost simultaneously by Romieux,[17]
who further speculated on the equilibrium between the weight of the
elevated land mass and that of the total waters of the ocean, and
deduced some interesting relations between them. Murray, as the result
of his study, divided the earth's surface into three zones--the
_continental area_ containing all dry land, the _transitional area_
including the submarine slopes down to 1000 fathoms, and the _abysmal
area_ consisting of the floor of the ocean beyond that depth; and Mill
proposed to take the line of mean-sphere level, instead of the
empirical depth of 1000 fathoms, as the boundary between the
transitional and abysmal areas.

An elaborate criticism of all the existing data regarding the volume
relations of the vertical relief of the globe was made in 1894 by
Professor Hermann Wagner, whose recalculations of volumes and mean
heights--the best results which have yet been obtained--led to the
following conclusions.[18]

Areas of the crust according to Wagner.

The area of the dry land was taken as 28.3% of the surface of the
globe, and that of the oceans as 71.7%. The mean height deduced for
the land was 2300 ft. above sea-level, the mean depth of the sea
11,500 ft. below, while the position of mean-sphere level comes out as
7500 ft. (1250 fathoms) below sea-level. From this it would appear
that 43% of the earth's surface was above and 57% below the mean
level. It must be noted, however, that since 1895 the soundings of
Nansen in the north polar area, of the "Valdivia," "Belgica," "Gauss"
and "Scotia" in the Southern Ocean, and of various surveying ships in
the North and South Pacific, have proved that the mean depth of the
ocean is considerably greater than had been supposed, and mean-sphere
level must therefore lie deeper than the calculations of 1895 show;
possibly not far from the position deduced from the freer estimate of
1888. The whole of the available data were utilized by the prince of
Monaco in 1905 in the preparation of a complete bathymetrical map of
the oceans on a uniform scale, which must long remain the standard
work for reference on ocean depths.

By the device of a hypsographic curve co-ordinating the vertical
relief and the areas of the earth's surface occupied by each zone of
elevation, according to the system introduced by Supan,[19] Wagner
showed his results graphically.

This curve with the values reduced from metres to feet is reproduced
below.

Wagner subdivides the earth's surface, according to elevation, into
the following five regions:

_Wagner's Divisions of the Earth's Crust:_

+---------------------+-----------+-------------+-------------+
| Name. |Per cent of| From | To |
| | Surface. | | |
+---------------------+-----------+-------------+-------------+
| Depressed area | 3 | Deepest. |-16,400 feet.|
| Oceanic plateau | 54 |-16,400 feet.|- 7,400 " |
| Continental slope | 9 |- 7,400 " |- 660 " |
| Continental plateau | 28 |- 660 " |+ 3,000 " |
| Culminating area | 6 |+ 3,300 " | Highest. |
+---------------------+-----------+-------------+-------------+

The continental plateau might for purposes of detailed study be
divided into the _continental shelf_ from -660 ft. to sea-level, and
_lowlands_ from sea-level to +660 ft. (corresponding to the mean level
of the whole globe).[20] _Uplands_ reaching from 660 ft. to 2300 (the
approximate mean level of the land), and _highlands_, from 2300
upwards, might also be distinguished.

Arrangement of world-ridges and hollows.

A striking fact in the configuration of the crust is that each
continent, or elevated mass of the crust, is diametrically opposite to
an ocean basin or great depression; the only partial exception being
in the case of southern South America, which is antipodal to eastern
Asia. Professor C. Lapworth has generalized the grand features of
crustal relief in a scheme of attractive simplicity. He sees
throughout all the chaos of irregular crust-forms the recurrence of a
certain harmony, a succession of folds or waves which build up all the
minor features.[21] One great series of crust waves from east to west
is crossed by a second great series of crust waves from north to
south, giving rise by their interference to six great elevated masses
(the continents), arranged in three groups, each consisting of a
northern and a southern member separated by a minor depression. These
elevated masses are divided from one another by similar great
depressions.

Lapworth's fold-theory.

He says: "The surface of each of our great continental masses of land
resembles that of a long and broad arch-like form, of which we see the
simplest type in the New World. The surface of the North American arch
is sagged downwards in the middle into a central depression which lies
between two long marginal plateaus, and these plateaus are finally
crowned by the wrinkled crests which form its two modern mountain
systems. The surface of each of our ocean floors exactly resembles
that of a continent turned upside down. Taking the Atlantic as our
simplest type, we may say that the surface of an ocean basin resembles
that of a mighty trough or syncline, buckled up more or less centrally
in a medial ridge, which is bounded by two long and deep marginal
hollows, in the cores of which still deeper grooves sink to the
profoundest depths. This complementary relationship descends even to
the minor features of the two. Where the great continental sag sinks
below the ocean level, we have our gulfs and our Mediterraneans, seen
in our type continent, as the Mexican Gulf and Hudson Bay. Where the
central oceanic buckle attains the water-line we have our oceanic
islands, seen in our type ocean, as St Helena and the Azores. Although
the apparent crust-waves are neither equal in size nor symmetrical in
form, this complementary relationship between them is always
discernible. The broad Pacific depression seems to answer to the broad
elevation of the Old World--the narrow trough of the Atlantic to the
narrow continent of America."

