After plowing its way north for forty-five miles between Switzerland and
Austrian Vorarlberg, the river enters the Lake of Constance, soon after
leaving which, its water a deep transparent green, it plunges down the
falls of Schaffhausen, nearly seventy feet, in three leaps, and flows
westward to Basel, separating Baden from Switzerland. In this stretch
the river (four hundred and ninety feet wide), receives from the left
the waters of the Aar. At Basel (seven hundred and forty-two feet), now
two hundred and twenty-five yards wide, it wheels round to the north,
and traversing an open shallow valley that separates Alsace and the
Bavarian Palatinate from Baden, reaches Mainz, split into many side arms
and studded with green islands. Navigation begins at Basel.