The Mersey has its origin in three other streams that come down to it from Yorkshire and Derbyshire uplands; and when it becomes for the first time entitled to the name, it is among huge factories, and not by willow-covered banks. The three streams in question are the Tame, the Goyt, and the Etherow. Starting from the Peak district, and running between Derbyshire and Cheshire, the Goyt strikes a northerly course, and for a considerable distance forms the boundary line between the two counties. Near to the village of Mellor it receives the Etherow, which has come down from the breezy region known as the backbone of England, almost at the meeting-point between Yorkshire, Derbyshire, and Cheshire. Like the Goyt, the Etherow serves as a boundary line between Derbyshire and Cheshire. It runs through Longdendale, where is one of those artificial lake districts which come by way of compensation to the country from the town; for here, on the slopes of Blackstone-edge, are the reservoirs which until recently were thought sufficient for the water-supply of Manchester and district. Four in number, they mean a daily supply of 25,000,000 gallons; but that is not enough for the steadily increasing population of the great city and its environs, and Manchester has therefore gone much further afield, and tapped Thirlmere, so as to secure an additional supply of 50,000,000 gallons. From here the Etherow runs merrily down to where the Goyt comes northwards to meet it. The combined stream, now of somewhat doubtful identity, goes westward to Stockport, and receives there the Tame from beyond Saddleworth, on the Yorkshire borders. [Illustration: NORTHENDEN (_p. 245_).]