Suess's theory.

The most thorough discussion of the great features of terrestrial
relief in the light of their origin is that by Professor E. Suess,[22]
who points out that the plan of the earth is the result of two
movements of the crust--one, subsidence over wide areas, giving rise
to oceanic depressions and leaving the continents protuberant; the
other, folding along comparatively narrow belts, giving rise to
mountain ranges. This theory of crust blocks dropped by subsidence is
opposed to Lapworth's theory of vast crust-folds, but geology is the
science which has to decide between them.

Geomorphology is concerned, however, in the suggestions which have
been made as to the cause of the distribution of heap and hollow in
the larger features of the crust. Elie de Beaumont, in his
speculations on the relation between the direction of mountain ranges
and their geological age and character, was feeling towards a
comprehensive theory of the forms of crustal relief; but his ideas
were too geometrical, and his theory that the earth is a spheroid
built up on a rhombic dodecahedron, the pentagonal faces of which
determined the direction of mountain ranges, could not be proved.[23]
The "tetrahedral theory" brought forward by Lowthian Green,[24] that
the form of the earth is a spheroid based on a regular tetrahedron, is
more serviceable, because it accounts for three very interesting facts
of the terrestrial plan--(1) the antipodal position of continents and
ocean basins; (2) the triangular outline of the continents; and (3)
the excess of sea in the southern hemisphere. Recent investigations
have recalled attention to the work of Lowthian Green, but the
question is still in the controversial stage.[25] The study of tidal
strain in the earth's crust by Sir George Darwin has led that
physicist to indicate the possibility of the triangular form and
southerly direction of the continents being a result of the
differential or tidal attraction of the sun and moon. More recently
Professor A.E.H. Love has shown that the great features of the relief
of the lithosphere may be expressed by spherical harmonics of the
first, second and third degrees, and their formation related to
gravitational action in a sphere of unequal density.[26]

In any case it is fully recognized that the plan of the earth is so
clear as to leave no doubt as to its being due to some general cause
which should be capable of detection.

The continents.

If the level of the sea were to become coincident with the mean level
of the lithosphere, there would result one tri-radiate land-mass of
nearly uniform outline and one continuous sheet of water broken by
few islands. The actual position of sea-level lies so near the summit
of the crust-heap that the varied relief of the upper portion leads to
the formation of a complicated coast-line and a great number of
detached portions of land. The hydrosphere is, in fact, continuous,
and the land is all in insular masses: the largest is the Old World of
Europe, Asia and Africa; the next in size, America; the third,
possibly, Antarctica; the fourth, Australia; the fifth, Greenland.
After this there is a considerable gap before New Guinea, Borneo,
Madagascar, Sumatra and the vast multitude of smaller islands
descending in size by regular gradations to mere rocks. The contrast
between island and mainland was natural enough in the days before the
discovery of Australia, and the mainland of the Old World was
traditionally divided into three continents. These "continents,"
"parts of the earth," or "quarters of the globe," proved to be
convenient divisions; America was added as a fourth, and subsequently
divided into two, while Australia on its discovery was classed
sometimes as a new continent, sometimes merely as an island, sometimes
compromisingly as an island-continent, according to individual
opinion. The discovery of the insularity of Greenland might again give
rise to the argument as to the distinction between island and
continent. Although the name of continent was not applied to large
portions of land for any physical reasons, it so happens that there is
a certain physical similarity or homology between them which is not
shared by the smaller islands or peninsulas.

Homology of continents.

The typical continental form is triangular as regards its sea-level
outline. The relief of the surface typically includes a central plain,
sometimes dipping below sea-level, bounded by lateral highlands or
mountain ranges, loftier on one side than on the other, the higher
enclosing a plateau shut in by mountains. South America and North
America follow this type most closely; Eurasia (the land mass of
Europe and Asia) comes next, while Africa and Australia are farther
removed from the type, and the structure of Antarctica and Greenland
is unknown.

If the continuous, unbroken, horizontal extent of land in a continent
is termed its _trunk_,[27] and the portions cut up by inlets or
channels of the sea into islands and peninsulas the _limbs_, it is
possible to compare the continents in an instructive manner.

