41S (USA. 



mediate surface forms a gradual dope. Some have regular flat sur- 

 face*, but frequently they preaent a great variety in form and apiar- 

 aaoe. Some of them resemble palace*, or churches, or old castles, 

 with spire*, towers, windows, and arched gateways ; while others 

 resemble pyramids and obelisks, and others are like ships, trees, 

 animals, and human beings. When a number of them are near one 

 another, which frequently happens, they present the appearance of a 

 mountainous country. When seen from a short distance, they look 

 like huge hills of marble ; and when the sun shines on them, they 

 glitter like silver. Sometimes earth, gravel, and sand may be observed 

 in them. Their prevailing colour in the fresh fracture is grecnish- 

 gray, approaching to emerald-green. This colour resembles that of the 

 glaciers of Switzerland [GLACIERS, in NAT. HIST. Div.], and the ice- 

 bergs are mssnrs broken off from glaciers, or from barrier lines of 

 ice-cliff. They are rarely met with in the sea between Greenland and 

 gen, because in these port* only a few glaciers approach near 



sr..\. 



41 



SpiUberg 



Mb v, .-. : 



) water's edge. But on both sides of Davis's Strait and Baffin's Bay, 

 and alto on the eastern shore* of Greenland as far north as 70* N. lat, 

 glaciers cover the land, and in many places advance to the shores of 

 the sea. In some places they terminate in a precipitous edge on the 

 coast. It is only in the sea which surrounds these coasts that the 

 icebergs are numerous. They seem to owe their origin to the circum- 

 stance of glaciers being in a continual state of progress. The glaciers 

 of Greenland, which are situated on the margin of the sea, protrude 

 their exterior parts over the ocean, and in summer, when the ice 

 becomes brittle, the force of cohesion is overcome by the weight of the 

 prodigious masses that overhang the sea, and they are detached from 

 the glacier with a dreadful crash. Thus an iceberg is formed. These 

 icebergs, as it seems, are most common along the eastern shores of 

 Greenland, and at the distance of 15 to 20 miles from the coast, where 

 they occur by hundreds and thousands, forming a sort of barrier outside 

 the drift-ice which is near the shore, and preventing its removal by an 

 off-shore wind. Captain Graah states that this barrier of icebergs 

 renders it impossible for vessels to approach these shores. 



These masses of ice render navigation very dangerous ; and the ice- 

 fields especially have caused the loss of many whaling-vessels. These 

 extensive masses are frequently put into a rotatory movement by a 

 cause which has never been discovered. When thus whirled about, 

 their outer edges acquire a velocity of several miles per hour. A field 

 thus in motion,' coming in contact with another at rest, or with one 

 that has a contrary direction of movement, produces a dreadful shock. 

 The strongest ship is a mere atom between two such masses of matter 

 in motion, and many vessels have thus been destroyed. The ice-fields 

 are particularly dangerous in foggy weather, as their motions cannot 

 then be distinctly observed. Icebergs are much less dangerous, partly 

 on account of the small space which they occupy when compared with 

 ice-fields, and partly because they are easily distinguished at a distance 

 in the night by their natural brightness, and in foggy weather by a 

 peculiar blackness of the atmosphere. As, however, they occur far 

 from land and often in unexpected situations, sailors when crossing the 

 Atlantic between 50" and 60 N. lat., or even farther to the south, 

 must always be on the watch for them in the night time. Occasionally 

 the whale-fishers derive some advantage from them. As they sink 

 deep into the sea, they are very little affected by the wind, and they 

 furnish secure mooring to a ship in strong adverse winds, or when it is 

 required for other purposes. But mooring to lofty icebergs is attended 

 with considerable danger. Being sometimes very nicely balanced, they 

 are apt to lose their equilibrium ; and vessels have often been staved 

 and sometimes wrecked by the fall of their icy mooring, while boats 

 have been overwhelmed even at a considerable distance by the swell 

 occasioned . by such a catastrophe. Water is sometimes procured by 

 whaling-vessels from the deep pools of water that are formed in the 

 summer season on the depressions in icebergs, or from the streams 

 which run down their sides. 



1 On approaching a field or any compact aggregation of ice, the ice- 

 Wink is seen whenever the horizon is tolerably free from clouds, and 

 sometimes even under a thick sky. It consists of a stratum of lucid 

 whiteness, which appears over the ice in that part of the atmosphere 

 which joins the horizon. A clear sky presents a beautiful and perfect 

 map of the ice, 20 or 30 miles beyond the limit of direct vision, but 

 less distant in proportion as the atmosphere is more dense and obscure. 

 Each kind of ice has a different blink. Field-ice has the most lucid 

 blink, accompanied with a tinge of yellow ; that of packed ice is more 

 purely white ; and ice newly formed upon the sea has a grayish hue. 



According to the experiments of Scoresby, the specific gravity of 

 the ice, when compared with that of sea- water occurring in the Green- 

 land Sea, at the temperature of 35 was ascertained to be from 0-894 

 to 0-900. That part of the ice, therefore, which is above the surface 

 appears to be, to that below the surface, in the proportion of 1 to 

 between 8 and 9. For every solid foot of ice which is seen in a mass 

 floating in the sea, there 'must be 8 or 9 feet below. Hence it some- 

 times happens that large icebergs, when they are carried into shallow 

 water, take ground, and remain stationary for one or two years, until 

 so much of their volume has been wasted by the action of the sun and 

 of the atmosphere, that they begin to float again. 



