It is situated between a lake of fresh and very clear waters on the one side, and a river of great magnitude on the other, the waters of which, by a number of canals, large and small, are made to run through every quarter of the city,carry with them all the filth into the lake ,and ultimately to the sea.This, whist it contributes much to be purity of the air, furnishes communication by water, in addition to that by land, to all parts of the town;the canals and the streets being of sufficient width to allow of boats on the one, and carriages in the other, conveniently passing, with articles necessary for the consumption of the inhabitiants. It is commonly said that the number of bridges, of all sizes amounts to twelve thousand.Those which are thrown over the principal canals and are connected with the main streets, have arches so high, and built so much skill, that vessels with their masts can pass under them, whist, at the same time,carts and horse are passing over their heads-so well is the slope from the street adapted to the height of the arch. If they were not in fact so numerous, there would be no convenience of crossing from one place to another.