The following table is from the statistics of Professor H. Wagner,[28]
his metric measurements being transposed into British units:

_Comparison of the Continents._

+---------------+-------+-------+-------+------+--------+------+------+
| | | | | Area | | | |
| | Area | Mean | Area |penin-| Area | Area | Area |
| | total |height,| trunk,|sulas,|islands,|limbs,|limbs,|
| | mil. | feet. | mil. | mil. | mil. | mil. | per |
| | sq. m.| | sq. m.|sq. m.| sq. m. |sq. m.| cent.|
+---------------+-------+-------+-------+------+--------+------+------+
| Old World | 35.8 | 2360 | | | | | |
| New World | 16.2 | 2230 | | | | | |
| Eurasia | 20.85 | 2620 | 15.42 | 4.09 | 1.34 | 5.43 | 26 |
| Africa | 11.46 | 2130 | 11.22 | .. | 0.24 | 0.24 | 2.1 |
| North America | 9.26 | 2300 | 6.92 | 0.78 | 1.56 | 2.34 | 25 |
| South America | 6.84 | 1970 | 6.76 | 0.02 | 0.06 | 0.08 | 1.1 |
| Australia | 3.43 | 1310 | 2.77 | 0.16 | 0.50 | 0.66 | 19 |
| Asia | 17.02 | 3120 | 12.93 | 3.05 | 1.04 | 4.09 | 24 |
| Europe | 3.83 | 980 | 2.49 | 1.04 | 0.30 | 1.34 | 35 |
+---------------+-------+-------+-------+------+--------+------+------+

Islands.

The usual classification of islands is into continental and oceanic.
The former class includes all those which rise from the continental
shelf, or show evidence in the character of their rocks of having at
one time been continuous with a neighbouring continent. The latter
rise abruptly from the oceanic abysses. Oceanic islands are divided
according to their geological character into volcanic islands and
those of organic origin, including coral islands. More elaborate
subdivisions according to structure, origin and position have been
proposed.[29] In some cases a piece of land is only an island at high
water, and by imperceptible gradation the form passes into a
peninsula. The typical peninsula is connected with the mainland by a
relatively narrow isthmus; the name is, however, extended to any limb
projecting from the trunk of the mainland, even when, as in the Indian
peninsula, it is connected by its widest part.

Coasts.

Small peninsulas are known as promontories or headlands, and the
extremity as a cape. The opposite form, an inlet of the sea, is known
when wide as a gulf, bay or bight, according to size and degree of
inflection, or as a fjord or ria when long and narrow. It is
convenient to employ a specific name for a projection of a coast-line
less pronounced than a peninsula, and for an inlet less pronounced
than a bay or bight; outcurve and incurve may serve the turn. The
varieties of coast-lines were reduced to an exact classification by
Richthofen, who grouped them according to the height and slope of the
land into cliff-coasts (_Steilkusten_)--narrow beach coasts with
cliffs, wide beach coasts with cliffs, and low coasts, subdividing
each group according as the coast-line runs parallel to or crosses the
line of strike of the mountains, or is not related to mountain
structure. A further subdivision depends on the character of the
inter-relation of land and sea along the shore producing such types as
a fjord-coast, ria-coast or lagoon-coast. This extremely elaborate
subdivision may be reduced, as Wagner points out, to three types--the
continental coast where the sea comes up to the solid rock-material of
the land; the marine coast, which is formed entirely of soft material
sorted out by the sea; and the composite coast, in which both forms
are combined.

Coast-lines.

On large-scale maps it is necessary to show two coast-lines, one for
the highest, the other for the lowest tide; but in small-scale maps a
single line is usually wider than is required to represent the whole
breadth of the inter-tidal zone. The measurement of a coast-line is
difficult, because the length will necessarily be greater when
measured on a large-scale map where minute irregularities can be taken
into account. It is usual to distinguish between the general
coast-line measured from point to point of the headlands disregarding
the smaller bays, and the detailed coast-line which takes account of
every inflection shown by the map employed, and follows up river
entrances to the point where tidal action ceases. The ratio between
these two coast-lines represents the "coastal development" of any
region.

Submarine forms.

