The Monongahela River coming from the southward, and the Allegheny River flowing from the northward, drain the western defiles of the Alleghenies, and at Pittsburg unite to form the Ohio River. Each comes to the junction through a deeply-cut canyon, and at the confluence is a triangular flat upon which the original town was built. Like most American rivers, all these have names of Indian origin. Monongahela is the "river of high banks, breaking off in places and falling down." Ohio is a Seneca word, originally pronounced "O-hee-o," and meaning the "beautiful river" or the "fair water," and Allegheny in the language of the Delawares has much the same signification, meaning "the fairest stream." All the Indians regarded the two as really the same river, of which the Monongahela was a tributary. The first white men exploring this region were the French, who came down from the lakes and Canada, when they spread through the entire Mississippi Valley. In 1753, however, Washington with a surveying party was sent out by Virginia and carefully examined the site of Pittsburg, advising, on his return, that a fort should be built there to check the advance of the French, and the next year this was done. Scarcely was it completed, however, when the French sent a summons to surrender, addressed "From the Commander-in-chief of His Most Christian Majesty's troops now on the Beautiful River to the Commander of those of Great Britain." A French force soon appeared, and the fort was abandoned. This began the French and Indian Colonial War that continued seven years, the French then erecting their famous fort and trading-post guarding the head of the Ohio, which they named after the great French naval commander of the seventeenth century, Marquis Abraham Duquesne. Then came Braddock's defeat in 1755, and for some time the region was quiet. Moravian missionary influence, however, had by 1758 detached many of the Indians from the French interest, and after another British attack and repulse, General Forbes came with a large force, and the French abandoned the fort and blew it up. Immediately rebuilt by the English, a Virginia garrison occupied the post, and it was named Fort Pitt. Then a larger fort was built at a cost of $300,000 and garrisoned by artillery, which the enemy vainly besieged in 1763. The next year a town site was laid out near the fort, and in 1770 it had twenty log houses. After the long succession of wars and massacres on that frontier had ceased, the village grew, and business began developing--at first, boat- and vessel-building, and then smelting and coal mining and the manufacture of glass. In 1812 the first rolling-mill started, and the war with England in that year caused the opening of a cannon foundry, which became the Fort Pitt Iron Works. The village of Fort Pitt had become Pittsburg, and expanded vastly with the introduction of steam, and it became an extensive steamboat builder for the Western waters. Railroad