made available to human intercourse, and therefore to material unity, to the point where the Thames was earliest crossed and spanned. More special historical and social facts may be found attached to every old bridge. In war, especially, heroic achievement and desperate valor have often consecrated these narrow defiles and exclusive means of advance and retreat:-- "When the goodman mends his armor And trims his helmet's plume, When the good-wife's shuttle merrily Goes flashing through the loom, With weeping and with laughter Still is the story told How well Horatius kept the bridge In the good old days of old." The bridge of Darius spanned the Bosphorus,--of Xerxes, the Hellespont,--of Caesar, the Rhine,--and of Trajan, the Danube; while the victorious march of Napoleon has left few traces so unexceptionably memorable as the massive causeways of the Simplon. Cicero arrested the bearer of letters to Catiline on the Pons Milonis, built in the time of Sylla on the ancient Via Flaminia; and by virtue of the blazing cross which he saw in the sky from the Ponte Molle the Christian emperor Constantine conquered Maxentius. The Pont du Gard near Nismes and the St. Esprit near Lyons were originally of Roman construction. During the war of freedom, so admirably described by our countryman, whereby rose the Dutch Republic, the Huguenots, at the siege of Valenciennes, we are told, "made forays upon the monasteries for the purpose of procuring supplies, and the broken statues of the dismantled churches were used to build a bridge across an arm of the river, which was called, in derision, the Bridge of Idols."