While the forms of the sea-bed are not yet sufficiently well known to
admit of exact classification, they are recognized to be as a rule
distinct from the forms of the land, and the importance of using a
distinctive terminology is felt. Efforts have been made to arrive at a
definite international agreement on this subject, and certain terms
suggested by a committee were adopted by the Eighth International
Geographical Congress at New York in 1904.[30] The forms of the ocean
floor include the "shelf," or shallow sea margin, the "depression," a
general term applied to all submarine hollows, and the "elevation." A
depression when of great extent is termed a "basin," when it is of a
more or less round form with approximately equal diameters, a "trough"
when it is wide and elongated with gently sloping borders, and a
"trench" when narrow and elongated with steeply sloping borders, one
of which rises higher than the other. The extension of a trough or
basin penetrating the land or an elevation is termed an "embayment"
when wide, and a "gully" when long and narrow; and the deepest part of
a depression is termed a "deep." A depression of small extent when
steep-sided is termed a "caldron," and a long narrow depression
crossing a part of the continental border is termed a "furrow." An
elevation of great extent which rises at a very gentle angle from a
surrounding depression is termed a "rise," one which is relatively
narrow and steep-sided a "ridge," and one which is approximately equal
in length and breadth but steep-sided a "plateau," whether it springs
direct from a depression or from a rise. An elevation of small extent
is distinguished as a "dome" when it is more than 100 fathoms from the
surface, a "bank" when it is nearer the surface than 100 fathoms but
deeper than 6 fathoms, and a "shoal" when it comes within 6 fathoms of
the surface and so becomes a serious danger to shipping. The highest
point of an elevation is termed a "height," if it does not form an
island or one of the minor forms.

Land forms.

The forms of the dry land are of infinite variety, and have been
studied in great detail.[31] From the descriptive or topographical
point of view, geometrical form alone should be considered; but the
origin and geological structure of land forms must in many cases be
taken into account when dealing with the function they exercise in the
control of mobile distributions. The geographers who have hitherto
given most attention to the forms of the land have been trained as
geologists, and consequently there is a general tendency to make
origin or structure the basis of classification rather than form
alone.

The six elementary land forms.

The fundamental form-elements may be reduced to the six proposed by
Professor Penck as the basis of his double system of classification by
form and origin.[32] These may be looked upon as being all derived by
various modifications or arrangements of the single form-unit, the
_slope_ or inclined plane surface. No one form occurs alone, but
always grouped together with others in various ways to make up
districts, regions and lands of distinctive characters. The
form-elements are:

1. The _plain_ or gently inclined uniform surface.

2. The _scarp_ or steeply inclined slope; this is necessarily of small
extent except in the direction of its length.

3. The _valley_, composed of two lateral parallel slopes inclined
towards a narrow strip of plain at a lower level which itself slopes
downwards in the direction of its length. Many varieties of this
fundamental form may be distinguished.

4. The _mount_, composed of a surface falling away on every side from
a particular place. This place may either be a point, as in a volcanic
cone, or a line, as in a mountain range or ridge of hills.

5. The _hollow_ or form produced by a land surface sloping inwards
from all sides to a particular lowest place, the converse of a mount.

6. The _cavern_ or space entirely surrounded by a land surface.

Geology and land forms.

These forms never occur scattered haphazard over a region, but always
in an orderly subordination depending on their mode of origin. The
dominant forms result from crustal movements, the subsidiary from
secondary reactions during the action of the primitive forms on mobile
distributions. The geological structure and the mineral composition of
the rocks are often the chief causes determining the character of the
land forms of a region. Thus the scenery of a limestone country
depends on the solubility and permeability of the rocks, leading to
the typical Karst-formations of caverns, swallow-holes and underground
stream courses, with the contingent phenomena of dry valleys and
natural bridges. A sandy beach or desert owes its character to the
mobility of its constituent sand-grains, which are readily drifted and
piled up in the form of dunes. A region where volcanic activity has
led to the embedding of dykes or bosses of hard rock amongst softer
strata produces a plain broken by abrupt and isolated eminences.[33]

Classification of mountains.

It would be impracticable to go fully into the varieties of each
specific form; but, partly as an example of modern geographical
classification, partly because of the exceptional importance of
mountains amongst the features of the land, one exception may be made.
The classification of mountains into types has usually had regard
rather to geological structure than to external form, so that some
geologists would even apply the name of a mountain range to a region
not distinguished by relief from the rest of the country if it bear
geological evidence of having once been a true range. A mountain may
be described (it cannot be defined) as an elevated region of irregular
surface rising comparatively abruptly from lower ground. The actual
elevation of a summit above sea-level does not necessarily affect its
mountainous character; a gentle eminence, for instance, rising a few
hundred feet above a tableland, even if at an elevation of say 15,000
ft., could only be called a hill.[34] But it may be said that any
abrupt slope of 2000 ft. or more in vertical height may justly be
called a mountain, while abrupt slopes of lesser height may be called
hills. Existing classifications, however, do not take account of any
difference in kind between mountain and hills, although it is common
in the German language to speak of _Hugelland_, _Mittelgebirge_ and
_Hochgebirge_ with a definite significance.