“ On this account navigation is attended with difficulties and risks between its mouth and Barca d’Alva; but a railway, running for the most part along the right bank, skirts the river during the greater part of its course through Portugal. The mouth of the river is partly blocked by a sandy bar; only ships of light draught can enter, while those of greater burden are accommodated at the harbour of Leixões, an artificial basin constructed about 3 m. N. On its way through Portugal the Douro traverses the Paiz do Vinho, one of the richest wine-producing territories in the world ”