MAGNITUDE.

In respect to magnitude, it ranks amongst the largest islands in the world; but its breadth throughout is determined with so little accuracy that any attempt to calculate its superficies must be liable to very considerable error. Like Great Britain it is broadest at the southern extremity, narrowing gradually to the north; and to this island it is perhaps in size more nearly allied than in shape.

MOUNTAINS.

A chain of mountains runs through its whole extent, the ranges being in many parts double and treble, but situated in general much nearer to the western than the opposite coast, being on the former seldom so much as twenty miles from the sea, whilst on the eastern side the extent of level country, in the broader part of the island, through which run the great rivers of Siak, Indragiri, Jambi, and Palembang, cannot be less than a hundred and fifty. The height of these mountains, though very great, is not sufficient to occasion their being covered with snow during any part of the year, as those in South America between the tropics are found to be. Mount Ophir,* or Gunong Pasaman, situated immediately under the equinoctial line, is supposed to be the highest visible from the sea, its summit being elevated thirteen thousand eight hundred and forty-two feet above that level; which is no more than two-thirds of the altitude the French astronomers have ascribed to the loftiest of the Andes, but somewhat exceeds that of the Peak of Tenerife.

(*Footnote. The following is the result of observations made by Mr. Robert Nairne of the height of Mount Ophir:

Height of the peak above the level of the sea, in feet: 13,842.
English miles: 2.6216.
Nautical miles: 2.26325.
Inland, nearly: 26 nautical miles.
Distance from Massang Point: 32 nautical miles.
Distance at sea before the peak is sunk under the horizon: 125 nautical miles.
Latitude of the peak: 0 degrees 6 minutes north.
A volcano mountain, south of Ophir, is short of that in height by: 1377 feet.
Inland, nearly 29 nautical miles.
In order to form a comparison I subjoin the height, as computed by mathematicians, of other mountains in different parts of the world:
Chimborazo, the highest of the Andes, 3220 toises or 20,633 English feet. Of this about 2400 feet from the summit are covered with eternal snow.
Carazon, ascended by the French astronomers: 15,800 English feet.
Peak of Tenerife. Feuille: 2270 toises or 13,265 feet.
Mount Blanc, Savoy. Sr. G. Shuckburgh: 15,662.
Mount Etna, Sr. G. Shuckburgh: 10,954.

Between these ridges of mountains are extensive plains, considerably elevated above the surface of the maritime lands, where the air is cool; and from this advantage they are esteemed the most eligible portion of the country, are consequently the best inhabited and the most cleared from woods, which elsewhere in general throughout Sumatra cover both hills and valleys with an eternal shade. Here too are found many large and beautiful lakes that extend at intervals through the heart of the country, and facilitate much the communication between the different parts, but their dimensions, situation, or direction, are very little known, though the natives make frequent mention of them in the accounts of their journeys. Those principally spoken of are: one of great extent but unascertained situation in the Batta country; one in the Korinchi country, lately visited by Mr. C. Campbel; and another in the Lampong country, extending towards Pasummah, navigated by boats of a large class with sails, and requires a day and night to effect the passage across it; which may be the case in the rainy season, as that part of the island through which the Tulang Bawang River flows is subject to extensive inundations, causing it to communicate with the river of the Palembang. In a journey made many years since by a son of the sultan of the latter place, to visit the English resident at Croee, he is said to have proceeded by the way of that lake. It is much to be regretted that the situation of so important a feature in the geography of the island should be at this day the subject of uncertain conjecture.

WATERFALLS.

Waterfalls and cascades are not uncommon, as may be supposed in a country of so uneven a surface as that of the western coast. A remarkable one descends from the north side of Mount Pugong. The island of Mansalar, lying off and affording shelter to the bay of Tappanuli, presents to the view a fall of very striking appearance, the reservoir of which the natives assert (in their fondness for the marvellous) to be a huge shell of the species called kima (Chama gigas) found in great quantities in that bay, as well as at New Guinea and other parts of the east.* At the bottom of this fall ships occasionally take in their water without being under the necessity of landing their casks; but such attempts are liable to extreme hazard. A ship from England (the Elgin) attracted by the appearance from sea of a small but beautiful cascade descending perpendicularly from the steep cliff, that, like an immense rampart, lines the seashore near Manna, sent a boat in order to procure fresh water; but she was lost in the surf, and the crew drowned.

(*Footnote. The largest I have seen was brought from Tappanuli by Mr. James Moore of Arno's Vale in the north of Ireland. It is 3 feet 3 1/2 inches in its longest diameter, and 2 feet 1 1/4 inches across. One of the methods of taking them in deep water is by thrusting a long bamboo between the valves as they lie open, when, by the immediate closure which follows, they are made fast. The substance of the shell is perfectly white, several inches thick, is worked by the natives into arm-rings, and in the hands of our artists is found to take a polish equal to the finest statuary marble.)

RIVERS.