. American engineer and railroad journal . ventilators car-ried through chimneys built in the towers of the wall surrounding the old city. The system of carrying all waste to the sewers works verywell for the city ; but the people on the river banks below com-plained of the pollution of tlie waters, and it was resolved toerect works for purifying the sewage before turning it into theriver. As the local circumstances forbid the use of sewage onthe soil, the engineers were obliged to have recourse to someplan for mechanical and chemical purification. The works are ber of which in the world is es
. American engineer and railroad journal . ventilators car-ried through chimneys built in the towers of the wall surrounding the old city. The system of carrying all waste to the sewers works verywell for the city ; but the people on the river banks below com-plained of the pollution of tlie waters, and it was resolved toerect works for purifying the sewage before turning it into theriver. As the local circumstances forbid the use of sewage onthe soil, the engineers were obliged to have recourse to someplan for mechanical and chemical purification. The works are ber of which in the world is estimated at 105,000, representinga total of 5,500,000 to 7,000,000 All the steam-engines of the world, Including locomotives,would produce a force equivalent to 40,000,000 if workingtogether. A French Masonry Bridge.—There has been recently amongFrench engineers a tendency to return to the use of masonryfor bridges, especially in localities where suitable stone can beobtained at a reasonable cost. One instance of this is a new. ARCH OF THE BOUCICAUT situated about three miles below the city. The foul water iscarried there by the collecting sewers, one ol which is carriedunderneath the Main by a siphon. There are two groups ofsix settling basins, each group being able to treat in ordinarytimes about 700,000 cub. ft. per day, and twice that quantityin rainy seasons. In these settling basins the heavier mattersheld in suspension are deposited, and from the basins the wateris passed through gratings which retain floating bodies. Thesettling works very well, thanks to the slowness of the move-ment of water through the basins and the use of chemicalreagents—sulphate of alumina and chalk. About 2,200 lbs. ofthe first named and 550 lbs. of the second are used to 210,000cub. ft. of water. The cost is very small, amounting toabout 25 cents per inhabitant of the city per year, including inthis sum interest on the cost of the works and a sinking fund, aswell as the cost of wor
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
