The mines in the valley of the Clyde were worked first chiefly for the coal, and the coal was used to drive steam machinery for spinning and weaving, and for other manufacturing purposes. The river was in those days a small and insignificant stream. It was only about five feet deep, so that the vessels that came to take away the coal and the manufactured goods had to stop near the mouth of it, and the cargoes were brought down to them in boats and lighters. But in process of time they widened and deepened the river. They dug out the mud from the bottom of it, and built walls along the banks; and in the course of the last hundred years, they have improved it so much that now the largest ships can come quite up to Glasgow. The water is eighteen or twenty feet deep all the way. The Clyde is the river on which steamboats were first built in Great Britain. The man who was the first in England or Scotland that found a way of making a steam engine that could be put in a boat and made to turn paddle wheels so as to drive the boat along, was James Watt, who was born on the Clyde; and he is accordingly considered as the author and originator of English steam navigation, just as Fulton is regarded as the originator of the art in America. The Clyde, of course, very naturally became the centre of steamboat and steamship building. The iron for the engines was found close at hand, as well as abundant supplies of coal for the fires. The timber they brought from the Baltic. At length, however, they found that they could build ships of iron instead of wood, using iron beams for the framing, and covering them with plates of iron riveted together instead of planks. These ships were found very superior, in almost all respects, to those built of timber; and as iron in great abundance was found all along the banks of the Clyde, and as the workmen in the region were extremely skilful in working it, the business of building ships and steamers of this material increased wonderfully, until, at length, the banks of the river for miles below Glasgow became lined with ship yards, where countless steamers, of monstrous length and graceful forms, in all the stages of construction, lie; now sloping towards the water and down the stream, ready at the appointed time to glide majestically into the river, and thence to plough their way to every portion of the habitable globe.