TAGUS, named Tajo by the Spaniards, and Tejo by the Portuguese, is the largest river of the Spanish Peninsula. Tagus is the name in the Roman writers, and has been adopted in our language. The rivers by the confluence of which the Tagus is formed originate in the highest part of the table-land of Spain. In the elevated moun tain-masses of the Sierra Molina and Sierra de Albaracin rise three rivers, the Molina, the Tagus, and the Gundiela, which flow west north-west between high ridges and in narrow valleys. The Molina and Tagus unite on the boundary-line of the provinces of Soria and Cuenca, and after running south-west about 50 miles, arc joined by the Guadiela where the three provinces of Cuenca, Guadalajara, and Madrid meet. The united river continues to flow in a south-west direction until it enters the more open country of the plain, when it turns to the west, and is joined by the Jarama (Xarama). This river originates on the Soma Sierra, not far from Buytrago. It runs south, and Is first joined by the Henares about 15 miles east of Madrid, and then by the Tajuna, which joins the Jarama a few miles above its confluence with the Tagus. The country which is traversed by these branches of the Tagus is not much elevated above the water courses, possesses n considerable degree of fertility, and is the most populous tract on the table-land of Spain. The Jarama joins the Tagus a little below Aranjuez, and at this place the river flows through a wide level plain very little elevated above its bed, and so fertile, that it is justly called the Garden of Castile. From this place the general course of the Tagus, as far as it lies within Spain, is nearly due west. Below Aranjuez the bed of the river gradually sinks deeper beneath the surrounding country ; its banks are steep, and composed of rocks, which in some parts rise from the water Abruptly to the height of 200 feet. The adjacent country is uneven and some what broken, but not hilly. After having received the Cedron from the south, and encompassed the hill on which tho city of Toledo stands, the river again enters a level country, which extends for many miles westward, and iu which it is joined by the Guadarama and Albercho from the north, and several smaller rivers from the south. Below the town of Talavera do Is Reina the Tagus enters n hilly country, where it flow§ with great rapidity in a deep bed filled with rocks, and hi joined from the north by the rivers Tietar and ' which descend from the high ridge that divides the table lend of the two Castile& The Alagon originates in the icy masses which oover the summit of the Sierra do Griegos, and the volume of water which this river brings down is so considerable, that from the place of confluence at Alcantara the Tagus becomes navigable. Though tho Tagus has run above 350 miles before it reaches Alcantara, no part of it is navigable, which is partly to be ascribed to the great rapidity of its current through the plain of Castile. Besides this,
the greater part of its course is through narrow valleys, between steep hills, from which heavy masses of rocks have fallen down, which in many places greatly encumber the bed of the river, and cause rapids, which continue for several miles ; but the greatest impedi ment to. the navigation of the river is the small volume of water. The soil of the table-land absorbs a great quantity of moisture with out forming springs, and at the same time the quantity of rain which falls on this region is much less than what falls in other parts of Europe ; consequently the river is very scantily supplied with water, except during the few months when the rains are more abundant.
At Alcantara the level of the river is probably leas than 300 feet above the sea, and it has still a coarse of about 200 miles to its mouth. Its course below Alcantara and as far as the mouth of its tributary the Zesere, below Abrantes, is west and south-wee- For about 20 miles it constitutes the boundary-line between Spain and Portugal In this part of its course the river is navigable, but the navigation is extremely tedious and not without danger, as the sandbanks are numerous and subject to change. It can only be navigated by small flat-bottomed boats. The Zezere, in which the numerous rise:ilea unite that collect the waters originating on the southern declivity of the Serra de Estrella, always brings a considerable volume of water to the Tagus, and from this point downwards the river may be navi gated by veesele of 150 tons burden. In this part of its coarse numerous islands oocur, which at 'first are smell and rocky, but lower down are larger and alluvial. Below these islands the river expands into a lake-like basin, which extends from north-east to south-west, in the direction of the course of the river, nearly 30 miles, and is mostly about ]2 miles wide, but in several places it is narrowed to 6 miles by projecting headlands. The country north-west of the basin is covered with gently-eloping hills, the offsets of the Serra do Junto, and on the south-east of it is the sandy plain of Alemtejo. The most western part of the basin constitutes the harbour of Lisbon, which is spacious enough to contain all the fleets of Europe. Where the town of Lisbon terminates on the west, the Tagus turns westward, and a broad rocky headland, consisting of high hills, advances northward from the Serra de Arrabida, and narrows the basin to about a mile or a little more in width. At the same time the affects of the Serra da Cintm come close up to the river on the north, so that the Tagus passes to the sea between two rocky masses. The whole course of the Tagus exceeds 550 miles, and the area of the country drained by the river probably does not fall short of 40,000 square miles.