It excited some surprise when it was discovered that the ice floating 

 nl*mt in the sea consisted, of fresh water. It is true that it generally 

 contains a very small portion of salt, but it is probable that this small 



portion of salt is derived from the salt water contained in the pores 

 of the ice. If, says Scoresby, in confirmation of this opinion, the 

 newest and most porous ice be removed into the air, allowed to drain 

 for some time in a temperature of 32* and upwards, and then be 

 washed in fresh water, it will be found to be nearly quite free from 

 salt, and the water produced from it may be drunk. According to the 

 Russian explorer, Baron Wrangell, whenever the surface of the ice on 

 the north coast of Siberia is clear of snow, the salt may be found 

 deposited in crystals ; and in the neighbourhood of the polynia*, or 

 interior open seas of the Arctic regions already mentioned, the layer of 

 salt is often of considerable thickness. All this is in conformity with 

 the fact, first definitely ascertained by Dr. Faraday, that in the process 

 of freezing the foreign bodies contained in water are separated from 

 it; agreeably to a principle which appears to be manifested in tliu 

 crystallisation of most if not all fluids, of the separation of heteroge- 

 neous matter. On account of the salt contained in it, sea-water does 

 not, like pure water, freeze at the temperature of 32, but in the 

 Greenland Sea, where its specific gravity is 1-0263, it begins only to 

 freeze at 28i". 



There is not any portion of the surface of the sea which is not 

 subjected to some kind of motion, and this circumstance must t. ml 

 greatly to preserve its purity. The water in some parts of the sea is 

 always propelled in the same direction by the currents. [ATLANTIC 

 OCEAN; PACIFIC OCEAN, in GEOO. Div.] Nearly the whole sea is four 

 times in the day subject to a change in its level by the movements of 

 the tides. The motion produced by the winds, and known by the 

 name of waves, is much less regular. Each wave presents a gently 

 ascending surface to the windward, and a perpendicular descent lee- 

 ward. The elevation of the waves varies according to the strength of 

 the wind. A rather heavy gale raises them from six to eight feet 

 above the common sea-level ; but in very strong gales they attain an 

 elevation of thirty feet. This motion of the surface of the sea is not 

 perceptible to a great depth. In the strongest gales it is supposed not 

 to extend beyond 72 feet below the surface,'and at a depth of 90 feet 

 the sea is perfectly still. The form and even the size of the waves 

 vary according to the depth and the extent of the sea. In shallow 

 water, where the lower part of the waves approaches the bottom, and 

 meets with resistance, the waves are abrupt and irregular, and this is 

 also the case in confined seas ; whilst on the open ocean they are wide 

 and long, and rise and fall with great regularity. When the waves 

 run to a low shore, the slope of the ground breaks their force, and they 

 terminate in a tranquil manner; but when they are impelled agmnst 

 an elevated rocky coast, being repelled by the rock, they produce what 

 i.< called a turf. This violent rising of the sea on a rocky coast some- 

 times attains an elevation of 100 feet above the sea-level. The surf is 

 always dangerous to pass, except in boats of a peculiar construction. 

 The waves do not subside simultaneously with the wind. The momen- 

 tum of the water preserves the sea in its agitated state for many hours. 

 The air being little agitated, or not at all, is unable to depress the 

 undulations of the sea, and therefore the waves during a calm after a 

 gale rise higher, and their most elevated part forms a more acute 

 angle than during the gale. Such a state of the sea is called a hollow 

 sea. [WAVE.] 



The term Ocean (a Greek word, Oceanus, ntttavos) is applied in a 

 general and somewhat indefinite manner to distinguish the greater 

 areas of sea. The word first occurs in Homer, who uses it to designate 

 the river or stream which, according to hia ideas, surrounded the sur- 

 face of the earth like a circle. The Greek geographers, however, knew 

 that the ocean was a wide expanse of water, which surrounded the 

 land, and the term ocean was used by them in this sense. They 

 supposed that it penetrated deep into the mass of the continent by 

 four great bays or seas : these were, on the south the Arabian Sea and 

 the Persian Gulf ; on the west the Mediterranean ; and on the north 

 an imaginary strait which connected the Northern Ocean with the 

 Caspian Sea. (Strabo, p. 121 ; Pomp. Mela, i. 1.) [GEOOKAPHY.] 



The actual surface of the globe may be reckoned at about 

 197,000,000 of square British statute miles ; of which 145,000,000 are 

 covered by the waters of the ocean now using thia term in its widest 

 and most emphatic sense, as meaning the entire collection of seas 

 while the area of the land is about 52,000,000 of miles ; the proportion 

 of land to sea being thus as about 1 to 3, the land occupying one- 

 fourth, and the sea three-fourths of the entire surface of our planet. 

 The latter, however, is so unequally distributed that there is three 

 times more land in the northern than in the southern hemisphere. 

 The torrid zone is principally occupied by sea, and only one-twenty- 

 seventh part of the land on one side of the earth has land opposite to 

 it on the other. Sir John Herschel has recorded, that " one result of 

 maritime discovery on the great scale, is, so to speak, mtuiirc enough 

 to call for mention as an astronomical feature" of our planet. " AVh< n 

 the continents and seas are laid down on a globe (and since the dis- 

 covery of Australia, and the recent addition to our Antarctic know- 

 ledge of Victoria Land by Sir J. C. Ross, we are sure that no very 

 extensive tracts of land remain unknown) we find that it is possible so 

 to divide the globe into two hemispheres, that one shall contain nearly 

 nil the land ; the other being almost entirely sea. It is a fact, not a 

 little interesting to Englishmen, and, combined with our insular 

 station in that great highway of nations, the Atlantic, not a little 

 explanatory of our commercial eminence, that London occupies nearly 



